diff options
| author | Devtools Arcadia <arcadia-devtools@yandex-team.ru> | 2022-02-07 18:08:42 +0300 |
|---|---|---|
| committer | Devtools Arcadia <arcadia-devtools@mous.vla.yp-c.yandex.net> | 2022-02-07 18:08:42 +0300 |
| commit | 1110808a9d39d4b808aef724c861a2e1a38d2a69 (patch) | |
| tree | e26c9fed0de5d9873cce7e00bc214573dc2195b7 /contrib/libs/llvm12/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| download | ydb-1110808a9d39d4b808aef724c861a2e1a38d2a69.tar.gz | |
intermediate changes
ref:cde9a383711a11544ce7e107a78147fb96cc4029
Diffstat (limited to 'contrib/libs/llvm12/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | contrib/libs/llvm12/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 22754 |
1 files changed, 22754 insertions, 0 deletions
diff --git a/contrib/libs/llvm12/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/contrib/libs/llvm12/lib/CodeGen/SelectionDAG/DAGCombiner.cpp new file mode 100644 index 0000000000..7f2add81e8 --- /dev/null +++ b/contrib/libs/llvm12/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -0,0 +1,22754 @@ +//===- DAGCombiner.cpp - Implement a DAG node combiner --------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run +// both before and after the DAG is legalized. +// +// This pass is not a substitute for the LLVM IR instcombine pass. This pass is +// primarily intended to handle simplification opportunities that are implicit +// in the LLVM IR and exposed by the various codegen lowering phases. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/APFloat.h" +#include "llvm/ADT/APInt.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/IntervalMap.h" +#include "llvm/ADT/None.h" +#include "llvm/ADT/Optional.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SetVector.h" +#include "llvm/ADT/SmallBitVector.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallSet.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Analysis/AliasAnalysis.h" +#include "llvm/Analysis/MemoryLocation.h" +#include "llvm/Analysis/TargetLibraryInfo.h" +#include "llvm/Analysis/VectorUtils.h" +#include "llvm/CodeGen/DAGCombine.h" +#include "llvm/CodeGen/ISDOpcodes.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineMemOperand.h" +#include "llvm/CodeGen/RuntimeLibcalls.h" +#include "llvm/CodeGen/SelectionDAG.h" +#include "llvm/CodeGen/SelectionDAGAddressAnalysis.h" +#include "llvm/CodeGen/SelectionDAGNodes.h" +#include "llvm/CodeGen/SelectionDAGTargetInfo.h" +#include "llvm/CodeGen/TargetLowering.h" +#include "llvm/CodeGen/TargetRegisterInfo.h" +#include "llvm/CodeGen/TargetSubtargetInfo.h" +#include "llvm/CodeGen/ValueTypes.h" +#include "llvm/IR/Attributes.h" +#include "llvm/IR/Constant.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/DerivedTypes.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/LLVMContext.h" +#include "llvm/IR/Metadata.h" +#include "llvm/Support/Casting.h" +#include "llvm/Support/CodeGen.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Compiler.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/KnownBits.h" +#include "llvm/Support/MachineValueType.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetOptions.h" +#include <algorithm> +#include <cassert> +#include <cstdint> +#include <functional> +#include <iterator> +#include <string> +#include <tuple> +#include <utility> + +using namespace llvm; + +#define DEBUG_TYPE "dagcombine" + +STATISTIC(NodesCombined , "Number of dag nodes combined"); +STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created"); +STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created"); +STATISTIC(OpsNarrowed , "Number of load/op/store narrowed"); +STATISTIC(LdStFP2Int , "Number of fp load/store pairs transformed to int"); +STATISTIC(SlicedLoads, "Number of load sliced"); +STATISTIC(NumFPLogicOpsConv, "Number of logic ops converted to fp ops"); + +static cl::opt<bool> +CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden, + cl::desc("Enable DAG combiner's use of IR alias analysis")); + +static cl::opt<bool> +UseTBAA("combiner-use-tbaa", cl::Hidden, cl::init(true), + cl::desc("Enable DAG combiner's use of TBAA")); + +#ifndef NDEBUG +static cl::opt<std::string> +CombinerAAOnlyFunc("combiner-aa-only-func", cl::Hidden, + cl::desc("Only use DAG-combiner alias analysis in this" + " function")); +#endif + +/// Hidden option to stress test load slicing, i.e., when this option +/// is enabled, load slicing bypasses most of its profitability guards. +static cl::opt<bool> +StressLoadSlicing("combiner-stress-load-slicing", cl::Hidden, + cl::desc("Bypass the profitability model of load slicing"), + cl::init(false)); + +static cl::opt<bool> + MaySplitLoadIndex("combiner-split-load-index", cl::Hidden, cl::init(true), + cl::desc("DAG combiner may split indexing from loads")); + +static cl::opt<bool> + EnableStoreMerging("combiner-store-merging", cl::Hidden, cl::init(true), + cl::desc("DAG combiner enable merging multiple stores " + "into a wider store")); + +static cl::opt<unsigned> TokenFactorInlineLimit( + "combiner-tokenfactor-inline-limit", cl::Hidden, cl::init(2048), + cl::desc("Limit the number of operands to inline for Token Factors")); + +static cl::opt<unsigned> StoreMergeDependenceLimit( + "combiner-store-merge-dependence-limit", cl::Hidden, cl::init(10), + cl::desc("Limit the number of times for the same StoreNode and RootNode " + "to bail out in store merging dependence check")); + +static cl::opt<bool> EnableReduceLoadOpStoreWidth( + "combiner-reduce-load-op-store-width", cl::Hidden, cl::init(true), + cl::desc("DAG cominber enable reducing the width of load/op/store " + "sequence")); + +static cl::opt<bool> EnableShrinkLoadReplaceStoreWithStore( + "combiner-shrink-load-replace-store-with-store", cl::Hidden, cl::init(true), + cl::desc("DAG cominber enable load/<replace bytes>/store with " + "a narrower store")); + +namespace { + + class DAGCombiner { + SelectionDAG &DAG; + const TargetLowering &TLI; + const SelectionDAGTargetInfo *STI; + CombineLevel Level; + CodeGenOpt::Level OptLevel; + bool LegalDAG = false; + bool LegalOperations = false; + bool LegalTypes = false; + bool ForCodeSize; + bool DisableGenericCombines; + + /// Worklist of all of the nodes that need to be simplified. + /// + /// This must behave as a stack -- new nodes to process are pushed onto the + /// back and when processing we pop off of the back. + /// + /// The worklist will not contain duplicates but may contain null entries + /// due to nodes being deleted from the underlying DAG. + SmallVector<SDNode *, 64> Worklist; + + /// Mapping from an SDNode to its position on the worklist. + /// + /// This is used to find and remove nodes from the worklist (by nulling + /// them) when they are deleted from the underlying DAG. It relies on + /// stable indices of nodes within the worklist. + DenseMap<SDNode *, unsigned> WorklistMap; + /// This records all nodes attempted to add to the worklist since we + /// considered a new worklist entry. As we keep do not add duplicate nodes + /// in the worklist, this is different from the tail of the worklist. + SmallSetVector<SDNode *, 32> PruningList; + + /// Set of nodes which have been combined (at least once). + /// + /// This is used to allow us to reliably add any operands of a DAG node + /// which have not yet been combined to the worklist. + SmallPtrSet<SDNode *, 32> CombinedNodes; + + /// Map from candidate StoreNode to the pair of RootNode and count. + /// The count is used to track how many times we have seen the StoreNode + /// with the same RootNode bail out in dependence check. If we have seen + /// the bail out for the same pair many times over a limit, we won't + /// consider the StoreNode with the same RootNode as store merging + /// candidate again. + DenseMap<SDNode *, std::pair<SDNode *, unsigned>> StoreRootCountMap; + + // AA - Used for DAG load/store alias analysis. + AliasAnalysis *AA; + + /// When an instruction is simplified, add all users of the instruction to + /// the work lists because they might get more simplified now. + void AddUsersToWorklist(SDNode *N) { + for (SDNode *Node : N->uses()) + AddToWorklist(Node); + } + + /// Convenient shorthand to add a node and all of its user to the worklist. + void AddToWorklistWithUsers(SDNode *N) { + AddUsersToWorklist(N); + AddToWorklist(N); + } + + // Prune potentially dangling nodes. This is called after + // any visit to a node, but should also be called during a visit after any + // failed combine which may have created a DAG node. + void clearAddedDanglingWorklistEntries() { + // Check any nodes added to the worklist to see if they are prunable. + while (!PruningList.empty()) { + auto *N = PruningList.pop_back_val(); + if (N->use_empty()) + recursivelyDeleteUnusedNodes(N); + } + } + + SDNode *getNextWorklistEntry() { + // Before we do any work, remove nodes that are not in use. + clearAddedDanglingWorklistEntries(); + SDNode *N = nullptr; + // The Worklist holds the SDNodes in order, but it may contain null + // entries. + while (!N && !Worklist.empty()) { + N = Worklist.pop_back_val(); + } + + if (N) { + bool GoodWorklistEntry = WorklistMap.erase(N); + (void)GoodWorklistEntry; + assert(GoodWorklistEntry && + "Found a worklist entry without a corresponding map entry!"); + } + return N; + } + + /// Call the node-specific routine that folds each particular type of node. + SDValue visit(SDNode *N); + + public: + DAGCombiner(SelectionDAG &D, AliasAnalysis *AA, CodeGenOpt::Level OL) + : DAG(D), TLI(D.getTargetLoweringInfo()), + STI(D.getSubtarget().getSelectionDAGInfo()), + Level(BeforeLegalizeTypes), OptLevel(OL), AA(AA) { + ForCodeSize = DAG.shouldOptForSize(); + DisableGenericCombines = STI && STI->disableGenericCombines(OptLevel); + + MaximumLegalStoreInBits = 0; + // We use the minimum store size here, since that's all we can guarantee + // for the scalable vector types. + for (MVT VT : MVT::all_valuetypes()) + if (EVT(VT).isSimple() && VT != MVT::Other && + TLI.isTypeLegal(EVT(VT)) && + VT.getSizeInBits().getKnownMinSize() >= MaximumLegalStoreInBits) + MaximumLegalStoreInBits = VT.getSizeInBits().getKnownMinSize(); + } + + void ConsiderForPruning(SDNode *N) { + // Mark this for potential pruning. + PruningList.insert(N); + } + + /// Add to the worklist making sure its instance is at the back (next to be + /// processed.) + void AddToWorklist(SDNode *N) { + assert(N->getOpcode() != ISD::DELETED_NODE && + "Deleted Node added to Worklist"); + + // Skip handle nodes as they can't usefully be combined and confuse the + // zero-use deletion strategy. + if (N->getOpcode() == ISD::HANDLENODE) + return; + + ConsiderForPruning(N); + + if (WorklistMap.insert(std::make_pair(N, Worklist.size())).second) + Worklist.push_back(N); + } + + /// Remove all instances of N from the worklist. + void removeFromWorklist(SDNode *N) { + CombinedNodes.erase(N); + PruningList.remove(N); + StoreRootCountMap.erase(N); + + auto It = WorklistMap.find(N); + if (It == WorklistMap.end()) + return; // Not in the worklist. + + // Null out the entry rather than erasing it to avoid a linear operation. + Worklist[It->second] = nullptr; + WorklistMap.erase(It); + } + + void deleteAndRecombine(SDNode *N); + bool recursivelyDeleteUnusedNodes(SDNode *N); + + /// Replaces all uses of the results of one DAG node with new values. + SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, + bool AddTo = true); + + /// Replaces all uses of the results of one DAG node with new values. + SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) { + return CombineTo(N, &Res, 1, AddTo); + } + + /// Replaces all uses of the results of one DAG node with new values. + SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, + bool AddTo = true) { + SDValue To[] = { Res0, Res1 }; + return CombineTo(N, To, 2, AddTo); + } + + void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO); + + private: + unsigned MaximumLegalStoreInBits; + + /// Check the specified integer node value to see if it can be simplified or + /// if things it uses can be simplified by bit propagation. + /// If so, return true. + bool SimplifyDemandedBits(SDValue Op) { + unsigned BitWidth = Op.getScalarValueSizeInBits(); + APInt DemandedBits = APInt::getAllOnesValue(BitWidth); + return SimplifyDemandedBits(Op, DemandedBits); + } + + bool SimplifyDemandedBits(SDValue Op, const APInt &DemandedBits) { + TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations); + KnownBits Known; + if (!TLI.SimplifyDemandedBits(Op, DemandedBits, Known, TLO, 0, false)) + return false; + + // Revisit the node. + AddToWorklist(Op.getNode()); + + CommitTargetLoweringOpt(TLO); + return true; + } + + /// Check the specified vector node value to see if it can be simplified or + /// if things it uses can be simplified as it only uses some of the + /// elements. If so, return true. + bool SimplifyDemandedVectorElts(SDValue Op) { + // TODO: For now just pretend it cannot be simplified. + if (Op.getValueType().isScalableVector()) + return false; + + unsigned NumElts = Op.getValueType().getVectorNumElements(); + APInt DemandedElts = APInt::getAllOnesValue(NumElts); + return SimplifyDemandedVectorElts(Op, DemandedElts); + } + + bool SimplifyDemandedBits(SDValue Op, const APInt &DemandedBits, + const APInt &DemandedElts, + bool AssumeSingleUse = false); + bool SimplifyDemandedVectorElts(SDValue Op, const APInt &DemandedElts, + bool AssumeSingleUse = false); + + bool CombineToPreIndexedLoadStore(SDNode *N); + bool CombineToPostIndexedLoadStore(SDNode *N); + SDValue SplitIndexingFromLoad(LoadSDNode *LD); + bool SliceUpLoad(SDNode *N); + + // Scalars have size 0 to distinguish from singleton vectors. + SDValue ForwardStoreValueToDirectLoad(LoadSDNode *LD); + bool getTruncatedStoreValue(StoreSDNode *ST, SDValue &Val); + bool extendLoadedValueToExtension(LoadSDNode *LD, SDValue &Val); + + /// Replace an ISD::EXTRACT_VECTOR_ELT of a load with a narrowed + /// load. + /// + /// \param EVE ISD::EXTRACT_VECTOR_ELT to be replaced. + /// \param InVecVT type of the input vector to EVE with bitcasts resolved. + /// \param EltNo index of the vector element to load. + /// \param OriginalLoad load that EVE came from to be replaced. + /// \returns EVE on success SDValue() on failure. + SDValue scalarizeExtractedVectorLoad(SDNode *EVE, EVT InVecVT, + SDValue EltNo, + LoadSDNode *OriginalLoad); + void ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad); + SDValue PromoteOperand(SDValue Op, EVT PVT, bool &Replace); + SDValue SExtPromoteOperand(SDValue Op, EVT PVT); + SDValue ZExtPromoteOperand(SDValue Op, EVT PVT); + SDValue PromoteIntBinOp(SDValue Op); + SDValue PromoteIntShiftOp(SDValue Op); + SDValue PromoteExtend(SDValue Op); + bool PromoteLoad(SDValue Op); + + /// Call the node-specific routine that knows how to fold each + /// particular type of node. If that doesn't do anything, try the + /// target-specific DAG combines. + SDValue combine(SDNode *N); + + // Visitation implementation - Implement dag node combining for different + // node types. The semantics are as follows: + // Return Value: + // SDValue.getNode() == 0 - No change was made + // SDValue.getNode() == N - N was replaced, is dead and has been handled. + // otherwise - N should be replaced by the returned Operand. + // + SDValue visitTokenFactor(SDNode *N); + SDValue visitMERGE_VALUES(SDNode *N); + SDValue visitADD(SDNode *N); + SDValue visitADDLike(SDNode *N); + SDValue visitADDLikeCommutative(SDValue N0, SDValue N1, SDNode *LocReference); + SDValue visitSUB(SDNode *N); + SDValue visitADDSAT(SDNode *N); + SDValue visitSUBSAT(SDNode *N); + SDValue visitADDC(SDNode *N); + SDValue visitADDO(SDNode *N); + SDValue visitUADDOLike(SDValue N0, SDValue N1, SDNode *N); + SDValue visitSUBC(SDNode *N); + SDValue visitSUBO(SDNode *N); + SDValue visitADDE(SDNode *N); + SDValue visitADDCARRY(SDNode *N); + SDValue visitSADDO_CARRY(SDNode *N); + SDValue visitADDCARRYLike(SDValue N0, SDValue N1, SDValue CarryIn, SDNode *N); + SDValue visitSUBE(SDNode *N); + SDValue visitSUBCARRY(SDNode *N); + SDValue visitSSUBO_CARRY(SDNode *N); + SDValue visitMUL(SDNode *N); + SDValue visitMULFIX(SDNode *N); + SDValue useDivRem(SDNode *N); + SDValue visitSDIV(SDNode *N); + SDValue visitSDIVLike(SDValue N0, SDValue N1, SDNode *N); + SDValue visitUDIV(SDNode *N); + SDValue visitUDIVLike(SDValue N0, SDValue N1, SDNode *N); + SDValue visitREM(SDNode *N); + SDValue visitMULHU(SDNode *N); + SDValue visitMULHS(SDNode *N); + SDValue visitSMUL_LOHI(SDNode *N); + SDValue visitUMUL_LOHI(SDNode *N); + SDValue visitMULO(SDNode *N); + SDValue visitIMINMAX(SDNode *N); + SDValue visitAND(SDNode *N); + SDValue visitANDLike(SDValue N0, SDValue N1, SDNode *N); + SDValue visitOR(SDNode *N); + SDValue visitORLike(SDValue N0, SDValue N1, SDNode *N); + SDValue visitXOR(SDNode *N); + SDValue SimplifyVBinOp(SDNode *N); + SDValue visitSHL(SDNode *N); + SDValue visitSRA(SDNode *N); + SDValue visitSRL(SDNode *N); + SDValue visitFunnelShift(SDNode *N); + SDValue visitRotate(SDNode *N); + SDValue visitABS(SDNode *N); + SDValue visitBSWAP(SDNode *N); + SDValue visitBITREVERSE(SDNode *N); + SDValue visitCTLZ(SDNode *N); + SDValue visitCTLZ_ZERO_UNDEF(SDNode *N); + SDValue visitCTTZ(SDNode *N); + SDValue visitCTTZ_ZERO_UNDEF(SDNode *N); + SDValue visitCTPOP(SDNode *N); + SDValue visitSELECT(SDNode *N); + SDValue visitVSELECT(SDNode *N); + SDValue visitSELECT_CC(SDNode *N); + SDValue visitSETCC(SDNode *N); + SDValue visitSETCCCARRY(SDNode *N); + SDValue visitSIGN_EXTEND(SDNode *N); + SDValue visitZERO_EXTEND(SDNode *N); + SDValue visitANY_EXTEND(SDNode *N); + SDValue visitAssertExt(SDNode *N); + SDValue visitAssertAlign(SDNode *N); + SDValue visitSIGN_EXTEND_INREG(SDNode *N); + SDValue visitSIGN_EXTEND_VECTOR_INREG(SDNode *N); + SDValue visitZERO_EXTEND_VECTOR_INREG(SDNode *N); + SDValue visitTRUNCATE(SDNode *N); + SDValue visitBITCAST(SDNode *N); + SDValue visitFREEZE(SDNode *N); + SDValue visitBUILD_PAIR(SDNode *N); + SDValue visitFADD(SDNode *N); + SDValue visitSTRICT_FADD(SDNode *N); + SDValue visitFSUB(SDNode *N); + SDValue visitFMUL(SDNode *N); + SDValue visitFMA(SDNode *N); + SDValue visitFDIV(SDNode *N); + SDValue visitFREM(SDNode *N); + SDValue visitFSQRT(SDNode *N); + SDValue visitFCOPYSIGN(SDNode *N); + SDValue visitFPOW(SDNode *N); + SDValue visitSINT_TO_FP(SDNode *N); + SDValue visitUINT_TO_FP(SDNode *N); + SDValue visitFP_TO_SINT(SDNode *N); + SDValue visitFP_TO_UINT(SDNode *N); + SDValue visitFP_ROUND(SDNode *N); + SDValue visitFP_EXTEND(SDNode *N); + SDValue visitFNEG(SDNode *N); + SDValue visitFABS(SDNode *N); + SDValue visitFCEIL(SDNode *N); + SDValue visitFTRUNC(SDNode *N); + SDValue visitFFLOOR(SDNode *N); + SDValue visitFMINNUM(SDNode *N); + SDValue visitFMAXNUM(SDNode *N); + SDValue visitFMINIMUM(SDNode *N); + SDValue visitFMAXIMUM(SDNode *N); + SDValue visitBRCOND(SDNode *N); + SDValue visitBR_CC(SDNode *N); + SDValue visitLOAD(SDNode *N); + + SDValue replaceStoreChain(StoreSDNode *ST, SDValue BetterChain); + SDValue replaceStoreOfFPConstant(StoreSDNode *ST); + + SDValue visitSTORE(SDNode *N); + SDValue visitLIFETIME_END(SDNode *N); + SDValue visitINSERT_VECTOR_ELT(SDNode *N); + SDValue visitEXTRACT_VECTOR_ELT(SDNode *N); + SDValue visitBUILD_VECTOR(SDNode *N); + SDValue visitCONCAT_VECTORS(SDNode *N); + SDValue visitEXTRACT_SUBVECTOR(SDNode *N); + SDValue visitVECTOR_SHUFFLE(SDNode *N); + SDValue visitSCALAR_TO_VECTOR(SDNode *N); + SDValue visitINSERT_SUBVECTOR(SDNode *N); + SDValue visitMLOAD(SDNode *N); + SDValue visitMSTORE(SDNode *N); + SDValue visitMGATHER(SDNode *N); + SDValue visitMSCATTER(SDNode *N); + SDValue visitFP_TO_FP16(SDNode *N); + SDValue visitFP16_TO_FP(SDNode *N); + SDValue visitVECREDUCE(SDNode *N); + + SDValue visitFADDForFMACombine(SDNode *N); + SDValue visitFSUBForFMACombine(SDNode *N); + SDValue visitFMULForFMADistributiveCombine(SDNode *N); + + SDValue XformToShuffleWithZero(SDNode *N); + bool reassociationCanBreakAddressingModePattern(unsigned Opc, + const SDLoc &DL, SDValue N0, + SDValue N1); + SDValue reassociateOpsCommutative(unsigned Opc, const SDLoc &DL, SDValue N0, + SDValue N1); + SDValue reassociateOps(unsigned Opc, const SDLoc &DL, SDValue N0, + SDValue N1, SDNodeFlags Flags); + + SDValue visitShiftByConstant(SDNode *N); + + SDValue foldSelectOfConstants(SDNode *N); + SDValue foldVSelectOfConstants(SDNode *N); + SDValue foldBinOpIntoSelect(SDNode *BO); + bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS); + SDValue hoistLogicOpWithSameOpcodeHands(SDNode *N); + SDValue SimplifySelect(const SDLoc &DL, SDValue N0, SDValue N1, SDValue N2); + SDValue SimplifySelectCC(const SDLoc &DL, SDValue N0, SDValue N1, + SDValue N2, SDValue N3, ISD::CondCode CC, + bool NotExtCompare = false); + SDValue convertSelectOfFPConstantsToLoadOffset( + const SDLoc &DL, SDValue N0, SDValue N1, SDValue N2, SDValue N3, + ISD::CondCode CC); + SDValue foldSignChangeInBitcast(SDNode *N); + SDValue foldSelectCCToShiftAnd(const SDLoc &DL, SDValue N0, SDValue N1, + SDValue N2, SDValue N3, ISD::CondCode CC); + SDValue foldLogicOfSetCCs(bool IsAnd, SDValue N0, SDValue N1, + const SDLoc &DL); + SDValue unfoldMaskedMerge(SDNode *N); + SDValue unfoldExtremeBitClearingToShifts(SDNode *N); + SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond, + const SDLoc &DL, bool foldBooleans); + SDValue rebuildSetCC(SDValue N); + + bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS, + SDValue &CC, bool MatchStrict = false) const; + bool isOneUseSetCC(SDValue N) const; + + SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, + unsigned HiOp); + SDValue CombineConsecutiveLoads(SDNode *N, EVT VT); + SDValue CombineExtLoad(SDNode *N); + SDValue CombineZExtLogicopShiftLoad(SDNode *N); + SDValue combineRepeatedFPDivisors(SDNode *N); + SDValue combineInsertEltToShuffle(SDNode *N, unsigned InsIndex); + SDValue ConstantFoldBITCASTofBUILD_VECTOR(SDNode *, EVT); + SDValue BuildSDIV(SDNode *N); + SDValue BuildSDIVPow2(SDNode *N); + SDValue BuildUDIV(SDNode *N); + SDValue BuildLogBase2(SDValue V, const SDLoc &DL); + SDValue BuildDivEstimate(SDValue N, SDValue Op, SDNodeFlags Flags); + SDValue buildRsqrtEstimate(SDValue Op, SDNodeFlags Flags); + SDValue buildSqrtEstimate(SDValue Op, SDNodeFlags Flags); + SDValue buildSqrtEstimateImpl(SDValue Op, SDNodeFlags Flags, bool Recip); + SDValue buildSqrtNROneConst(SDValue Arg, SDValue Est, unsigned Iterations, + SDNodeFlags Flags, bool Reciprocal); + SDValue buildSqrtNRTwoConst(SDValue Arg, SDValue Est, unsigned Iterations, + SDNodeFlags Flags, bool Reciprocal); + SDValue MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1, + bool DemandHighBits = true); + SDValue MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1); + SDValue MatchRotatePosNeg(SDValue Shifted, SDValue Pos, SDValue Neg, + SDValue InnerPos, SDValue InnerNeg, + unsigned PosOpcode, unsigned NegOpcode, + const SDLoc &DL); + SDValue MatchFunnelPosNeg(SDValue N0, SDValue N1, SDValue Pos, SDValue Neg, + SDValue InnerPos, SDValue InnerNeg, + unsigned PosOpcode, unsigned NegOpcode, + const SDLoc &DL); + SDValue MatchRotate(SDValue LHS, SDValue RHS, const SDLoc &DL); + SDValue MatchLoadCombine(SDNode *N); + SDValue mergeTruncStores(StoreSDNode *N); + SDValue ReduceLoadWidth(SDNode *N); + SDValue ReduceLoadOpStoreWidth(SDNode *N); + SDValue splitMergedValStore(StoreSDNode *ST); + SDValue TransformFPLoadStorePair(SDNode *N); + SDValue convertBuildVecZextToZext(SDNode *N); + SDValue reduceBuildVecExtToExtBuildVec(SDNode *N); + SDValue reduceBuildVecTruncToBitCast(SDNode *N); + SDValue reduceBuildVecToShuffle(SDNode *N); + SDValue createBuildVecShuffle(const SDLoc &DL, SDNode *N, + ArrayRef<int> VectorMask, SDValue VecIn1, + SDValue VecIn2, unsigned LeftIdx, + bool DidSplitVec); + SDValue matchVSelectOpSizesWithSetCC(SDNode *Cast); + + /// Walk up chain skipping non-aliasing memory nodes, + /// looking for aliasing nodes and adding them to the Aliases vector. + void GatherAllAliases(SDNode *N, SDValue OriginalChain, + SmallVectorImpl<SDValue> &Aliases); + + /// Return true if there is any possibility that the two addresses overlap. + bool isAlias(SDNode *Op0, SDNode *Op1) const; + + /// Walk up chain skipping non-aliasing memory nodes, looking for a better + /// chain (aliasing node.) + SDValue FindBetterChain(SDNode *N, SDValue Chain); + + /// Try to replace a store and any possibly adjacent stores on + /// consecutive chains with better chains. Return true only if St is + /// replaced. + /// + /// Notice that other chains may still be replaced even if the function + /// returns false. + bool findBetterNeighborChains(StoreSDNode *St); + + // Helper for findBetterNeighborChains. Walk up store chain add additional + // chained stores that do not overlap and can be parallelized. + bool parallelizeChainedStores(StoreSDNode *St); + + /// Holds a pointer to an LSBaseSDNode as well as information on where it + /// is located in a sequence of memory operations connected by a chain. + struct MemOpLink { + // Ptr to the mem node. + LSBaseSDNode *MemNode; + + // Offset from the base ptr. + int64_t OffsetFromBase; + + MemOpLink(LSBaseSDNode *N, int64_t Offset) + : MemNode(N), OffsetFromBase(Offset) {} + }; + + // Classify the origin of a stored value. + enum class StoreSource { Unknown, Constant, Extract, Load }; + StoreSource getStoreSource(SDValue StoreVal) { + switch (StoreVal.getOpcode()) { + case ISD::Constant: + case ISD::ConstantFP: + return StoreSource::Constant; + case ISD::EXTRACT_VECTOR_ELT: + case ISD::EXTRACT_SUBVECTOR: + return StoreSource::Extract; + case ISD::LOAD: + return StoreSource::Load; + default: + return StoreSource::Unknown; + } + } + + /// This is a helper function for visitMUL to check the profitability + /// of folding (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2). + /// MulNode is the original multiply, AddNode is (add x, c1), + /// and ConstNode is c2. + bool isMulAddWithConstProfitable(SDNode *MulNode, + SDValue &AddNode, + SDValue &ConstNode); + + /// This is a helper function for visitAND and visitZERO_EXTEND. Returns + /// true if the (and (load x) c) pattern matches an extload. ExtVT returns + /// the type of the loaded value to be extended. + bool isAndLoadExtLoad(ConstantSDNode *AndC, LoadSDNode *LoadN, + EVT LoadResultTy, EVT &ExtVT); + + /// Helper function to calculate whether the given Load/Store can have its + /// width reduced to ExtVT. + bool isLegalNarrowLdSt(LSBaseSDNode *LDSTN, ISD::LoadExtType ExtType, + EVT &MemVT, unsigned ShAmt = 0); + + /// Used by BackwardsPropagateMask to find suitable loads. + bool SearchForAndLoads(SDNode *N, SmallVectorImpl<LoadSDNode*> &Loads, + SmallPtrSetImpl<SDNode*> &NodesWithConsts, + ConstantSDNode *Mask, SDNode *&NodeToMask); + /// Attempt to propagate a given AND node back to load leaves so that they + /// can be combined into narrow loads. + bool BackwardsPropagateMask(SDNode *N); + + /// Helper function for mergeConsecutiveStores which merges the component + /// store chains. + SDValue getMergeStoreChains(SmallVectorImpl<MemOpLink> &StoreNodes, + unsigned NumStores); + + /// This is a helper function for mergeConsecutiveStores. When the source + /// elements of the consecutive stores are all constants or all extracted + /// vector elements, try to merge them into one larger store introducing + /// bitcasts if necessary. \return True if a merged store was created. + bool mergeStoresOfConstantsOrVecElts(SmallVectorImpl<MemOpLink> &StoreNodes, + EVT MemVT, unsigned NumStores, + bool IsConstantSrc, bool UseVector, + bool UseTrunc); + + /// This is a helper function for mergeConsecutiveStores. Stores that + /// potentially may be merged with St are placed in StoreNodes. RootNode is + /// a chain predecessor to all store candidates. + void getStoreMergeCandidates(StoreSDNode *St, + SmallVectorImpl<MemOpLink> &StoreNodes, + SDNode *&Root); + + /// Helper function for mergeConsecutiveStores. Checks if candidate stores + /// have indirect dependency through their operands. RootNode is the + /// predecessor to all stores calculated by getStoreMergeCandidates and is + /// used to prune the dependency check. \return True if safe to merge. + bool checkMergeStoreCandidatesForDependencies( + SmallVectorImpl<MemOpLink> &StoreNodes, unsigned NumStores, + SDNode *RootNode); + + /// This is a helper function for mergeConsecutiveStores. Given a list of + /// store candidates, find the first N that are consecutive in memory. + /// Returns 0 if there are not at least 2 consecutive stores to try merging. + unsigned getConsecutiveStores(SmallVectorImpl<MemOpLink> &StoreNodes, + int64_t ElementSizeBytes) const; + + /// This is a helper function for mergeConsecutiveStores. It is used for + /// store chains that are composed entirely of constant values. + bool tryStoreMergeOfConstants(SmallVectorImpl<MemOpLink> &StoreNodes, + unsigned NumConsecutiveStores, + EVT MemVT, SDNode *Root, bool AllowVectors); + + /// This is a helper function for mergeConsecutiveStores. It is used for + /// store chains that are composed entirely of extracted vector elements. + /// When extracting multiple vector elements, try to store them in one + /// vector store rather than a sequence of scalar stores. + bool tryStoreMergeOfExtracts(SmallVectorImpl<MemOpLink> &StoreNodes, + unsigned NumConsecutiveStores, EVT MemVT, + SDNode *Root); + + /// This is a helper function for mergeConsecutiveStores. It is used for + /// store chains that are composed entirely of loaded values. + bool tryStoreMergeOfLoads(SmallVectorImpl<MemOpLink> &StoreNodes, + unsigned NumConsecutiveStores, EVT MemVT, + SDNode *Root, bool AllowVectors, + bool IsNonTemporalStore, bool IsNonTemporalLoad); + + /// Merge consecutive store operations into a wide store. + /// This optimization uses wide integers or vectors when possible. + /// \return true if stores were merged. + bool mergeConsecutiveStores(StoreSDNode *St); + + /// Try to transform a truncation where C is a constant: + /// (trunc (and X, C)) -> (and (trunc X), (trunc C)) + /// + /// \p N needs to be a truncation and its first operand an AND. Other + /// requirements are checked by the function (e.g. that trunc is + /// single-use) and if missed an empty SDValue is returned. + SDValue distributeTruncateThroughAnd(SDNode *N); + + /// Helper function to determine whether the target supports operation + /// given by \p Opcode for type \p VT, that is, whether the operation + /// is legal or custom before legalizing operations, and whether is + /// legal (but not custom) after legalization. + bool hasOperation(unsigned Opcode, EVT VT) { + return TLI.isOperationLegalOrCustom(Opcode, VT, LegalOperations); + } + + public: + /// Runs the dag combiner on all nodes in the work list + void Run(CombineLevel AtLevel); + + SelectionDAG &getDAG() const { return DAG; } + + /// Returns a type large enough to hold any valid shift amount - before type + /// legalization these can be huge. + EVT getShiftAmountTy(EVT LHSTy) { + assert(LHSTy.isInteger() && "Shift amount is not an integer type!"); + return TLI.getShiftAmountTy(LHSTy, DAG.getDataLayout(), LegalTypes); + } + + /// This method returns true if we are running before type legalization or + /// if the specified VT is legal. + bool isTypeLegal(const EVT &VT) { + if (!LegalTypes) return true; + return TLI.isTypeLegal(VT); + } + + /// Convenience wrapper around TargetLowering::getSetCCResultType + EVT getSetCCResultType(EVT VT) const { + return TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT); + } + + void ExtendSetCCUses(const SmallVectorImpl<SDNode *> &SetCCs, + SDValue OrigLoad, SDValue ExtLoad, + ISD::NodeType ExtType); + }; + +/// This class is a DAGUpdateListener that removes any deleted +/// nodes from the worklist. +class WorklistRemover : public SelectionDAG::DAGUpdateListener { + DAGCombiner &DC; + +public: + explicit WorklistRemover(DAGCombiner &dc) + : SelectionDAG::DAGUpdateListener(dc.getDAG()), DC(dc) {} + + void NodeDeleted(SDNode *N, SDNode *E) override { + DC.removeFromWorklist(N); + } +}; + +class WorklistInserter : public SelectionDAG::DAGUpdateListener { + DAGCombiner &DC; + +public: + explicit WorklistInserter(DAGCombiner &dc) + : SelectionDAG::DAGUpdateListener(dc.getDAG()), DC(dc) {} + + // FIXME: Ideally we could add N to the worklist, but this causes exponential + // compile time costs in large DAGs, e.g. Halide. + void NodeInserted(SDNode *N) override { DC.ConsiderForPruning(N); } +}; + +} // end anonymous namespace + +//===----------------------------------------------------------------------===// +// TargetLowering::DAGCombinerInfo implementation +//===----------------------------------------------------------------------===// + +void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { + ((DAGCombiner*)DC)->AddToWorklist(N); +} + +SDValue TargetLowering::DAGCombinerInfo:: +CombineTo(SDNode *N, ArrayRef<SDValue> To, bool AddTo) { + return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size(), AddTo); +} + +SDValue TargetLowering::DAGCombinerInfo:: +CombineTo(SDNode *N, SDValue Res, bool AddTo) { + return ((DAGCombiner*)DC)->CombineTo(N, Res, AddTo); +} + +SDValue TargetLowering::DAGCombinerInfo:: +CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) { + return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo); +} + +bool TargetLowering::DAGCombinerInfo:: +recursivelyDeleteUnusedNodes(SDNode *N) { + return ((DAGCombiner*)DC)->recursivelyDeleteUnusedNodes(N); +} + +void TargetLowering::DAGCombinerInfo:: +CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { + return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO); +} + +//===----------------------------------------------------------------------===// +// Helper Functions +//===----------------------------------------------------------------------===// + +void DAGCombiner::deleteAndRecombine(SDNode *N) { + removeFromWorklist(N); + + // If the operands of this node are only used by the node, they will now be + // dead. Make sure to re-visit them and recursively delete dead nodes. + for (const SDValue &Op : N->ops()) + // For an operand generating multiple values, one of the values may + // become dead allowing further simplification (e.g. split index + // arithmetic from an indexed load). + if (Op->hasOneUse() || Op->getNumValues() > 1) + AddToWorklist(Op.getNode()); + + DAG.DeleteNode(N); +} + +// APInts must be the same size for most operations, this helper +// function zero extends the shorter of the pair so that they match. +// We provide an Offset so that we can create bitwidths that won't overflow. +static void zeroExtendToMatch(APInt &LHS, APInt &RHS, unsigned Offset = 0) { + unsigned Bits = Offset + std::max(LHS.getBitWidth(), RHS.getBitWidth()); + LHS = LHS.zextOrSelf(Bits); + RHS = RHS.zextOrSelf(Bits); +} + +// Return true if this node is a setcc, or is a select_cc +// that selects between the target values used for true and false, making it +// equivalent to a setcc. Also, set the incoming LHS, RHS, and CC references to +// the appropriate nodes based on the type of node we are checking. This +// simplifies life a bit for the callers. +bool DAGCombiner::isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS, + SDValue &CC, bool MatchStrict) const { + if (N.getOpcode() == ISD::SETCC) { + LHS = N.getOperand(0); + RHS = N.getOperand(1); + CC = N.getOperand(2); + return true; + } + + if (MatchStrict && + (N.getOpcode() == ISD::STRICT_FSETCC || + N.getOpcode() == ISD::STRICT_FSETCCS)) { + LHS = N.getOperand(1); + RHS = N.getOperand(2); + CC = N.getOperand(3); + return true; + } + + if (N.getOpcode() != ISD::SELECT_CC || + !TLI.isConstTrueVal(N.getOperand(2).getNode()) || + !TLI.isConstFalseVal(N.getOperand(3).getNode())) + return false; + + if (TLI.getBooleanContents(N.getValueType()) == + TargetLowering::UndefinedBooleanContent) + return false; + + LHS = N.getOperand(0); + RHS = N.getOperand(1); + CC = N.getOperand(4); + return true; +} + +/// Return true if this is a SetCC-equivalent operation with only one use. +/// If this is true, it allows the users to invert the operation for free when +/// it is profitable to do so. +bool DAGCombiner::isOneUseSetCC(SDValue N) const { + SDValue N0, N1, N2; + if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse()) + return true; + return false; +} + +static bool isConstantSplatVectorMaskForType(SDNode *N, EVT ScalarTy) { + if (!ScalarTy.isSimple()) + return false; + + uint64_t MaskForTy = 0ULL; + switch (ScalarTy.getSimpleVT().SimpleTy) { + case MVT::i8: + MaskForTy = 0xFFULL; + break; + case MVT::i16: + MaskForTy = 0xFFFFULL; + break; + case MVT::i32: + MaskForTy = 0xFFFFFFFFULL; + break; + default: + return false; + break; + } + + APInt Val; + if (ISD::isConstantSplatVector(N, Val)) + return Val.getLimitedValue() == MaskForTy; + + return false; +} + +// Determines if it is a constant integer or a splat/build vector of constant +// integers (and undefs). +// Do not permit build vector implicit truncation. +static bool isConstantOrConstantVector(SDValue N, bool NoOpaques = false) { + if (ConstantSDNode *Const = dyn_cast<ConstantSDNode>(N)) + return !(Const->isOpaque() && NoOpaques); + if (N.getOpcode() != ISD::BUILD_VECTOR && N.getOpcode() != ISD::SPLAT_VECTOR) + return false; + unsigned BitWidth = N.getScalarValueSizeInBits(); + for (const SDValue &Op : N->op_values()) { + if (Op.isUndef()) + continue; + ConstantSDNode *Const = dyn_cast<ConstantSDNode>(Op); + if (!Const || Const->getAPIntValue().getBitWidth() != BitWidth || + (Const->isOpaque() && NoOpaques)) + return false; + } + return true; +} + +// Determines if a BUILD_VECTOR is composed of all-constants possibly mixed with +// undef's. +static bool isAnyConstantBuildVector(SDValue V, bool NoOpaques = false) { + if (V.getOpcode() != ISD::BUILD_VECTOR) + return false; + return isConstantOrConstantVector(V, NoOpaques) || + ISD::isBuildVectorOfConstantFPSDNodes(V.getNode()); +} + +// Determine if this an indexed load with an opaque target constant index. +static bool canSplitIdx(LoadSDNode *LD) { + return MaySplitLoadIndex && + (LD->getOperand(2).getOpcode() != ISD::TargetConstant || + !cast<ConstantSDNode>(LD->getOperand(2))->isOpaque()); +} + +bool DAGCombiner::reassociationCanBreakAddressingModePattern(unsigned Opc, + const SDLoc &DL, + SDValue N0, + SDValue N1) { + // Currently this only tries to ensure we don't undo the GEP splits done by + // CodeGenPrepare when shouldConsiderGEPOffsetSplit is true. To ensure this, + // we check if the following transformation would be problematic: + // (load/store (add, (add, x, offset1), offset2)) -> + // (load/store (add, x, offset1+offset2)). + + if (Opc != ISD::ADD || N0.getOpcode() != ISD::ADD) + return false; + + if (N0.hasOneUse()) + return false; + + auto *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + auto *C2 = dyn_cast<ConstantSDNode>(N1); + if (!C1 || !C2) + return false; + + const APInt &C1APIntVal = C1->getAPIntValue(); + const APInt &C2APIntVal = C2->getAPIntValue(); + if (C1APIntVal.getBitWidth() > 64 || C2APIntVal.getBitWidth() > 64) + return false; + + const APInt CombinedValueIntVal = C1APIntVal + C2APIntVal; + if (CombinedValueIntVal.getBitWidth() > 64) + return false; + const int64_t CombinedValue = CombinedValueIntVal.getSExtValue(); + + for (SDNode *Node : N0->uses()) { + auto LoadStore = dyn_cast<MemSDNode>(Node); + if (LoadStore) { + // Is x[offset2] already not a legal addressing mode? If so then + // reassociating the constants breaks nothing (we test offset2 because + // that's the one we hope to fold into the load or store). + TargetLoweringBase::AddrMode AM; + AM.HasBaseReg = true; + AM.BaseOffs = C2APIntVal.getSExtValue(); + EVT VT = LoadStore->getMemoryVT(); + unsigned AS = LoadStore->getAddressSpace(); + Type *AccessTy = VT.getTypeForEVT(*DAG.getContext()); + if (!TLI.isLegalAddressingMode(DAG.getDataLayout(), AM, AccessTy, AS)) + continue; + + // Would x[offset1+offset2] still be a legal addressing mode? + AM.BaseOffs = CombinedValue; + if (!TLI.isLegalAddressingMode(DAG.getDataLayout(), AM, AccessTy, AS)) + return true; + } + } + + return false; +} + +// Helper for DAGCombiner::reassociateOps. Try to reassociate an expression +// such as (Opc N0, N1), if \p N0 is the same kind of operation as \p Opc. +SDValue DAGCombiner::reassociateOpsCommutative(unsigned Opc, const SDLoc &DL, + SDValue N0, SDValue N1) { + EVT VT = N0.getValueType(); + + if (N0.getOpcode() != Opc) + return SDValue(); + + if (DAG.isConstantIntBuildVectorOrConstantInt(N0.getOperand(1))) { + if (DAG.isConstantIntBuildVectorOrConstantInt(N1)) { + // Reassociate: (op (op x, c1), c2) -> (op x, (op c1, c2)) + if (SDValue OpNode = + DAG.FoldConstantArithmetic(Opc, DL, VT, {N0.getOperand(1), N1})) + return DAG.getNode(Opc, DL, VT, N0.getOperand(0), OpNode); + return SDValue(); + } + if (N0.hasOneUse()) { + // Reassociate: (op (op x, c1), y) -> (op (op x, y), c1) + // iff (op x, c1) has one use + SDValue OpNode = DAG.getNode(Opc, SDLoc(N0), VT, N0.getOperand(0), N1); + if (!OpNode.getNode()) + return SDValue(); + return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1)); + } + } + return SDValue(); +} + +// Try to reassociate commutative binops. +SDValue DAGCombiner::reassociateOps(unsigned Opc, const SDLoc &DL, SDValue N0, + SDValue N1, SDNodeFlags Flags) { + assert(TLI.isCommutativeBinOp(Opc) && "Operation not commutative."); + + // Floating-point reassociation is not allowed without loose FP math. + if (N0.getValueType().isFloatingPoint() || + N1.getValueType().isFloatingPoint()) + if (!Flags.hasAllowReassociation() || !Flags.hasNoSignedZeros()) + return SDValue(); + + if (SDValue Combined = reassociateOpsCommutative(Opc, DL, N0, N1)) + return Combined; + if (SDValue Combined = reassociateOpsCommutative(Opc, DL, N1, N0)) + return Combined; + return SDValue(); +} + +SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo, + bool AddTo) { + assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); + ++NodesCombined; + LLVM_DEBUG(dbgs() << "\nReplacing.1 "; N->dump(&DAG); dbgs() << "\nWith: "; + To[0].getNode()->dump(&DAG); + dbgs() << " and " << NumTo - 1 << " other values\n"); + for (unsigned i = 0, e = NumTo; i != e; ++i) + assert((!To[i].getNode() || + N->getValueType(i) == To[i].getValueType()) && + "Cannot combine value to value of different type!"); + + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesWith(N, To); + if (AddTo) { + // Push the new nodes and any users onto the worklist + for (unsigned i = 0, e = NumTo; i != e; ++i) { + if (To[i].getNode()) { + AddToWorklist(To[i].getNode()); + AddUsersToWorklist(To[i].getNode()); + } + } + } + + // Finally, if the node is now dead, remove it from the graph. The node + // may not be dead if the replacement process recursively simplified to + // something else needing this node. + if (N->use_empty()) + deleteAndRecombine(N); + return SDValue(N, 0); +} + +void DAGCombiner:: +CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) { + // Replace the old value with the new one. + ++NodesCombined; + LLVM_DEBUG(dbgs() << "\nReplacing.2 "; TLO.Old.getNode()->dump(&DAG); + dbgs() << "\nWith: "; TLO.New.getNode()->dump(&DAG); + dbgs() << '\n'); + + // Replace all uses. If any nodes become isomorphic to other nodes and + // are deleted, make sure to remove them from our worklist. + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New); + + // Push the new node and any (possibly new) users onto the worklist. + AddToWorklistWithUsers(TLO.New.getNode()); + + // Finally, if the node is now dead, remove it from the graph. The node + // may not be dead if the replacement process recursively simplified to + // something else needing this node. + if (TLO.Old.getNode()->use_empty()) + deleteAndRecombine(TLO.Old.getNode()); +} + +/// Check the specified integer node value to see if it can be simplified or if +/// things it uses can be simplified by bit propagation. If so, return true. +bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &DemandedBits, + const APInt &DemandedElts, + bool AssumeSingleUse) { + TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations); + KnownBits Known; + if (!TLI.SimplifyDemandedBits(Op, DemandedBits, DemandedElts, Known, TLO, 0, + AssumeSingleUse)) + return false; + + // Revisit the node. + AddToWorklist(Op.getNode()); + + CommitTargetLoweringOpt(TLO); + return true; +} + +/// Check the specified vector node value to see if it can be simplified or +/// if things it uses can be simplified as it only uses some of the elements. +/// If so, return true. +bool DAGCombiner::SimplifyDemandedVectorElts(SDValue Op, + const APInt &DemandedElts, + bool AssumeSingleUse) { + TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations); + APInt KnownUndef, KnownZero; + if (!TLI.SimplifyDemandedVectorElts(Op, DemandedElts, KnownUndef, KnownZero, + TLO, 0, AssumeSingleUse)) + return false; + + // Revisit the node. + AddToWorklist(Op.getNode()); + + CommitTargetLoweringOpt(TLO); + return true; +} + +void DAGCombiner::ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad) { + SDLoc DL(Load); + EVT VT = Load->getValueType(0); + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, DL, VT, SDValue(ExtLoad, 0)); + + LLVM_DEBUG(dbgs() << "\nReplacing.9 "; Load->dump(&DAG); dbgs() << "\nWith: "; + Trunc.getNode()->dump(&DAG); dbgs() << '\n'); + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 0), Trunc); + DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), SDValue(ExtLoad, 1)); + deleteAndRecombine(Load); + AddToWorklist(Trunc.getNode()); +} + +SDValue DAGCombiner::PromoteOperand(SDValue Op, EVT PVT, bool &Replace) { + Replace = false; + SDLoc DL(Op); + if (ISD::isUNINDEXEDLoad(Op.getNode())) { + LoadSDNode *LD = cast<LoadSDNode>(Op); + EVT MemVT = LD->getMemoryVT(); + ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD) ? ISD::EXTLOAD + : LD->getExtensionType(); + Replace = true; + return DAG.getExtLoad(ExtType, DL, PVT, + LD->getChain(), LD->getBasePtr(), + MemVT, LD->getMemOperand()); + } + + unsigned Opc = Op.getOpcode(); + switch (Opc) { + default: break; + case ISD::AssertSext: + if (SDValue Op0 = SExtPromoteOperand(Op.getOperand(0), PVT)) + return DAG.getNode(ISD::AssertSext, DL, PVT, Op0, Op.getOperand(1)); + break; + case ISD::AssertZext: + if (SDValue Op0 = ZExtPromoteOperand(Op.getOperand(0), PVT)) + return DAG.getNode(ISD::AssertZext, DL, PVT, Op0, Op.getOperand(1)); + break; + case ISD::Constant: { + unsigned ExtOpc = + Op.getValueType().isByteSized() ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND; + return DAG.getNode(ExtOpc, DL, PVT, Op); + } + } + + if (!TLI.isOperationLegal(ISD::ANY_EXTEND, PVT)) + return SDValue(); + return DAG.getNode(ISD::ANY_EXTEND, DL, PVT, Op); +} + +SDValue DAGCombiner::SExtPromoteOperand(SDValue Op, EVT PVT) { + if (!TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, PVT)) + return SDValue(); + EVT OldVT = Op.getValueType(); + SDLoc DL(Op); + bool Replace = false; + SDValue NewOp = PromoteOperand(Op, PVT, Replace); + if (!NewOp.getNode()) + return SDValue(); + AddToWorklist(NewOp.getNode()); + + if (Replace) + ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode()); + return DAG.getNode(ISD::SIGN_EXTEND_INREG, DL, NewOp.getValueType(), NewOp, + DAG.getValueType(OldVT)); +} + +SDValue DAGCombiner::ZExtPromoteOperand(SDValue Op, EVT PVT) { + EVT OldVT = Op.getValueType(); + SDLoc DL(Op); + bool Replace = false; + SDValue NewOp = PromoteOperand(Op, PVT, Replace); + if (!NewOp.getNode()) + return SDValue(); + AddToWorklist(NewOp.getNode()); + + if (Replace) + ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode()); + return DAG.getZeroExtendInReg(NewOp, DL, OldVT); +} + +/// Promote the specified integer binary operation if the target indicates it is +/// beneficial. e.g. On x86, it's usually better to promote i16 operations to +/// i32 since i16 instructions are longer. +SDValue DAGCombiner::PromoteIntBinOp(SDValue Op) { + if (!LegalOperations) + return SDValue(); + + EVT VT = Op.getValueType(); + if (VT.isVector() || !VT.isInteger()) + return SDValue(); + + // If operation type is 'undesirable', e.g. i16 on x86, consider + // promoting it. + unsigned Opc = Op.getOpcode(); + if (TLI.isTypeDesirableForOp(Opc, VT)) + return SDValue(); + + EVT PVT = VT; + // Consult target whether it is a good idea to promote this operation and + // what's the right type to promote it to. + if (TLI.IsDesirableToPromoteOp(Op, PVT)) { + assert(PVT != VT && "Don't know what type to promote to!"); + + LLVM_DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG)); + + bool Replace0 = false; + SDValue N0 = Op.getOperand(0); + SDValue NN0 = PromoteOperand(N0, PVT, Replace0); + + bool Replace1 = false; + SDValue N1 = Op.getOperand(1); + SDValue NN1 = PromoteOperand(N1, PVT, Replace1); + SDLoc DL(Op); + + SDValue RV = + DAG.getNode(ISD::TRUNCATE, DL, VT, DAG.getNode(Opc, DL, PVT, NN0, NN1)); + + // We are always replacing N0/N1's use in N and only need additional + // replacements if there are additional uses. + // Note: We are checking uses of the *nodes* (SDNode) rather than values + // (SDValue) here because the node may reference multiple values + // (for example, the chain value of a load node). + Replace0 &= !N0->hasOneUse(); + Replace1 &= (N0 != N1) && !N1->hasOneUse(); + + // Combine Op here so it is preserved past replacements. + CombineTo(Op.getNode(), RV); + + // If operands have a use ordering, make sure we deal with + // predecessor first. + if (Replace0 && Replace1 && N0.getNode()->isPredecessorOf(N1.getNode())) { + std::swap(N0, N1); + std::swap(NN0, NN1); + } + + if (Replace0) { + AddToWorklist(NN0.getNode()); + ReplaceLoadWithPromotedLoad(N0.getNode(), NN0.getNode()); + } + if (Replace1) { + AddToWorklist(NN1.getNode()); + ReplaceLoadWithPromotedLoad(N1.getNode(), NN1.getNode()); + } + return Op; + } + return SDValue(); +} + +/// Promote the specified integer shift operation if the target indicates it is +/// beneficial. e.g. On x86, it's usually better to promote i16 operations to +/// i32 since i16 instructions are longer. +SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) { + if (!LegalOperations) + return SDValue(); + + EVT VT = Op.getValueType(); + if (VT.isVector() || !VT.isInteger()) + return SDValue(); + + // If operation type is 'undesirable', e.g. i16 on x86, consider + // promoting it. + unsigned Opc = Op.getOpcode(); + if (TLI.isTypeDesirableForOp(Opc, VT)) + return SDValue(); + + EVT PVT = VT; + // Consult target whether it is a good idea to promote this operation and + // what's the right type to promote it to. + if (TLI.IsDesirableToPromoteOp(Op, PVT)) { + assert(PVT != VT && "Don't know what type to promote to!"); + + LLVM_DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG)); + + bool Replace = false; + SDValue N0 = Op.getOperand(0); + SDValue N1 = Op.getOperand(1); + if (Opc == ISD::SRA) + N0 = SExtPromoteOperand(N0, PVT); + else if (Opc == ISD::SRL) + N0 = ZExtPromoteOperand(N0, PVT); + else + N0 = PromoteOperand(N0, PVT, Replace); + + if (!N0.getNode()) + return SDValue(); + + SDLoc DL(Op); + SDValue RV = + DAG.getNode(ISD::TRUNCATE, DL, VT, DAG.getNode(Opc, DL, PVT, N0, N1)); + + if (Replace) + ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode()); + + // Deal with Op being deleted. + if (Op && Op.getOpcode() != ISD::DELETED_NODE) + return RV; + } + return SDValue(); +} + +SDValue DAGCombiner::PromoteExtend(SDValue Op) { + if (!LegalOperations) + return SDValue(); + + EVT VT = Op.getValueType(); + if (VT.isVector() || !VT.isInteger()) + return SDValue(); + + // If operation type is 'undesirable', e.g. i16 on x86, consider + // promoting it. + unsigned Opc = Op.getOpcode(); + if (TLI.isTypeDesirableForOp(Opc, VT)) + return SDValue(); + + EVT PVT = VT; + // Consult target whether it is a good idea to promote this operation and + // what's the right type to promote it to. + if (TLI.IsDesirableToPromoteOp(Op, PVT)) { + assert(PVT != VT && "Don't know what type to promote to!"); + // fold (aext (aext x)) -> (aext x) + // fold (aext (zext x)) -> (zext x) + // fold (aext (sext x)) -> (sext x) + LLVM_DEBUG(dbgs() << "\nPromoting "; Op.getNode()->dump(&DAG)); + return DAG.getNode(Op.getOpcode(), SDLoc(Op), VT, Op.getOperand(0)); + } + return SDValue(); +} + +bool DAGCombiner::PromoteLoad(SDValue Op) { + if (!LegalOperations) + return false; + + if (!ISD::isUNINDEXEDLoad(Op.getNode())) + return false; + + EVT VT = Op.getValueType(); + if (VT.isVector() || !VT.isInteger()) + return false; + + // If operation type is 'undesirable', e.g. i16 on x86, consider + // promoting it. + unsigned Opc = Op.getOpcode(); + if (TLI.isTypeDesirableForOp(Opc, VT)) + return false; + + EVT PVT = VT; + // Consult target whether it is a good idea to promote this operation and + // what's the right type to promote it to. + if (TLI.IsDesirableToPromoteOp(Op, PVT)) { + assert(PVT != VT && "Don't know what type to promote to!"); + + SDLoc DL(Op); + SDNode *N = Op.getNode(); + LoadSDNode *LD = cast<LoadSDNode>(N); + EVT MemVT = LD->getMemoryVT(); + ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD) ? ISD::EXTLOAD + : LD->getExtensionType(); + SDValue NewLD = DAG.getExtLoad(ExtType, DL, PVT, + LD->getChain(), LD->getBasePtr(), + MemVT, LD->getMemOperand()); + SDValue Result = DAG.getNode(ISD::TRUNCATE, DL, VT, NewLD); + + LLVM_DEBUG(dbgs() << "\nPromoting "; N->dump(&DAG); dbgs() << "\nTo: "; + Result.getNode()->dump(&DAG); dbgs() << '\n'); + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), NewLD.getValue(1)); + deleteAndRecombine(N); + AddToWorklist(Result.getNode()); + return true; + } + return false; +} + +/// Recursively delete a node which has no uses and any operands for +/// which it is the only use. +/// +/// Note that this both deletes the nodes and removes them from the worklist. +/// It also adds any nodes who have had a user deleted to the worklist as they +/// may now have only one use and subject to other combines. +bool DAGCombiner::recursivelyDeleteUnusedNodes(SDNode *N) { + if (!N->use_empty()) + return false; + + SmallSetVector<SDNode *, 16> Nodes; + Nodes.insert(N); + do { + N = Nodes.pop_back_val(); + if (!N) + continue; + + if (N->use_empty()) { + for (const SDValue &ChildN : N->op_values()) + Nodes.insert(ChildN.getNode()); + + removeFromWorklist(N); + DAG.DeleteNode(N); + } else { + AddToWorklist(N); + } + } while (!Nodes.empty()); + return true; +} + +//===----------------------------------------------------------------------===// +// Main DAG Combiner implementation +//===----------------------------------------------------------------------===// + +void DAGCombiner::Run(CombineLevel AtLevel) { + // set the instance variables, so that the various visit routines may use it. + Level = AtLevel; + LegalDAG = Level >= AfterLegalizeDAG; + LegalOperations = Level >= AfterLegalizeVectorOps; + LegalTypes = Level >= AfterLegalizeTypes; + + WorklistInserter AddNodes(*this); + + // Add all the dag nodes to the worklist. + for (SDNode &Node : DAG.allnodes()) + AddToWorklist(&Node); + + // Create a dummy node (which is not added to allnodes), that adds a reference + // to the root node, preventing it from being deleted, and tracking any + // changes of the root. + HandleSDNode Dummy(DAG.getRoot()); + + // While we have a valid worklist entry node, try to combine it. + while (SDNode *N = getNextWorklistEntry()) { + // If N has no uses, it is dead. Make sure to revisit all N's operands once + // N is deleted from the DAG, since they too may now be dead or may have a + // reduced number of uses, allowing other xforms. + if (recursivelyDeleteUnusedNodes(N)) + continue; + + WorklistRemover DeadNodes(*this); + + // If this combine is running after legalizing the DAG, re-legalize any + // nodes pulled off the worklist. + if (LegalDAG) { + SmallSetVector<SDNode *, 16> UpdatedNodes; + bool NIsValid = DAG.LegalizeOp(N, UpdatedNodes); + + for (SDNode *LN : UpdatedNodes) + AddToWorklistWithUsers(LN); + + if (!NIsValid) + continue; + } + + LLVM_DEBUG(dbgs() << "\nCombining: "; N->dump(&DAG)); + + // Add any operands of the new node which have not yet been combined to the + // worklist as well. Because the worklist uniques things already, this + // won't repeatedly process the same operand. + CombinedNodes.insert(N); + for (const SDValue &ChildN : N->op_values()) + if (!CombinedNodes.count(ChildN.getNode())) + AddToWorklist(ChildN.getNode()); + + SDValue RV = combine(N); + + if (!RV.getNode()) + continue; + + ++NodesCombined; + + // If we get back the same node we passed in, rather than a new node or + // zero, we know that the node must have defined multiple values and + // CombineTo was used. Since CombineTo takes care of the worklist + // mechanics for us, we have no work to do in this case. + if (RV.getNode() == N) + continue; + + assert(N->getOpcode() != ISD::DELETED_NODE && + RV.getOpcode() != ISD::DELETED_NODE && + "Node was deleted but visit returned new node!"); + + LLVM_DEBUG(dbgs() << " ... into: "; RV.getNode()->dump(&DAG)); + + if (N->getNumValues() == RV.getNode()->getNumValues()) + DAG.ReplaceAllUsesWith(N, RV.getNode()); + else { + assert(N->getValueType(0) == RV.getValueType() && + N->getNumValues() == 1 && "Type mismatch"); + DAG.ReplaceAllUsesWith(N, &RV); + } + + // Push the new node and any users onto the worklist. Omit this if the + // new node is the EntryToken (e.g. if a store managed to get optimized + // out), because re-visiting the EntryToken and its users will not uncover + // any additional opportunities, but there may be a large number of such + // users, potentially causing compile time explosion. + if (RV.getOpcode() != ISD::EntryToken) { + AddToWorklist(RV.getNode()); + AddUsersToWorklist(RV.getNode()); + } + + // Finally, if the node is now dead, remove it from the graph. The node + // may not be dead if the replacement process recursively simplified to + // something else needing this node. This will also take care of adding any + // operands which have lost a user to the worklist. + recursivelyDeleteUnusedNodes(N); + } + + // If the root changed (e.g. it was a dead load, update the root). + DAG.setRoot(Dummy.getValue()); + DAG.RemoveDeadNodes(); +} + +SDValue DAGCombiner::visit(SDNode *N) { + switch (N->getOpcode()) { + default: break; + case ISD::TokenFactor: return visitTokenFactor(N); + case ISD::MERGE_VALUES: return visitMERGE_VALUES(N); + case ISD::ADD: return visitADD(N); + case ISD::SUB: return visitSUB(N); + case ISD::SADDSAT: + case ISD::UADDSAT: return visitADDSAT(N); + case ISD::SSUBSAT: + case ISD::USUBSAT: return visitSUBSAT(N); + case ISD::ADDC: return visitADDC(N); + case ISD::SADDO: + case ISD::UADDO: return visitADDO(N); + case ISD::SUBC: return visitSUBC(N); + case ISD::SSUBO: + case ISD::USUBO: return visitSUBO(N); + case ISD::ADDE: return visitADDE(N); + case ISD::ADDCARRY: return visitADDCARRY(N); + case ISD::SADDO_CARRY: return visitSADDO_CARRY(N); + case ISD::SUBE: return visitSUBE(N); + case ISD::SUBCARRY: return visitSUBCARRY(N); + case ISD::SSUBO_CARRY: return visitSSUBO_CARRY(N); + case ISD::SMULFIX: + case ISD::SMULFIXSAT: + case ISD::UMULFIX: + case ISD::UMULFIXSAT: return visitMULFIX(N); + case ISD::MUL: return visitMUL(N); + case ISD::SDIV: return visitSDIV(N); + case ISD::UDIV: return visitUDIV(N); + case ISD::SREM: + case ISD::UREM: return visitREM(N); + case ISD::MULHU: return visitMULHU(N); + case ISD::MULHS: return visitMULHS(N); + case ISD::SMUL_LOHI: return visitSMUL_LOHI(N); + case ISD::UMUL_LOHI: return visitUMUL_LOHI(N); + case ISD::SMULO: + case ISD::UMULO: return visitMULO(N); + case ISD::SMIN: + case ISD::SMAX: + case ISD::UMIN: + case ISD::UMAX: return visitIMINMAX(N); + case ISD::AND: return visitAND(N); + case ISD::OR: return visitOR(N); + case ISD::XOR: return visitXOR(N); + case ISD::SHL: return visitSHL(N); + case ISD::SRA: return visitSRA(N); + case ISD::SRL: return visitSRL(N); + case ISD::ROTR: + case ISD::ROTL: return visitRotate(N); + case ISD::FSHL: + case ISD::FSHR: return visitFunnelShift(N); + case ISD::ABS: return visitABS(N); + case ISD::BSWAP: return visitBSWAP(N); + case ISD::BITREVERSE: return visitBITREVERSE(N); + case ISD::CTLZ: return visitCTLZ(N); + case ISD::CTLZ_ZERO_UNDEF: return visitCTLZ_ZERO_UNDEF(N); + case ISD::CTTZ: return visitCTTZ(N); + case ISD::CTTZ_ZERO_UNDEF: return visitCTTZ_ZERO_UNDEF(N); + case ISD::CTPOP: return visitCTPOP(N); + case ISD::SELECT: return visitSELECT(N); + case ISD::VSELECT: return visitVSELECT(N); + case ISD::SELECT_CC: return visitSELECT_CC(N); + case ISD::SETCC: return visitSETCC(N); + case ISD::SETCCCARRY: return visitSETCCCARRY(N); + case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); + case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); + case ISD::ANY_EXTEND: return visitANY_EXTEND(N); + case ISD::AssertSext: + case ISD::AssertZext: return visitAssertExt(N); + case ISD::AssertAlign: return visitAssertAlign(N); + case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); + case ISD::SIGN_EXTEND_VECTOR_INREG: return visitSIGN_EXTEND_VECTOR_INREG(N); + case ISD::ZERO_EXTEND_VECTOR_INREG: return visitZERO_EXTEND_VECTOR_INREG(N); + case ISD::TRUNCATE: return visitTRUNCATE(N); + case ISD::BITCAST: return visitBITCAST(N); + case ISD::BUILD_PAIR: return visitBUILD_PAIR(N); + case ISD::FADD: return visitFADD(N); + case ISD::STRICT_FADD: return visitSTRICT_FADD(N); + case ISD::FSUB: return visitFSUB(N); + case ISD::FMUL: return visitFMUL(N); + case ISD::FMA: return visitFMA(N); + case ISD::FDIV: return visitFDIV(N); + case ISD::FREM: return visitFREM(N); + case ISD::FSQRT: return visitFSQRT(N); + case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); + case ISD::FPOW: return visitFPOW(N); + case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); + case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); + case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); + case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); + case ISD::FP_ROUND: return visitFP_ROUND(N); + case ISD::FP_EXTEND: return visitFP_EXTEND(N); + case ISD::FNEG: return visitFNEG(N); + case ISD::FABS: return visitFABS(N); + case ISD::FFLOOR: return visitFFLOOR(N); + case ISD::FMINNUM: return visitFMINNUM(N); + case ISD::FMAXNUM: return visitFMAXNUM(N); + case ISD::FMINIMUM: return visitFMINIMUM(N); + case ISD::FMAXIMUM: return visitFMAXIMUM(N); + case ISD::FCEIL: return visitFCEIL(N); + case ISD::FTRUNC: return visitFTRUNC(N); + case ISD::BRCOND: return visitBRCOND(N); + case ISD::BR_CC: return visitBR_CC(N); + case ISD::LOAD: return visitLOAD(N); + case ISD::STORE: return visitSTORE(N); + case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); + case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N); + case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N); + case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); + case ISD::EXTRACT_SUBVECTOR: return visitEXTRACT_SUBVECTOR(N); + case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); + case ISD::SCALAR_TO_VECTOR: return visitSCALAR_TO_VECTOR(N); + case ISD::INSERT_SUBVECTOR: return visitINSERT_SUBVECTOR(N); + case ISD::MGATHER: return visitMGATHER(N); + case ISD::MLOAD: return visitMLOAD(N); + case ISD::MSCATTER: return visitMSCATTER(N); + case ISD::MSTORE: return visitMSTORE(N); + case ISD::LIFETIME_END: return visitLIFETIME_END(N); + case ISD::FP_TO_FP16: return visitFP_TO_FP16(N); + case ISD::FP16_TO_FP: return visitFP16_TO_FP(N); + case ISD::FREEZE: return visitFREEZE(N); + case ISD::VECREDUCE_FADD: + case ISD::VECREDUCE_FMUL: + case ISD::VECREDUCE_ADD: + case ISD::VECREDUCE_MUL: + case ISD::VECREDUCE_AND: + case ISD::VECREDUCE_OR: + case ISD::VECREDUCE_XOR: + case ISD::VECREDUCE_SMAX: + case ISD::VECREDUCE_SMIN: + case ISD::VECREDUCE_UMAX: + case ISD::VECREDUCE_UMIN: + case ISD::VECREDUCE_FMAX: + case ISD::VECREDUCE_FMIN: return visitVECREDUCE(N); + } + return SDValue(); +} + +SDValue DAGCombiner::combine(SDNode *N) { + SDValue RV; + if (!DisableGenericCombines) + RV = visit(N); + + // If nothing happened, try a target-specific DAG combine. + if (!RV.getNode()) { + assert(N->getOpcode() != ISD::DELETED_NODE && + "Node was deleted but visit returned NULL!"); + + if (N->getOpcode() >= ISD::BUILTIN_OP_END || + TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) { + + // Expose the DAG combiner to the target combiner impls. + TargetLowering::DAGCombinerInfo + DagCombineInfo(DAG, Level, false, this); + + RV = TLI.PerformDAGCombine(N, DagCombineInfo); + } + } + + // If nothing happened still, try promoting the operation. + if (!RV.getNode()) { + switch (N->getOpcode()) { + default: break; + case ISD::ADD: + case ISD::SUB: + case ISD::MUL: + case ISD::AND: + case ISD::OR: + case ISD::XOR: + RV = PromoteIntBinOp(SDValue(N, 0)); + break; + case ISD::SHL: + case ISD::SRA: + case ISD::SRL: + RV = PromoteIntShiftOp(SDValue(N, 0)); + break; + case ISD::SIGN_EXTEND: + case ISD::ZERO_EXTEND: + case ISD::ANY_EXTEND: + RV = PromoteExtend(SDValue(N, 0)); + break; + case ISD::LOAD: + if (PromoteLoad(SDValue(N, 0))) + RV = SDValue(N, 0); + break; + } + } + + // If N is a commutative binary node, try to eliminate it if the commuted + // version is already present in the DAG. + if (!RV.getNode() && TLI.isCommutativeBinOp(N->getOpcode()) && + N->getNumValues() == 1) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + + // Constant operands are canonicalized to RHS. + if (N0 != N1 && (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1))) { + SDValue Ops[] = {N1, N0}; + SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(), Ops, + N->getFlags()); + if (CSENode) + return SDValue(CSENode, 0); + } + } + + return RV; +} + +/// Given a node, return its input chain if it has one, otherwise return a null +/// sd operand. +static SDValue getInputChainForNode(SDNode *N) { + if (unsigned NumOps = N->getNumOperands()) { + if (N->getOperand(0).getValueType() == MVT::Other) + return N->getOperand(0); + if (N->getOperand(NumOps-1).getValueType() == MVT::Other) + return N->getOperand(NumOps-1); + for (unsigned i = 1; i < NumOps-1; ++i) + if (N->getOperand(i).getValueType() == MVT::Other) + return N->getOperand(i); + } + return SDValue(); +} + +SDValue DAGCombiner::visitTokenFactor(SDNode *N) { + // If N has two operands, where one has an input chain equal to the other, + // the 'other' chain is redundant. + if (N->getNumOperands() == 2) { + if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1)) + return N->getOperand(0); + if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0)) + return N->getOperand(1); + } + + // Don't simplify token factors if optnone. + if (OptLevel == CodeGenOpt::None) + return SDValue(); + + // Don't simplify the token factor if the node itself has too many operands. + if (N->getNumOperands() > TokenFactorInlineLimit) + return SDValue(); + + // If the sole user is a token factor, we should make sure we have a + // chance to merge them together. This prevents TF chains from inhibiting + // optimizations. + if (N->hasOneUse() && N->use_begin()->getOpcode() == ISD::TokenFactor) + AddToWorklist(*(N->use_begin())); + + SmallVector<SDNode *, 8> TFs; // List of token factors to visit. + SmallVector<SDValue, 8> Ops; // Ops for replacing token factor. + SmallPtrSet<SDNode*, 16> SeenOps; + bool Changed = false; // If we should replace this token factor. + + // Start out with this token factor. + TFs.push_back(N); + + // Iterate through token factors. The TFs grows when new token factors are + // encountered. + for (unsigned i = 0; i < TFs.size(); ++i) { + // Limit number of nodes to inline, to avoid quadratic compile times. + // We have to add the outstanding Token Factors to Ops, otherwise we might + // drop Ops from the resulting Token Factors. + if (Ops.size() > TokenFactorInlineLimit) { + for (unsigned j = i; j < TFs.size(); j++) + Ops.emplace_back(TFs[j], 0); + // Drop unprocessed Token Factors from TFs, so we do not add them to the + // combiner worklist later. + TFs.resize(i); + break; + } + + SDNode *TF = TFs[i]; + // Check each of the operands. + for (const SDValue &Op : TF->op_values()) { + switch (Op.getOpcode()) { + case ISD::EntryToken: + // Entry tokens don't need to be added to the list. They are + // redundant. + Changed = true; + break; + + case ISD::TokenFactor: + if (Op.hasOneUse() && !is_contained(TFs, Op.getNode())) { + // Queue up for processing. + TFs.push_back(Op.getNode()); + Changed = true; + break; + } + LLVM_FALLTHROUGH; + + default: + // Only add if it isn't already in the list. + if (SeenOps.insert(Op.getNode()).second) + Ops.push_back(Op); + else + Changed = true; + break; + } + } + } + + // Re-visit inlined Token Factors, to clean them up in case they have been + // removed. Skip the first Token Factor, as this is the current node. + for (unsigned i = 1, e = TFs.size(); i < e; i++) + AddToWorklist(TFs[i]); + + // Remove Nodes that are chained to another node in the list. Do so + // by walking up chains breath-first stopping when we've seen + // another operand. In general we must climb to the EntryNode, but we can exit + // early if we find all remaining work is associated with just one operand as + // no further pruning is possible. + + // List of nodes to search through and original Ops from which they originate. + SmallVector<std::pair<SDNode *, unsigned>, 8> Worklist; + SmallVector<unsigned, 8> OpWorkCount; // Count of work for each Op. + SmallPtrSet<SDNode *, 16> SeenChains; + bool DidPruneOps = false; + + unsigned NumLeftToConsider = 0; + for (const SDValue &Op : Ops) { + Worklist.push_back(std::make_pair(Op.getNode(), NumLeftToConsider++)); + OpWorkCount.push_back(1); + } + + auto AddToWorklist = [&](unsigned CurIdx, SDNode *Op, unsigned OpNumber) { + // If this is an Op, we can remove the op from the list. Remark any + // search associated with it as from the current OpNumber. + if (SeenOps.contains(Op)) { + Changed = true; + DidPruneOps = true; + unsigned OrigOpNumber = 0; + while (OrigOpNumber < Ops.size() && Ops[OrigOpNumber].getNode() != Op) + OrigOpNumber++; + assert((OrigOpNumber != Ops.size()) && + "expected to find TokenFactor Operand"); + // Re-mark worklist from OrigOpNumber to OpNumber + for (unsigned i = CurIdx + 1; i < Worklist.size(); ++i) { + if (Worklist[i].second == OrigOpNumber) { + Worklist[i].second = OpNumber; + } + } + OpWorkCount[OpNumber] += OpWorkCount[OrigOpNumber]; + OpWorkCount[OrigOpNumber] = 0; + NumLeftToConsider--; + } + // Add if it's a new chain + if (SeenChains.insert(Op).second) { + OpWorkCount[OpNumber]++; + Worklist.push_back(std::make_pair(Op, OpNumber)); + } + }; + + for (unsigned i = 0; i < Worklist.size() && i < 1024; ++i) { + // We need at least be consider at least 2 Ops to prune. + if (NumLeftToConsider <= 1) + break; + auto CurNode = Worklist[i].first; + auto CurOpNumber = Worklist[i].second; + assert((OpWorkCount[CurOpNumber] > 0) && + "Node should not appear in worklist"); + switch (CurNode->getOpcode()) { + case ISD::EntryToken: + // Hitting EntryToken is the only way for the search to terminate without + // hitting + // another operand's search. Prevent us from marking this operand + // considered. + NumLeftToConsider++; + break; + case ISD::TokenFactor: + for (const SDValue &Op : CurNode->op_values()) + AddToWorklist(i, Op.getNode(), CurOpNumber); + break; + case ISD::LIFETIME_START: + case ISD::LIFETIME_END: + case ISD::CopyFromReg: + case ISD::CopyToReg: + AddToWorklist(i, CurNode->getOperand(0).getNode(), CurOpNumber); + break; + default: + if (auto *MemNode = dyn_cast<MemSDNode>(CurNode)) + AddToWorklist(i, MemNode->getChain().getNode(), CurOpNumber); + break; + } + OpWorkCount[CurOpNumber]--; + if (OpWorkCount[CurOpNumber] == 0) + NumLeftToConsider--; + } + + // If we've changed things around then replace token factor. + if (Changed) { + SDValue Result; + if (Ops.empty()) { + // The entry token is the only possible outcome. + Result = DAG.getEntryNode(); + } else { + if (DidPruneOps) { + SmallVector<SDValue, 8> PrunedOps; + // + for (const SDValue &Op : Ops) { + if (SeenChains.count(Op.getNode()) == 0) + PrunedOps.push_back(Op); + } + Result = DAG.getTokenFactor(SDLoc(N), PrunedOps); + } else { + Result = DAG.getTokenFactor(SDLoc(N), Ops); + } + } + return Result; + } + return SDValue(); +} + +/// MERGE_VALUES can always be eliminated. +SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) { + WorklistRemover DeadNodes(*this); + // Replacing results may cause a different MERGE_VALUES to suddenly + // be CSE'd with N, and carry its uses with it. Iterate until no + // uses remain, to ensure that the node can be safely deleted. + // First add the users of this node to the work list so that they + // can be tried again once they have new operands. + AddUsersToWorklist(N); + do { + // Do as a single replacement to avoid rewalking use lists. + SmallVector<SDValue, 8> Ops; + for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) + Ops.push_back(N->getOperand(i)); + DAG.ReplaceAllUsesWith(N, Ops.data()); + } while (!N->use_empty()); + deleteAndRecombine(N); + return SDValue(N, 0); // Return N so it doesn't get rechecked! +} + +/// If \p N is a ConstantSDNode with isOpaque() == false return it casted to a +/// ConstantSDNode pointer else nullptr. +static ConstantSDNode *getAsNonOpaqueConstant(SDValue N) { + ConstantSDNode *Const = dyn_cast<ConstantSDNode>(N); + return Const != nullptr && !Const->isOpaque() ? Const : nullptr; +} + +/// Return true if 'Use' is a load or a store that uses N as its base pointer +/// and that N may be folded in the load / store addressing mode. +static bool canFoldInAddressingMode(SDNode *N, SDNode *Use, SelectionDAG &DAG, + const TargetLowering &TLI) { + EVT VT; + unsigned AS; + + if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Use)) { + if (LD->isIndexed() || LD->getBasePtr().getNode() != N) + return false; + VT = LD->getMemoryVT(); + AS = LD->getAddressSpace(); + } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(Use)) { + if (ST->isIndexed() || ST->getBasePtr().getNode() != N) + return false; + VT = ST->getMemoryVT(); + AS = ST->getAddressSpace(); + } else if (MaskedLoadSDNode *LD = dyn_cast<MaskedLoadSDNode>(Use)) { + if (LD->isIndexed() || LD->getBasePtr().getNode() != N) + return false; + VT = LD->getMemoryVT(); + AS = LD->getAddressSpace(); + } else if (MaskedStoreSDNode *ST = dyn_cast<MaskedStoreSDNode>(Use)) { + if (ST->isIndexed() || ST->getBasePtr().getNode() != N) + return false; + VT = ST->getMemoryVT(); + AS = ST->getAddressSpace(); + } else + return false; + + TargetLowering::AddrMode AM; + if (N->getOpcode() == ISD::ADD) { + AM.HasBaseReg = true; + ConstantSDNode *Offset = dyn_cast<ConstantSDNode>(N->getOperand(1)); + if (Offset) + // [reg +/- imm] + AM.BaseOffs = Offset->getSExtValue(); + else + // [reg +/- reg] + AM.Scale = 1; + } else if (N->getOpcode() == ISD::SUB) { + AM.HasBaseReg = true; + ConstantSDNode *Offset = dyn_cast<ConstantSDNode>(N->getOperand(1)); + if (Offset) + // [reg +/- imm] + AM.BaseOffs = -Offset->getSExtValue(); + else + // [reg +/- reg] + AM.Scale = 1; + } else + return false; + + return TLI.isLegalAddressingMode(DAG.getDataLayout(), AM, + VT.getTypeForEVT(*DAG.getContext()), AS); +} + +SDValue DAGCombiner::foldBinOpIntoSelect(SDNode *BO) { + assert(TLI.isBinOp(BO->getOpcode()) && BO->getNumValues() == 1 && + "Unexpected binary operator"); + + // Don't do this unless the old select is going away. We want to eliminate the + // binary operator, not replace a binop with a select. + // TODO: Handle ISD::SELECT_CC. + unsigned SelOpNo = 0; + SDValue Sel = BO->getOperand(0); + if (Sel.getOpcode() != ISD::SELECT || !Sel.hasOneUse()) { + SelOpNo = 1; + Sel = BO->getOperand(1); + } + + if (Sel.getOpcode() != ISD::SELECT || !Sel.hasOneUse()) + return SDValue(); + + SDValue CT = Sel.getOperand(1); + if (!isConstantOrConstantVector(CT, true) && + !DAG.isConstantFPBuildVectorOrConstantFP(CT)) + return SDValue(); + + SDValue CF = Sel.getOperand(2); + if (!isConstantOrConstantVector(CF, true) && + !DAG.isConstantFPBuildVectorOrConstantFP(CF)) + return SDValue(); + + // Bail out if any constants are opaque because we can't constant fold those. + // The exception is "and" and "or" with either 0 or -1 in which case we can + // propagate non constant operands into select. I.e.: + // and (select Cond, 0, -1), X --> select Cond, 0, X + // or X, (select Cond, -1, 0) --> select Cond, -1, X + auto BinOpcode = BO->getOpcode(); + bool CanFoldNonConst = + (BinOpcode == ISD::AND || BinOpcode == ISD::OR) && + (isNullOrNullSplat(CT) || isAllOnesOrAllOnesSplat(CT)) && + (isNullOrNullSplat(CF) || isAllOnesOrAllOnesSplat(CF)); + + SDValue CBO = BO->getOperand(SelOpNo ^ 1); + if (!CanFoldNonConst && + !isConstantOrConstantVector(CBO, true) && + !DAG.isConstantFPBuildVectorOrConstantFP(CBO)) + return SDValue(); + + EVT VT = BO->getValueType(0); + + // We have a select-of-constants followed by a binary operator with a + // constant. Eliminate the binop by pulling the constant math into the select. + // Example: add (select Cond, CT, CF), CBO --> select Cond, CT + CBO, CF + CBO + SDLoc DL(Sel); + SDValue NewCT = SelOpNo ? DAG.getNode(BinOpcode, DL, VT, CBO, CT) + : DAG.getNode(BinOpcode, DL, VT, CT, CBO); + if (!CanFoldNonConst && !NewCT.isUndef() && + !isConstantOrConstantVector(NewCT, true) && + !DAG.isConstantFPBuildVectorOrConstantFP(NewCT)) + return SDValue(); + + SDValue NewCF = SelOpNo ? DAG.getNode(BinOpcode, DL, VT, CBO, CF) + : DAG.getNode(BinOpcode, DL, VT, CF, CBO); + if (!CanFoldNonConst && !NewCF.isUndef() && + !isConstantOrConstantVector(NewCF, true) && + !DAG.isConstantFPBuildVectorOrConstantFP(NewCF)) + return SDValue(); + + SDValue SelectOp = DAG.getSelect(DL, VT, Sel.getOperand(0), NewCT, NewCF); + SelectOp->setFlags(BO->getFlags()); + return SelectOp; +} + +static SDValue foldAddSubBoolOfMaskedVal(SDNode *N, SelectionDAG &DAG) { + assert((N->getOpcode() == ISD::ADD || N->getOpcode() == ISD::SUB) && + "Expecting add or sub"); + + // Match a constant operand and a zext operand for the math instruction: + // add Z, C + // sub C, Z + bool IsAdd = N->getOpcode() == ISD::ADD; + SDValue C = IsAdd ? N->getOperand(1) : N->getOperand(0); + SDValue Z = IsAdd ? N->getOperand(0) : N->getOperand(1); + auto *CN = dyn_cast<ConstantSDNode>(C); + if (!CN || Z.getOpcode() != ISD::ZERO_EXTEND) + return SDValue(); + + // Match the zext operand as a setcc of a boolean. + if (Z.getOperand(0).getOpcode() != ISD::SETCC || + Z.getOperand(0).getValueType() != MVT::i1) + return SDValue(); + + // Match the compare as: setcc (X & 1), 0, eq. + SDValue SetCC = Z.getOperand(0); + ISD::CondCode CC = cast<CondCodeSDNode>(SetCC->getOperand(2))->get(); + if (CC != ISD::SETEQ || !isNullConstant(SetCC.getOperand(1)) || + SetCC.getOperand(0).getOpcode() != ISD::AND || + !isOneConstant(SetCC.getOperand(0).getOperand(1))) + return SDValue(); + + // We are adding/subtracting a constant and an inverted low bit. Turn that + // into a subtract/add of the low bit with incremented/decremented constant: + // add (zext i1 (seteq (X & 1), 0)), C --> sub C+1, (zext (X & 1)) + // sub C, (zext i1 (seteq (X & 1), 0)) --> add C-1, (zext (X & 1)) + EVT VT = C.getValueType(); + SDLoc DL(N); + SDValue LowBit = DAG.getZExtOrTrunc(SetCC.getOperand(0), DL, VT); + SDValue C1 = IsAdd ? DAG.getConstant(CN->getAPIntValue() + 1, DL, VT) : + DAG.getConstant(CN->getAPIntValue() - 1, DL, VT); + return DAG.getNode(IsAdd ? ISD::SUB : ISD::ADD, DL, VT, C1, LowBit); +} + +/// Try to fold a 'not' shifted sign-bit with add/sub with constant operand into +/// a shift and add with a different constant. +static SDValue foldAddSubOfSignBit(SDNode *N, SelectionDAG &DAG) { + assert((N->getOpcode() == ISD::ADD || N->getOpcode() == ISD::SUB) && + "Expecting add or sub"); + + // We need a constant operand for the add/sub, and the other operand is a + // logical shift right: add (srl), C or sub C, (srl). + bool IsAdd = N->getOpcode() == ISD::ADD; + SDValue ConstantOp = IsAdd ? N->getOperand(1) : N->getOperand(0); + SDValue ShiftOp = IsAdd ? N->getOperand(0) : N->getOperand(1); + if (!DAG.isConstantIntBuildVectorOrConstantInt(ConstantOp) || + ShiftOp.getOpcode() != ISD::SRL) + return SDValue(); + + // The shift must be of a 'not' value. + SDValue Not = ShiftOp.getOperand(0); + if (!Not.hasOneUse() || !isBitwiseNot(Not)) + return SDValue(); + + // The shift must be moving the sign bit to the least-significant-bit. + EVT VT = ShiftOp.getValueType(); + SDValue ShAmt = ShiftOp.getOperand(1); + ConstantSDNode *ShAmtC = isConstOrConstSplat(ShAmt); + if (!ShAmtC || ShAmtC->getAPIntValue() != (VT.getScalarSizeInBits() - 1)) + return SDValue(); + + // Eliminate the 'not' by adjusting the shift and add/sub constant: + // add (srl (not X), 31), C --> add (sra X, 31), (C + 1) + // sub C, (srl (not X), 31) --> add (srl X, 31), (C - 1) + SDLoc DL(N); + auto ShOpcode = IsAdd ? ISD::SRA : ISD::SRL; + SDValue NewShift = DAG.getNode(ShOpcode, DL, VT, Not.getOperand(0), ShAmt); + if (SDValue NewC = + DAG.FoldConstantArithmetic(IsAdd ? ISD::ADD : ISD::SUB, DL, VT, + {ConstantOp, DAG.getConstant(1, DL, VT)})) + return DAG.getNode(ISD::ADD, DL, VT, NewShift, NewC); + return SDValue(); +} + +/// Try to fold a node that behaves like an ADD (note that N isn't necessarily +/// an ISD::ADD here, it could for example be an ISD::OR if we know that there +/// are no common bits set in the operands). +SDValue DAGCombiner::visitADDLike(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (add x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N1; + } + + // fold (add x, undef) -> undef + if (N0.isUndef()) + return N0; + + if (N1.isUndef()) + return N1; + + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) { + // canonicalize constant to RHS + if (!DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(ISD::ADD, DL, VT, N1, N0); + // fold (add c1, c2) -> c1+c2 + return DAG.FoldConstantArithmetic(ISD::ADD, DL, VT, {N0, N1}); + } + + // fold (add x, 0) -> x + if (isNullConstant(N1)) + return N0; + + if (isConstantOrConstantVector(N1, /* NoOpaque */ true)) { + // fold ((A-c1)+c2) -> (A+(c2-c1)) + if (N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(1), /* NoOpaque */ true)) { + SDValue Sub = + DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N1, N0.getOperand(1)}); + assert(Sub && "Constant folding failed"); + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), Sub); + } + + // fold ((c1-A)+c2) -> (c1+c2)-A + if (N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(0), /* NoOpaque */ true)) { + SDValue Add = + DAG.FoldConstantArithmetic(ISD::ADD, DL, VT, {N1, N0.getOperand(0)}); + assert(Add && "Constant folding failed"); + return DAG.getNode(ISD::SUB, DL, VT, Add, N0.getOperand(1)); + } + + // add (sext i1 X), 1 -> zext (not i1 X) + // We don't transform this pattern: + // add (zext i1 X), -1 -> sext (not i1 X) + // because most (?) targets generate better code for the zext form. + if (N0.getOpcode() == ISD::SIGN_EXTEND && N0.hasOneUse() && + isOneOrOneSplat(N1)) { + SDValue X = N0.getOperand(0); + if ((!LegalOperations || + (TLI.isOperationLegal(ISD::XOR, X.getValueType()) && + TLI.isOperationLegal(ISD::ZERO_EXTEND, VT))) && + X.getScalarValueSizeInBits() == 1) { + SDValue Not = DAG.getNOT(DL, X, X.getValueType()); + return DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Not); + } + } + + // Fold (add (or x, c0), c1) -> (add x, (c0 + c1)) if (or x, c0) is + // equivalent to (add x, c0). + if (N0.getOpcode() == ISD::OR && + isConstantOrConstantVector(N0.getOperand(1), /* NoOpaque */ true) && + DAG.haveNoCommonBitsSet(N0.getOperand(0), N0.getOperand(1))) { + if (SDValue Add0 = DAG.FoldConstantArithmetic(ISD::ADD, DL, VT, + {N1, N0.getOperand(1)})) + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), Add0); + } + } + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // reassociate add + if (!reassociationCanBreakAddressingModePattern(ISD::ADD, DL, N0, N1)) { + if (SDValue RADD = reassociateOps(ISD::ADD, DL, N0, N1, N->getFlags())) + return RADD; + } + // fold ((0-A) + B) -> B-A + if (N0.getOpcode() == ISD::SUB && isNullOrNullSplat(N0.getOperand(0))) + return DAG.getNode(ISD::SUB, DL, VT, N1, N0.getOperand(1)); + + // fold (A + (0-B)) -> A-B + if (N1.getOpcode() == ISD::SUB && isNullOrNullSplat(N1.getOperand(0))) + return DAG.getNode(ISD::SUB, DL, VT, N0, N1.getOperand(1)); + + // fold (A+(B-A)) -> B + if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) + return N1.getOperand(0); + + // fold ((B-A)+A) -> B + if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1)) + return N0.getOperand(0); + + // fold ((A-B)+(C-A)) -> (C-B) + if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB && + N0.getOperand(0) == N1.getOperand(1)) + return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0), + N0.getOperand(1)); + + // fold ((A-B)+(B-C)) -> (A-C) + if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB && + N0.getOperand(1) == N1.getOperand(0)) + return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), + N1.getOperand(1)); + + // fold (A+(B-(A+C))) to (B-C) + if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && + N0 == N1.getOperand(1).getOperand(0)) + return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0), + N1.getOperand(1).getOperand(1)); + + // fold (A+(B-(C+A))) to (B-C) + if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && + N0 == N1.getOperand(1).getOperand(1)) + return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0), + N1.getOperand(1).getOperand(0)); + + // fold (A+((B-A)+or-C)) to (B+or-C) + if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) && + N1.getOperand(0).getOpcode() == ISD::SUB && + N0 == N1.getOperand(0).getOperand(1)) + return DAG.getNode(N1.getOpcode(), DL, VT, N1.getOperand(0).getOperand(0), + N1.getOperand(1)); + + // fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant + if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) { + SDValue N00 = N0.getOperand(0); + SDValue N01 = N0.getOperand(1); + SDValue N10 = N1.getOperand(0); + SDValue N11 = N1.getOperand(1); + + if (isConstantOrConstantVector(N00) || isConstantOrConstantVector(N10)) + return DAG.getNode(ISD::SUB, DL, VT, + DAG.getNode(ISD::ADD, SDLoc(N0), VT, N00, N10), + DAG.getNode(ISD::ADD, SDLoc(N1), VT, N01, N11)); + } + + // fold (add (umax X, C), -C) --> (usubsat X, C) + if (N0.getOpcode() == ISD::UMAX && hasOperation(ISD::USUBSAT, VT)) { + auto MatchUSUBSAT = [](ConstantSDNode *Max, ConstantSDNode *Op) { + return (!Max && !Op) || + (Max && Op && Max->getAPIntValue() == (-Op->getAPIntValue())); + }; + if (ISD::matchBinaryPredicate(N0.getOperand(1), N1, MatchUSUBSAT, + /*AllowUndefs*/ true)) + return DAG.getNode(ISD::USUBSAT, DL, VT, N0.getOperand(0), + N0.getOperand(1)); + } + + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + if (isOneOrOneSplat(N1)) { + // fold (add (xor a, -1), 1) -> (sub 0, a) + if (isBitwiseNot(N0)) + return DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), + N0.getOperand(0)); + + // fold (add (add (xor a, -1), b), 1) -> (sub b, a) + if (N0.getOpcode() == ISD::ADD || + N0.getOpcode() == ISD::UADDO || + N0.getOpcode() == ISD::SADDO) { + SDValue A, Xor; + + if (isBitwiseNot(N0.getOperand(0))) { + A = N0.getOperand(1); + Xor = N0.getOperand(0); + } else if (isBitwiseNot(N0.getOperand(1))) { + A = N0.getOperand(0); + Xor = N0.getOperand(1); + } + + if (Xor) + return DAG.getNode(ISD::SUB, DL, VT, A, Xor.getOperand(0)); + } + + // Look for: + // add (add x, y), 1 + // And if the target does not like this form then turn into: + // sub y, (xor x, -1) + if (!TLI.preferIncOfAddToSubOfNot(VT) && N0.hasOneUse() && + N0.getOpcode() == ISD::ADD) { + SDValue Not = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(0), + DAG.getAllOnesConstant(DL, VT)); + return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(1), Not); + } + } + + // (x - y) + -1 -> add (xor y, -1), x + if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && + isAllOnesOrAllOnesSplat(N1)) { + SDValue Xor = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(1), N1); + return DAG.getNode(ISD::ADD, DL, VT, Xor, N0.getOperand(0)); + } + + if (SDValue Combined = visitADDLikeCommutative(N0, N1, N)) + return Combined; + + if (SDValue Combined = visitADDLikeCommutative(N1, N0, N)) + return Combined; + + return SDValue(); +} + +SDValue DAGCombiner::visitADD(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + if (SDValue Combined = visitADDLike(N)) + return Combined; + + if (SDValue V = foldAddSubBoolOfMaskedVal(N, DAG)) + return V; + + if (SDValue V = foldAddSubOfSignBit(N, DAG)) + return V; + + // fold (a+b) -> (a|b) iff a and b share no bits. + if ((!LegalOperations || TLI.isOperationLegal(ISD::OR, VT)) && + DAG.haveNoCommonBitsSet(N0, N1)) + return DAG.getNode(ISD::OR, DL, VT, N0, N1); + + // Fold (add (vscale * C0), (vscale * C1)) to (vscale * (C0 + C1)). + if (N0.getOpcode() == ISD::VSCALE && N1.getOpcode() == ISD::VSCALE) { + const APInt &C0 = N0->getConstantOperandAPInt(0); + const APInt &C1 = N1->getConstantOperandAPInt(0); + return DAG.getVScale(DL, VT, C0 + C1); + } + + // fold a+vscale(c1)+vscale(c2) -> a+vscale(c1+c2) + if ((N0.getOpcode() == ISD::ADD) && + (N0.getOperand(1).getOpcode() == ISD::VSCALE) && + (N1.getOpcode() == ISD::VSCALE)) { + const APInt &VS0 = N0.getOperand(1)->getConstantOperandAPInt(0); + const APInt &VS1 = N1->getConstantOperandAPInt(0); + SDValue VS = DAG.getVScale(DL, VT, VS0 + VS1); + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), VS); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitADDSAT(SDNode *N) { + unsigned Opcode = N->getOpcode(); + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + // fold vector ops + if (VT.isVector()) { + // TODO SimplifyVBinOp + + // fold (add_sat x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N1; + } + + // fold (add_sat x, undef) -> -1 + if (N0.isUndef() || N1.isUndef()) + return DAG.getAllOnesConstant(DL, VT); + + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) { + // canonicalize constant to RHS + if (!DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(Opcode, DL, VT, N1, N0); + // fold (add_sat c1, c2) -> c3 + return DAG.FoldConstantArithmetic(Opcode, DL, VT, {N0, N1}); + } + + // fold (add_sat x, 0) -> x + if (isNullConstant(N1)) + return N0; + + // If it cannot overflow, transform into an add. + if (Opcode == ISD::UADDSAT) + if (DAG.computeOverflowKind(N0, N1) == SelectionDAG::OFK_Never) + return DAG.getNode(ISD::ADD, DL, VT, N0, N1); + + return SDValue(); +} + +static SDValue getAsCarry(const TargetLowering &TLI, SDValue V) { + bool Masked = false; + + // First, peel away TRUNCATE/ZERO_EXTEND/AND nodes due to legalization. + while (true) { + if (V.getOpcode() == ISD::TRUNCATE || V.getOpcode() == ISD::ZERO_EXTEND) { + V = V.getOperand(0); + continue; + } + + if (V.getOpcode() == ISD::AND && isOneConstant(V.getOperand(1))) { + Masked = true; + V = V.getOperand(0); + continue; + } + + break; + } + + // If this is not a carry, return. + if (V.getResNo() != 1) + return SDValue(); + + if (V.getOpcode() != ISD::ADDCARRY && V.getOpcode() != ISD::SUBCARRY && + V.getOpcode() != ISD::UADDO && V.getOpcode() != ISD::USUBO) + return SDValue(); + + EVT VT = V.getNode()->getValueType(0); + if (!TLI.isOperationLegalOrCustom(V.getOpcode(), VT)) + return SDValue(); + + // If the result is masked, then no matter what kind of bool it is we can + // return. If it isn't, then we need to make sure the bool type is either 0 or + // 1 and not other values. + if (Masked || + TLI.getBooleanContents(V.getValueType()) == + TargetLoweringBase::ZeroOrOneBooleanContent) + return V; + + return SDValue(); +} + +/// Given the operands of an add/sub operation, see if the 2nd operand is a +/// masked 0/1 whose source operand is actually known to be 0/-1. If so, invert +/// the opcode and bypass the mask operation. +static SDValue foldAddSubMasked1(bool IsAdd, SDValue N0, SDValue N1, + SelectionDAG &DAG, const SDLoc &DL) { + if (N1.getOpcode() != ISD::AND || !isOneOrOneSplat(N1->getOperand(1))) + return SDValue(); + + EVT VT = N0.getValueType(); + if (DAG.ComputeNumSignBits(N1.getOperand(0)) != VT.getScalarSizeInBits()) + return SDValue(); + + // add N0, (and (AssertSext X, i1), 1) --> sub N0, X + // sub N0, (and (AssertSext X, i1), 1) --> add N0, X + return DAG.getNode(IsAdd ? ISD::SUB : ISD::ADD, DL, VT, N0, N1.getOperand(0)); +} + +/// Helper for doing combines based on N0 and N1 being added to each other. +SDValue DAGCombiner::visitADDLikeCommutative(SDValue N0, SDValue N1, + SDNode *LocReference) { + EVT VT = N0.getValueType(); + SDLoc DL(LocReference); + + // fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n)) + if (N1.getOpcode() == ISD::SHL && N1.getOperand(0).getOpcode() == ISD::SUB && + isNullOrNullSplat(N1.getOperand(0).getOperand(0))) + return DAG.getNode(ISD::SUB, DL, VT, N0, + DAG.getNode(ISD::SHL, DL, VT, + N1.getOperand(0).getOperand(1), + N1.getOperand(1))); + + if (SDValue V = foldAddSubMasked1(true, N0, N1, DAG, DL)) + return V; + + // Look for: + // add (add x, 1), y + // And if the target does not like this form then turn into: + // sub y, (xor x, -1) + if (!TLI.preferIncOfAddToSubOfNot(VT) && N0.hasOneUse() && + N0.getOpcode() == ISD::ADD && isOneOrOneSplat(N0.getOperand(1))) { + SDValue Not = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(0), + DAG.getAllOnesConstant(DL, VT)); + return DAG.getNode(ISD::SUB, DL, VT, N1, Not); + } + + // Hoist one-use subtraction by non-opaque constant: + // (x - C) + y -> (x + y) - C + // This is necessary because SUB(X,C) -> ADD(X,-C) doesn't work for vectors. + if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(1), /*NoOpaques=*/true)) { + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), N1); + return DAG.getNode(ISD::SUB, DL, VT, Add, N0.getOperand(1)); + } + // Hoist one-use subtraction from non-opaque constant: + // (C - x) + y -> (y - x) + C + if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(0), /*NoOpaques=*/true)) { + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N1, N0.getOperand(1)); + return DAG.getNode(ISD::ADD, DL, VT, Sub, N0.getOperand(0)); + } + + // If the target's bool is represented as 0/1, prefer to make this 'sub 0/1' + // rather than 'add 0/-1' (the zext should get folded). + // add (sext i1 Y), X --> sub X, (zext i1 Y) + if (N0.getOpcode() == ISD::SIGN_EXTEND && + N0.getOperand(0).getScalarValueSizeInBits() == 1 && + TLI.getBooleanContents(VT) == TargetLowering::ZeroOrOneBooleanContent) { + SDValue ZExt = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)); + return DAG.getNode(ISD::SUB, DL, VT, N1, ZExt); + } + + // add X, (sextinreg Y i1) -> sub X, (and Y 1) + if (N1.getOpcode() == ISD::SIGN_EXTEND_INREG) { + VTSDNode *TN = cast<VTSDNode>(N1.getOperand(1)); + if (TN->getVT() == MVT::i1) { + SDValue ZExt = DAG.getNode(ISD::AND, DL, VT, N1.getOperand(0), + DAG.getConstant(1, DL, VT)); + return DAG.getNode(ISD::SUB, DL, VT, N0, ZExt); + } + } + + // (add X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry) + if (N1.getOpcode() == ISD::ADDCARRY && isNullConstant(N1.getOperand(1)) && + N1.getResNo() == 0) + return DAG.getNode(ISD::ADDCARRY, DL, N1->getVTList(), + N0, N1.getOperand(0), N1.getOperand(2)); + + // (add X, Carry) -> (addcarry X, 0, Carry) + if (TLI.isOperationLegalOrCustom(ISD::ADDCARRY, VT)) + if (SDValue Carry = getAsCarry(TLI, N1)) + return DAG.getNode(ISD::ADDCARRY, DL, + DAG.getVTList(VT, Carry.getValueType()), N0, + DAG.getConstant(0, DL, VT), Carry); + + return SDValue(); +} + +SDValue DAGCombiner::visitADDC(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + // If the flag result is dead, turn this into an ADD. + if (!N->hasAnyUseOfValue(1)) + return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1), + DAG.getNode(ISD::CARRY_FALSE, DL, MVT::Glue)); + + // canonicalize constant to RHS. + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + if (N0C && !N1C) + return DAG.getNode(ISD::ADDC, DL, N->getVTList(), N1, N0); + + // fold (addc x, 0) -> x + no carry out + if (isNullConstant(N1)) + return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, + DL, MVT::Glue)); + + // If it cannot overflow, transform into an add. + if (DAG.computeOverflowKind(N0, N1) == SelectionDAG::OFK_Never) + return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1), + DAG.getNode(ISD::CARRY_FALSE, DL, MVT::Glue)); + + return SDValue(); +} + +/** + * Flips a boolean if it is cheaper to compute. If the Force parameters is set, + * then the flip also occurs if computing the inverse is the same cost. + * This function returns an empty SDValue in case it cannot flip the boolean + * without increasing the cost of the computation. If you want to flip a boolean + * no matter what, use DAG.getLogicalNOT. + */ +static SDValue extractBooleanFlip(SDValue V, SelectionDAG &DAG, + const TargetLowering &TLI, + bool Force) { + if (Force && isa<ConstantSDNode>(V)) + return DAG.getLogicalNOT(SDLoc(V), V, V.getValueType()); + + if (V.getOpcode() != ISD::XOR) + return SDValue(); + + ConstantSDNode *Const = isConstOrConstSplat(V.getOperand(1), false); + if (!Const) + return SDValue(); + + EVT VT = V.getValueType(); + + bool IsFlip = false; + switch(TLI.getBooleanContents(VT)) { + case TargetLowering::ZeroOrOneBooleanContent: + IsFlip = Const->isOne(); + break; + case TargetLowering::ZeroOrNegativeOneBooleanContent: + IsFlip = Const->isAllOnesValue(); + break; + case TargetLowering::UndefinedBooleanContent: + IsFlip = (Const->getAPIntValue() & 0x01) == 1; + break; + } + + if (IsFlip) + return V.getOperand(0); + if (Force) + return DAG.getLogicalNOT(SDLoc(V), V, V.getValueType()); + return SDValue(); +} + +SDValue DAGCombiner::visitADDO(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + bool IsSigned = (ISD::SADDO == N->getOpcode()); + + EVT CarryVT = N->getValueType(1); + SDLoc DL(N); + + // If the flag result is dead, turn this into an ADD. + if (!N->hasAnyUseOfValue(1)) + return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1), + DAG.getUNDEF(CarryVT)); + + // canonicalize constant to RHS. + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(N->getOpcode(), DL, N->getVTList(), N1, N0); + + // fold (addo x, 0) -> x + no carry out + if (isNullOrNullSplat(N1)) + return CombineTo(N, N0, DAG.getConstant(0, DL, CarryVT)); + + if (!IsSigned) { + // If it cannot overflow, transform into an add. + if (DAG.computeOverflowKind(N0, N1) == SelectionDAG::OFK_Never) + return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1), + DAG.getConstant(0, DL, CarryVT)); + + // fold (uaddo (xor a, -1), 1) -> (usub 0, a) and flip carry. + if (isBitwiseNot(N0) && isOneOrOneSplat(N1)) { + SDValue Sub = DAG.getNode(ISD::USUBO, DL, N->getVTList(), + DAG.getConstant(0, DL, VT), N0.getOperand(0)); + return CombineTo( + N, Sub, DAG.getLogicalNOT(DL, Sub.getValue(1), Sub->getValueType(1))); + } + + if (SDValue Combined = visitUADDOLike(N0, N1, N)) + return Combined; + + if (SDValue Combined = visitUADDOLike(N1, N0, N)) + return Combined; + } + + return SDValue(); +} + +SDValue DAGCombiner::visitUADDOLike(SDValue N0, SDValue N1, SDNode *N) { + EVT VT = N0.getValueType(); + if (VT.isVector()) + return SDValue(); + + // (uaddo X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry) + // If Y + 1 cannot overflow. + if (N1.getOpcode() == ISD::ADDCARRY && isNullConstant(N1.getOperand(1))) { + SDValue Y = N1.getOperand(0); + SDValue One = DAG.getConstant(1, SDLoc(N), Y.getValueType()); + if (DAG.computeOverflowKind(Y, One) == SelectionDAG::OFK_Never) + return DAG.getNode(ISD::ADDCARRY, SDLoc(N), N->getVTList(), N0, Y, + N1.getOperand(2)); + } + + // (uaddo X, Carry) -> (addcarry X, 0, Carry) + if (TLI.isOperationLegalOrCustom(ISD::ADDCARRY, VT)) + if (SDValue Carry = getAsCarry(TLI, N1)) + return DAG.getNode(ISD::ADDCARRY, SDLoc(N), N->getVTList(), N0, + DAG.getConstant(0, SDLoc(N), VT), Carry); + + return SDValue(); +} + +SDValue DAGCombiner::visitADDE(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue CarryIn = N->getOperand(2); + + // canonicalize constant to RHS + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + if (N0C && !N1C) + return DAG.getNode(ISD::ADDE, SDLoc(N), N->getVTList(), + N1, N0, CarryIn); + + // fold (adde x, y, false) -> (addc x, y) + if (CarryIn.getOpcode() == ISD::CARRY_FALSE) + return DAG.getNode(ISD::ADDC, SDLoc(N), N->getVTList(), N0, N1); + + return SDValue(); +} + +SDValue DAGCombiner::visitADDCARRY(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue CarryIn = N->getOperand(2); + SDLoc DL(N); + + // canonicalize constant to RHS + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + if (N0C && !N1C) + return DAG.getNode(ISD::ADDCARRY, DL, N->getVTList(), N1, N0, CarryIn); + + // fold (addcarry x, y, false) -> (uaddo x, y) + if (isNullConstant(CarryIn)) { + if (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::UADDO, N->getValueType(0))) + return DAG.getNode(ISD::UADDO, DL, N->getVTList(), N0, N1); + } + + // fold (addcarry 0, 0, X) -> (and (ext/trunc X), 1) and no carry. + if (isNullConstant(N0) && isNullConstant(N1)) { + EVT VT = N0.getValueType(); + EVT CarryVT = CarryIn.getValueType(); + SDValue CarryExt = DAG.getBoolExtOrTrunc(CarryIn, DL, VT, CarryVT); + AddToWorklist(CarryExt.getNode()); + return CombineTo(N, DAG.getNode(ISD::AND, DL, VT, CarryExt, + DAG.getConstant(1, DL, VT)), + DAG.getConstant(0, DL, CarryVT)); + } + + if (SDValue Combined = visitADDCARRYLike(N0, N1, CarryIn, N)) + return Combined; + + if (SDValue Combined = visitADDCARRYLike(N1, N0, CarryIn, N)) + return Combined; + + return SDValue(); +} + +SDValue DAGCombiner::visitSADDO_CARRY(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue CarryIn = N->getOperand(2); + SDLoc DL(N); + + // canonicalize constant to RHS + ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + if (N0C && !N1C) + return DAG.getNode(ISD::SADDO_CARRY, DL, N->getVTList(), N1, N0, CarryIn); + + // fold (saddo_carry x, y, false) -> (saddo x, y) + if (isNullConstant(CarryIn)) { + if (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::SADDO, N->getValueType(0))) + return DAG.getNode(ISD::SADDO, DL, N->getVTList(), N0, N1); + } + + return SDValue(); +} + +/** + * If we are facing some sort of diamond carry propapagtion pattern try to + * break it up to generate something like: + * (addcarry X, 0, (addcarry A, B, Z):Carry) + * + * The end result is usually an increase in operation required, but because the + * carry is now linearized, other tranforms can kick in and optimize the DAG. + * + * Patterns typically look something like + * (uaddo A, B) + * / \ + * Carry Sum + * | \ + * | (addcarry *, 0, Z) + * | / + * \ Carry + * | / + * (addcarry X, *, *) + * + * But numerous variation exist. Our goal is to identify A, B, X and Z and + * produce a combine with a single path for carry propagation. + */ +static SDValue combineADDCARRYDiamond(DAGCombiner &Combiner, SelectionDAG &DAG, + SDValue X, SDValue Carry0, SDValue Carry1, + SDNode *N) { + if (Carry1.getResNo() != 1 || Carry0.getResNo() != 1) + return SDValue(); + if (Carry1.getOpcode() != ISD::UADDO) + return SDValue(); + + SDValue Z; + + /** + * First look for a suitable Z. It will present itself in the form of + * (addcarry Y, 0, Z) or its equivalent (uaddo Y, 1) for Z=true + */ + if (Carry0.getOpcode() == ISD::ADDCARRY && + isNullConstant(Carry0.getOperand(1))) { + Z = Carry0.getOperand(2); + } else if (Carry0.getOpcode() == ISD::UADDO && + isOneConstant(Carry0.getOperand(1))) { + EVT VT = Combiner.getSetCCResultType(Carry0.getValueType()); + Z = DAG.getConstant(1, SDLoc(Carry0.getOperand(1)), VT); + } else { + // We couldn't find a suitable Z. + return SDValue(); + } + + + auto cancelDiamond = [&](SDValue A,SDValue B) { + SDLoc DL(N); + SDValue NewY = DAG.getNode(ISD::ADDCARRY, DL, Carry0->getVTList(), A, B, Z); + Combiner.AddToWorklist(NewY.getNode()); + return DAG.getNode(ISD::ADDCARRY, DL, N->getVTList(), X, + DAG.getConstant(0, DL, X.getValueType()), + NewY.getValue(1)); + }; + + /** + * (uaddo A, B) + * | + * Sum + * | + * (addcarry *, 0, Z) + */ + if (Carry0.getOperand(0) == Carry1.getValue(0)) { + return cancelDiamond(Carry1.getOperand(0), Carry1.getOperand(1)); + } + + /** + * (addcarry A, 0, Z) + * | + * Sum + * | + * (uaddo *, B) + */ + if (Carry1.getOperand(0) == Carry0.getValue(0)) { + return cancelDiamond(Carry0.getOperand(0), Carry1.getOperand(1)); + } + + if (Carry1.getOperand(1) == Carry0.getValue(0)) { + return cancelDiamond(Carry1.getOperand(0), Carry0.getOperand(0)); + } + + return SDValue(); +} + +// If we are facing some sort of diamond carry/borrow in/out pattern try to +// match patterns like: +// +// (uaddo A, B) CarryIn +// | \ | +// | \ | +// PartialSum PartialCarryOutX / +// | | / +// | ____|____________/ +// | / | +// (uaddo *, *) \________ +// | \ \ +// | \ | +// | PartialCarryOutY | +// | \ | +// | \ / +// AddCarrySum | ______/ +// | / +// CarryOut = (or *, *) +// +// And generate ADDCARRY (or SUBCARRY) with two result values: +// +// {AddCarrySum, CarryOut} = (addcarry A, B, CarryIn) +// +// Our goal is to identify A, B, and CarryIn and produce ADDCARRY/SUBCARRY with +// a single path for carry/borrow out propagation: +static SDValue combineCarryDiamond(DAGCombiner &Combiner, SelectionDAG &DAG, + const TargetLowering &TLI, SDValue Carry0, + SDValue Carry1, SDNode *N) { + if (Carry0.getResNo() != 1 || Carry1.getResNo() != 1) + return SDValue(); + unsigned Opcode = Carry0.getOpcode(); + if (Opcode != Carry1.getOpcode()) + return SDValue(); + if (Opcode != ISD::UADDO && Opcode != ISD::USUBO) + return SDValue(); + + // Canonicalize the add/sub of A and B as Carry0 and the add/sub of the + // carry/borrow in as Carry1. (The top and middle uaddo nodes respectively in + // the above ASCII art.) + if (Carry1.getOperand(0) != Carry0.getValue(0) && + Carry1.getOperand(1) != Carry0.getValue(0)) + std::swap(Carry0, Carry1); + if (Carry1.getOperand(0) != Carry0.getValue(0) && + Carry1.getOperand(1) != Carry0.getValue(0)) + return SDValue(); + + // The carry in value must be on the righthand side for subtraction. + unsigned CarryInOperandNum = + Carry1.getOperand(0) == Carry0.getValue(0) ? 1 : 0; + if (Opcode == ISD::USUBO && CarryInOperandNum != 1) + return SDValue(); + SDValue CarryIn = Carry1.getOperand(CarryInOperandNum); + + unsigned NewOp = Opcode == ISD::UADDO ? ISD::ADDCARRY : ISD::SUBCARRY; + if (!TLI.isOperationLegalOrCustom(NewOp, Carry0.getValue(0).getValueType())) + return SDValue(); + + // Verify that the carry/borrow in is plausibly a carry/borrow bit. + // TODO: make getAsCarry() aware of how partial carries are merged. + if (CarryIn.getOpcode() != ISD::ZERO_EXTEND) + return SDValue(); + CarryIn = CarryIn.getOperand(0); + if (CarryIn.getValueType() != MVT::i1) + return SDValue(); + + SDLoc DL(N); + SDValue Merged = + DAG.getNode(NewOp, DL, Carry1->getVTList(), Carry0.getOperand(0), + Carry0.getOperand(1), CarryIn); + + // Please note that because we have proven that the result of the UADDO/USUBO + // of A and B feeds into the UADDO/USUBO that does the carry/borrow in, we can + // therefore prove that if the first UADDO/USUBO overflows, the second + // UADDO/USUBO cannot. For example consider 8-bit numbers where 0xFF is the + // maximum value. + // + // 0xFF + 0xFF == 0xFE with carry but 0xFE + 1 does not carry + // 0x00 - 0xFF == 1 with a carry/borrow but 1 - 1 == 0 (no carry/borrow) + // + // This is important because it means that OR and XOR can be used to merge + // carry flags; and that AND can return a constant zero. + // + // TODO: match other operations that can merge flags (ADD, etc) + DAG.ReplaceAllUsesOfValueWith(Carry1.getValue(0), Merged.getValue(0)); + if (N->getOpcode() == ISD::AND) + return DAG.getConstant(0, DL, MVT::i1); + return Merged.getValue(1); +} + +SDValue DAGCombiner::visitADDCARRYLike(SDValue N0, SDValue N1, SDValue CarryIn, + SDNode *N) { + // fold (addcarry (xor a, -1), b, c) -> (subcarry b, a, !c) and flip carry. + if (isBitwiseNot(N0)) + if (SDValue NotC = extractBooleanFlip(CarryIn, DAG, TLI, true)) { + SDLoc DL(N); + SDValue Sub = DAG.getNode(ISD::SUBCARRY, DL, N->getVTList(), N1, + N0.getOperand(0), NotC); + return CombineTo( + N, Sub, DAG.getLogicalNOT(DL, Sub.getValue(1), Sub->getValueType(1))); + } + + // Iff the flag result is dead: + // (addcarry (add|uaddo X, Y), 0, Carry) -> (addcarry X, Y, Carry) + // Don't do this if the Carry comes from the uaddo. It won't remove the uaddo + // or the dependency between the instructions. + if ((N0.getOpcode() == ISD::ADD || + (N0.getOpcode() == ISD::UADDO && N0.getResNo() == 0 && + N0.getValue(1) != CarryIn)) && + isNullConstant(N1) && !N->hasAnyUseOfValue(1)) + return DAG.getNode(ISD::ADDCARRY, SDLoc(N), N->getVTList(), + N0.getOperand(0), N0.getOperand(1), CarryIn); + + /** + * When one of the addcarry argument is itself a carry, we may be facing + * a diamond carry propagation. In which case we try to transform the DAG + * to ensure linear carry propagation if that is possible. + */ + if (auto Y = getAsCarry(TLI, N1)) { + // Because both are carries, Y and Z can be swapped. + if (auto R = combineADDCARRYDiamond(*this, DAG, N0, Y, CarryIn, N)) + return R; + if (auto R = combineADDCARRYDiamond(*this, DAG, N0, CarryIn, Y, N)) + return R; + } + + return SDValue(); +} + +// Since it may not be valid to emit a fold to zero for vector initializers +// check if we can before folding. +static SDValue tryFoldToZero(const SDLoc &DL, const TargetLowering &TLI, EVT VT, + SelectionDAG &DAG, bool LegalOperations) { + if (!VT.isVector()) + return DAG.getConstant(0, DL, VT); + if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) + return DAG.getConstant(0, DL, VT); + return SDValue(); +} + +SDValue DAGCombiner::visitSUB(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (sub x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + } + + // fold (sub x, x) -> 0 + // FIXME: Refactor this and xor and other similar operations together. + if (N0 == N1) + return tryFoldToZero(DL, TLI, VT, DAG, LegalOperations); + + // fold (sub c1, c2) -> c3 + if (SDValue C = DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N0, N1})) + return C; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + ConstantSDNode *N1C = getAsNonOpaqueConstant(N1); + + // fold (sub x, c) -> (add x, -c) + if (N1C) { + return DAG.getNode(ISD::ADD, DL, VT, N0, + DAG.getConstant(-N1C->getAPIntValue(), DL, VT)); + } + + if (isNullOrNullSplat(N0)) { + unsigned BitWidth = VT.getScalarSizeInBits(); + // Right-shifting everything out but the sign bit followed by negation is + // the same as flipping arithmetic/logical shift type without the negation: + // -(X >>u 31) -> (X >>s 31) + // -(X >>s 31) -> (X >>u 31) + if (N1->getOpcode() == ISD::SRA || N1->getOpcode() == ISD::SRL) { + ConstantSDNode *ShiftAmt = isConstOrConstSplat(N1.getOperand(1)); + if (ShiftAmt && ShiftAmt->getAPIntValue() == (BitWidth - 1)) { + auto NewSh = N1->getOpcode() == ISD::SRA ? ISD::SRL : ISD::SRA; + if (!LegalOperations || TLI.isOperationLegal(NewSh, VT)) + return DAG.getNode(NewSh, DL, VT, N1.getOperand(0), N1.getOperand(1)); + } + } + + // 0 - X --> 0 if the sub is NUW. + if (N->getFlags().hasNoUnsignedWrap()) + return N0; + + if (DAG.MaskedValueIsZero(N1, ~APInt::getSignMask(BitWidth))) { + // N1 is either 0 or the minimum signed value. If the sub is NSW, then + // N1 must be 0 because negating the minimum signed value is undefined. + if (N->getFlags().hasNoSignedWrap()) + return N0; + + // 0 - X --> X if X is 0 or the minimum signed value. + return N1; + } + + // Convert 0 - abs(x). + SDValue Result; + if (N1->getOpcode() == ISD::ABS && + !TLI.isOperationLegalOrCustom(ISD::ABS, VT) && + TLI.expandABS(N1.getNode(), Result, DAG, true)) + return Result; + } + + // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1) + if (isAllOnesOrAllOnesSplat(N0)) + return DAG.getNode(ISD::XOR, DL, VT, N1, N0); + + // fold (A - (0-B)) -> A+B + if (N1.getOpcode() == ISD::SUB && isNullOrNullSplat(N1.getOperand(0))) + return DAG.getNode(ISD::ADD, DL, VT, N0, N1.getOperand(1)); + + // fold A-(A-B) -> B + if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(0)) + return N1.getOperand(1); + + // fold (A+B)-A -> B + if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) + return N0.getOperand(1); + + // fold (A+B)-B -> A + if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) + return N0.getOperand(0); + + // fold (A+C1)-C2 -> A+(C1-C2) + if (N0.getOpcode() == ISD::ADD && + isConstantOrConstantVector(N1, /* NoOpaques */ true) && + isConstantOrConstantVector(N0.getOperand(1), /* NoOpaques */ true)) { + SDValue NewC = + DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N0.getOperand(1), N1}); + assert(NewC && "Constant folding failed"); + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), NewC); + } + + // fold C2-(A+C1) -> (C2-C1)-A + if (N1.getOpcode() == ISD::ADD) { + SDValue N11 = N1.getOperand(1); + if (isConstantOrConstantVector(N0, /* NoOpaques */ true) && + isConstantOrConstantVector(N11, /* NoOpaques */ true)) { + SDValue NewC = DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N0, N11}); + assert(NewC && "Constant folding failed"); + return DAG.getNode(ISD::SUB, DL, VT, NewC, N1.getOperand(0)); + } + } + + // fold (A-C1)-C2 -> A-(C1+C2) + if (N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N1, /* NoOpaques */ true) && + isConstantOrConstantVector(N0.getOperand(1), /* NoOpaques */ true)) { + SDValue NewC = + DAG.FoldConstantArithmetic(ISD::ADD, DL, VT, {N0.getOperand(1), N1}); + assert(NewC && "Constant folding failed"); + return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), NewC); + } + + // fold (c1-A)-c2 -> (c1-c2)-A + if (N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N1, /* NoOpaques */ true) && + isConstantOrConstantVector(N0.getOperand(0), /* NoOpaques */ true)) { + SDValue NewC = + DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, {N0.getOperand(0), N1}); + assert(NewC && "Constant folding failed"); + return DAG.getNode(ISD::SUB, DL, VT, NewC, N0.getOperand(1)); + } + + // fold ((A+(B+or-C))-B) -> A+or-C + if (N0.getOpcode() == ISD::ADD && + (N0.getOperand(1).getOpcode() == ISD::SUB || + N0.getOperand(1).getOpcode() == ISD::ADD) && + N0.getOperand(1).getOperand(0) == N1) + return DAG.getNode(N0.getOperand(1).getOpcode(), DL, VT, N0.getOperand(0), + N0.getOperand(1).getOperand(1)); + + // fold ((A+(C+B))-B) -> A+C + if (N0.getOpcode() == ISD::ADD && N0.getOperand(1).getOpcode() == ISD::ADD && + N0.getOperand(1).getOperand(1) == N1) + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), + N0.getOperand(1).getOperand(0)); + + // fold ((A-(B-C))-C) -> A-B + if (N0.getOpcode() == ISD::SUB && N0.getOperand(1).getOpcode() == ISD::SUB && + N0.getOperand(1).getOperand(1) == N1) + return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), + N0.getOperand(1).getOperand(0)); + + // fold (A-(B-C)) -> A+(C-B) + if (N1.getOpcode() == ISD::SUB && N1.hasOneUse()) + return DAG.getNode(ISD::ADD, DL, VT, N0, + DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(1), + N1.getOperand(0))); + + // A - (A & B) -> A & (~B) + if (N1.getOpcode() == ISD::AND) { + SDValue A = N1.getOperand(0); + SDValue B = N1.getOperand(1); + if (A != N0) + std::swap(A, B); + if (A == N0 && + (N1.hasOneUse() || isConstantOrConstantVector(B, /*NoOpaques=*/true))) { + SDValue InvB = + DAG.getNode(ISD::XOR, DL, VT, B, DAG.getAllOnesConstant(DL, VT)); + return DAG.getNode(ISD::AND, DL, VT, A, InvB); + } + } + + // fold (X - (-Y * Z)) -> (X + (Y * Z)) + if (N1.getOpcode() == ISD::MUL && N1.hasOneUse()) { + if (N1.getOperand(0).getOpcode() == ISD::SUB && + isNullOrNullSplat(N1.getOperand(0).getOperand(0))) { + SDValue Mul = DAG.getNode(ISD::MUL, DL, VT, + N1.getOperand(0).getOperand(1), + N1.getOperand(1)); + return DAG.getNode(ISD::ADD, DL, VT, N0, Mul); + } + if (N1.getOperand(1).getOpcode() == ISD::SUB && + isNullOrNullSplat(N1.getOperand(1).getOperand(0))) { + SDValue Mul = DAG.getNode(ISD::MUL, DL, VT, + N1.getOperand(0), + N1.getOperand(1).getOperand(1)); + return DAG.getNode(ISD::ADD, DL, VT, N0, Mul); + } + } + + // If either operand of a sub is undef, the result is undef + if (N0.isUndef()) + return N0; + if (N1.isUndef()) + return N1; + + if (SDValue V = foldAddSubBoolOfMaskedVal(N, DAG)) + return V; + + if (SDValue V = foldAddSubOfSignBit(N, DAG)) + return V; + + if (SDValue V = foldAddSubMasked1(false, N0, N1, DAG, SDLoc(N))) + return V; + + // (x - y) - 1 -> add (xor y, -1), x + if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && isOneOrOneSplat(N1)) { + SDValue Xor = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(1), + DAG.getAllOnesConstant(DL, VT)); + return DAG.getNode(ISD::ADD, DL, VT, Xor, N0.getOperand(0)); + } + + // Look for: + // sub y, (xor x, -1) + // And if the target does not like this form then turn into: + // add (add x, y), 1 + if (TLI.preferIncOfAddToSubOfNot(VT) && N1.hasOneUse() && isBitwiseNot(N1)) { + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N0, N1.getOperand(0)); + return DAG.getNode(ISD::ADD, DL, VT, Add, DAG.getConstant(1, DL, VT)); + } + + // Hoist one-use addition by non-opaque constant: + // (x + C) - y -> (x - y) + C + if (N0.hasOneUse() && N0.getOpcode() == ISD::ADD && + isConstantOrConstantVector(N0.getOperand(1), /*NoOpaques=*/true)) { + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), N1); + return DAG.getNode(ISD::ADD, DL, VT, Sub, N0.getOperand(1)); + } + // y - (x + C) -> (y - x) - C + if (N1.hasOneUse() && N1.getOpcode() == ISD::ADD && + isConstantOrConstantVector(N1.getOperand(1), /*NoOpaques=*/true)) { + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0, N1.getOperand(0)); + return DAG.getNode(ISD::SUB, DL, VT, Sub, N1.getOperand(1)); + } + // (x - C) - y -> (x - y) - C + // This is necessary because SUB(X,C) -> ADD(X,-C) doesn't work for vectors. + if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(1), /*NoOpaques=*/true)) { + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), N1); + return DAG.getNode(ISD::SUB, DL, VT, Sub, N0.getOperand(1)); + } + // (C - x) - y -> C - (x + y) + if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(0), /*NoOpaques=*/true)) { + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(1), N1); + return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), Add); + } + + // If the target's bool is represented as 0/-1, prefer to make this 'add 0/-1' + // rather than 'sub 0/1' (the sext should get folded). + // sub X, (zext i1 Y) --> add X, (sext i1 Y) + if (N1.getOpcode() == ISD::ZERO_EXTEND && + N1.getOperand(0).getScalarValueSizeInBits() == 1 && + TLI.getBooleanContents(VT) == + TargetLowering::ZeroOrNegativeOneBooleanContent) { + SDValue SExt = DAG.getNode(ISD::SIGN_EXTEND, DL, VT, N1.getOperand(0)); + return DAG.getNode(ISD::ADD, DL, VT, N0, SExt); + } + + // fold Y = sra (X, size(X)-1); sub (xor (X, Y), Y) -> (abs X) + if (TLI.isOperationLegalOrCustom(ISD::ABS, VT)) { + if (N0.getOpcode() == ISD::XOR && N1.getOpcode() == ISD::SRA) { + SDValue X0 = N0.getOperand(0), X1 = N0.getOperand(1); + SDValue S0 = N1.getOperand(0); + if ((X0 == S0 && X1 == N1) || (X0 == N1 && X1 == S0)) + if (ConstantSDNode *C = isConstOrConstSplat(N1.getOperand(1))) + if (C->getAPIntValue() == (VT.getScalarSizeInBits() - 1)) + return DAG.getNode(ISD::ABS, SDLoc(N), VT, S0); + } + } + + // If the relocation model supports it, consider symbol offsets. + if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) + if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) { + // fold (sub Sym, c) -> Sym-c + if (N1C && GA->getOpcode() == ISD::GlobalAddress) + return DAG.getGlobalAddress(GA->getGlobal(), SDLoc(N1C), VT, + GA->getOffset() - + (uint64_t)N1C->getSExtValue()); + // fold (sub Sym+c1, Sym+c2) -> c1-c2 + if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1)) + if (GA->getGlobal() == GB->getGlobal()) + return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(), + DL, VT); + } + + // sub X, (sextinreg Y i1) -> add X, (and Y 1) + if (N1.getOpcode() == ISD::SIGN_EXTEND_INREG) { + VTSDNode *TN = cast<VTSDNode>(N1.getOperand(1)); + if (TN->getVT() == MVT::i1) { + SDValue ZExt = DAG.getNode(ISD::AND, DL, VT, N1.getOperand(0), + DAG.getConstant(1, DL, VT)); + return DAG.getNode(ISD::ADD, DL, VT, N0, ZExt); + } + } + + // canonicalize (sub X, (vscale * C)) to (add X, (vscale * -C)) + if (N1.getOpcode() == ISD::VSCALE) { + const APInt &IntVal = N1.getConstantOperandAPInt(0); + return DAG.getNode(ISD::ADD, DL, VT, N0, DAG.getVScale(DL, VT, -IntVal)); + } + + // Prefer an add for more folding potential and possibly better codegen: + // sub N0, (lshr N10, width-1) --> add N0, (ashr N10, width-1) + if (!LegalOperations && N1.getOpcode() == ISD::SRL && N1.hasOneUse()) { + SDValue ShAmt = N1.getOperand(1); + ConstantSDNode *ShAmtC = isConstOrConstSplat(ShAmt); + if (ShAmtC && + ShAmtC->getAPIntValue() == (N1.getScalarValueSizeInBits() - 1)) { + SDValue SRA = DAG.getNode(ISD::SRA, DL, VT, N1.getOperand(0), ShAmt); + return DAG.getNode(ISD::ADD, DL, VT, N0, SRA); + } + } + + if (TLI.isOperationLegalOrCustom(ISD::ADDCARRY, VT)) { + // (sub Carry, X) -> (addcarry (sub 0, X), 0, Carry) + if (SDValue Carry = getAsCarry(TLI, N0)) { + SDValue X = N1; + SDValue Zero = DAG.getConstant(0, DL, VT); + SDValue NegX = DAG.getNode(ISD::SUB, DL, VT, Zero, X); + return DAG.getNode(ISD::ADDCARRY, DL, + DAG.getVTList(VT, Carry.getValueType()), NegX, Zero, + Carry); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitSUBSAT(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + // fold vector ops + if (VT.isVector()) { + // TODO SimplifyVBinOp + + // fold (sub_sat x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + } + + // fold (sub_sat x, undef) -> 0 + if (N0.isUndef() || N1.isUndef()) + return DAG.getConstant(0, DL, VT); + + // fold (sub_sat x, x) -> 0 + if (N0 == N1) + return DAG.getConstant(0, DL, VT); + + // fold (sub_sat c1, c2) -> c3 + if (SDValue C = DAG.FoldConstantArithmetic(N->getOpcode(), DL, VT, {N0, N1})) + return C; + + // fold (sub_sat x, 0) -> x + if (isNullConstant(N1)) + return N0; + + return SDValue(); +} + +SDValue DAGCombiner::visitSUBC(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + SDLoc DL(N); + + // If the flag result is dead, turn this into an SUB. + if (!N->hasAnyUseOfValue(1)) + return CombineTo(N, DAG.getNode(ISD::SUB, DL, VT, N0, N1), + DAG.getNode(ISD::CARRY_FALSE, DL, MVT::Glue)); + + // fold (subc x, x) -> 0 + no borrow + if (N0 == N1) + return CombineTo(N, DAG.getConstant(0, DL, VT), + DAG.getNode(ISD::CARRY_FALSE, DL, MVT::Glue)); + + // fold (subc x, 0) -> x + no borrow + if (isNullConstant(N1)) + return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, DL, MVT::Glue)); + + // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1) + no borrow + if (isAllOnesConstant(N0)) + return CombineTo(N, DAG.getNode(ISD::XOR, DL, VT, N1, N0), + DAG.getNode(ISD::CARRY_FALSE, DL, MVT::Glue)); + + return SDValue(); +} + +SDValue DAGCombiner::visitSUBO(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + bool IsSigned = (ISD::SSUBO == N->getOpcode()); + + EVT CarryVT = N->getValueType(1); + SDLoc DL(N); + + // If the flag result is dead, turn this into an SUB. + if (!N->hasAnyUseOfValue(1)) + return CombineTo(N, DAG.getNode(ISD::SUB, DL, VT, N0, N1), + DAG.getUNDEF(CarryVT)); + + // fold (subo x, x) -> 0 + no borrow + if (N0 == N1) + return CombineTo(N, DAG.getConstant(0, DL, VT), + DAG.getConstant(0, DL, CarryVT)); + + ConstantSDNode *N1C = getAsNonOpaqueConstant(N1); + + // fold (subox, c) -> (addo x, -c) + if (IsSigned && N1C && !N1C->getAPIntValue().isMinSignedValue()) { + return DAG.getNode(ISD::SADDO, DL, N->getVTList(), N0, + DAG.getConstant(-N1C->getAPIntValue(), DL, VT)); + } + + // fold (subo x, 0) -> x + no borrow + if (isNullOrNullSplat(N1)) + return CombineTo(N, N0, DAG.getConstant(0, DL, CarryVT)); + + // Canonicalize (usubo -1, x) -> ~x, i.e. (xor x, -1) + no borrow + if (!IsSigned && isAllOnesOrAllOnesSplat(N0)) + return CombineTo(N, DAG.getNode(ISD::XOR, DL, VT, N1, N0), + DAG.getConstant(0, DL, CarryVT)); + + return SDValue(); +} + +SDValue DAGCombiner::visitSUBE(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue CarryIn = N->getOperand(2); + + // fold (sube x, y, false) -> (subc x, y) + if (CarryIn.getOpcode() == ISD::CARRY_FALSE) + return DAG.getNode(ISD::SUBC, SDLoc(N), N->getVTList(), N0, N1); + + return SDValue(); +} + +SDValue DAGCombiner::visitSUBCARRY(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue CarryIn = N->getOperand(2); + + // fold (subcarry x, y, false) -> (usubo x, y) + if (isNullConstant(CarryIn)) { + if (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::USUBO, N->getValueType(0))) + return DAG.getNode(ISD::USUBO, SDLoc(N), N->getVTList(), N0, N1); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitSSUBO_CARRY(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue CarryIn = N->getOperand(2); + + // fold (ssubo_carry x, y, false) -> (ssubo x, y) + if (isNullConstant(CarryIn)) { + if (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::SSUBO, N->getValueType(0))) + return DAG.getNode(ISD::SSUBO, SDLoc(N), N->getVTList(), N0, N1); + } + + return SDValue(); +} + +// Notice that "mulfix" can be any of SMULFIX, SMULFIXSAT, UMULFIX and +// UMULFIXSAT here. +SDValue DAGCombiner::visitMULFIX(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue Scale = N->getOperand(2); + EVT VT = N0.getValueType(); + + // fold (mulfix x, undef, scale) -> 0 + if (N0.isUndef() || N1.isUndef()) + return DAG.getConstant(0, SDLoc(N), VT); + + // Canonicalize constant to RHS (vector doesn't have to splat) + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(N->getOpcode(), SDLoc(N), VT, N1, N0, Scale); + + // fold (mulfix x, 0, scale) -> 0 + if (isNullConstant(N1)) + return DAG.getConstant(0, SDLoc(N), VT); + + return SDValue(); +} + +SDValue DAGCombiner::visitMUL(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + + // fold (mul x, undef) -> 0 + if (N0.isUndef() || N1.isUndef()) + return DAG.getConstant(0, SDLoc(N), VT); + + bool N1IsConst = false; + bool N1IsOpaqueConst = false; + APInt ConstValue1; + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + N1IsConst = ISD::isConstantSplatVector(N1.getNode(), ConstValue1); + assert((!N1IsConst || + ConstValue1.getBitWidth() == VT.getScalarSizeInBits()) && + "Splat APInt should be element width"); + } else { + N1IsConst = isa<ConstantSDNode>(N1); + if (N1IsConst) { + ConstValue1 = cast<ConstantSDNode>(N1)->getAPIntValue(); + N1IsOpaqueConst = cast<ConstantSDNode>(N1)->isOpaque(); + } + } + + // fold (mul c1, c2) -> c1*c2 + if (SDValue C = DAG.FoldConstantArithmetic(ISD::MUL, SDLoc(N), VT, {N0, N1})) + return C; + + // canonicalize constant to RHS (vector doesn't have to splat) + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(ISD::MUL, SDLoc(N), VT, N1, N0); + + // fold (mul x, 0) -> 0 + if (N1IsConst && ConstValue1.isNullValue()) + return N1; + + // fold (mul x, 1) -> x + if (N1IsConst && ConstValue1.isOneValue()) + return N0; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // fold (mul x, -1) -> 0-x + if (N1IsConst && ConstValue1.isAllOnesValue()) { + SDLoc DL(N); + return DAG.getNode(ISD::SUB, DL, VT, + DAG.getConstant(0, DL, VT), N0); + } + + // fold (mul x, (1 << c)) -> x << c + if (isConstantOrConstantVector(N1, /*NoOpaques*/ true) && + DAG.isKnownToBeAPowerOfTwo(N1) && + (!VT.isVector() || Level <= AfterLegalizeVectorOps)) { + SDLoc DL(N); + SDValue LogBase2 = BuildLogBase2(N1, DL); + EVT ShiftVT = getShiftAmountTy(N0.getValueType()); + SDValue Trunc = DAG.getZExtOrTrunc(LogBase2, DL, ShiftVT); + return DAG.getNode(ISD::SHL, DL, VT, N0, Trunc); + } + + // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c + if (N1IsConst && !N1IsOpaqueConst && (-ConstValue1).isPowerOf2()) { + unsigned Log2Val = (-ConstValue1).logBase2(); + SDLoc DL(N); + // FIXME: If the input is something that is easily negated (e.g. a + // single-use add), we should put the negate there. + return DAG.getNode(ISD::SUB, DL, VT, + DAG.getConstant(0, DL, VT), + DAG.getNode(ISD::SHL, DL, VT, N0, + DAG.getConstant(Log2Val, DL, + getShiftAmountTy(N0.getValueType())))); + } + + // Try to transform: + // (1) multiply-by-(power-of-2 +/- 1) into shift and add/sub. + // mul x, (2^N + 1) --> add (shl x, N), x + // mul x, (2^N - 1) --> sub (shl x, N), x + // Examples: x * 33 --> (x << 5) + x + // x * 15 --> (x << 4) - x + // x * -33 --> -((x << 5) + x) + // x * -15 --> -((x << 4) - x) ; this reduces --> x - (x << 4) + // (2) multiply-by-(power-of-2 +/- power-of-2) into shifts and add/sub. + // mul x, (2^N + 2^M) --> (add (shl x, N), (shl x, M)) + // mul x, (2^N - 2^M) --> (sub (shl x, N), (shl x, M)) + // Examples: x * 0x8800 --> (x << 15) + (x << 11) + // x * 0xf800 --> (x << 16) - (x << 11) + // x * -0x8800 --> -((x << 15) + (x << 11)) + // x * -0xf800 --> -((x << 16) - (x << 11)) ; (x << 11) - (x << 16) + if (N1IsConst && TLI.decomposeMulByConstant(*DAG.getContext(), VT, N1)) { + // TODO: We could handle more general decomposition of any constant by + // having the target set a limit on number of ops and making a + // callback to determine that sequence (similar to sqrt expansion). + unsigned MathOp = ISD::DELETED_NODE; + APInt MulC = ConstValue1.abs(); + // The constant `2` should be treated as (2^0 + 1). + unsigned TZeros = MulC == 2 ? 0 : MulC.countTrailingZeros(); + MulC.lshrInPlace(TZeros); + if ((MulC - 1).isPowerOf2()) + MathOp = ISD::ADD; + else if ((MulC + 1).isPowerOf2()) + MathOp = ISD::SUB; + + if (MathOp != ISD::DELETED_NODE) { + unsigned ShAmt = + MathOp == ISD::ADD ? (MulC - 1).logBase2() : (MulC + 1).logBase2(); + ShAmt += TZeros; + assert(ShAmt < VT.getScalarSizeInBits() && + "multiply-by-constant generated out of bounds shift"); + SDLoc DL(N); + SDValue Shl = + DAG.getNode(ISD::SHL, DL, VT, N0, DAG.getConstant(ShAmt, DL, VT)); + SDValue R = + TZeros ? DAG.getNode(MathOp, DL, VT, Shl, + DAG.getNode(ISD::SHL, DL, VT, N0, + DAG.getConstant(TZeros, DL, VT))) + : DAG.getNode(MathOp, DL, VT, Shl, N0); + if (ConstValue1.isNegative()) + R = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), R); + return R; + } + } + + // (mul (shl X, c1), c2) -> (mul X, c2 << c1) + if (N0.getOpcode() == ISD::SHL && + isConstantOrConstantVector(N1, /* NoOpaques */ true) && + isConstantOrConstantVector(N0.getOperand(1), /* NoOpaques */ true)) { + SDValue C3 = DAG.getNode(ISD::SHL, SDLoc(N), VT, N1, N0.getOperand(1)); + if (isConstantOrConstantVector(C3)) + return DAG.getNode(ISD::MUL, SDLoc(N), VT, N0.getOperand(0), C3); + } + + // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one + // use. + { + SDValue Sh(nullptr, 0), Y(nullptr, 0); + + // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). + if (N0.getOpcode() == ISD::SHL && + isConstantOrConstantVector(N0.getOperand(1)) && + N0.getNode()->hasOneUse()) { + Sh = N0; Y = N1; + } else if (N1.getOpcode() == ISD::SHL && + isConstantOrConstantVector(N1.getOperand(1)) && + N1.getNode()->hasOneUse()) { + Sh = N1; Y = N0; + } + + if (Sh.getNode()) { + SDValue Mul = DAG.getNode(ISD::MUL, SDLoc(N), VT, Sh.getOperand(0), Y); + return DAG.getNode(ISD::SHL, SDLoc(N), VT, Mul, Sh.getOperand(1)); + } + } + + // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) + if (DAG.isConstantIntBuildVectorOrConstantInt(N1) && + N0.getOpcode() == ISD::ADD && + DAG.isConstantIntBuildVectorOrConstantInt(N0.getOperand(1)) && + isMulAddWithConstProfitable(N, N0, N1)) + return DAG.getNode(ISD::ADD, SDLoc(N), VT, + DAG.getNode(ISD::MUL, SDLoc(N0), VT, + N0.getOperand(0), N1), + DAG.getNode(ISD::MUL, SDLoc(N1), VT, + N0.getOperand(1), N1)); + + // Fold (mul (vscale * C0), C1) to (vscale * (C0 * C1)). + if (N0.getOpcode() == ISD::VSCALE) + if (ConstantSDNode *NC1 = isConstOrConstSplat(N1)) { + const APInt &C0 = N0.getConstantOperandAPInt(0); + const APInt &C1 = NC1->getAPIntValue(); + return DAG.getVScale(SDLoc(N), VT, C0 * C1); + } + + // Fold ((mul x, 0/undef) -> 0, + // (mul x, 1) -> x) -> x) + // -> and(x, mask) + // We can replace vectors with '0' and '1' factors with a clearing mask. + if (VT.isFixedLengthVector()) { + unsigned NumElts = VT.getVectorNumElements(); + SmallBitVector ClearMask; + ClearMask.reserve(NumElts); + auto IsClearMask = [&ClearMask](ConstantSDNode *V) { + if (!V || V->isNullValue()) { + ClearMask.push_back(true); + return true; + } + ClearMask.push_back(false); + return V->isOne(); + }; + if ((!LegalOperations || TLI.isOperationLegalOrCustom(ISD::AND, VT)) && + ISD::matchUnaryPredicate(N1, IsClearMask, /*AllowUndefs*/ true)) { + assert(N1.getOpcode() == ISD::BUILD_VECTOR && "Unknown constant vector"); + SDLoc DL(N); + EVT LegalSVT = N1.getOperand(0).getValueType(); + SDValue Zero = DAG.getConstant(0, DL, LegalSVT); + SDValue AllOnes = DAG.getAllOnesConstant(DL, LegalSVT); + SmallVector<SDValue, 16> Mask(NumElts, AllOnes); + for (unsigned I = 0; I != NumElts; ++I) + if (ClearMask[I]) + Mask[I] = Zero; + return DAG.getNode(ISD::AND, DL, VT, N0, DAG.getBuildVector(VT, DL, Mask)); + } + } + + // reassociate mul + if (SDValue RMUL = reassociateOps(ISD::MUL, SDLoc(N), N0, N1, N->getFlags())) + return RMUL; + + return SDValue(); +} + +/// Return true if divmod libcall is available. +static bool isDivRemLibcallAvailable(SDNode *Node, bool isSigned, + const TargetLowering &TLI) { + RTLIB::Libcall LC; + EVT NodeType = Node->getValueType(0); + if (!NodeType.isSimple()) + return false; + switch (NodeType.getSimpleVT().SimpleTy) { + default: return false; // No libcall for vector types. + case MVT::i8: LC= isSigned ? RTLIB::SDIVREM_I8 : RTLIB::UDIVREM_I8; break; + case MVT::i16: LC= isSigned ? RTLIB::SDIVREM_I16 : RTLIB::UDIVREM_I16; break; + case MVT::i32: LC= isSigned ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32; break; + case MVT::i64: LC= isSigned ? RTLIB::SDIVREM_I64 : RTLIB::UDIVREM_I64; break; + case MVT::i128: LC= isSigned ? RTLIB::SDIVREM_I128:RTLIB::UDIVREM_I128; break; + } + + return TLI.getLibcallName(LC) != nullptr; +} + +/// Issue divrem if both quotient and remainder are needed. +SDValue DAGCombiner::useDivRem(SDNode *Node) { + if (Node->use_empty()) + return SDValue(); // This is a dead node, leave it alone. + + unsigned Opcode = Node->getOpcode(); + bool isSigned = (Opcode == ISD::SDIV) || (Opcode == ISD::SREM); + unsigned DivRemOpc = isSigned ? ISD::SDIVREM : ISD::UDIVREM; + + // DivMod lib calls can still work on non-legal types if using lib-calls. + EVT VT = Node->getValueType(0); + if (VT.isVector() || !VT.isInteger()) + return SDValue(); + + if (!TLI.isTypeLegal(VT) && !TLI.isOperationCustom(DivRemOpc, VT)) + return SDValue(); + + // If DIVREM is going to get expanded into a libcall, + // but there is no libcall available, then don't combine. + if (!TLI.isOperationLegalOrCustom(DivRemOpc, VT) && + !isDivRemLibcallAvailable(Node, isSigned, TLI)) + return SDValue(); + + // If div is legal, it's better to do the normal expansion + unsigned OtherOpcode = 0; + if ((Opcode == ISD::SDIV) || (Opcode == ISD::UDIV)) { + OtherOpcode = isSigned ? ISD::SREM : ISD::UREM; + if (TLI.isOperationLegalOrCustom(Opcode, VT)) + return SDValue(); + } else { + OtherOpcode = isSigned ? ISD::SDIV : ISD::UDIV; + if (TLI.isOperationLegalOrCustom(OtherOpcode, VT)) + return SDValue(); + } + + SDValue Op0 = Node->getOperand(0); + SDValue Op1 = Node->getOperand(1); + SDValue combined; + for (SDNode::use_iterator UI = Op0.getNode()->use_begin(), + UE = Op0.getNode()->use_end(); UI != UE; ++UI) { + SDNode *User = *UI; + if (User == Node || User->getOpcode() == ISD::DELETED_NODE || + User->use_empty()) + continue; + // Convert the other matching node(s), too; + // otherwise, the DIVREM may get target-legalized into something + // target-specific that we won't be able to recognize. + unsigned UserOpc = User->getOpcode(); + if ((UserOpc == Opcode || UserOpc == OtherOpcode || UserOpc == DivRemOpc) && + User->getOperand(0) == Op0 && + User->getOperand(1) == Op1) { + if (!combined) { + if (UserOpc == OtherOpcode) { + SDVTList VTs = DAG.getVTList(VT, VT); + combined = DAG.getNode(DivRemOpc, SDLoc(Node), VTs, Op0, Op1); + } else if (UserOpc == DivRemOpc) { + combined = SDValue(User, 0); + } else { + assert(UserOpc == Opcode); + continue; + } + } + if (UserOpc == ISD::SDIV || UserOpc == ISD::UDIV) + CombineTo(User, combined); + else if (UserOpc == ISD::SREM || UserOpc == ISD::UREM) + CombineTo(User, combined.getValue(1)); + } + } + return combined; +} + +static SDValue simplifyDivRem(SDNode *N, SelectionDAG &DAG) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + SDLoc DL(N); + + unsigned Opc = N->getOpcode(); + bool IsDiv = (ISD::SDIV == Opc) || (ISD::UDIV == Opc); + ConstantSDNode *N1C = isConstOrConstSplat(N1); + + // X / undef -> undef + // X % undef -> undef + // X / 0 -> undef + // X % 0 -> undef + // NOTE: This includes vectors where any divisor element is zero/undef. + if (DAG.isUndef(Opc, {N0, N1})) + return DAG.getUNDEF(VT); + + // undef / X -> 0 + // undef % X -> 0 + if (N0.isUndef()) + return DAG.getConstant(0, DL, VT); + + // 0 / X -> 0 + // 0 % X -> 0 + ConstantSDNode *N0C = isConstOrConstSplat(N0); + if (N0C && N0C->isNullValue()) + return N0; + + // X / X -> 1 + // X % X -> 0 + if (N0 == N1) + return DAG.getConstant(IsDiv ? 1 : 0, DL, VT); + + // X / 1 -> X + // X % 1 -> 0 + // If this is a boolean op (single-bit element type), we can't have + // division-by-zero or remainder-by-zero, so assume the divisor is 1. + // TODO: Similarly, if we're zero-extending a boolean divisor, then assume + // it's a 1. + if ((N1C && N1C->isOne()) || (VT.getScalarType() == MVT::i1)) + return IsDiv ? N0 : DAG.getConstant(0, DL, VT); + + return SDValue(); +} + +SDValue DAGCombiner::visitSDIV(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + EVT CCVT = getSetCCResultType(VT); + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + SDLoc DL(N); + + // fold (sdiv c1, c2) -> c1/c2 + ConstantSDNode *N1C = isConstOrConstSplat(N1); + if (SDValue C = DAG.FoldConstantArithmetic(ISD::SDIV, DL, VT, {N0, N1})) + return C; + + // fold (sdiv X, -1) -> 0-X + if (N1C && N1C->isAllOnesValue()) + return DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), N0); + + // fold (sdiv X, MIN_SIGNED) -> select(X == MIN_SIGNED, 1, 0) + if (N1C && N1C->getAPIntValue().isMinSignedValue()) + return DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, N0, N1, ISD::SETEQ), + DAG.getConstant(1, DL, VT), + DAG.getConstant(0, DL, VT)); + + if (SDValue V = simplifyDivRem(N, DAG)) + return V; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // If we know the sign bits of both operands are zero, strength reduce to a + // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 + if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) + return DAG.getNode(ISD::UDIV, DL, N1.getValueType(), N0, N1); + + if (SDValue V = visitSDIVLike(N0, N1, N)) { + // If the corresponding remainder node exists, update its users with + // (Dividend - (Quotient * Divisor). + if (SDNode *RemNode = DAG.getNodeIfExists(ISD::SREM, N->getVTList(), + { N0, N1 })) { + SDValue Mul = DAG.getNode(ISD::MUL, DL, VT, V, N1); + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0, Mul); + AddToWorklist(Mul.getNode()); + AddToWorklist(Sub.getNode()); + CombineTo(RemNode, Sub); + } + return V; + } + + // sdiv, srem -> sdivrem + // If the divisor is constant, then return DIVREM only if isIntDivCheap() is + // true. Otherwise, we break the simplification logic in visitREM(). + AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes(); + if (!N1C || TLI.isIntDivCheap(N->getValueType(0), Attr)) + if (SDValue DivRem = useDivRem(N)) + return DivRem; + + return SDValue(); +} + +SDValue DAGCombiner::visitSDIVLike(SDValue N0, SDValue N1, SDNode *N) { + SDLoc DL(N); + EVT VT = N->getValueType(0); + EVT CCVT = getSetCCResultType(VT); + unsigned BitWidth = VT.getScalarSizeInBits(); + + // Helper for determining whether a value is a power-2 constant scalar or a + // vector of such elements. + auto IsPowerOfTwo = [](ConstantSDNode *C) { + if (C->isNullValue() || C->isOpaque()) + return false; + if (C->getAPIntValue().isPowerOf2()) + return true; + if ((-C->getAPIntValue()).isPowerOf2()) + return true; + return false; + }; + + // fold (sdiv X, pow2) -> simple ops after legalize + // FIXME: We check for the exact bit here because the generic lowering gives + // better results in that case. The target-specific lowering should learn how + // to handle exact sdivs efficiently. + if (!N->getFlags().hasExact() && ISD::matchUnaryPredicate(N1, IsPowerOfTwo)) { + // Target-specific implementation of sdiv x, pow2. + if (SDValue Res = BuildSDIVPow2(N)) + return Res; + + // Create constants that are functions of the shift amount value. + EVT ShiftAmtTy = getShiftAmountTy(N0.getValueType()); + SDValue Bits = DAG.getConstant(BitWidth, DL, ShiftAmtTy); + SDValue C1 = DAG.getNode(ISD::CTTZ, DL, VT, N1); + C1 = DAG.getZExtOrTrunc(C1, DL, ShiftAmtTy); + SDValue Inexact = DAG.getNode(ISD::SUB, DL, ShiftAmtTy, Bits, C1); + if (!isConstantOrConstantVector(Inexact)) + return SDValue(); + + // Splat the sign bit into the register + SDValue Sign = DAG.getNode(ISD::SRA, DL, VT, N0, + DAG.getConstant(BitWidth - 1, DL, ShiftAmtTy)); + AddToWorklist(Sign.getNode()); + + // Add (N0 < 0) ? abs2 - 1 : 0; + SDValue Srl = DAG.getNode(ISD::SRL, DL, VT, Sign, Inexact); + AddToWorklist(Srl.getNode()); + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N0, Srl); + AddToWorklist(Add.getNode()); + SDValue Sra = DAG.getNode(ISD::SRA, DL, VT, Add, C1); + AddToWorklist(Sra.getNode()); + + // Special case: (sdiv X, 1) -> X + // Special Case: (sdiv X, -1) -> 0-X + SDValue One = DAG.getConstant(1, DL, VT); + SDValue AllOnes = DAG.getAllOnesConstant(DL, VT); + SDValue IsOne = DAG.getSetCC(DL, CCVT, N1, One, ISD::SETEQ); + SDValue IsAllOnes = DAG.getSetCC(DL, CCVT, N1, AllOnes, ISD::SETEQ); + SDValue IsOneOrAllOnes = DAG.getNode(ISD::OR, DL, CCVT, IsOne, IsAllOnes); + Sra = DAG.getSelect(DL, VT, IsOneOrAllOnes, N0, Sra); + + // If dividing by a positive value, we're done. Otherwise, the result must + // be negated. + SDValue Zero = DAG.getConstant(0, DL, VT); + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, Zero, Sra); + + // FIXME: Use SELECT_CC once we improve SELECT_CC constant-folding. + SDValue IsNeg = DAG.getSetCC(DL, CCVT, N1, Zero, ISD::SETLT); + SDValue Res = DAG.getSelect(DL, VT, IsNeg, Sub, Sra); + return Res; + } + + // If integer divide is expensive and we satisfy the requirements, emit an + // alternate sequence. Targets may check function attributes for size/speed + // trade-offs. + AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes(); + if (isConstantOrConstantVector(N1) && + !TLI.isIntDivCheap(N->getValueType(0), Attr)) + if (SDValue Op = BuildSDIV(N)) + return Op; + + return SDValue(); +} + +SDValue DAGCombiner::visitUDIV(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + EVT CCVT = getSetCCResultType(VT); + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + SDLoc DL(N); + + // fold (udiv c1, c2) -> c1/c2 + ConstantSDNode *N1C = isConstOrConstSplat(N1); + if (SDValue C = DAG.FoldConstantArithmetic(ISD::UDIV, DL, VT, {N0, N1})) + return C; + + // fold (udiv X, -1) -> select(X == -1, 1, 0) + if (N1C && N1C->getAPIntValue().isAllOnesValue()) + return DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, N0, N1, ISD::SETEQ), + DAG.getConstant(1, DL, VT), + DAG.getConstant(0, DL, VT)); + + if (SDValue V = simplifyDivRem(N, DAG)) + return V; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + if (SDValue V = visitUDIVLike(N0, N1, N)) { + // If the corresponding remainder node exists, update its users with + // (Dividend - (Quotient * Divisor). + if (SDNode *RemNode = DAG.getNodeIfExists(ISD::UREM, N->getVTList(), + { N0, N1 })) { + SDValue Mul = DAG.getNode(ISD::MUL, DL, VT, V, N1); + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0, Mul); + AddToWorklist(Mul.getNode()); + AddToWorklist(Sub.getNode()); + CombineTo(RemNode, Sub); + } + return V; + } + + // sdiv, srem -> sdivrem + // If the divisor is constant, then return DIVREM only if isIntDivCheap() is + // true. Otherwise, we break the simplification logic in visitREM(). + AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes(); + if (!N1C || TLI.isIntDivCheap(N->getValueType(0), Attr)) + if (SDValue DivRem = useDivRem(N)) + return DivRem; + + return SDValue(); +} + +SDValue DAGCombiner::visitUDIVLike(SDValue N0, SDValue N1, SDNode *N) { + SDLoc DL(N); + EVT VT = N->getValueType(0); + + // fold (udiv x, (1 << c)) -> x >>u c + if (isConstantOrConstantVector(N1, /*NoOpaques*/ true) && + DAG.isKnownToBeAPowerOfTwo(N1)) { + SDValue LogBase2 = BuildLogBase2(N1, DL); + AddToWorklist(LogBase2.getNode()); + + EVT ShiftVT = getShiftAmountTy(N0.getValueType()); + SDValue Trunc = DAG.getZExtOrTrunc(LogBase2, DL, ShiftVT); + AddToWorklist(Trunc.getNode()); + return DAG.getNode(ISD::SRL, DL, VT, N0, Trunc); + } + + // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 + if (N1.getOpcode() == ISD::SHL) { + SDValue N10 = N1.getOperand(0); + if (isConstantOrConstantVector(N10, /*NoOpaques*/ true) && + DAG.isKnownToBeAPowerOfTwo(N10)) { + SDValue LogBase2 = BuildLogBase2(N10, DL); + AddToWorklist(LogBase2.getNode()); + + EVT ADDVT = N1.getOperand(1).getValueType(); + SDValue Trunc = DAG.getZExtOrTrunc(LogBase2, DL, ADDVT); + AddToWorklist(Trunc.getNode()); + SDValue Add = DAG.getNode(ISD::ADD, DL, ADDVT, N1.getOperand(1), Trunc); + AddToWorklist(Add.getNode()); + return DAG.getNode(ISD::SRL, DL, VT, N0, Add); + } + } + + // fold (udiv x, c) -> alternate + AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes(); + if (isConstantOrConstantVector(N1) && + !TLI.isIntDivCheap(N->getValueType(0), Attr)) + if (SDValue Op = BuildUDIV(N)) + return Op; + + return SDValue(); +} + +// handles ISD::SREM and ISD::UREM +SDValue DAGCombiner::visitREM(SDNode *N) { + unsigned Opcode = N->getOpcode(); + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + EVT CCVT = getSetCCResultType(VT); + + bool isSigned = (Opcode == ISD::SREM); + SDLoc DL(N); + + // fold (rem c1, c2) -> c1%c2 + ConstantSDNode *N1C = isConstOrConstSplat(N1); + if (SDValue C = DAG.FoldConstantArithmetic(Opcode, DL, VT, {N0, N1})) + return C; + + // fold (urem X, -1) -> select(X == -1, 0, x) + if (!isSigned && N1C && N1C->getAPIntValue().isAllOnesValue()) + return DAG.getSelect(DL, VT, DAG.getSetCC(DL, CCVT, N0, N1, ISD::SETEQ), + DAG.getConstant(0, DL, VT), N0); + + if (SDValue V = simplifyDivRem(N, DAG)) + return V; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + if (isSigned) { + // If we know the sign bits of both operands are zero, strength reduce to a + // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 + if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0)) + return DAG.getNode(ISD::UREM, DL, VT, N0, N1); + } else { + if (DAG.isKnownToBeAPowerOfTwo(N1)) { + // fold (urem x, pow2) -> (and x, pow2-1) + SDValue NegOne = DAG.getAllOnesConstant(DL, VT); + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N1, NegOne); + AddToWorklist(Add.getNode()); + return DAG.getNode(ISD::AND, DL, VT, N0, Add); + } + if (N1.getOpcode() == ISD::SHL && + DAG.isKnownToBeAPowerOfTwo(N1.getOperand(0))) { + // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) + SDValue NegOne = DAG.getAllOnesConstant(DL, VT); + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, N1, NegOne); + AddToWorklist(Add.getNode()); + return DAG.getNode(ISD::AND, DL, VT, N0, Add); + } + } + + AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes(); + + // If X/C can be simplified by the division-by-constant logic, lower + // X%C to the equivalent of X-X/C*C. + // Reuse the SDIVLike/UDIVLike combines - to avoid mangling nodes, the + // speculative DIV must not cause a DIVREM conversion. We guard against this + // by skipping the simplification if isIntDivCheap(). When div is not cheap, + // combine will not return a DIVREM. Regardless, checking cheapness here + // makes sense since the simplification results in fatter code. + if (DAG.isKnownNeverZero(N1) && !TLI.isIntDivCheap(VT, Attr)) { + SDValue OptimizedDiv = + isSigned ? visitSDIVLike(N0, N1, N) : visitUDIVLike(N0, N1, N); + if (OptimizedDiv.getNode()) { + // If the equivalent Div node also exists, update its users. + unsigned DivOpcode = isSigned ? ISD::SDIV : ISD::UDIV; + if (SDNode *DivNode = DAG.getNodeIfExists(DivOpcode, N->getVTList(), + { N0, N1 })) + CombineTo(DivNode, OptimizedDiv); + SDValue Mul = DAG.getNode(ISD::MUL, DL, VT, OptimizedDiv, N1); + SDValue Sub = DAG.getNode(ISD::SUB, DL, VT, N0, Mul); + AddToWorklist(OptimizedDiv.getNode()); + AddToWorklist(Mul.getNode()); + return Sub; + } + } + + // sdiv, srem -> sdivrem + if (SDValue DivRem = useDivRem(N)) + return DivRem.getValue(1); + + return SDValue(); +} + +SDValue DAGCombiner::visitMULHS(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + SDLoc DL(N); + + if (VT.isVector()) { + // fold (mulhs x, 0) -> 0 + // do not return N0/N1, because undef node may exist. + if (ISD::isBuildVectorAllZeros(N0.getNode()) || + ISD::isBuildVectorAllZeros(N1.getNode())) + return DAG.getConstant(0, DL, VT); + } + + // fold (mulhs x, 0) -> 0 + if (isNullConstant(N1)) + return N1; + // fold (mulhs x, 1) -> (sra x, size(x)-1) + if (isOneConstant(N1)) + return DAG.getNode(ISD::SRA, DL, N0.getValueType(), N0, + DAG.getConstant(N0.getScalarValueSizeInBits() - 1, DL, + getShiftAmountTy(N0.getValueType()))); + + // fold (mulhs x, undef) -> 0 + if (N0.isUndef() || N1.isUndef()) + return DAG.getConstant(0, DL, VT); + + // If the type twice as wide is legal, transform the mulhs to a wider multiply + // plus a shift. + if (!TLI.isOperationLegalOrCustom(ISD::MULHS, VT) && VT.isSimple() && + !VT.isVector()) { + MVT Simple = VT.getSimpleVT(); + unsigned SimpleSize = Simple.getSizeInBits(); + EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); + if (TLI.isOperationLegal(ISD::MUL, NewVT)) { + N0 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N0); + N1 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N1); + N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1); + N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1, + DAG.getConstant(SimpleSize, DL, + getShiftAmountTy(N1.getValueType()))); + return DAG.getNode(ISD::TRUNCATE, DL, VT, N1); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitMULHU(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + SDLoc DL(N); + + if (VT.isVector()) { + // fold (mulhu x, 0) -> 0 + // do not return N0/N1, because undef node may exist. + if (ISD::isBuildVectorAllZeros(N0.getNode()) || + ISD::isBuildVectorAllZeros(N1.getNode())) + return DAG.getConstant(0, DL, VT); + } + + // fold (mulhu x, 0) -> 0 + if (isNullConstant(N1)) + return N1; + // fold (mulhu x, 1) -> 0 + if (isOneConstant(N1)) + return DAG.getConstant(0, DL, N0.getValueType()); + // fold (mulhu x, undef) -> 0 + if (N0.isUndef() || N1.isUndef()) + return DAG.getConstant(0, DL, VT); + + // fold (mulhu x, (1 << c)) -> x >> (bitwidth - c) + if (isConstantOrConstantVector(N1, /*NoOpaques*/ true) && + DAG.isKnownToBeAPowerOfTwo(N1) && hasOperation(ISD::SRL, VT)) { + unsigned NumEltBits = VT.getScalarSizeInBits(); + SDValue LogBase2 = BuildLogBase2(N1, DL); + SDValue SRLAmt = DAG.getNode( + ISD::SUB, DL, VT, DAG.getConstant(NumEltBits, DL, VT), LogBase2); + EVT ShiftVT = getShiftAmountTy(N0.getValueType()); + SDValue Trunc = DAG.getZExtOrTrunc(SRLAmt, DL, ShiftVT); + return DAG.getNode(ISD::SRL, DL, VT, N0, Trunc); + } + + // If the type twice as wide is legal, transform the mulhu to a wider multiply + // plus a shift. + if (!TLI.isOperationLegalOrCustom(ISD::MULHU, VT) && VT.isSimple() && + !VT.isVector()) { + MVT Simple = VT.getSimpleVT(); + unsigned SimpleSize = Simple.getSizeInBits(); + EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); + if (TLI.isOperationLegal(ISD::MUL, NewVT)) { + N0 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N0); + N1 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N1); + N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1); + N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1, + DAG.getConstant(SimpleSize, DL, + getShiftAmountTy(N1.getValueType()))); + return DAG.getNode(ISD::TRUNCATE, DL, VT, N1); + } + } + + return SDValue(); +} + +/// Perform optimizations common to nodes that compute two values. LoOp and HiOp +/// give the opcodes for the two computations that are being performed. Return +/// true if a simplification was made. +SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp, + unsigned HiOp) { + // If the high half is not needed, just compute the low half. + bool HiExists = N->hasAnyUseOfValue(1); + if (!HiExists && (!LegalOperations || + TLI.isOperationLegalOrCustom(LoOp, N->getValueType(0)))) { + SDValue Res = DAG.getNode(LoOp, SDLoc(N), N->getValueType(0), N->ops()); + return CombineTo(N, Res, Res); + } + + // If the low half is not needed, just compute the high half. + bool LoExists = N->hasAnyUseOfValue(0); + if (!LoExists && (!LegalOperations || + TLI.isOperationLegalOrCustom(HiOp, N->getValueType(1)))) { + SDValue Res = DAG.getNode(HiOp, SDLoc(N), N->getValueType(1), N->ops()); + return CombineTo(N, Res, Res); + } + + // If both halves are used, return as it is. + if (LoExists && HiExists) + return SDValue(); + + // If the two computed results can be simplified separately, separate them. + if (LoExists) { + SDValue Lo = DAG.getNode(LoOp, SDLoc(N), N->getValueType(0), N->ops()); + AddToWorklist(Lo.getNode()); + SDValue LoOpt = combine(Lo.getNode()); + if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() && + (!LegalOperations || + TLI.isOperationLegalOrCustom(LoOpt.getOpcode(), LoOpt.getValueType()))) + return CombineTo(N, LoOpt, LoOpt); + } + + if (HiExists) { + SDValue Hi = DAG.getNode(HiOp, SDLoc(N), N->getValueType(1), N->ops()); + AddToWorklist(Hi.getNode()); + SDValue HiOpt = combine(Hi.getNode()); + if (HiOpt.getNode() && HiOpt != Hi && + (!LegalOperations || + TLI.isOperationLegalOrCustom(HiOpt.getOpcode(), HiOpt.getValueType()))) + return CombineTo(N, HiOpt, HiOpt); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) { + if (SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS)) + return Res; + + EVT VT = N->getValueType(0); + SDLoc DL(N); + + // If the type is twice as wide is legal, transform the mulhu to a wider + // multiply plus a shift. + if (VT.isSimple() && !VT.isVector()) { + MVT Simple = VT.getSimpleVT(); + unsigned SimpleSize = Simple.getSizeInBits(); + EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); + if (TLI.isOperationLegal(ISD::MUL, NewVT)) { + SDValue Lo = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(0)); + SDValue Hi = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(1)); + Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi); + // Compute the high part as N1. + Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo, + DAG.getConstant(SimpleSize, DL, + getShiftAmountTy(Lo.getValueType()))); + Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi); + // Compute the low part as N0. + Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo); + return CombineTo(N, Lo, Hi); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) { + if (SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU)) + return Res; + + EVT VT = N->getValueType(0); + SDLoc DL(N); + + // (umul_lohi N0, 0) -> (0, 0) + if (isNullConstant(N->getOperand(1))) { + SDValue Zero = DAG.getConstant(0, DL, VT); + return CombineTo(N, Zero, Zero); + } + + // (umul_lohi N0, 1) -> (N0, 0) + if (isOneConstant(N->getOperand(1))) { + SDValue Zero = DAG.getConstant(0, DL, VT); + return CombineTo(N, N->getOperand(0), Zero); + } + + // If the type is twice as wide is legal, transform the mulhu to a wider + // multiply plus a shift. + if (VT.isSimple() && !VT.isVector()) { + MVT Simple = VT.getSimpleVT(); + unsigned SimpleSize = Simple.getSizeInBits(); + EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2); + if (TLI.isOperationLegal(ISD::MUL, NewVT)) { + SDValue Lo = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(0)); + SDValue Hi = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(1)); + Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi); + // Compute the high part as N1. + Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo, + DAG.getConstant(SimpleSize, DL, + getShiftAmountTy(Lo.getValueType()))); + Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi); + // Compute the low part as N0. + Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo); + return CombineTo(N, Lo, Hi); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitMULO(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + bool IsSigned = (ISD::SMULO == N->getOpcode()); + + EVT CarryVT = N->getValueType(1); + SDLoc DL(N); + + // canonicalize constant to RHS. + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(N->getOpcode(), DL, N->getVTList(), N1, N0); + + // fold (mulo x, 0) -> 0 + no carry out + if (isNullOrNullSplat(N1)) + return CombineTo(N, DAG.getConstant(0, DL, VT), + DAG.getConstant(0, DL, CarryVT)); + + // (mulo x, 2) -> (addo x, x) + if (ConstantSDNode *C2 = isConstOrConstSplat(N1)) + if (C2->getAPIntValue() == 2) + return DAG.getNode(IsSigned ? ISD::SADDO : ISD::UADDO, DL, + N->getVTList(), N0, N0); + + return SDValue(); +} + +SDValue DAGCombiner::visitIMINMAX(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + unsigned Opcode = N->getOpcode(); + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold operation with constant operands. + if (SDValue C = DAG.FoldConstantArithmetic(Opcode, SDLoc(N), VT, {N0, N1})) + return C; + + // canonicalize constant to RHS + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(N->getOpcode(), SDLoc(N), VT, N1, N0); + + // Is sign bits are zero, flip between UMIN/UMAX and SMIN/SMAX. + // Only do this if the current op isn't legal and the flipped is. + if (!TLI.isOperationLegal(Opcode, VT) && + (N0.isUndef() || DAG.SignBitIsZero(N0)) && + (N1.isUndef() || DAG.SignBitIsZero(N1))) { + unsigned AltOpcode; + switch (Opcode) { + case ISD::SMIN: AltOpcode = ISD::UMIN; break; + case ISD::SMAX: AltOpcode = ISD::UMAX; break; + case ISD::UMIN: AltOpcode = ISD::SMIN; break; + case ISD::UMAX: AltOpcode = ISD::SMAX; break; + default: llvm_unreachable("Unknown MINMAX opcode"); + } + if (TLI.isOperationLegal(AltOpcode, VT)) + return DAG.getNode(AltOpcode, SDLoc(N), VT, N0, N1); + } + + // Simplify the operands using demanded-bits information. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + return SDValue(); +} + +/// If this is a bitwise logic instruction and both operands have the same +/// opcode, try to sink the other opcode after the logic instruction. +SDValue DAGCombiner::hoistLogicOpWithSameOpcodeHands(SDNode *N) { + SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + unsigned LogicOpcode = N->getOpcode(); + unsigned HandOpcode = N0.getOpcode(); + assert((LogicOpcode == ISD::AND || LogicOpcode == ISD::OR || + LogicOpcode == ISD::XOR) && "Expected logic opcode"); + assert(HandOpcode == N1.getOpcode() && "Bad input!"); + + // Bail early if none of these transforms apply. + if (N0.getNumOperands() == 0) + return SDValue(); + + // FIXME: We should check number of uses of the operands to not increase + // the instruction count for all transforms. + + // Handle size-changing casts. + SDValue X = N0.getOperand(0); + SDValue Y = N1.getOperand(0); + EVT XVT = X.getValueType(); + SDLoc DL(N); + if (HandOpcode == ISD::ANY_EXTEND || HandOpcode == ISD::ZERO_EXTEND || + HandOpcode == ISD::SIGN_EXTEND) { + // If both operands have other uses, this transform would create extra + // instructions without eliminating anything. + if (!N0.hasOneUse() && !N1.hasOneUse()) + return SDValue(); + // We need matching integer source types. + if (XVT != Y.getValueType()) + return SDValue(); + // Don't create an illegal op during or after legalization. Don't ever + // create an unsupported vector op. + if ((VT.isVector() || LegalOperations) && + !TLI.isOperationLegalOrCustom(LogicOpcode, XVT)) + return SDValue(); + // Avoid infinite looping with PromoteIntBinOp. + // TODO: Should we apply desirable/legal constraints to all opcodes? + if (HandOpcode == ISD::ANY_EXTEND && LegalTypes && + !TLI.isTypeDesirableForOp(LogicOpcode, XVT)) + return SDValue(); + // logic_op (hand_op X), (hand_op Y) --> hand_op (logic_op X, Y) + SDValue Logic = DAG.getNode(LogicOpcode, DL, XVT, X, Y); + return DAG.getNode(HandOpcode, DL, VT, Logic); + } + + // logic_op (truncate x), (truncate y) --> truncate (logic_op x, y) + if (HandOpcode == ISD::TRUNCATE) { + // If both operands have other uses, this transform would create extra + // instructions without eliminating anything. + if (!N0.hasOneUse() && !N1.hasOneUse()) + return SDValue(); + // We need matching source types. + if (XVT != Y.getValueType()) + return SDValue(); + // Don't create an illegal op during or after legalization. + if (LegalOperations && !TLI.isOperationLegal(LogicOpcode, XVT)) + return SDValue(); + // Be extra careful sinking truncate. If it's free, there's no benefit in + // widening a binop. Also, don't create a logic op on an illegal type. + if (TLI.isZExtFree(VT, XVT) && TLI.isTruncateFree(XVT, VT)) + return SDValue(); + if (!TLI.isTypeLegal(XVT)) + return SDValue(); + SDValue Logic = DAG.getNode(LogicOpcode, DL, XVT, X, Y); + return DAG.getNode(HandOpcode, DL, VT, Logic); + } + + // For binops SHL/SRL/SRA/AND: + // logic_op (OP x, z), (OP y, z) --> OP (logic_op x, y), z + if ((HandOpcode == ISD::SHL || HandOpcode == ISD::SRL || + HandOpcode == ISD::SRA || HandOpcode == ISD::AND) && + N0.getOperand(1) == N1.getOperand(1)) { + // If either operand has other uses, this transform is not an improvement. + if (!N0.hasOneUse() || !N1.hasOneUse()) + return SDValue(); + SDValue Logic = DAG.getNode(LogicOpcode, DL, XVT, X, Y); + return DAG.getNode(HandOpcode, DL, VT, Logic, N0.getOperand(1)); + } + + // Unary ops: logic_op (bswap x), (bswap y) --> bswap (logic_op x, y) + if (HandOpcode == ISD::BSWAP) { + // If either operand has other uses, this transform is not an improvement. + if (!N0.hasOneUse() || !N1.hasOneUse()) + return SDValue(); + SDValue Logic = DAG.getNode(LogicOpcode, DL, XVT, X, Y); + return DAG.getNode(HandOpcode, DL, VT, Logic); + } + + // Simplify xor/and/or (bitcast(A), bitcast(B)) -> bitcast(op (A,B)) + // Only perform this optimization up until type legalization, before + // LegalizeVectorOprs. LegalizeVectorOprs promotes vector operations by + // adding bitcasts. For example (xor v4i32) is promoted to (v2i64), and + // we don't want to undo this promotion. + // We also handle SCALAR_TO_VECTOR because xor/or/and operations are cheaper + // on scalars. + if ((HandOpcode == ISD::BITCAST || HandOpcode == ISD::SCALAR_TO_VECTOR) && + Level <= AfterLegalizeTypes) { + // Input types must be integer and the same. + if (XVT.isInteger() && XVT == Y.getValueType() && + !(VT.isVector() && TLI.isTypeLegal(VT) && + !XVT.isVector() && !TLI.isTypeLegal(XVT))) { + SDValue Logic = DAG.getNode(LogicOpcode, DL, XVT, X, Y); + return DAG.getNode(HandOpcode, DL, VT, Logic); + } + } + + // Xor/and/or are indifferent to the swizzle operation (shuffle of one value). + // Simplify xor/and/or (shuff(A), shuff(B)) -> shuff(op (A,B)) + // If both shuffles use the same mask, and both shuffle within a single + // vector, then it is worthwhile to move the swizzle after the operation. + // The type-legalizer generates this pattern when loading illegal + // vector types from memory. In many cases this allows additional shuffle + // optimizations. + // There are other cases where moving the shuffle after the xor/and/or + // is profitable even if shuffles don't perform a swizzle. + // If both shuffles use the same mask, and both shuffles have the same first + // or second operand, then it might still be profitable to move the shuffle + // after the xor/and/or operation. + if (HandOpcode == ISD::VECTOR_SHUFFLE && Level < AfterLegalizeDAG) { + auto *SVN0 = cast<ShuffleVectorSDNode>(N0); + auto *SVN1 = cast<ShuffleVectorSDNode>(N1); + assert(X.getValueType() == Y.getValueType() && + "Inputs to shuffles are not the same type"); + + // Check that both shuffles use the same mask. The masks are known to be of + // the same length because the result vector type is the same. + // Check also that shuffles have only one use to avoid introducing extra + // instructions. + if (!SVN0->hasOneUse() || !SVN1->hasOneUse() || + !SVN0->getMask().equals(SVN1->getMask())) + return SDValue(); + + // Don't try to fold this node if it requires introducing a + // build vector of all zeros that might be illegal at this stage. + SDValue ShOp = N0.getOperand(1); + if (LogicOpcode == ISD::XOR && !ShOp.isUndef()) + ShOp = tryFoldToZero(DL, TLI, VT, DAG, LegalOperations); + + // (logic_op (shuf (A, C), shuf (B, C))) --> shuf (logic_op (A, B), C) + if (N0.getOperand(1) == N1.getOperand(1) && ShOp.getNode()) { + SDValue Logic = DAG.getNode(LogicOpcode, DL, VT, + N0.getOperand(0), N1.getOperand(0)); + return DAG.getVectorShuffle(VT, DL, Logic, ShOp, SVN0->getMask()); + } + + // Don't try to fold this node if it requires introducing a + // build vector of all zeros that might be illegal at this stage. + ShOp = N0.getOperand(0); + if (LogicOpcode == ISD::XOR && !ShOp.isUndef()) + ShOp = tryFoldToZero(DL, TLI, VT, DAG, LegalOperations); + + // (logic_op (shuf (C, A), shuf (C, B))) --> shuf (C, logic_op (A, B)) + if (N0.getOperand(0) == N1.getOperand(0) && ShOp.getNode()) { + SDValue Logic = DAG.getNode(LogicOpcode, DL, VT, N0.getOperand(1), + N1.getOperand(1)); + return DAG.getVectorShuffle(VT, DL, ShOp, Logic, SVN0->getMask()); + } + } + + return SDValue(); +} + +/// Try to make (and/or setcc (LL, LR), setcc (RL, RR)) more efficient. +SDValue DAGCombiner::foldLogicOfSetCCs(bool IsAnd, SDValue N0, SDValue N1, + const SDLoc &DL) { + SDValue LL, LR, RL, RR, N0CC, N1CC; + if (!isSetCCEquivalent(N0, LL, LR, N0CC) || + !isSetCCEquivalent(N1, RL, RR, N1CC)) + return SDValue(); + + assert(N0.getValueType() == N1.getValueType() && + "Unexpected operand types for bitwise logic op"); + assert(LL.getValueType() == LR.getValueType() && + RL.getValueType() == RR.getValueType() && + "Unexpected operand types for setcc"); + + // If we're here post-legalization or the logic op type is not i1, the logic + // op type must match a setcc result type. Also, all folds require new + // operations on the left and right operands, so those types must match. + EVT VT = N0.getValueType(); + EVT OpVT = LL.getValueType(); + if (LegalOperations || VT.getScalarType() != MVT::i1) + if (VT != getSetCCResultType(OpVT)) + return SDValue(); + if (OpVT != RL.getValueType()) + return SDValue(); + + ISD::CondCode CC0 = cast<CondCodeSDNode>(N0CC)->get(); + ISD::CondCode CC1 = cast<CondCodeSDNode>(N1CC)->get(); + bool IsInteger = OpVT.isInteger(); + if (LR == RR && CC0 == CC1 && IsInteger) { + bool IsZero = isNullOrNullSplat(LR); + bool IsNeg1 = isAllOnesOrAllOnesSplat(LR); + + // All bits clear? + bool AndEqZero = IsAnd && CC1 == ISD::SETEQ && IsZero; + // All sign bits clear? + bool AndGtNeg1 = IsAnd && CC1 == ISD::SETGT && IsNeg1; + // Any bits set? + bool OrNeZero = !IsAnd && CC1 == ISD::SETNE && IsZero; + // Any sign bits set? + bool OrLtZero = !IsAnd && CC1 == ISD::SETLT && IsZero; + + // (and (seteq X, 0), (seteq Y, 0)) --> (seteq (or X, Y), 0) + // (and (setgt X, -1), (setgt Y, -1)) --> (setgt (or X, Y), -1) + // (or (setne X, 0), (setne Y, 0)) --> (setne (or X, Y), 0) + // (or (setlt X, 0), (setlt Y, 0)) --> (setlt (or X, Y), 0) + if (AndEqZero || AndGtNeg1 || OrNeZero || OrLtZero) { + SDValue Or = DAG.getNode(ISD::OR, SDLoc(N0), OpVT, LL, RL); + AddToWorklist(Or.getNode()); + return DAG.getSetCC(DL, VT, Or, LR, CC1); + } + + // All bits set? + bool AndEqNeg1 = IsAnd && CC1 == ISD::SETEQ && IsNeg1; + // All sign bits set? + bool AndLtZero = IsAnd && CC1 == ISD::SETLT && IsZero; + // Any bits clear? + bool OrNeNeg1 = !IsAnd && CC1 == ISD::SETNE && IsNeg1; + // Any sign bits clear? + bool OrGtNeg1 = !IsAnd && CC1 == ISD::SETGT && IsNeg1; + + // (and (seteq X, -1), (seteq Y, -1)) --> (seteq (and X, Y), -1) + // (and (setlt X, 0), (setlt Y, 0)) --> (setlt (and X, Y), 0) + // (or (setne X, -1), (setne Y, -1)) --> (setne (and X, Y), -1) + // (or (setgt X, -1), (setgt Y -1)) --> (setgt (and X, Y), -1) + if (AndEqNeg1 || AndLtZero || OrNeNeg1 || OrGtNeg1) { + SDValue And = DAG.getNode(ISD::AND, SDLoc(N0), OpVT, LL, RL); + AddToWorklist(And.getNode()); + return DAG.getSetCC(DL, VT, And, LR, CC1); + } + } + + // TODO: What is the 'or' equivalent of this fold? + // (and (setne X, 0), (setne X, -1)) --> (setuge (add X, 1), 2) + if (IsAnd && LL == RL && CC0 == CC1 && OpVT.getScalarSizeInBits() > 1 && + IsInteger && CC0 == ISD::SETNE && + ((isNullConstant(LR) && isAllOnesConstant(RR)) || + (isAllOnesConstant(LR) && isNullConstant(RR)))) { + SDValue One = DAG.getConstant(1, DL, OpVT); + SDValue Two = DAG.getConstant(2, DL, OpVT); + SDValue Add = DAG.getNode(ISD::ADD, SDLoc(N0), OpVT, LL, One); + AddToWorklist(Add.getNode()); + return DAG.getSetCC(DL, VT, Add, Two, ISD::SETUGE); + } + + // Try more general transforms if the predicates match and the only user of + // the compares is the 'and' or 'or'. + if (IsInteger && TLI.convertSetCCLogicToBitwiseLogic(OpVT) && CC0 == CC1 && + N0.hasOneUse() && N1.hasOneUse()) { + // and (seteq A, B), (seteq C, D) --> seteq (or (xor A, B), (xor C, D)), 0 + // or (setne A, B), (setne C, D) --> setne (or (xor A, B), (xor C, D)), 0 + if ((IsAnd && CC1 == ISD::SETEQ) || (!IsAnd && CC1 == ISD::SETNE)) { + SDValue XorL = DAG.getNode(ISD::XOR, SDLoc(N0), OpVT, LL, LR); + SDValue XorR = DAG.getNode(ISD::XOR, SDLoc(N1), OpVT, RL, RR); + SDValue Or = DAG.getNode(ISD::OR, DL, OpVT, XorL, XorR); + SDValue Zero = DAG.getConstant(0, DL, OpVT); + return DAG.getSetCC(DL, VT, Or, Zero, CC1); + } + + // Turn compare of constants whose difference is 1 bit into add+and+setcc. + // TODO - support non-uniform vector amounts. + if ((IsAnd && CC1 == ISD::SETNE) || (!IsAnd && CC1 == ISD::SETEQ)) { + // Match a shared variable operand and 2 non-opaque constant operands. + ConstantSDNode *C0 = isConstOrConstSplat(LR); + ConstantSDNode *C1 = isConstOrConstSplat(RR); + if (LL == RL && C0 && C1 && !C0->isOpaque() && !C1->isOpaque()) { + // Canonicalize larger constant as C0. + if (C1->getAPIntValue().ugt(C0->getAPIntValue())) + std::swap(C0, C1); + + // The difference of the constants must be a single bit. + const APInt &C0Val = C0->getAPIntValue(); + const APInt &C1Val = C1->getAPIntValue(); + if ((C0Val - C1Val).isPowerOf2()) { + // and/or (setcc X, C0, ne), (setcc X, C1, ne/eq) --> + // setcc ((add X, -C1), ~(C0 - C1)), 0, ne/eq + SDValue OffsetC = DAG.getConstant(-C1Val, DL, OpVT); + SDValue Add = DAG.getNode(ISD::ADD, DL, OpVT, LL, OffsetC); + SDValue MaskC = DAG.getConstant(~(C0Val - C1Val), DL, OpVT); + SDValue And = DAG.getNode(ISD::AND, DL, OpVT, Add, MaskC); + SDValue Zero = DAG.getConstant(0, DL, OpVT); + return DAG.getSetCC(DL, VT, And, Zero, CC0); + } + } + } + } + + // Canonicalize equivalent operands to LL == RL. + if (LL == RR && LR == RL) { + CC1 = ISD::getSetCCSwappedOperands(CC1); + std::swap(RL, RR); + } + + // (and (setcc X, Y, CC0), (setcc X, Y, CC1)) --> (setcc X, Y, NewCC) + // (or (setcc X, Y, CC0), (setcc X, Y, CC1)) --> (setcc X, Y, NewCC) + if (LL == RL && LR == RR) { + ISD::CondCode NewCC = IsAnd ? ISD::getSetCCAndOperation(CC0, CC1, OpVT) + : ISD::getSetCCOrOperation(CC0, CC1, OpVT); + if (NewCC != ISD::SETCC_INVALID && + (!LegalOperations || + (TLI.isCondCodeLegal(NewCC, LL.getSimpleValueType()) && + TLI.isOperationLegal(ISD::SETCC, OpVT)))) + return DAG.getSetCC(DL, VT, LL, LR, NewCC); + } + + return SDValue(); +} + +/// This contains all DAGCombine rules which reduce two values combined by +/// an And operation to a single value. This makes them reusable in the context +/// of visitSELECT(). Rules involving constants are not included as +/// visitSELECT() already handles those cases. +SDValue DAGCombiner::visitANDLike(SDValue N0, SDValue N1, SDNode *N) { + EVT VT = N1.getValueType(); + SDLoc DL(N); + + // fold (and x, undef) -> 0 + if (N0.isUndef() || N1.isUndef()) + return DAG.getConstant(0, DL, VT); + + if (SDValue V = foldLogicOfSetCCs(true, N0, N1, DL)) + return V; + + if (N0.getOpcode() == ISD::ADD && N1.getOpcode() == ISD::SRL && + VT.getSizeInBits() <= 64) { + if (ConstantSDNode *ADDI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { + if (ConstantSDNode *SRLI = dyn_cast<ConstantSDNode>(N1.getOperand(1))) { + // Look for (and (add x, c1), (lshr y, c2)). If C1 wasn't a legal + // immediate for an add, but it is legal if its top c2 bits are set, + // transform the ADD so the immediate doesn't need to be materialized + // in a register. + APInt ADDC = ADDI->getAPIntValue(); + APInt SRLC = SRLI->getAPIntValue(); + if (ADDC.getMinSignedBits() <= 64 && + SRLC.ult(VT.getSizeInBits()) && + !TLI.isLegalAddImmediate(ADDC.getSExtValue())) { + APInt Mask = APInt::getHighBitsSet(VT.getSizeInBits(), + SRLC.getZExtValue()); + if (DAG.MaskedValueIsZero(N0.getOperand(1), Mask)) { + ADDC |= Mask; + if (TLI.isLegalAddImmediate(ADDC.getSExtValue())) { + SDLoc DL0(N0); + SDValue NewAdd = + DAG.getNode(ISD::ADD, DL0, VT, + N0.getOperand(0), DAG.getConstant(ADDC, DL, VT)); + CombineTo(N0.getNode(), NewAdd); + // Return N so it doesn't get rechecked! + return SDValue(N, 0); + } + } + } + } + } + } + + // Reduce bit extract of low half of an integer to the narrower type. + // (and (srl i64:x, K), KMask) -> + // (i64 zero_extend (and (srl (i32 (trunc i64:x)), K)), KMask) + if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) { + if (ConstantSDNode *CAnd = dyn_cast<ConstantSDNode>(N1)) { + if (ConstantSDNode *CShift = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { + unsigned Size = VT.getSizeInBits(); + const APInt &AndMask = CAnd->getAPIntValue(); + unsigned ShiftBits = CShift->getZExtValue(); + + // Bail out, this node will probably disappear anyway. + if (ShiftBits == 0) + return SDValue(); + + unsigned MaskBits = AndMask.countTrailingOnes(); + EVT HalfVT = EVT::getIntegerVT(*DAG.getContext(), Size / 2); + + if (AndMask.isMask() && + // Required bits must not span the two halves of the integer and + // must fit in the half size type. + (ShiftBits + MaskBits <= Size / 2) && + TLI.isNarrowingProfitable(VT, HalfVT) && + TLI.isTypeDesirableForOp(ISD::AND, HalfVT) && + TLI.isTypeDesirableForOp(ISD::SRL, HalfVT) && + TLI.isTruncateFree(VT, HalfVT) && + TLI.isZExtFree(HalfVT, VT)) { + // The isNarrowingProfitable is to avoid regressions on PPC and + // AArch64 which match a few 64-bit bit insert / bit extract patterns + // on downstream users of this. Those patterns could probably be + // extended to handle extensions mixed in. + + SDValue SL(N0); + assert(MaskBits <= Size); + + // Extracting the highest bit of the low half. + EVT ShiftVT = TLI.getShiftAmountTy(HalfVT, DAG.getDataLayout()); + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SL, HalfVT, + N0.getOperand(0)); + + SDValue NewMask = DAG.getConstant(AndMask.trunc(Size / 2), SL, HalfVT); + SDValue ShiftK = DAG.getConstant(ShiftBits, SL, ShiftVT); + SDValue Shift = DAG.getNode(ISD::SRL, SL, HalfVT, Trunc, ShiftK); + SDValue And = DAG.getNode(ISD::AND, SL, HalfVT, Shift, NewMask); + return DAG.getNode(ISD::ZERO_EXTEND, SL, VT, And); + } + } + } + } + + return SDValue(); +} + +bool DAGCombiner::isAndLoadExtLoad(ConstantSDNode *AndC, LoadSDNode *LoadN, + EVT LoadResultTy, EVT &ExtVT) { + if (!AndC->getAPIntValue().isMask()) + return false; + + unsigned ActiveBits = AndC->getAPIntValue().countTrailingOnes(); + + ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits); + EVT LoadedVT = LoadN->getMemoryVT(); + + if (ExtVT == LoadedVT && + (!LegalOperations || + TLI.isLoadExtLegal(ISD::ZEXTLOAD, LoadResultTy, ExtVT))) { + // ZEXTLOAD will match without needing to change the size of the value being + // loaded. + return true; + } + + // Do not change the width of a volatile or atomic loads. + if (!LoadN->isSimple()) + return false; + + // Do not generate loads of non-round integer types since these can + // be expensive (and would be wrong if the type is not byte sized). + if (!LoadedVT.bitsGT(ExtVT) || !ExtVT.isRound()) + return false; + + if (LegalOperations && + !TLI.isLoadExtLegal(ISD::ZEXTLOAD, LoadResultTy, ExtVT)) + return false; + + if (!TLI.shouldReduceLoadWidth(LoadN, ISD::ZEXTLOAD, ExtVT)) + return false; + + return true; +} + +bool DAGCombiner::isLegalNarrowLdSt(LSBaseSDNode *LDST, + ISD::LoadExtType ExtType, EVT &MemVT, + unsigned ShAmt) { + if (!LDST) + return false; + // Only allow byte offsets. + if (ShAmt % 8) + return false; + + // Do not generate loads of non-round integer types since these can + // be expensive (and would be wrong if the type is not byte sized). + if (!MemVT.isRound()) + return false; + + // Don't change the width of a volatile or atomic loads. + if (!LDST->isSimple()) + return false; + + EVT LdStMemVT = LDST->getMemoryVT(); + + // Bail out when changing the scalable property, since we can't be sure that + // we're actually narrowing here. + if (LdStMemVT.isScalableVector() != MemVT.isScalableVector()) + return false; + + // Verify that we are actually reducing a load width here. + if (LdStMemVT.bitsLT(MemVT)) + return false; + + // Ensure that this isn't going to produce an unsupported memory access. + if (ShAmt) { + assert(ShAmt % 8 == 0 && "ShAmt is byte offset"); + const unsigned ByteShAmt = ShAmt / 8; + const Align LDSTAlign = LDST->getAlign(); + const Align NarrowAlign = commonAlignment(LDSTAlign, ByteShAmt); + if (!TLI.allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(), MemVT, + LDST->getAddressSpace(), NarrowAlign, + LDST->getMemOperand()->getFlags())) + return false; + } + + // It's not possible to generate a constant of extended or untyped type. + EVT PtrType = LDST->getBasePtr().getValueType(); + if (PtrType == MVT::Untyped || PtrType.isExtended()) + return false; + + if (isa<LoadSDNode>(LDST)) { + LoadSDNode *Load = cast<LoadSDNode>(LDST); + // Don't transform one with multiple uses, this would require adding a new + // load. + if (!SDValue(Load, 0).hasOneUse()) + return false; + + if (LegalOperations && + !TLI.isLoadExtLegal(ExtType, Load->getValueType(0), MemVT)) + return false; + + // For the transform to be legal, the load must produce only two values + // (the value loaded and the chain). Don't transform a pre-increment + // load, for example, which produces an extra value. Otherwise the + // transformation is not equivalent, and the downstream logic to replace + // uses gets things wrong. + if (Load->getNumValues() > 2) + return false; + + // If the load that we're shrinking is an extload and we're not just + // discarding the extension we can't simply shrink the load. Bail. + // TODO: It would be possible to merge the extensions in some cases. + if (Load->getExtensionType() != ISD::NON_EXTLOAD && + Load->getMemoryVT().getSizeInBits() < MemVT.getSizeInBits() + ShAmt) + return false; + + if (!TLI.shouldReduceLoadWidth(Load, ExtType, MemVT)) + return false; + } else { + assert(isa<StoreSDNode>(LDST) && "It is not a Load nor a Store SDNode"); + StoreSDNode *Store = cast<StoreSDNode>(LDST); + // Can't write outside the original store + if (Store->getMemoryVT().getSizeInBits() < MemVT.getSizeInBits() + ShAmt) + return false; + + if (LegalOperations && + !TLI.isTruncStoreLegal(Store->getValue().getValueType(), MemVT)) + return false; + } + return true; +} + +bool DAGCombiner::SearchForAndLoads(SDNode *N, + SmallVectorImpl<LoadSDNode*> &Loads, + SmallPtrSetImpl<SDNode*> &NodesWithConsts, + ConstantSDNode *Mask, + SDNode *&NodeToMask) { + // Recursively search for the operands, looking for loads which can be + // narrowed. + for (SDValue Op : N->op_values()) { + if (Op.getValueType().isVector()) + return false; + + // Some constants may need fixing up later if they are too large. + if (auto *C = dyn_cast<ConstantSDNode>(Op)) { + if ((N->getOpcode() == ISD::OR || N->getOpcode() == ISD::XOR) && + (Mask->getAPIntValue() & C->getAPIntValue()) != C->getAPIntValue()) + NodesWithConsts.insert(N); + continue; + } + + if (!Op.hasOneUse()) + return false; + + switch(Op.getOpcode()) { + case ISD::LOAD: { + auto *Load = cast<LoadSDNode>(Op); + EVT ExtVT; + if (isAndLoadExtLoad(Mask, Load, Load->getValueType(0), ExtVT) && + isLegalNarrowLdSt(Load, ISD::ZEXTLOAD, ExtVT)) { + + // ZEXTLOAD is already small enough. + if (Load->getExtensionType() == ISD::ZEXTLOAD && + ExtVT.bitsGE(Load->getMemoryVT())) + continue; + + // Use LE to convert equal sized loads to zext. + if (ExtVT.bitsLE(Load->getMemoryVT())) + Loads.push_back(Load); + + continue; + } + return false; + } + case ISD::ZERO_EXTEND: + case ISD::AssertZext: { + unsigned ActiveBits = Mask->getAPIntValue().countTrailingOnes(); + EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits); + EVT VT = Op.getOpcode() == ISD::AssertZext ? + cast<VTSDNode>(Op.getOperand(1))->getVT() : + Op.getOperand(0).getValueType(); + + // We can accept extending nodes if the mask is wider or an equal + // width to the original type. + if (ExtVT.bitsGE(VT)) + continue; + break; + } + case ISD::OR: + case ISD::XOR: + case ISD::AND: + if (!SearchForAndLoads(Op.getNode(), Loads, NodesWithConsts, Mask, + NodeToMask)) + return false; + continue; + } + + // Allow one node which will masked along with any loads found. + if (NodeToMask) + return false; + + // Also ensure that the node to be masked only produces one data result. + NodeToMask = Op.getNode(); + if (NodeToMask->getNumValues() > 1) { + bool HasValue = false; + for (unsigned i = 0, e = NodeToMask->getNumValues(); i < e; ++i) { + MVT VT = SDValue(NodeToMask, i).getSimpleValueType(); + if (VT != MVT::Glue && VT != MVT::Other) { + if (HasValue) { + NodeToMask = nullptr; + return false; + } + HasValue = true; + } + } + assert(HasValue && "Node to be masked has no data result?"); + } + } + return true; +} + +bool DAGCombiner::BackwardsPropagateMask(SDNode *N) { + auto *Mask = dyn_cast<ConstantSDNode>(N->getOperand(1)); + if (!Mask) + return false; + + if (!Mask->getAPIntValue().isMask()) + return false; + + // No need to do anything if the and directly uses a load. + if (isa<LoadSDNode>(N->getOperand(0))) + return false; + + SmallVector<LoadSDNode*, 8> Loads; + SmallPtrSet<SDNode*, 2> NodesWithConsts; + SDNode *FixupNode = nullptr; + if (SearchForAndLoads(N, Loads, NodesWithConsts, Mask, FixupNode)) { + if (Loads.size() == 0) + return false; + + LLVM_DEBUG(dbgs() << "Backwards propagate AND: "; N->dump()); + SDValue MaskOp = N->getOperand(1); + + // If it exists, fixup the single node we allow in the tree that needs + // masking. + if (FixupNode) { + LLVM_DEBUG(dbgs() << "First, need to fix up: "; FixupNode->dump()); + SDValue And = DAG.getNode(ISD::AND, SDLoc(FixupNode), + FixupNode->getValueType(0), + SDValue(FixupNode, 0), MaskOp); + DAG.ReplaceAllUsesOfValueWith(SDValue(FixupNode, 0), And); + if (And.getOpcode() == ISD ::AND) + DAG.UpdateNodeOperands(And.getNode(), SDValue(FixupNode, 0), MaskOp); + } + + // Narrow any constants that need it. + for (auto *LogicN : NodesWithConsts) { + SDValue Op0 = LogicN->getOperand(0); + SDValue Op1 = LogicN->getOperand(1); + + if (isa<ConstantSDNode>(Op0)) + std::swap(Op0, Op1); + + SDValue And = DAG.getNode(ISD::AND, SDLoc(Op1), Op1.getValueType(), + Op1, MaskOp); + + DAG.UpdateNodeOperands(LogicN, Op0, And); + } + + // Create narrow loads. + for (auto *Load : Loads) { + LLVM_DEBUG(dbgs() << "Propagate AND back to: "; Load->dump()); + SDValue And = DAG.getNode(ISD::AND, SDLoc(Load), Load->getValueType(0), + SDValue(Load, 0), MaskOp); + DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 0), And); + if (And.getOpcode() == ISD ::AND) + And = SDValue( + DAG.UpdateNodeOperands(And.getNode(), SDValue(Load, 0), MaskOp), 0); + SDValue NewLoad = ReduceLoadWidth(And.getNode()); + assert(NewLoad && + "Shouldn't be masking the load if it can't be narrowed"); + CombineTo(Load, NewLoad, NewLoad.getValue(1)); + } + DAG.ReplaceAllUsesWith(N, N->getOperand(0).getNode()); + return true; + } + return false; +} + +// Unfold +// x & (-1 'logical shift' y) +// To +// (x 'opposite logical shift' y) 'logical shift' y +// if it is better for performance. +SDValue DAGCombiner::unfoldExtremeBitClearingToShifts(SDNode *N) { + assert(N->getOpcode() == ISD::AND); + + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + + // Do we actually prefer shifts over mask? + if (!TLI.shouldFoldMaskToVariableShiftPair(N0)) + return SDValue(); + + // Try to match (-1 '[outer] logical shift' y) + unsigned OuterShift; + unsigned InnerShift; // The opposite direction to the OuterShift. + SDValue Y; // Shift amount. + auto matchMask = [&OuterShift, &InnerShift, &Y](SDValue M) -> bool { + if (!M.hasOneUse()) + return false; + OuterShift = M->getOpcode(); + if (OuterShift == ISD::SHL) + InnerShift = ISD::SRL; + else if (OuterShift == ISD::SRL) + InnerShift = ISD::SHL; + else + return false; + if (!isAllOnesConstant(M->getOperand(0))) + return false; + Y = M->getOperand(1); + return true; + }; + + SDValue X; + if (matchMask(N1)) + X = N0; + else if (matchMask(N0)) + X = N1; + else + return SDValue(); + + SDLoc DL(N); + EVT VT = N->getValueType(0); + + // tmp = x 'opposite logical shift' y + SDValue T0 = DAG.getNode(InnerShift, DL, VT, X, Y); + // ret = tmp 'logical shift' y + SDValue T1 = DAG.getNode(OuterShift, DL, VT, T0, Y); + + return T1; +} + +/// Try to replace shift/logic that tests if a bit is clear with mask + setcc. +/// For a target with a bit test, this is expected to become test + set and save +/// at least 1 instruction. +static SDValue combineShiftAnd1ToBitTest(SDNode *And, SelectionDAG &DAG) { + assert(And->getOpcode() == ISD::AND && "Expected an 'and' op"); + + // This is probably not worthwhile without a supported type. + EVT VT = And->getValueType(0); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + if (!TLI.isTypeLegal(VT)) + return SDValue(); + + // Look through an optional extension and find a 'not'. + // TODO: Should we favor test+set even without the 'not' op? + SDValue Not = And->getOperand(0), And1 = And->getOperand(1); + if (Not.getOpcode() == ISD::ANY_EXTEND) + Not = Not.getOperand(0); + if (!isBitwiseNot(Not) || !Not.hasOneUse() || !isOneConstant(And1)) + return SDValue(); + + // Look though an optional truncation. The source operand may not be the same + // type as the original 'and', but that is ok because we are masking off + // everything but the low bit. + SDValue Srl = Not.getOperand(0); + if (Srl.getOpcode() == ISD::TRUNCATE) + Srl = Srl.getOperand(0); + + // Match a shift-right by constant. + if (Srl.getOpcode() != ISD::SRL || !Srl.hasOneUse() || + !isa<ConstantSDNode>(Srl.getOperand(1))) + return SDValue(); + + // We might have looked through casts that make this transform invalid. + // TODO: If the source type is wider than the result type, do the mask and + // compare in the source type. + const APInt &ShiftAmt = Srl.getConstantOperandAPInt(1); + unsigned VTBitWidth = VT.getSizeInBits(); + if (ShiftAmt.uge(VTBitWidth)) + return SDValue(); + + // Turn this into a bit-test pattern using mask op + setcc: + // and (not (srl X, C)), 1 --> (and X, 1<<C) == 0 + SDLoc DL(And); + SDValue X = DAG.getZExtOrTrunc(Srl.getOperand(0), DL, VT); + EVT CCVT = TLI.getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT); + SDValue Mask = DAG.getConstant( + APInt::getOneBitSet(VTBitWidth, ShiftAmt.getZExtValue()), DL, VT); + SDValue NewAnd = DAG.getNode(ISD::AND, DL, VT, X, Mask); + SDValue Zero = DAG.getConstant(0, DL, VT); + SDValue Setcc = DAG.getSetCC(DL, CCVT, NewAnd, Zero, ISD::SETEQ); + return DAG.getZExtOrTrunc(Setcc, DL, VT); +} + +SDValue DAGCombiner::visitAND(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N1.getValueType(); + + // x & x --> x + if (N0 == N1) + return N0; + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (and x, 0) -> 0, vector edition + if (ISD::isBuildVectorAllZeros(N0.getNode())) + // do not return N0, because undef node may exist in N0 + return DAG.getConstant(APInt::getNullValue(N0.getScalarValueSizeInBits()), + SDLoc(N), N0.getValueType()); + if (ISD::isBuildVectorAllZeros(N1.getNode())) + // do not return N1, because undef node may exist in N1 + return DAG.getConstant(APInt::getNullValue(N1.getScalarValueSizeInBits()), + SDLoc(N), N1.getValueType()); + + // fold (and x, -1) -> x, vector edition + if (ISD::isBuildVectorAllOnes(N0.getNode())) + return N1; + if (ISD::isBuildVectorAllOnes(N1.getNode())) + return N0; + + // fold (and (masked_load) (build_vec (x, ...))) to zext_masked_load + auto *MLoad = dyn_cast<MaskedLoadSDNode>(N0); + auto *BVec = dyn_cast<BuildVectorSDNode>(N1); + if (MLoad && BVec && MLoad->getExtensionType() == ISD::EXTLOAD && + N0.hasOneUse() && N1.hasOneUse()) { + EVT LoadVT = MLoad->getMemoryVT(); + EVT ExtVT = VT; + if (TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT, LoadVT)) { + // For this AND to be a zero extension of the masked load the elements + // of the BuildVec must mask the bottom bits of the extended element + // type + if (ConstantSDNode *Splat = BVec->getConstantSplatNode()) { + uint64_t ElementSize = + LoadVT.getVectorElementType().getScalarSizeInBits(); + if (Splat->getAPIntValue().isMask(ElementSize)) { + return DAG.getMaskedLoad( + ExtVT, SDLoc(N), MLoad->getChain(), MLoad->getBasePtr(), + MLoad->getOffset(), MLoad->getMask(), MLoad->getPassThru(), + LoadVT, MLoad->getMemOperand(), MLoad->getAddressingMode(), + ISD::ZEXTLOAD, MLoad->isExpandingLoad()); + } + } + } + } + } + + // fold (and c1, c2) -> c1&c2 + ConstantSDNode *N1C = isConstOrConstSplat(N1); + if (SDValue C = DAG.FoldConstantArithmetic(ISD::AND, SDLoc(N), VT, {N0, N1})) + return C; + + // canonicalize constant to RHS + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(ISD::AND, SDLoc(N), VT, N1, N0); + + // fold (and x, -1) -> x + if (isAllOnesConstant(N1)) + return N0; + + // if (and x, c) is known to be zero, return 0 + unsigned BitWidth = VT.getScalarSizeInBits(); + if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), + APInt::getAllOnesValue(BitWidth))) + return DAG.getConstant(0, SDLoc(N), VT); + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // reassociate and + if (SDValue RAND = reassociateOps(ISD::AND, SDLoc(N), N0, N1, N->getFlags())) + return RAND; + + // Try to convert a constant mask AND into a shuffle clear mask. + if (VT.isVector()) + if (SDValue Shuffle = XformToShuffleWithZero(N)) + return Shuffle; + + if (SDValue Combined = combineCarryDiamond(*this, DAG, TLI, N0, N1, N)) + return Combined; + + // fold (and (or x, C), D) -> D if (C & D) == D + auto MatchSubset = [](ConstantSDNode *LHS, ConstantSDNode *RHS) { + return RHS->getAPIntValue().isSubsetOf(LHS->getAPIntValue()); + }; + if (N0.getOpcode() == ISD::OR && + ISD::matchBinaryPredicate(N0.getOperand(1), N1, MatchSubset)) + return N1; + // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. + if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { + SDValue N0Op0 = N0.getOperand(0); + APInt Mask = ~N1C->getAPIntValue(); + Mask = Mask.trunc(N0Op0.getScalarValueSizeInBits()); + if (DAG.MaskedValueIsZero(N0Op0, Mask)) { + SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N), + N0.getValueType(), N0Op0); + + // Replace uses of the AND with uses of the Zero extend node. + CombineTo(N, Zext); + + // We actually want to replace all uses of the any_extend with the + // zero_extend, to avoid duplicating things. This will later cause this + // AND to be folded. + CombineTo(N0.getNode(), Zext); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // similarly fold (and (X (load ([non_ext|any_ext|zero_ext] V))), c) -> + // (X (load ([non_ext|zero_ext] V))) if 'and' only clears top bits which must + // already be zero by virtue of the width of the base type of the load. + // + // the 'X' node here can either be nothing or an extract_vector_elt to catch + // more cases. + if ((N0.getOpcode() == ISD::EXTRACT_VECTOR_ELT && + N0.getValueSizeInBits() == N0.getOperand(0).getScalarValueSizeInBits() && + N0.getOperand(0).getOpcode() == ISD::LOAD && + N0.getOperand(0).getResNo() == 0) || + (N0.getOpcode() == ISD::LOAD && N0.getResNo() == 0)) { + LoadSDNode *Load = cast<LoadSDNode>( (N0.getOpcode() == ISD::LOAD) ? + N0 : N0.getOperand(0) ); + + // Get the constant (if applicable) the zero'th operand is being ANDed with. + // This can be a pure constant or a vector splat, in which case we treat the + // vector as a scalar and use the splat value. + APInt Constant = APInt::getNullValue(1); + if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(N1)) { + Constant = C->getAPIntValue(); + } else if (BuildVectorSDNode *Vector = dyn_cast<BuildVectorSDNode>(N1)) { + APInt SplatValue, SplatUndef; + unsigned SplatBitSize; + bool HasAnyUndefs; + bool IsSplat = Vector->isConstantSplat(SplatValue, SplatUndef, + SplatBitSize, HasAnyUndefs); + if (IsSplat) { + // Undef bits can contribute to a possible optimisation if set, so + // set them. + SplatValue |= SplatUndef; + + // The splat value may be something like "0x00FFFFFF", which means 0 for + // the first vector value and FF for the rest, repeating. We need a mask + // that will apply equally to all members of the vector, so AND all the + // lanes of the constant together. + unsigned EltBitWidth = Vector->getValueType(0).getScalarSizeInBits(); + + // If the splat value has been compressed to a bitlength lower + // than the size of the vector lane, we need to re-expand it to + // the lane size. + if (EltBitWidth > SplatBitSize) + for (SplatValue = SplatValue.zextOrTrunc(EltBitWidth); + SplatBitSize < EltBitWidth; SplatBitSize = SplatBitSize * 2) + SplatValue |= SplatValue.shl(SplatBitSize); + + // Make sure that variable 'Constant' is only set if 'SplatBitSize' is a + // multiple of 'BitWidth'. Otherwise, we could propagate a wrong value. + if ((SplatBitSize % EltBitWidth) == 0) { + Constant = APInt::getAllOnesValue(EltBitWidth); + for (unsigned i = 0, n = (SplatBitSize / EltBitWidth); i < n; ++i) + Constant &= SplatValue.extractBits(EltBitWidth, i * EltBitWidth); + } + } + } + + // If we want to change an EXTLOAD to a ZEXTLOAD, ensure a ZEXTLOAD is + // actually legal and isn't going to get expanded, else this is a false + // optimisation. + bool CanZextLoadProfitably = TLI.isLoadExtLegal(ISD::ZEXTLOAD, + Load->getValueType(0), + Load->getMemoryVT()); + + // Resize the constant to the same size as the original memory access before + // extension. If it is still the AllOnesValue then this AND is completely + // unneeded. + Constant = Constant.zextOrTrunc(Load->getMemoryVT().getScalarSizeInBits()); + + bool B; + switch (Load->getExtensionType()) { + default: B = false; break; + case ISD::EXTLOAD: B = CanZextLoadProfitably; break; + case ISD::ZEXTLOAD: + case ISD::NON_EXTLOAD: B = true; break; + } + + if (B && Constant.isAllOnesValue()) { + // If the load type was an EXTLOAD, convert to ZEXTLOAD in order to + // preserve semantics once we get rid of the AND. + SDValue NewLoad(Load, 0); + + // Fold the AND away. NewLoad may get replaced immediately. + CombineTo(N, (N0.getNode() == Load) ? NewLoad : N0); + + if (Load->getExtensionType() == ISD::EXTLOAD) { + NewLoad = DAG.getLoad(Load->getAddressingMode(), ISD::ZEXTLOAD, + Load->getValueType(0), SDLoc(Load), + Load->getChain(), Load->getBasePtr(), + Load->getOffset(), Load->getMemoryVT(), + Load->getMemOperand()); + // Replace uses of the EXTLOAD with the new ZEXTLOAD. + if (Load->getNumValues() == 3) { + // PRE/POST_INC loads have 3 values. + SDValue To[] = { NewLoad.getValue(0), NewLoad.getValue(1), + NewLoad.getValue(2) }; + CombineTo(Load, To, 3, true); + } else { + CombineTo(Load, NewLoad.getValue(0), NewLoad.getValue(1)); + } + } + + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // fold (and (masked_gather x)) -> (zext_masked_gather x) + if (auto *GN0 = dyn_cast<MaskedGatherSDNode>(N0)) { + EVT MemVT = GN0->getMemoryVT(); + EVT ScalarVT = MemVT.getScalarType(); + + if (SDValue(GN0, 0).hasOneUse() && + isConstantSplatVectorMaskForType(N1.getNode(), ScalarVT) && + TLI.isVectorLoadExtDesirable(SDValue(SDValue(GN0, 0)))) { + SDValue Ops[] = {GN0->getChain(), GN0->getPassThru(), GN0->getMask(), + GN0->getBasePtr(), GN0->getIndex(), GN0->getScale()}; + + SDValue ZExtLoad = DAG.getMaskedGather( + DAG.getVTList(VT, MVT::Other), MemVT, SDLoc(N), Ops, + GN0->getMemOperand(), GN0->getIndexType(), ISD::ZEXTLOAD); + + CombineTo(N, ZExtLoad); + AddToWorklist(ZExtLoad.getNode()); + // Avoid recheck of N. + return SDValue(N, 0); + } + } + + // fold (and (load x), 255) -> (zextload x, i8) + // fold (and (extload x, i16), 255) -> (zextload x, i8) + // fold (and (any_ext (extload x, i16)), 255) -> (zextload x, i8) + if (!VT.isVector() && N1C && (N0.getOpcode() == ISD::LOAD || + (N0.getOpcode() == ISD::ANY_EXTEND && + N0.getOperand(0).getOpcode() == ISD::LOAD))) { + if (SDValue Res = ReduceLoadWidth(N)) { + LoadSDNode *LN0 = N0->getOpcode() == ISD::ANY_EXTEND + ? cast<LoadSDNode>(N0.getOperand(0)) : cast<LoadSDNode>(N0); + AddToWorklist(N); + DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 0), Res); + return SDValue(N, 0); + } + } + + if (LegalTypes) { + // Attempt to propagate the AND back up to the leaves which, if they're + // loads, can be combined to narrow loads and the AND node can be removed. + // Perform after legalization so that extend nodes will already be + // combined into the loads. + if (BackwardsPropagateMask(N)) + return SDValue(N, 0); + } + + if (SDValue Combined = visitANDLike(N0, N1, N)) + return Combined; + + // Simplify: (and (op x...), (op y...)) -> (op (and x, y)) + if (N0.getOpcode() == N1.getOpcode()) + if (SDValue V = hoistLogicOpWithSameOpcodeHands(N)) + return V; + + // Masking the negated extension of a boolean is just the zero-extended + // boolean: + // and (sub 0, zext(bool X)), 1 --> zext(bool X) + // and (sub 0, sext(bool X)), 1 --> zext(bool X) + // + // Note: the SimplifyDemandedBits fold below can make an information-losing + // transform, and then we have no way to find this better fold. + if (N1C && N1C->isOne() && N0.getOpcode() == ISD::SUB) { + if (isNullOrNullSplat(N0.getOperand(0))) { + SDValue SubRHS = N0.getOperand(1); + if (SubRHS.getOpcode() == ISD::ZERO_EXTEND && + SubRHS.getOperand(0).getScalarValueSizeInBits() == 1) + return SubRHS; + if (SubRHS.getOpcode() == ISD::SIGN_EXTEND && + SubRHS.getOperand(0).getScalarValueSizeInBits() == 1) + return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N), VT, SubRHS.getOperand(0)); + } + } + + // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) + // fold (and (sra)) -> (and (srl)) when possible. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // fold (zext_inreg (extload x)) -> (zextload x) + // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use + if (ISD::isUNINDEXEDLoad(N0.getNode()) && + (ISD::isEXTLoad(N0.getNode()) || + (ISD::isSEXTLoad(N0.getNode()) && N0.hasOneUse()))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + EVT MemVT = LN0->getMemoryVT(); + // If we zero all the possible extended bits, then we can turn this into + // a zextload if we are running before legalize or the operation is legal. + unsigned ExtBitSize = N1.getScalarValueSizeInBits(); + unsigned MemBitSize = MemVT.getScalarSizeInBits(); + APInt ExtBits = APInt::getHighBitsSet(ExtBitSize, ExtBitSize - MemBitSize); + if (DAG.MaskedValueIsZero(N1, ExtBits) && + ((!LegalOperations && LN0->isSimple()) || + TLI.isLoadExtLegal(ISD::ZEXTLOAD, VT, MemVT))) { + SDValue ExtLoad = + DAG.getExtLoad(ISD::ZEXTLOAD, SDLoc(N0), VT, LN0->getChain(), + LN0->getBasePtr(), MemVT, LN0->getMemOperand()); + AddToWorklist(N); + CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // fold (and (or (srl N, 8), (shl N, 8)), 0xffff) -> (srl (bswap N), const) + if (N1C && N1C->getAPIntValue() == 0xffff && N0.getOpcode() == ISD::OR) { + if (SDValue BSwap = MatchBSwapHWordLow(N0.getNode(), N0.getOperand(0), + N0.getOperand(1), false)) + return BSwap; + } + + if (SDValue Shifts = unfoldExtremeBitClearingToShifts(N)) + return Shifts; + + if (TLI.hasBitTest(N0, N1)) + if (SDValue V = combineShiftAnd1ToBitTest(N, DAG)) + return V; + + // Recognize the following pattern: + // + // AndVT = (and (sign_extend NarrowVT to AndVT) #bitmask) + // + // where bitmask is a mask that clears the upper bits of AndVT. The + // number of bits in bitmask must be a power of two. + auto IsAndZeroExtMask = [](SDValue LHS, SDValue RHS) { + if (LHS->getOpcode() != ISD::SIGN_EXTEND) + return false; + + auto *C = dyn_cast<ConstantSDNode>(RHS); + if (!C) + return false; + + if (!C->getAPIntValue().isMask( + LHS.getOperand(0).getValueType().getFixedSizeInBits())) + return false; + + return true; + }; + + // Replace (and (sign_extend ...) #bitmask) with (zero_extend ...). + if (IsAndZeroExtMask(N0, N1)) + return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N), VT, N0.getOperand(0)); + + return SDValue(); +} + +/// Match (a >> 8) | (a << 8) as (bswap a) >> 16. +SDValue DAGCombiner::MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1, + bool DemandHighBits) { + if (!LegalOperations) + return SDValue(); + + EVT VT = N->getValueType(0); + if (VT != MVT::i64 && VT != MVT::i32 && VT != MVT::i16) + return SDValue(); + if (!TLI.isOperationLegalOrCustom(ISD::BSWAP, VT)) + return SDValue(); + + // Recognize (and (shl a, 8), 0xff00), (and (srl a, 8), 0xff) + bool LookPassAnd0 = false; + bool LookPassAnd1 = false; + if (N0.getOpcode() == ISD::AND && N0.getOperand(0).getOpcode() == ISD::SRL) + std::swap(N0, N1); + if (N1.getOpcode() == ISD::AND && N1.getOperand(0).getOpcode() == ISD::SHL) + std::swap(N0, N1); + if (N0.getOpcode() == ISD::AND) { + if (!N0.getNode()->hasOneUse()) + return SDValue(); + ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + // Also handle 0xffff since the LHS is guaranteed to have zeros there. + // This is needed for X86. + if (!N01C || (N01C->getZExtValue() != 0xFF00 && + N01C->getZExtValue() != 0xFFFF)) + return SDValue(); + N0 = N0.getOperand(0); + LookPassAnd0 = true; + } + + if (N1.getOpcode() == ISD::AND) { + if (!N1.getNode()->hasOneUse()) + return SDValue(); + ConstantSDNode *N11C = dyn_cast<ConstantSDNode>(N1.getOperand(1)); + if (!N11C || N11C->getZExtValue() != 0xFF) + return SDValue(); + N1 = N1.getOperand(0); + LookPassAnd1 = true; + } + + if (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SHL) + std::swap(N0, N1); + if (N0.getOpcode() != ISD::SHL || N1.getOpcode() != ISD::SRL) + return SDValue(); + if (!N0.getNode()->hasOneUse() || !N1.getNode()->hasOneUse()) + return SDValue(); + + ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + ConstantSDNode *N11C = dyn_cast<ConstantSDNode>(N1.getOperand(1)); + if (!N01C || !N11C) + return SDValue(); + if (N01C->getZExtValue() != 8 || N11C->getZExtValue() != 8) + return SDValue(); + + // Look for (shl (and a, 0xff), 8), (srl (and a, 0xff00), 8) + SDValue N00 = N0->getOperand(0); + if (!LookPassAnd0 && N00.getOpcode() == ISD::AND) { + if (!N00.getNode()->hasOneUse()) + return SDValue(); + ConstantSDNode *N001C = dyn_cast<ConstantSDNode>(N00.getOperand(1)); + if (!N001C || N001C->getZExtValue() != 0xFF) + return SDValue(); + N00 = N00.getOperand(0); + LookPassAnd0 = true; + } + + SDValue N10 = N1->getOperand(0); + if (!LookPassAnd1 && N10.getOpcode() == ISD::AND) { + if (!N10.getNode()->hasOneUse()) + return SDValue(); + ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N10.getOperand(1)); + // Also allow 0xFFFF since the bits will be shifted out. This is needed + // for X86. + if (!N101C || (N101C->getZExtValue() != 0xFF00 && + N101C->getZExtValue() != 0xFFFF)) + return SDValue(); + N10 = N10.getOperand(0); + LookPassAnd1 = true; + } + + if (N00 != N10) + return SDValue(); + + // Make sure everything beyond the low halfword gets set to zero since the SRL + // 16 will clear the top bits. + unsigned OpSizeInBits = VT.getSizeInBits(); + if (DemandHighBits && OpSizeInBits > 16) { + // If the left-shift isn't masked out then the only way this is a bswap is + // if all bits beyond the low 8 are 0. In that case the entire pattern + // reduces to a left shift anyway: leave it for other parts of the combiner. + if (!LookPassAnd0) + return SDValue(); + + // However, if the right shift isn't masked out then it might be because + // it's not needed. See if we can spot that too. + if (!LookPassAnd1 && + !DAG.MaskedValueIsZero( + N10, APInt::getHighBitsSet(OpSizeInBits, OpSizeInBits - 16))) + return SDValue(); + } + + SDValue Res = DAG.getNode(ISD::BSWAP, SDLoc(N), VT, N00); + if (OpSizeInBits > 16) { + SDLoc DL(N); + Res = DAG.getNode(ISD::SRL, DL, VT, Res, + DAG.getConstant(OpSizeInBits - 16, DL, + getShiftAmountTy(VT))); + } + return Res; +} + +/// Return true if the specified node is an element that makes up a 32-bit +/// packed halfword byteswap. +/// ((x & 0x000000ff) << 8) | +/// ((x & 0x0000ff00) >> 8) | +/// ((x & 0x00ff0000) << 8) | +/// ((x & 0xff000000) >> 8) +static bool isBSwapHWordElement(SDValue N, MutableArrayRef<SDNode *> Parts) { + if (!N.getNode()->hasOneUse()) + return false; + + unsigned Opc = N.getOpcode(); + if (Opc != ISD::AND && Opc != ISD::SHL && Opc != ISD::SRL) + return false; + + SDValue N0 = N.getOperand(0); + unsigned Opc0 = N0.getOpcode(); + if (Opc0 != ISD::AND && Opc0 != ISD::SHL && Opc0 != ISD::SRL) + return false; + + ConstantSDNode *N1C = nullptr; + // SHL or SRL: look upstream for AND mask operand + if (Opc == ISD::AND) + N1C = dyn_cast<ConstantSDNode>(N.getOperand(1)); + else if (Opc0 == ISD::AND) + N1C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + if (!N1C) + return false; + + unsigned MaskByteOffset; + switch (N1C->getZExtValue()) { + default: + return false; + case 0xFF: MaskByteOffset = 0; break; + case 0xFF00: MaskByteOffset = 1; break; + case 0xFFFF: + // In case demanded bits didn't clear the bits that will be shifted out. + // This is needed for X86. + if (Opc == ISD::SRL || (Opc == ISD::AND && Opc0 == ISD::SHL)) { + MaskByteOffset = 1; + break; + } + return false; + case 0xFF0000: MaskByteOffset = 2; break; + case 0xFF000000: MaskByteOffset = 3; break; + } + + // Look for (x & 0xff) << 8 as well as ((x << 8) & 0xff00). + if (Opc == ISD::AND) { + if (MaskByteOffset == 0 || MaskByteOffset == 2) { + // (x >> 8) & 0xff + // (x >> 8) & 0xff0000 + if (Opc0 != ISD::SRL) + return false; + ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + if (!C || C->getZExtValue() != 8) + return false; + } else { + // (x << 8) & 0xff00 + // (x << 8) & 0xff000000 + if (Opc0 != ISD::SHL) + return false; + ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + if (!C || C->getZExtValue() != 8) + return false; + } + } else if (Opc == ISD::SHL) { + // (x & 0xff) << 8 + // (x & 0xff0000) << 8 + if (MaskByteOffset != 0 && MaskByteOffset != 2) + return false; + ConstantSDNode *C = dyn_cast<ConstantSDNode>(N.getOperand(1)); + if (!C || C->getZExtValue() != 8) + return false; + } else { // Opc == ISD::SRL + // (x & 0xff00) >> 8 + // (x & 0xff000000) >> 8 + if (MaskByteOffset != 1 && MaskByteOffset != 3) + return false; + ConstantSDNode *C = dyn_cast<ConstantSDNode>(N.getOperand(1)); + if (!C || C->getZExtValue() != 8) + return false; + } + + if (Parts[MaskByteOffset]) + return false; + + Parts[MaskByteOffset] = N0.getOperand(0).getNode(); + return true; +} + +// Match 2 elements of a packed halfword bswap. +static bool isBSwapHWordPair(SDValue N, MutableArrayRef<SDNode *> Parts) { + if (N.getOpcode() == ISD::OR) + return isBSwapHWordElement(N.getOperand(0), Parts) && + isBSwapHWordElement(N.getOperand(1), Parts); + + if (N.getOpcode() == ISD::SRL && N.getOperand(0).getOpcode() == ISD::BSWAP) { + ConstantSDNode *C = isConstOrConstSplat(N.getOperand(1)); + if (!C || C->getAPIntValue() != 16) + return false; + Parts[0] = Parts[1] = N.getOperand(0).getOperand(0).getNode(); + return true; + } + + return false; +} + +// Match this pattern: +// (or (and (shl (A, 8)), 0xff00ff00), (and (srl (A, 8)), 0x00ff00ff)) +// And rewrite this to: +// (rotr (bswap A), 16) +static SDValue matchBSwapHWordOrAndAnd(const TargetLowering &TLI, + SelectionDAG &DAG, SDNode *N, SDValue N0, + SDValue N1, EVT VT, EVT ShiftAmountTy) { + assert(N->getOpcode() == ISD::OR && VT == MVT::i32 && + "MatchBSwapHWordOrAndAnd: expecting i32"); + if (!TLI.isOperationLegalOrCustom(ISD::ROTR, VT)) + return SDValue(); + if (N0.getOpcode() != ISD::AND || N1.getOpcode() != ISD::AND) + return SDValue(); + // TODO: this is too restrictive; lifting this restriction requires more tests + if (!N0->hasOneUse() || !N1->hasOneUse()) + return SDValue(); + ConstantSDNode *Mask0 = isConstOrConstSplat(N0.getOperand(1)); + ConstantSDNode *Mask1 = isConstOrConstSplat(N1.getOperand(1)); + if (!Mask0 || !Mask1) + return SDValue(); + if (Mask0->getAPIntValue() != 0xff00ff00 || + Mask1->getAPIntValue() != 0x00ff00ff) + return SDValue(); + SDValue Shift0 = N0.getOperand(0); + SDValue Shift1 = N1.getOperand(0); + if (Shift0.getOpcode() != ISD::SHL || Shift1.getOpcode() != ISD::SRL) + return SDValue(); + ConstantSDNode *ShiftAmt0 = isConstOrConstSplat(Shift0.getOperand(1)); + ConstantSDNode *ShiftAmt1 = isConstOrConstSplat(Shift1.getOperand(1)); + if (!ShiftAmt0 || !ShiftAmt1) + return SDValue(); + if (ShiftAmt0->getAPIntValue() != 8 || ShiftAmt1->getAPIntValue() != 8) + return SDValue(); + if (Shift0.getOperand(0) != Shift1.getOperand(0)) + return SDValue(); + + SDLoc DL(N); + SDValue BSwap = DAG.getNode(ISD::BSWAP, DL, VT, Shift0.getOperand(0)); + SDValue ShAmt = DAG.getConstant(16, DL, ShiftAmountTy); + return DAG.getNode(ISD::ROTR, DL, VT, BSwap, ShAmt); +} + +/// Match a 32-bit packed halfword bswap. That is +/// ((x & 0x000000ff) << 8) | +/// ((x & 0x0000ff00) >> 8) | +/// ((x & 0x00ff0000) << 8) | +/// ((x & 0xff000000) >> 8) +/// => (rotl (bswap x), 16) +SDValue DAGCombiner::MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1) { + if (!LegalOperations) + return SDValue(); + + EVT VT = N->getValueType(0); + if (VT != MVT::i32) + return SDValue(); + if (!TLI.isOperationLegalOrCustom(ISD::BSWAP, VT)) + return SDValue(); + + if (SDValue BSwap = matchBSwapHWordOrAndAnd(TLI, DAG, N, N0, N1, VT, + getShiftAmountTy(VT))) + return BSwap; + + // Try again with commuted operands. + if (SDValue BSwap = matchBSwapHWordOrAndAnd(TLI, DAG, N, N1, N0, VT, + getShiftAmountTy(VT))) + return BSwap; + + + // Look for either + // (or (bswaphpair), (bswaphpair)) + // (or (or (bswaphpair), (and)), (and)) + // (or (or (and), (bswaphpair)), (and)) + SDNode *Parts[4] = {}; + + if (isBSwapHWordPair(N0, Parts)) { + // (or (or (and), (and)), (or (and), (and))) + if (!isBSwapHWordPair(N1, Parts)) + return SDValue(); + } else if (N0.getOpcode() == ISD::OR) { + // (or (or (or (and), (and)), (and)), (and)) + if (!isBSwapHWordElement(N1, Parts)) + return SDValue(); + SDValue N00 = N0.getOperand(0); + SDValue N01 = N0.getOperand(1); + if (!(isBSwapHWordElement(N01, Parts) && isBSwapHWordPair(N00, Parts)) && + !(isBSwapHWordElement(N00, Parts) && isBSwapHWordPair(N01, Parts))) + return SDValue(); + } else + return SDValue(); + + // Make sure the parts are all coming from the same node. + if (Parts[0] != Parts[1] || Parts[0] != Parts[2] || Parts[0] != Parts[3]) + return SDValue(); + + SDLoc DL(N); + SDValue BSwap = DAG.getNode(ISD::BSWAP, DL, VT, + SDValue(Parts[0], 0)); + + // Result of the bswap should be rotated by 16. If it's not legal, then + // do (x << 16) | (x >> 16). + SDValue ShAmt = DAG.getConstant(16, DL, getShiftAmountTy(VT)); + if (TLI.isOperationLegalOrCustom(ISD::ROTL, VT)) + return DAG.getNode(ISD::ROTL, DL, VT, BSwap, ShAmt); + if (TLI.isOperationLegalOrCustom(ISD::ROTR, VT)) + return DAG.getNode(ISD::ROTR, DL, VT, BSwap, ShAmt); + return DAG.getNode(ISD::OR, DL, VT, + DAG.getNode(ISD::SHL, DL, VT, BSwap, ShAmt), + DAG.getNode(ISD::SRL, DL, VT, BSwap, ShAmt)); +} + +/// This contains all DAGCombine rules which reduce two values combined by +/// an Or operation to a single value \see visitANDLike(). +SDValue DAGCombiner::visitORLike(SDValue N0, SDValue N1, SDNode *N) { + EVT VT = N1.getValueType(); + SDLoc DL(N); + + // fold (or x, undef) -> -1 + if (!LegalOperations && (N0.isUndef() || N1.isUndef())) + return DAG.getAllOnesConstant(DL, VT); + + if (SDValue V = foldLogicOfSetCCs(false, N0, N1, DL)) + return V; + + // (or (and X, C1), (and Y, C2)) -> (and (or X, Y), C3) if possible. + if (N0.getOpcode() == ISD::AND && N1.getOpcode() == ISD::AND && + // Don't increase # computations. + (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) { + // We can only do this xform if we know that bits from X that are set in C2 + // but not in C1 are already zero. Likewise for Y. + if (const ConstantSDNode *N0O1C = + getAsNonOpaqueConstant(N0.getOperand(1))) { + if (const ConstantSDNode *N1O1C = + getAsNonOpaqueConstant(N1.getOperand(1))) { + // We can only do this xform if we know that bits from X that are set in + // C2 but not in C1 are already zero. Likewise for Y. + const APInt &LHSMask = N0O1C->getAPIntValue(); + const APInt &RHSMask = N1O1C->getAPIntValue(); + + if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && + DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { + SDValue X = DAG.getNode(ISD::OR, SDLoc(N0), VT, + N0.getOperand(0), N1.getOperand(0)); + return DAG.getNode(ISD::AND, DL, VT, X, + DAG.getConstant(LHSMask | RHSMask, DL, VT)); + } + } + } + } + + // (or (and X, M), (and X, N)) -> (and X, (or M, N)) + if (N0.getOpcode() == ISD::AND && + N1.getOpcode() == ISD::AND && + N0.getOperand(0) == N1.getOperand(0) && + // Don't increase # computations. + (N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) { + SDValue X = DAG.getNode(ISD::OR, SDLoc(N0), VT, + N0.getOperand(1), N1.getOperand(1)); + return DAG.getNode(ISD::AND, DL, VT, N0.getOperand(0), X); + } + + return SDValue(); +} + +/// OR combines for which the commuted variant will be tried as well. +static SDValue visitORCommutative( + SelectionDAG &DAG, SDValue N0, SDValue N1, SDNode *N) { + EVT VT = N0.getValueType(); + if (N0.getOpcode() == ISD::AND) { + // fold (or (and X, (xor Y, -1)), Y) -> (or X, Y) + if (isBitwiseNot(N0.getOperand(1)) && N0.getOperand(1).getOperand(0) == N1) + return DAG.getNode(ISD::OR, SDLoc(N), VT, N0.getOperand(0), N1); + + // fold (or (and (xor Y, -1), X), Y) -> (or X, Y) + if (isBitwiseNot(N0.getOperand(0)) && N0.getOperand(0).getOperand(0) == N1) + return DAG.getNode(ISD::OR, SDLoc(N), VT, N0.getOperand(1), N1); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitOR(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N1.getValueType(); + + // x | x --> x + if (N0 == N1) + return N0; + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (or x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N1; + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + + // fold (or x, -1) -> -1, vector edition + if (ISD::isBuildVectorAllOnes(N0.getNode())) + // do not return N0, because undef node may exist in N0 + return DAG.getAllOnesConstant(SDLoc(N), N0.getValueType()); + if (ISD::isBuildVectorAllOnes(N1.getNode())) + // do not return N1, because undef node may exist in N1 + return DAG.getAllOnesConstant(SDLoc(N), N1.getValueType()); + + // fold (or (shuf A, V_0, MA), (shuf B, V_0, MB)) -> (shuf A, B, Mask) + // Do this only if the resulting shuffle is legal. + if (isa<ShuffleVectorSDNode>(N0) && + isa<ShuffleVectorSDNode>(N1) && + // Avoid folding a node with illegal type. + TLI.isTypeLegal(VT)) { + bool ZeroN00 = ISD::isBuildVectorAllZeros(N0.getOperand(0).getNode()); + bool ZeroN01 = ISD::isBuildVectorAllZeros(N0.getOperand(1).getNode()); + bool ZeroN10 = ISD::isBuildVectorAllZeros(N1.getOperand(0).getNode()); + bool ZeroN11 = ISD::isBuildVectorAllZeros(N1.getOperand(1).getNode()); + // Ensure both shuffles have a zero input. + if ((ZeroN00 != ZeroN01) && (ZeroN10 != ZeroN11)) { + assert((!ZeroN00 || !ZeroN01) && "Both inputs zero!"); + assert((!ZeroN10 || !ZeroN11) && "Both inputs zero!"); + const ShuffleVectorSDNode *SV0 = cast<ShuffleVectorSDNode>(N0); + const ShuffleVectorSDNode *SV1 = cast<ShuffleVectorSDNode>(N1); + bool CanFold = true; + int NumElts = VT.getVectorNumElements(); + SmallVector<int, 4> Mask(NumElts); + + for (int i = 0; i != NumElts; ++i) { + int M0 = SV0->getMaskElt(i); + int M1 = SV1->getMaskElt(i); + + // Determine if either index is pointing to a zero vector. + bool M0Zero = M0 < 0 || (ZeroN00 == (M0 < NumElts)); + bool M1Zero = M1 < 0 || (ZeroN10 == (M1 < NumElts)); + + // If one element is zero and the otherside is undef, keep undef. + // This also handles the case that both are undef. + if ((M0Zero && M1 < 0) || (M1Zero && M0 < 0)) { + Mask[i] = -1; + continue; + } + + // Make sure only one of the elements is zero. + if (M0Zero == M1Zero) { + CanFold = false; + break; + } + + assert((M0 >= 0 || M1 >= 0) && "Undef index!"); + + // We have a zero and non-zero element. If the non-zero came from + // SV0 make the index a LHS index. If it came from SV1, make it + // a RHS index. We need to mod by NumElts because we don't care + // which operand it came from in the original shuffles. + Mask[i] = M1Zero ? M0 % NumElts : (M1 % NumElts) + NumElts; + } + + if (CanFold) { + SDValue NewLHS = ZeroN00 ? N0.getOperand(1) : N0.getOperand(0); + SDValue NewRHS = ZeroN10 ? N1.getOperand(1) : N1.getOperand(0); + + SDValue LegalShuffle = + TLI.buildLegalVectorShuffle(VT, SDLoc(N), NewLHS, NewRHS, + Mask, DAG); + if (LegalShuffle) + return LegalShuffle; + } + } + } + } + + // fold (or c1, c2) -> c1|c2 + ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); + if (SDValue C = DAG.FoldConstantArithmetic(ISD::OR, SDLoc(N), VT, {N0, N1})) + return C; + + // canonicalize constant to RHS + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(ISD::OR, SDLoc(N), VT, N1, N0); + + // fold (or x, 0) -> x + if (isNullConstant(N1)) + return N0; + + // fold (or x, -1) -> -1 + if (isAllOnesConstant(N1)) + return N1; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // fold (or x, c) -> c iff (x & ~c) == 0 + if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue())) + return N1; + + if (SDValue Combined = visitORLike(N0, N1, N)) + return Combined; + + if (SDValue Combined = combineCarryDiamond(*this, DAG, TLI, N0, N1, N)) + return Combined; + + // Recognize halfword bswaps as (bswap + rotl 16) or (bswap + shl 16) + if (SDValue BSwap = MatchBSwapHWord(N, N0, N1)) + return BSwap; + if (SDValue BSwap = MatchBSwapHWordLow(N, N0, N1)) + return BSwap; + + // reassociate or + if (SDValue ROR = reassociateOps(ISD::OR, SDLoc(N), N0, N1, N->getFlags())) + return ROR; + + // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) + // iff (c1 & c2) != 0 or c1/c2 are undef. + auto MatchIntersect = [](ConstantSDNode *C1, ConstantSDNode *C2) { + return !C1 || !C2 || C1->getAPIntValue().intersects(C2->getAPIntValue()); + }; + if (N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() && + ISD::matchBinaryPredicate(N0.getOperand(1), N1, MatchIntersect, true)) { + if (SDValue COR = DAG.FoldConstantArithmetic(ISD::OR, SDLoc(N1), VT, + {N1, N0.getOperand(1)})) { + SDValue IOR = DAG.getNode(ISD::OR, SDLoc(N0), VT, N0.getOperand(0), N1); + AddToWorklist(IOR.getNode()); + return DAG.getNode(ISD::AND, SDLoc(N), VT, COR, IOR); + } + } + + if (SDValue Combined = visitORCommutative(DAG, N0, N1, N)) + return Combined; + if (SDValue Combined = visitORCommutative(DAG, N1, N0, N)) + return Combined; + + // Simplify: (or (op x...), (op y...)) -> (op (or x, y)) + if (N0.getOpcode() == N1.getOpcode()) + if (SDValue V = hoistLogicOpWithSameOpcodeHands(N)) + return V; + + // See if this is some rotate idiom. + if (SDValue Rot = MatchRotate(N0, N1, SDLoc(N))) + return Rot; + + if (SDValue Load = MatchLoadCombine(N)) + return Load; + + // Simplify the operands using demanded-bits information. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // If OR can be rewritten into ADD, try combines based on ADD. + if ((!LegalOperations || TLI.isOperationLegal(ISD::ADD, VT)) && + DAG.haveNoCommonBitsSet(N0, N1)) + if (SDValue Combined = visitADDLike(N)) + return Combined; + + return SDValue(); +} + +static SDValue stripConstantMask(SelectionDAG &DAG, SDValue Op, SDValue &Mask) { + if (Op.getOpcode() == ISD::AND && + DAG.isConstantIntBuildVectorOrConstantInt(Op.getOperand(1))) { + Mask = Op.getOperand(1); + return Op.getOperand(0); + } + return Op; +} + +/// Match "(X shl/srl V1) & V2" where V2 may not be present. +static bool matchRotateHalf(SelectionDAG &DAG, SDValue Op, SDValue &Shift, + SDValue &Mask) { + Op = stripConstantMask(DAG, Op, Mask); + if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { + Shift = Op; + return true; + } + return false; +} + +/// Helper function for visitOR to extract the needed side of a rotate idiom +/// from a shl/srl/mul/udiv. This is meant to handle cases where +/// InstCombine merged some outside op with one of the shifts from +/// the rotate pattern. +/// \returns An empty \c SDValue if the needed shift couldn't be extracted. +/// Otherwise, returns an expansion of \p ExtractFrom based on the following +/// patterns: +/// +/// (or (add v v) (shrl v bitwidth-1)): +/// expands (add v v) -> (shl v 1) +/// +/// (or (mul v c0) (shrl (mul v c1) c2)): +/// expands (mul v c0) -> (shl (mul v c1) c3) +/// +/// (or (udiv v c0) (shl (udiv v c1) c2)): +/// expands (udiv v c0) -> (shrl (udiv v c1) c3) +/// +/// (or (shl v c0) (shrl (shl v c1) c2)): +/// expands (shl v c0) -> (shl (shl v c1) c3) +/// +/// (or (shrl v c0) (shl (shrl v c1) c2)): +/// expands (shrl v c0) -> (shrl (shrl v c1) c3) +/// +/// Such that in all cases, c3+c2==bitwidth(op v c1). +static SDValue extractShiftForRotate(SelectionDAG &DAG, SDValue OppShift, + SDValue ExtractFrom, SDValue &Mask, + const SDLoc &DL) { + assert(OppShift && ExtractFrom && "Empty SDValue"); + assert( + (OppShift.getOpcode() == ISD::SHL || OppShift.getOpcode() == ISD::SRL) && + "Existing shift must be valid as a rotate half"); + + ExtractFrom = stripConstantMask(DAG, ExtractFrom, Mask); + + // Value and Type of the shift. + SDValue OppShiftLHS = OppShift.getOperand(0); + EVT ShiftedVT = OppShiftLHS.getValueType(); + + // Amount of the existing shift. + ConstantSDNode *OppShiftCst = isConstOrConstSplat(OppShift.getOperand(1)); + + // (add v v) -> (shl v 1) + // TODO: Should this be a general DAG canonicalization? + if (OppShift.getOpcode() == ISD::SRL && OppShiftCst && + ExtractFrom.getOpcode() == ISD::ADD && + ExtractFrom.getOperand(0) == ExtractFrom.getOperand(1) && + ExtractFrom.getOperand(0) == OppShiftLHS && + OppShiftCst->getAPIntValue() == ShiftedVT.getScalarSizeInBits() - 1) + return DAG.getNode(ISD::SHL, DL, ShiftedVT, OppShiftLHS, + DAG.getShiftAmountConstant(1, ShiftedVT, DL)); + + // Preconditions: + // (or (op0 v c0) (shiftl/r (op0 v c1) c2)) + // + // Find opcode of the needed shift to be extracted from (op0 v c0). + unsigned Opcode = ISD::DELETED_NODE; + bool IsMulOrDiv = false; + // Set Opcode and IsMulOrDiv if the extract opcode matches the needed shift + // opcode or its arithmetic (mul or udiv) variant. + auto SelectOpcode = [&](unsigned NeededShift, unsigned MulOrDivVariant) { + IsMulOrDiv = ExtractFrom.getOpcode() == MulOrDivVariant; + if (!IsMulOrDiv && ExtractFrom.getOpcode() != NeededShift) + return false; + Opcode = NeededShift; + return true; + }; + // op0 must be either the needed shift opcode or the mul/udiv equivalent + // that the needed shift can be extracted from. + if ((OppShift.getOpcode() != ISD::SRL || !SelectOpcode(ISD::SHL, ISD::MUL)) && + (OppShift.getOpcode() != ISD::SHL || !SelectOpcode(ISD::SRL, ISD::UDIV))) + return SDValue(); + + // op0 must be the same opcode on both sides, have the same LHS argument, + // and produce the same value type. + if (OppShiftLHS.getOpcode() != ExtractFrom.getOpcode() || + OppShiftLHS.getOperand(0) != ExtractFrom.getOperand(0) || + ShiftedVT != ExtractFrom.getValueType()) + return SDValue(); + + // Constant mul/udiv/shift amount from the RHS of the shift's LHS op. + ConstantSDNode *OppLHSCst = isConstOrConstSplat(OppShiftLHS.getOperand(1)); + // Constant mul/udiv/shift amount from the RHS of the ExtractFrom op. + ConstantSDNode *ExtractFromCst = + isConstOrConstSplat(ExtractFrom.getOperand(1)); + // TODO: We should be able to handle non-uniform constant vectors for these values + // Check that we have constant values. + if (!OppShiftCst || !OppShiftCst->getAPIntValue() || + !OppLHSCst || !OppLHSCst->getAPIntValue() || + !ExtractFromCst || !ExtractFromCst->getAPIntValue()) + return SDValue(); + + // Compute the shift amount we need to extract to complete the rotate. + const unsigned VTWidth = ShiftedVT.getScalarSizeInBits(); + if (OppShiftCst->getAPIntValue().ugt(VTWidth)) + return SDValue(); + APInt NeededShiftAmt = VTWidth - OppShiftCst->getAPIntValue(); + // Normalize the bitwidth of the two mul/udiv/shift constant operands. + APInt ExtractFromAmt = ExtractFromCst->getAPIntValue(); + APInt OppLHSAmt = OppLHSCst->getAPIntValue(); + zeroExtendToMatch(ExtractFromAmt, OppLHSAmt); + + // Now try extract the needed shift from the ExtractFrom op and see if the + // result matches up with the existing shift's LHS op. + if (IsMulOrDiv) { + // Op to extract from is a mul or udiv by a constant. + // Check: + // c2 / (1 << (bitwidth(op0 v c0) - c1)) == c0 + // c2 % (1 << (bitwidth(op0 v c0) - c1)) == 0 + const APInt ExtractDiv = APInt::getOneBitSet(ExtractFromAmt.getBitWidth(), + NeededShiftAmt.getZExtValue()); + APInt ResultAmt; + APInt Rem; + APInt::udivrem(ExtractFromAmt, ExtractDiv, ResultAmt, Rem); + if (Rem != 0 || ResultAmt != OppLHSAmt) + return SDValue(); + } else { + // Op to extract from is a shift by a constant. + // Check: + // c2 - (bitwidth(op0 v c0) - c1) == c0 + if (OppLHSAmt != ExtractFromAmt - NeededShiftAmt.zextOrTrunc( + ExtractFromAmt.getBitWidth())) + return SDValue(); + } + + // Return the expanded shift op that should allow a rotate to be formed. + EVT ShiftVT = OppShift.getOperand(1).getValueType(); + EVT ResVT = ExtractFrom.getValueType(); + SDValue NewShiftNode = DAG.getConstant(NeededShiftAmt, DL, ShiftVT); + return DAG.getNode(Opcode, DL, ResVT, OppShiftLHS, NewShiftNode); +} + +// Return true if we can prove that, whenever Neg and Pos are both in the +// range [0, EltSize), Neg == (Pos == 0 ? 0 : EltSize - Pos). This means that +// for two opposing shifts shift1 and shift2 and a value X with OpBits bits: +// +// (or (shift1 X, Neg), (shift2 X, Pos)) +// +// reduces to a rotate in direction shift2 by Pos or (equivalently) a rotate +// in direction shift1 by Neg. The range [0, EltSize) means that we only need +// to consider shift amounts with defined behavior. +// +// The IsRotate flag should be set when the LHS of both shifts is the same. +// Otherwise if matching a general funnel shift, it should be clear. +static bool matchRotateSub(SDValue Pos, SDValue Neg, unsigned EltSize, + SelectionDAG &DAG, bool IsRotate) { + // If EltSize is a power of 2 then: + // + // (a) (Pos == 0 ? 0 : EltSize - Pos) == (EltSize - Pos) & (EltSize - 1) + // (b) Neg == Neg & (EltSize - 1) whenever Neg is in [0, EltSize). + // + // So if EltSize is a power of 2 and Neg is (and Neg', EltSize-1), we check + // for the stronger condition: + // + // Neg & (EltSize - 1) == (EltSize - Pos) & (EltSize - 1) [A] + // + // for all Neg and Pos. Since Neg & (EltSize - 1) == Neg' & (EltSize - 1) + // we can just replace Neg with Neg' for the rest of the function. + // + // In other cases we check for the even stronger condition: + // + // Neg == EltSize - Pos [B] + // + // for all Neg and Pos. Note that the (or ...) then invokes undefined + // behavior if Pos == 0 (and consequently Neg == EltSize). + // + // We could actually use [A] whenever EltSize is a power of 2, but the + // only extra cases that it would match are those uninteresting ones + // where Neg and Pos are never in range at the same time. E.g. for + // EltSize == 32, using [A] would allow a Neg of the form (sub 64, Pos) + // as well as (sub 32, Pos), but: + // + // (or (shift1 X, (sub 64, Pos)), (shift2 X, Pos)) + // + // always invokes undefined behavior for 32-bit X. + // + // Below, Mask == EltSize - 1 when using [A] and is all-ones otherwise. + // + // NOTE: We can only do this when matching an AND and not a general + // funnel shift. + unsigned MaskLoBits = 0; + if (IsRotate && Neg.getOpcode() == ISD::AND && isPowerOf2_64(EltSize)) { + if (ConstantSDNode *NegC = isConstOrConstSplat(Neg.getOperand(1))) { + KnownBits Known = DAG.computeKnownBits(Neg.getOperand(0)); + unsigned Bits = Log2_64(EltSize); + if (NegC->getAPIntValue().getActiveBits() <= Bits && + ((NegC->getAPIntValue() | Known.Zero).countTrailingOnes() >= Bits)) { + Neg = Neg.getOperand(0); + MaskLoBits = Bits; + } + } + } + + // Check whether Neg has the form (sub NegC, NegOp1) for some NegC and NegOp1. + if (Neg.getOpcode() != ISD::SUB) + return false; + ConstantSDNode *NegC = isConstOrConstSplat(Neg.getOperand(0)); + if (!NegC) + return false; + SDValue NegOp1 = Neg.getOperand(1); + + // On the RHS of [A], if Pos is Pos' & (EltSize - 1), just replace Pos with + // Pos'. The truncation is redundant for the purpose of the equality. + if (MaskLoBits && Pos.getOpcode() == ISD::AND) { + if (ConstantSDNode *PosC = isConstOrConstSplat(Pos.getOperand(1))) { + KnownBits Known = DAG.computeKnownBits(Pos.getOperand(0)); + if (PosC->getAPIntValue().getActiveBits() <= MaskLoBits && + ((PosC->getAPIntValue() | Known.Zero).countTrailingOnes() >= + MaskLoBits)) + Pos = Pos.getOperand(0); + } + } + + // The condition we need is now: + // + // (NegC - NegOp1) & Mask == (EltSize - Pos) & Mask + // + // If NegOp1 == Pos then we need: + // + // EltSize & Mask == NegC & Mask + // + // (because "x & Mask" is a truncation and distributes through subtraction). + // + // We also need to account for a potential truncation of NegOp1 if the amount + // has already been legalized to a shift amount type. + APInt Width; + if ((Pos == NegOp1) || + (NegOp1.getOpcode() == ISD::TRUNCATE && Pos == NegOp1.getOperand(0))) + Width = NegC->getAPIntValue(); + + // Check for cases where Pos has the form (add NegOp1, PosC) for some PosC. + // Then the condition we want to prove becomes: + // + // (NegC - NegOp1) & Mask == (EltSize - (NegOp1 + PosC)) & Mask + // + // which, again because "x & Mask" is a truncation, becomes: + // + // NegC & Mask == (EltSize - PosC) & Mask + // EltSize & Mask == (NegC + PosC) & Mask + else if (Pos.getOpcode() == ISD::ADD && Pos.getOperand(0) == NegOp1) { + if (ConstantSDNode *PosC = isConstOrConstSplat(Pos.getOperand(1))) + Width = PosC->getAPIntValue() + NegC->getAPIntValue(); + else + return false; + } else + return false; + + // Now we just need to check that EltSize & Mask == Width & Mask. + if (MaskLoBits) + // EltSize & Mask is 0 since Mask is EltSize - 1. + return Width.getLoBits(MaskLoBits) == 0; + return Width == EltSize; +} + +// A subroutine of MatchRotate used once we have found an OR of two opposite +// shifts of Shifted. If Neg == <operand size> - Pos then the OR reduces +// to both (PosOpcode Shifted, Pos) and (NegOpcode Shifted, Neg), with the +// former being preferred if supported. InnerPos and InnerNeg are Pos and +// Neg with outer conversions stripped away. +SDValue DAGCombiner::MatchRotatePosNeg(SDValue Shifted, SDValue Pos, + SDValue Neg, SDValue InnerPos, + SDValue InnerNeg, unsigned PosOpcode, + unsigned NegOpcode, const SDLoc &DL) { + // fold (or (shl x, (*ext y)), + // (srl x, (*ext (sub 32, y)))) -> + // (rotl x, y) or (rotr x, (sub 32, y)) + // + // fold (or (shl x, (*ext (sub 32, y))), + // (srl x, (*ext y))) -> + // (rotr x, y) or (rotl x, (sub 32, y)) + EVT VT = Shifted.getValueType(); + if (matchRotateSub(InnerPos, InnerNeg, VT.getScalarSizeInBits(), DAG, + /*IsRotate*/ true)) { + bool HasPos = TLI.isOperationLegalOrCustom(PosOpcode, VT); + return DAG.getNode(HasPos ? PosOpcode : NegOpcode, DL, VT, Shifted, + HasPos ? Pos : Neg); + } + + return SDValue(); +} + +// A subroutine of MatchRotate used once we have found an OR of two opposite +// shifts of N0 + N1. If Neg == <operand size> - Pos then the OR reduces +// to both (PosOpcode N0, N1, Pos) and (NegOpcode N0, N1, Neg), with the +// former being preferred if supported. InnerPos and InnerNeg are Pos and +// Neg with outer conversions stripped away. +// TODO: Merge with MatchRotatePosNeg. +SDValue DAGCombiner::MatchFunnelPosNeg(SDValue N0, SDValue N1, SDValue Pos, + SDValue Neg, SDValue InnerPos, + SDValue InnerNeg, unsigned PosOpcode, + unsigned NegOpcode, const SDLoc &DL) { + EVT VT = N0.getValueType(); + unsigned EltBits = VT.getScalarSizeInBits(); + + // fold (or (shl x0, (*ext y)), + // (srl x1, (*ext (sub 32, y)))) -> + // (fshl x0, x1, y) or (fshr x0, x1, (sub 32, y)) + // + // fold (or (shl x0, (*ext (sub 32, y))), + // (srl x1, (*ext y))) -> + // (fshr x0, x1, y) or (fshl x0, x1, (sub 32, y)) + if (matchRotateSub(InnerPos, InnerNeg, EltBits, DAG, /*IsRotate*/ N0 == N1)) { + bool HasPos = TLI.isOperationLegalOrCustom(PosOpcode, VT); + return DAG.getNode(HasPos ? PosOpcode : NegOpcode, DL, VT, N0, N1, + HasPos ? Pos : Neg); + } + + // Matching the shift+xor cases, we can't easily use the xor'd shift amount + // so for now just use the PosOpcode case if its legal. + // TODO: When can we use the NegOpcode case? + if (PosOpcode == ISD::FSHL && isPowerOf2_32(EltBits)) { + auto IsBinOpImm = [](SDValue Op, unsigned BinOpc, unsigned Imm) { + if (Op.getOpcode() != BinOpc) + return false; + ConstantSDNode *Cst = isConstOrConstSplat(Op.getOperand(1)); + return Cst && (Cst->getAPIntValue() == Imm); + }; + + // fold (or (shl x0, y), (srl (srl x1, 1), (xor y, 31))) + // -> (fshl x0, x1, y) + if (IsBinOpImm(N1, ISD::SRL, 1) && + IsBinOpImm(InnerNeg, ISD::XOR, EltBits - 1) && + InnerPos == InnerNeg.getOperand(0) && + TLI.isOperationLegalOrCustom(ISD::FSHL, VT)) { + return DAG.getNode(ISD::FSHL, DL, VT, N0, N1.getOperand(0), Pos); + } + + // fold (or (shl (shl x0, 1), (xor y, 31)), (srl x1, y)) + // -> (fshr x0, x1, y) + if (IsBinOpImm(N0, ISD::SHL, 1) && + IsBinOpImm(InnerPos, ISD::XOR, EltBits - 1) && + InnerNeg == InnerPos.getOperand(0) && + TLI.isOperationLegalOrCustom(ISD::FSHR, VT)) { + return DAG.getNode(ISD::FSHR, DL, VT, N0.getOperand(0), N1, Neg); + } + + // fold (or (shl (add x0, x0), (xor y, 31)), (srl x1, y)) + // -> (fshr x0, x1, y) + // TODO: Should add(x,x) -> shl(x,1) be a general DAG canonicalization? + if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N0.getOperand(1) && + IsBinOpImm(InnerPos, ISD::XOR, EltBits - 1) && + InnerNeg == InnerPos.getOperand(0) && + TLI.isOperationLegalOrCustom(ISD::FSHR, VT)) { + return DAG.getNode(ISD::FSHR, DL, VT, N0.getOperand(0), N1, Neg); + } + } + + return SDValue(); +} + +// MatchRotate - Handle an 'or' of two operands. If this is one of the many +// idioms for rotate, and if the target supports rotation instructions, generate +// a rot[lr]. This also matches funnel shift patterns, similar to rotation but +// with different shifted sources. +SDValue DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, const SDLoc &DL) { + // Must be a legal type. Expanded 'n promoted things won't work with rotates. + EVT VT = LHS.getValueType(); + if (!TLI.isTypeLegal(VT)) + return SDValue(); + + // The target must have at least one rotate/funnel flavor. + bool HasROTL = hasOperation(ISD::ROTL, VT); + bool HasROTR = hasOperation(ISD::ROTR, VT); + bool HasFSHL = hasOperation(ISD::FSHL, VT); + bool HasFSHR = hasOperation(ISD::FSHR, VT); + if (!HasROTL && !HasROTR && !HasFSHL && !HasFSHR) + return SDValue(); + + // Check for truncated rotate. + if (LHS.getOpcode() == ISD::TRUNCATE && RHS.getOpcode() == ISD::TRUNCATE && + LHS.getOperand(0).getValueType() == RHS.getOperand(0).getValueType()) { + assert(LHS.getValueType() == RHS.getValueType()); + if (SDValue Rot = MatchRotate(LHS.getOperand(0), RHS.getOperand(0), DL)) { + return DAG.getNode(ISD::TRUNCATE, SDLoc(LHS), LHS.getValueType(), Rot); + } + } + + // Match "(X shl/srl V1) & V2" where V2 may not be present. + SDValue LHSShift; // The shift. + SDValue LHSMask; // AND value if any. + matchRotateHalf(DAG, LHS, LHSShift, LHSMask); + + SDValue RHSShift; // The shift. + SDValue RHSMask; // AND value if any. + matchRotateHalf(DAG, RHS, RHSShift, RHSMask); + + // If neither side matched a rotate half, bail + if (!LHSShift && !RHSShift) + return SDValue(); + + // InstCombine may have combined a constant shl, srl, mul, or udiv with one + // side of the rotate, so try to handle that here. In all cases we need to + // pass the matched shift from the opposite side to compute the opcode and + // needed shift amount to extract. We still want to do this if both sides + // matched a rotate half because one half may be a potential overshift that + // can be broken down (ie if InstCombine merged two shl or srl ops into a + // single one). + + // Have LHS side of the rotate, try to extract the needed shift from the RHS. + if (LHSShift) + if (SDValue NewRHSShift = + extractShiftForRotate(DAG, LHSShift, RHS, RHSMask, DL)) + RHSShift = NewRHSShift; + // Have RHS side of the rotate, try to extract the needed shift from the LHS. + if (RHSShift) + if (SDValue NewLHSShift = + extractShiftForRotate(DAG, RHSShift, LHS, LHSMask, DL)) + LHSShift = NewLHSShift; + + // If a side is still missing, nothing else we can do. + if (!RHSShift || !LHSShift) + return SDValue(); + + // At this point we've matched or extracted a shift op on each side. + + if (LHSShift.getOpcode() == RHSShift.getOpcode()) + return SDValue(); // Shifts must disagree. + + bool IsRotate = LHSShift.getOperand(0) == RHSShift.getOperand(0); + if (!IsRotate && !(HasFSHL || HasFSHR)) + return SDValue(); // Requires funnel shift support. + + // Canonicalize shl to left side in a shl/srl pair. + if (RHSShift.getOpcode() == ISD::SHL) { + std::swap(LHS, RHS); + std::swap(LHSShift, RHSShift); + std::swap(LHSMask, RHSMask); + } + + unsigned EltSizeInBits = VT.getScalarSizeInBits(); + SDValue LHSShiftArg = LHSShift.getOperand(0); + SDValue LHSShiftAmt = LHSShift.getOperand(1); + SDValue RHSShiftArg = RHSShift.getOperand(0); + SDValue RHSShiftAmt = RHSShift.getOperand(1); + + // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) + // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) + // fold (or (shl x, C1), (srl y, C2)) -> (fshl x, y, C1) + // fold (or (shl x, C1), (srl y, C2)) -> (fshr x, y, C2) + // iff C1+C2 == EltSizeInBits + auto MatchRotateSum = [EltSizeInBits](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + return (LHS->getAPIntValue() + RHS->getAPIntValue()) == EltSizeInBits; + }; + if (ISD::matchBinaryPredicate(LHSShiftAmt, RHSShiftAmt, MatchRotateSum)) { + SDValue Res; + if (IsRotate && (HasROTL || HasROTR)) + Res = DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT, LHSShiftArg, + HasROTL ? LHSShiftAmt : RHSShiftAmt); + else + Res = DAG.getNode(HasFSHL ? ISD::FSHL : ISD::FSHR, DL, VT, LHSShiftArg, + RHSShiftArg, HasFSHL ? LHSShiftAmt : RHSShiftAmt); + + // If there is an AND of either shifted operand, apply it to the result. + if (LHSMask.getNode() || RHSMask.getNode()) { + SDValue AllOnes = DAG.getAllOnesConstant(DL, VT); + SDValue Mask = AllOnes; + + if (LHSMask.getNode()) { + SDValue RHSBits = DAG.getNode(ISD::SRL, DL, VT, AllOnes, RHSShiftAmt); + Mask = DAG.getNode(ISD::AND, DL, VT, Mask, + DAG.getNode(ISD::OR, DL, VT, LHSMask, RHSBits)); + } + if (RHSMask.getNode()) { + SDValue LHSBits = DAG.getNode(ISD::SHL, DL, VT, AllOnes, LHSShiftAmt); + Mask = DAG.getNode(ISD::AND, DL, VT, Mask, + DAG.getNode(ISD::OR, DL, VT, RHSMask, LHSBits)); + } + + Res = DAG.getNode(ISD::AND, DL, VT, Res, Mask); + } + + return Res; + } + + // If there is a mask here, and we have a variable shift, we can't be sure + // that we're masking out the right stuff. + if (LHSMask.getNode() || RHSMask.getNode()) + return SDValue(); + + // If the shift amount is sign/zext/any-extended just peel it off. + SDValue LExtOp0 = LHSShiftAmt; + SDValue RExtOp0 = RHSShiftAmt; + if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND || + LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND || + LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND || + LHSShiftAmt.getOpcode() == ISD::TRUNCATE) && + (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND || + RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND || + RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND || + RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) { + LExtOp0 = LHSShiftAmt.getOperand(0); + RExtOp0 = RHSShiftAmt.getOperand(0); + } + + if (IsRotate && (HasROTL || HasROTR)) { + SDValue TryL = + MatchRotatePosNeg(LHSShiftArg, LHSShiftAmt, RHSShiftAmt, LExtOp0, + RExtOp0, ISD::ROTL, ISD::ROTR, DL); + if (TryL) + return TryL; + + SDValue TryR = + MatchRotatePosNeg(RHSShiftArg, RHSShiftAmt, LHSShiftAmt, RExtOp0, + LExtOp0, ISD::ROTR, ISD::ROTL, DL); + if (TryR) + return TryR; + } + + SDValue TryL = + MatchFunnelPosNeg(LHSShiftArg, RHSShiftArg, LHSShiftAmt, RHSShiftAmt, + LExtOp0, RExtOp0, ISD::FSHL, ISD::FSHR, DL); + if (TryL) + return TryL; + + SDValue TryR = + MatchFunnelPosNeg(LHSShiftArg, RHSShiftArg, RHSShiftAmt, LHSShiftAmt, + RExtOp0, LExtOp0, ISD::FSHR, ISD::FSHL, DL); + if (TryR) + return TryR; + + return SDValue(); +} + +namespace { + +/// Represents known origin of an individual byte in load combine pattern. The +/// value of the byte is either constant zero or comes from memory. +struct ByteProvider { + // For constant zero providers Load is set to nullptr. For memory providers + // Load represents the node which loads the byte from memory. + // ByteOffset is the offset of the byte in the value produced by the load. + LoadSDNode *Load = nullptr; + unsigned ByteOffset = 0; + + ByteProvider() = default; + + static ByteProvider getMemory(LoadSDNode *Load, unsigned ByteOffset) { + return ByteProvider(Load, ByteOffset); + } + + static ByteProvider getConstantZero() { return ByteProvider(nullptr, 0); } + + bool isConstantZero() const { return !Load; } + bool isMemory() const { return Load; } + + bool operator==(const ByteProvider &Other) const { + return Other.Load == Load && Other.ByteOffset == ByteOffset; + } + +private: + ByteProvider(LoadSDNode *Load, unsigned ByteOffset) + : Load(Load), ByteOffset(ByteOffset) {} +}; + +} // end anonymous namespace + +/// Recursively traverses the expression calculating the origin of the requested +/// byte of the given value. Returns None if the provider can't be calculated. +/// +/// For all the values except the root of the expression verifies that the value +/// has exactly one use and if it's not true return None. This way if the origin +/// of the byte is returned it's guaranteed that the values which contribute to +/// the byte are not used outside of this expression. +/// +/// Because the parts of the expression are not allowed to have more than one +/// use this function iterates over trees, not DAGs. So it never visits the same +/// node more than once. +static const Optional<ByteProvider> +calculateByteProvider(SDValue Op, unsigned Index, unsigned Depth, + bool Root = false) { + // Typical i64 by i8 pattern requires recursion up to 8 calls depth + if (Depth == 10) + return None; + + if (!Root && !Op.hasOneUse()) + return None; + + assert(Op.getValueType().isScalarInteger() && "can't handle other types"); + unsigned BitWidth = Op.getValueSizeInBits(); + if (BitWidth % 8 != 0) + return None; + unsigned ByteWidth = BitWidth / 8; + assert(Index < ByteWidth && "invalid index requested"); + (void) ByteWidth; + + switch (Op.getOpcode()) { + case ISD::OR: { + auto LHS = calculateByteProvider(Op->getOperand(0), Index, Depth + 1); + if (!LHS) + return None; + auto RHS = calculateByteProvider(Op->getOperand(1), Index, Depth + 1); + if (!RHS) + return None; + + if (LHS->isConstantZero()) + return RHS; + if (RHS->isConstantZero()) + return LHS; + return None; + } + case ISD::SHL: { + auto ShiftOp = dyn_cast<ConstantSDNode>(Op->getOperand(1)); + if (!ShiftOp) + return None; + + uint64_t BitShift = ShiftOp->getZExtValue(); + if (BitShift % 8 != 0) + return None; + uint64_t ByteShift = BitShift / 8; + + return Index < ByteShift + ? ByteProvider::getConstantZero() + : calculateByteProvider(Op->getOperand(0), Index - ByteShift, + Depth + 1); + } + case ISD::ANY_EXTEND: + case ISD::SIGN_EXTEND: + case ISD::ZERO_EXTEND: { + SDValue NarrowOp = Op->getOperand(0); + unsigned NarrowBitWidth = NarrowOp.getScalarValueSizeInBits(); + if (NarrowBitWidth % 8 != 0) + return None; + uint64_t NarrowByteWidth = NarrowBitWidth / 8; + + if (Index >= NarrowByteWidth) + return Op.getOpcode() == ISD::ZERO_EXTEND + ? Optional<ByteProvider>(ByteProvider::getConstantZero()) + : None; + return calculateByteProvider(NarrowOp, Index, Depth + 1); + } + case ISD::BSWAP: + return calculateByteProvider(Op->getOperand(0), ByteWidth - Index - 1, + Depth + 1); + case ISD::LOAD: { + auto L = cast<LoadSDNode>(Op.getNode()); + if (!L->isSimple() || L->isIndexed()) + return None; + + unsigned NarrowBitWidth = L->getMemoryVT().getSizeInBits(); + if (NarrowBitWidth % 8 != 0) + return None; + uint64_t NarrowByteWidth = NarrowBitWidth / 8; + + if (Index >= NarrowByteWidth) + return L->getExtensionType() == ISD::ZEXTLOAD + ? Optional<ByteProvider>(ByteProvider::getConstantZero()) + : None; + return ByteProvider::getMemory(L, Index); + } + } + + return None; +} + +static unsigned littleEndianByteAt(unsigned BW, unsigned i) { + return i; +} + +static unsigned bigEndianByteAt(unsigned BW, unsigned i) { + return BW - i - 1; +} + +// Check if the bytes offsets we are looking at match with either big or +// little endian value loaded. Return true for big endian, false for little +// endian, and None if match failed. +static Optional<bool> isBigEndian(const ArrayRef<int64_t> ByteOffsets, + int64_t FirstOffset) { + // The endian can be decided only when it is 2 bytes at least. + unsigned Width = ByteOffsets.size(); + if (Width < 2) + return None; + + bool BigEndian = true, LittleEndian = true; + for (unsigned i = 0; i < Width; i++) { + int64_t CurrentByteOffset = ByteOffsets[i] - FirstOffset; + LittleEndian &= CurrentByteOffset == littleEndianByteAt(Width, i); + BigEndian &= CurrentByteOffset == bigEndianByteAt(Width, i); + if (!BigEndian && !LittleEndian) + return None; + } + + assert((BigEndian != LittleEndian) && "It should be either big endian or" + "little endian"); + return BigEndian; +} + +static SDValue stripTruncAndExt(SDValue Value) { + switch (Value.getOpcode()) { + case ISD::TRUNCATE: + case ISD::ZERO_EXTEND: + case ISD::SIGN_EXTEND: + case ISD::ANY_EXTEND: + return stripTruncAndExt(Value.getOperand(0)); + } + return Value; +} + +/// Match a pattern where a wide type scalar value is stored by several narrow +/// stores. Fold it into a single store or a BSWAP and a store if the targets +/// supports it. +/// +/// Assuming little endian target: +/// i8 *p = ... +/// i32 val = ... +/// p[0] = (val >> 0) & 0xFF; +/// p[1] = (val >> 8) & 0xFF; +/// p[2] = (val >> 16) & 0xFF; +/// p[3] = (val >> 24) & 0xFF; +/// => +/// *((i32)p) = val; +/// +/// i8 *p = ... +/// i32 val = ... +/// p[0] = (val >> 24) & 0xFF; +/// p[1] = (val >> 16) & 0xFF; +/// p[2] = (val >> 8) & 0xFF; +/// p[3] = (val >> 0) & 0xFF; +/// => +/// *((i32)p) = BSWAP(val); +SDValue DAGCombiner::mergeTruncStores(StoreSDNode *N) { + // The matching looks for "store (trunc x)" patterns that appear early but are + // likely to be replaced by truncating store nodes during combining. + // TODO: If there is evidence that running this later would help, this + // limitation could be removed. Legality checks may need to be added + // for the created store and optional bswap/rotate. + if (LegalOperations) + return SDValue(); + + // We only handle merging simple stores of 1-4 bytes. + // TODO: Allow unordered atomics when wider type is legal (see D66309) + EVT MemVT = N->getMemoryVT(); + if (!(MemVT == MVT::i8 || MemVT == MVT::i16 || MemVT == MVT::i32) || + !N->isSimple() || N->isIndexed()) + return SDValue(); + + // Collect all of the stores in the chain. + SDValue Chain = N->getChain(); + SmallVector<StoreSDNode *, 8> Stores = {N}; + while (auto *Store = dyn_cast<StoreSDNode>(Chain)) { + // All stores must be the same size to ensure that we are writing all of the + // bytes in the wide value. + // TODO: We could allow multiple sizes by tracking each stored byte. + if (Store->getMemoryVT() != MemVT || !Store->isSimple() || + Store->isIndexed()) + return SDValue(); + Stores.push_back(Store); + Chain = Store->getChain(); + } + // There is no reason to continue if we do not have at least a pair of stores. + if (Stores.size() < 2) + return SDValue(); + + // Handle simple types only. + LLVMContext &Context = *DAG.getContext(); + unsigned NumStores = Stores.size(); + unsigned NarrowNumBits = N->getMemoryVT().getScalarSizeInBits(); + unsigned WideNumBits = NumStores * NarrowNumBits; + EVT WideVT = EVT::getIntegerVT(Context, WideNumBits); + if (WideVT != MVT::i16 && WideVT != MVT::i32 && WideVT != MVT::i64) + return SDValue(); + + // Check if all bytes of the source value that we are looking at are stored + // to the same base address. Collect offsets from Base address into OffsetMap. + SDValue SourceValue; + SmallVector<int64_t, 8> OffsetMap(NumStores, INT64_MAX); + int64_t FirstOffset = INT64_MAX; + StoreSDNode *FirstStore = nullptr; + Optional<BaseIndexOffset> Base; + for (auto Store : Stores) { + // All the stores store different parts of the CombinedValue. A truncate is + // required to get the partial value. + SDValue Trunc = Store->getValue(); + if (Trunc.getOpcode() != ISD::TRUNCATE) + return SDValue(); + // Other than the first/last part, a shift operation is required to get the + // offset. + int64_t Offset = 0; + SDValue WideVal = Trunc.getOperand(0); + if ((WideVal.getOpcode() == ISD::SRL || WideVal.getOpcode() == ISD::SRA) && + isa<ConstantSDNode>(WideVal.getOperand(1))) { + // The shift amount must be a constant multiple of the narrow type. + // It is translated to the offset address in the wide source value "y". + // + // x = srl y, ShiftAmtC + // i8 z = trunc x + // store z, ... + uint64_t ShiftAmtC = WideVal.getConstantOperandVal(1); + if (ShiftAmtC % NarrowNumBits != 0) + return SDValue(); + + Offset = ShiftAmtC / NarrowNumBits; + WideVal = WideVal.getOperand(0); + } + + // Stores must share the same source value with different offsets. + // Truncate and extends should be stripped to get the single source value. + if (!SourceValue) + SourceValue = WideVal; + else if (stripTruncAndExt(SourceValue) != stripTruncAndExt(WideVal)) + return SDValue(); + else if (SourceValue.getValueType() != WideVT) { + if (WideVal.getValueType() == WideVT || + WideVal.getScalarValueSizeInBits() > + SourceValue.getScalarValueSizeInBits()) + SourceValue = WideVal; + // Give up if the source value type is smaller than the store size. + if (SourceValue.getScalarValueSizeInBits() < WideVT.getScalarSizeInBits()) + return SDValue(); + } + + // Stores must share the same base address. + BaseIndexOffset Ptr = BaseIndexOffset::match(Store, DAG); + int64_t ByteOffsetFromBase = 0; + if (!Base) + Base = Ptr; + else if (!Base->equalBaseIndex(Ptr, DAG, ByteOffsetFromBase)) + return SDValue(); + + // Remember the first store. + if (ByteOffsetFromBase < FirstOffset) { + FirstStore = Store; + FirstOffset = ByteOffsetFromBase; + } + // Map the offset in the store and the offset in the combined value, and + // early return if it has been set before. + if (Offset < 0 || Offset >= NumStores || OffsetMap[Offset] != INT64_MAX) + return SDValue(); + OffsetMap[Offset] = ByteOffsetFromBase; + } + + assert(FirstOffset != INT64_MAX && "First byte offset must be set"); + assert(FirstStore && "First store must be set"); + + // Check that a store of the wide type is both allowed and fast on the target + const DataLayout &Layout = DAG.getDataLayout(); + bool Fast = false; + bool Allowed = TLI.allowsMemoryAccess(Context, Layout, WideVT, + *FirstStore->getMemOperand(), &Fast); + if (!Allowed || !Fast) + return SDValue(); + + // Check if the pieces of the value are going to the expected places in memory + // to merge the stores. + auto checkOffsets = [&](bool MatchLittleEndian) { + if (MatchLittleEndian) { + for (unsigned i = 0; i != NumStores; ++i) + if (OffsetMap[i] != i * (NarrowNumBits / 8) + FirstOffset) + return false; + } else { // MatchBigEndian by reversing loop counter. + for (unsigned i = 0, j = NumStores - 1; i != NumStores; ++i, --j) + if (OffsetMap[j] != i * (NarrowNumBits / 8) + FirstOffset) + return false; + } + return true; + }; + + // Check if the offsets line up for the native data layout of this target. + bool NeedBswap = false; + bool NeedRotate = false; + if (!checkOffsets(Layout.isLittleEndian())) { + // Special-case: check if byte offsets line up for the opposite endian. + if (NarrowNumBits == 8 && checkOffsets(Layout.isBigEndian())) + NeedBswap = true; + else if (NumStores == 2 && checkOffsets(Layout.isBigEndian())) + NeedRotate = true; + else + return SDValue(); + } + + SDLoc DL(N); + if (WideVT != SourceValue.getValueType()) { + assert(SourceValue.getValueType().getScalarSizeInBits() > WideNumBits && + "Unexpected store value to merge"); + SourceValue = DAG.getNode(ISD::TRUNCATE, DL, WideVT, SourceValue); + } + + // Before legalize we can introduce illegal bswaps/rotates which will be later + // converted to an explicit bswap sequence. This way we end up with a single + // store and byte shuffling instead of several stores and byte shuffling. + if (NeedBswap) { + SourceValue = DAG.getNode(ISD::BSWAP, DL, WideVT, SourceValue); + } else if (NeedRotate) { + assert(WideNumBits % 2 == 0 && "Unexpected type for rotate"); + SDValue RotAmt = DAG.getConstant(WideNumBits / 2, DL, WideVT); + SourceValue = DAG.getNode(ISD::ROTR, DL, WideVT, SourceValue, RotAmt); + } + + SDValue NewStore = + DAG.getStore(Chain, DL, SourceValue, FirstStore->getBasePtr(), + FirstStore->getPointerInfo(), FirstStore->getAlign()); + + // Rely on other DAG combine rules to remove the other individual stores. + DAG.ReplaceAllUsesWith(N, NewStore.getNode()); + return NewStore; +} + +/// Match a pattern where a wide type scalar value is loaded by several narrow +/// loads and combined by shifts and ors. Fold it into a single load or a load +/// and a BSWAP if the targets supports it. +/// +/// Assuming little endian target: +/// i8 *a = ... +/// i32 val = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24) +/// => +/// i32 val = *((i32)a) +/// +/// i8 *a = ... +/// i32 val = (a[0] << 24) | (a[1] << 16) | (a[2] << 8) | a[3] +/// => +/// i32 val = BSWAP(*((i32)a)) +/// +/// TODO: This rule matches complex patterns with OR node roots and doesn't +/// interact well with the worklist mechanism. When a part of the pattern is +/// updated (e.g. one of the loads) its direct users are put into the worklist, +/// but the root node of the pattern which triggers the load combine is not +/// necessarily a direct user of the changed node. For example, once the address +/// of t28 load is reassociated load combine won't be triggered: +/// t25: i32 = add t4, Constant:i32<2> +/// t26: i64 = sign_extend t25 +/// t27: i64 = add t2, t26 +/// t28: i8,ch = load<LD1[%tmp9]> t0, t27, undef:i64 +/// t29: i32 = zero_extend t28 +/// t32: i32 = shl t29, Constant:i8<8> +/// t33: i32 = or t23, t32 +/// As a possible fix visitLoad can check if the load can be a part of a load +/// combine pattern and add corresponding OR roots to the worklist. +SDValue DAGCombiner::MatchLoadCombine(SDNode *N) { + assert(N->getOpcode() == ISD::OR && + "Can only match load combining against OR nodes"); + + // Handles simple types only + EVT VT = N->getValueType(0); + if (VT != MVT::i16 && VT != MVT::i32 && VT != MVT::i64) + return SDValue(); + unsigned ByteWidth = VT.getSizeInBits() / 8; + + bool IsBigEndianTarget = DAG.getDataLayout().isBigEndian(); + auto MemoryByteOffset = [&] (ByteProvider P) { + assert(P.isMemory() && "Must be a memory byte provider"); + unsigned LoadBitWidth = P.Load->getMemoryVT().getSizeInBits(); + assert(LoadBitWidth % 8 == 0 && + "can only analyze providers for individual bytes not bit"); + unsigned LoadByteWidth = LoadBitWidth / 8; + return IsBigEndianTarget + ? bigEndianByteAt(LoadByteWidth, P.ByteOffset) + : littleEndianByteAt(LoadByteWidth, P.ByteOffset); + }; + + Optional<BaseIndexOffset> Base; + SDValue Chain; + + SmallPtrSet<LoadSDNode *, 8> Loads; + Optional<ByteProvider> FirstByteProvider; + int64_t FirstOffset = INT64_MAX; + + // Check if all the bytes of the OR we are looking at are loaded from the same + // base address. Collect bytes offsets from Base address in ByteOffsets. + SmallVector<int64_t, 8> ByteOffsets(ByteWidth); + unsigned ZeroExtendedBytes = 0; + for (int i = ByteWidth - 1; i >= 0; --i) { + auto P = calculateByteProvider(SDValue(N, 0), i, 0, /*Root=*/true); + if (!P) + return SDValue(); + + if (P->isConstantZero()) { + // It's OK for the N most significant bytes to be 0, we can just + // zero-extend the load. + if (++ZeroExtendedBytes != (ByteWidth - static_cast<unsigned>(i))) + return SDValue(); + continue; + } + assert(P->isMemory() && "provenance should either be memory or zero"); + + LoadSDNode *L = P->Load; + assert(L->hasNUsesOfValue(1, 0) && L->isSimple() && + !L->isIndexed() && + "Must be enforced by calculateByteProvider"); + assert(L->getOffset().isUndef() && "Unindexed load must have undef offset"); + + // All loads must share the same chain + SDValue LChain = L->getChain(); + if (!Chain) + Chain = LChain; + else if (Chain != LChain) + return SDValue(); + + // Loads must share the same base address + BaseIndexOffset Ptr = BaseIndexOffset::match(L, DAG); + int64_t ByteOffsetFromBase = 0; + if (!Base) + Base = Ptr; + else if (!Base->equalBaseIndex(Ptr, DAG, ByteOffsetFromBase)) + return SDValue(); + + // Calculate the offset of the current byte from the base address + ByteOffsetFromBase += MemoryByteOffset(*P); + ByteOffsets[i] = ByteOffsetFromBase; + + // Remember the first byte load + if (ByteOffsetFromBase < FirstOffset) { + FirstByteProvider = P; + FirstOffset = ByteOffsetFromBase; + } + + Loads.insert(L); + } + assert(!Loads.empty() && "All the bytes of the value must be loaded from " + "memory, so there must be at least one load which produces the value"); + assert(Base && "Base address of the accessed memory location must be set"); + assert(FirstOffset != INT64_MAX && "First byte offset must be set"); + + bool NeedsZext = ZeroExtendedBytes > 0; + + EVT MemVT = + EVT::getIntegerVT(*DAG.getContext(), (ByteWidth - ZeroExtendedBytes) * 8); + + if (!MemVT.isSimple()) + return SDValue(); + + // Before legalize we can introduce too wide illegal loads which will be later + // split into legal sized loads. This enables us to combine i64 load by i8 + // patterns to a couple of i32 loads on 32 bit targets. + if (LegalOperations && + !TLI.isOperationLegal(NeedsZext ? ISD::ZEXTLOAD : ISD::NON_EXTLOAD, + MemVT)) + return SDValue(); + + // Check if the bytes of the OR we are looking at match with either big or + // little endian value load + Optional<bool> IsBigEndian = isBigEndian( + makeArrayRef(ByteOffsets).drop_back(ZeroExtendedBytes), FirstOffset); + if (!IsBigEndian.hasValue()) + return SDValue(); + + assert(FirstByteProvider && "must be set"); + + // Ensure that the first byte is loaded from zero offset of the first load. + // So the combined value can be loaded from the first load address. + if (MemoryByteOffset(*FirstByteProvider) != 0) + return SDValue(); + LoadSDNode *FirstLoad = FirstByteProvider->Load; + + // The node we are looking at matches with the pattern, check if we can + // replace it with a single (possibly zero-extended) load and bswap + shift if + // needed. + + // If the load needs byte swap check if the target supports it + bool NeedsBswap = IsBigEndianTarget != *IsBigEndian; + + // Before legalize we can introduce illegal bswaps which will be later + // converted to an explicit bswap sequence. This way we end up with a single + // load and byte shuffling instead of several loads and byte shuffling. + // We do not introduce illegal bswaps when zero-extending as this tends to + // introduce too many arithmetic instructions. + if (NeedsBswap && (LegalOperations || NeedsZext) && + !TLI.isOperationLegal(ISD::BSWAP, VT)) + return SDValue(); + + // If we need to bswap and zero extend, we have to insert a shift. Check that + // it is legal. + if (NeedsBswap && NeedsZext && LegalOperations && + !TLI.isOperationLegal(ISD::SHL, VT)) + return SDValue(); + + // Check that a load of the wide type is both allowed and fast on the target + bool Fast = false; + bool Allowed = + TLI.allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(), MemVT, + *FirstLoad->getMemOperand(), &Fast); + if (!Allowed || !Fast) + return SDValue(); + + SDValue NewLoad = + DAG.getExtLoad(NeedsZext ? ISD::ZEXTLOAD : ISD::NON_EXTLOAD, SDLoc(N), VT, + Chain, FirstLoad->getBasePtr(), + FirstLoad->getPointerInfo(), MemVT, FirstLoad->getAlign()); + + // Transfer chain users from old loads to the new load. + for (LoadSDNode *L : Loads) + DAG.ReplaceAllUsesOfValueWith(SDValue(L, 1), SDValue(NewLoad.getNode(), 1)); + + if (!NeedsBswap) + return NewLoad; + + SDValue ShiftedLoad = + NeedsZext + ? DAG.getNode(ISD::SHL, SDLoc(N), VT, NewLoad, + DAG.getShiftAmountConstant(ZeroExtendedBytes * 8, VT, + SDLoc(N), LegalOperations)) + : NewLoad; + return DAG.getNode(ISD::BSWAP, SDLoc(N), VT, ShiftedLoad); +} + +// If the target has andn, bsl, or a similar bit-select instruction, +// we want to unfold masked merge, with canonical pattern of: +// | A | |B| +// ((x ^ y) & m) ^ y +// | D | +// Into: +// (x & m) | (y & ~m) +// If y is a constant, and the 'andn' does not work with immediates, +// we unfold into a different pattern: +// ~(~x & m) & (m | y) +// NOTE: we don't unfold the pattern if 'xor' is actually a 'not', because at +// the very least that breaks andnpd / andnps patterns, and because those +// patterns are simplified in IR and shouldn't be created in the DAG +SDValue DAGCombiner::unfoldMaskedMerge(SDNode *N) { + assert(N->getOpcode() == ISD::XOR); + + // Don't touch 'not' (i.e. where y = -1). + if (isAllOnesOrAllOnesSplat(N->getOperand(1))) + return SDValue(); + + EVT VT = N->getValueType(0); + + // There are 3 commutable operators in the pattern, + // so we have to deal with 8 possible variants of the basic pattern. + SDValue X, Y, M; + auto matchAndXor = [&X, &Y, &M](SDValue And, unsigned XorIdx, SDValue Other) { + if (And.getOpcode() != ISD::AND || !And.hasOneUse()) + return false; + SDValue Xor = And.getOperand(XorIdx); + if (Xor.getOpcode() != ISD::XOR || !Xor.hasOneUse()) + return false; + SDValue Xor0 = Xor.getOperand(0); + SDValue Xor1 = Xor.getOperand(1); + // Don't touch 'not' (i.e. where y = -1). + if (isAllOnesOrAllOnesSplat(Xor1)) + return false; + if (Other == Xor0) + std::swap(Xor0, Xor1); + if (Other != Xor1) + return false; + X = Xor0; + Y = Xor1; + M = And.getOperand(XorIdx ? 0 : 1); + return true; + }; + + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + if (!matchAndXor(N0, 0, N1) && !matchAndXor(N0, 1, N1) && + !matchAndXor(N1, 0, N0) && !matchAndXor(N1, 1, N0)) + return SDValue(); + + // Don't do anything if the mask is constant. This should not be reachable. + // InstCombine should have already unfolded this pattern, and DAGCombiner + // probably shouldn't produce it, too. + if (isa<ConstantSDNode>(M.getNode())) + return SDValue(); + + // We can transform if the target has AndNot + if (!TLI.hasAndNot(M)) + return SDValue(); + + SDLoc DL(N); + + // If Y is a constant, check that 'andn' works with immediates. + if (!TLI.hasAndNot(Y)) { + assert(TLI.hasAndNot(X) && "Only mask is a variable? Unreachable."); + // If not, we need to do a bit more work to make sure andn is still used. + SDValue NotX = DAG.getNOT(DL, X, VT); + SDValue LHS = DAG.getNode(ISD::AND, DL, VT, NotX, M); + SDValue NotLHS = DAG.getNOT(DL, LHS, VT); + SDValue RHS = DAG.getNode(ISD::OR, DL, VT, M, Y); + return DAG.getNode(ISD::AND, DL, VT, NotLHS, RHS); + } + + SDValue LHS = DAG.getNode(ISD::AND, DL, VT, X, M); + SDValue NotM = DAG.getNOT(DL, M, VT); + SDValue RHS = DAG.getNode(ISD::AND, DL, VT, Y, NotM); + + return DAG.getNode(ISD::OR, DL, VT, LHS, RHS); +} + +SDValue DAGCombiner::visitXOR(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N0.getValueType(); + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (xor x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N1; + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + } + + // fold (xor undef, undef) -> 0. This is a common idiom (misuse). + SDLoc DL(N); + if (N0.isUndef() && N1.isUndef()) + return DAG.getConstant(0, DL, VT); + + // fold (xor x, undef) -> undef + if (N0.isUndef()) + return N0; + if (N1.isUndef()) + return N1; + + // fold (xor c1, c2) -> c1^c2 + if (SDValue C = DAG.FoldConstantArithmetic(ISD::XOR, DL, VT, {N0, N1})) + return C; + + // canonicalize constant to RHS + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + !DAG.isConstantIntBuildVectorOrConstantInt(N1)) + return DAG.getNode(ISD::XOR, DL, VT, N1, N0); + + // fold (xor x, 0) -> x + if (isNullConstant(N1)) + return N0; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // reassociate xor + if (SDValue RXOR = reassociateOps(ISD::XOR, DL, N0, N1, N->getFlags())) + return RXOR; + + // fold !(x cc y) -> (x !cc y) + unsigned N0Opcode = N0.getOpcode(); + SDValue LHS, RHS, CC; + if (TLI.isConstTrueVal(N1.getNode()) && + isSetCCEquivalent(N0, LHS, RHS, CC, /*MatchStrict*/true)) { + ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(), + LHS.getValueType()); + if (!LegalOperations || + TLI.isCondCodeLegal(NotCC, LHS.getSimpleValueType())) { + switch (N0Opcode) { + default: + llvm_unreachable("Unhandled SetCC Equivalent!"); + case ISD::SETCC: + return DAG.getSetCC(SDLoc(N0), VT, LHS, RHS, NotCC); + case ISD::SELECT_CC: + return DAG.getSelectCC(SDLoc(N0), LHS, RHS, N0.getOperand(2), + N0.getOperand(3), NotCC); + case ISD::STRICT_FSETCC: + case ISD::STRICT_FSETCCS: { + if (N0.hasOneUse()) { + // FIXME Can we handle multiple uses? Could we token factor the chain + // results from the new/old setcc? + SDValue SetCC = + DAG.getSetCC(SDLoc(N0), VT, LHS, RHS, NotCC, + N0.getOperand(0), N0Opcode == ISD::STRICT_FSETCCS); + CombineTo(N, SetCC); + DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), SetCC.getValue(1)); + recursivelyDeleteUnusedNodes(N0.getNode()); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + break; + } + } + } + } + + // fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y))) + if (isOneConstant(N1) && N0Opcode == ISD::ZERO_EXTEND && N0.hasOneUse() && + isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){ + SDValue V = N0.getOperand(0); + SDLoc DL0(N0); + V = DAG.getNode(ISD::XOR, DL0, V.getValueType(), V, + DAG.getConstant(1, DL0, V.getValueType())); + AddToWorklist(V.getNode()); + return DAG.getNode(ISD::ZERO_EXTEND, DL, VT, V); + } + + // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc + if (isOneConstant(N1) && VT == MVT::i1 && N0.hasOneUse() && + (N0Opcode == ISD::OR || N0Opcode == ISD::AND)) { + SDValue N00 = N0.getOperand(0), N01 = N0.getOperand(1); + if (isOneUseSetCC(N01) || isOneUseSetCC(N00)) { + unsigned NewOpcode = N0Opcode == ISD::AND ? ISD::OR : ISD::AND; + N00 = DAG.getNode(ISD::XOR, SDLoc(N00), VT, N00, N1); // N00 = ~N00 + N01 = DAG.getNode(ISD::XOR, SDLoc(N01), VT, N01, N1); // N01 = ~N01 + AddToWorklist(N00.getNode()); AddToWorklist(N01.getNode()); + return DAG.getNode(NewOpcode, DL, VT, N00, N01); + } + } + // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants + if (isAllOnesConstant(N1) && N0.hasOneUse() && + (N0Opcode == ISD::OR || N0Opcode == ISD::AND)) { + SDValue N00 = N0.getOperand(0), N01 = N0.getOperand(1); + if (isa<ConstantSDNode>(N01) || isa<ConstantSDNode>(N00)) { + unsigned NewOpcode = N0Opcode == ISD::AND ? ISD::OR : ISD::AND; + N00 = DAG.getNode(ISD::XOR, SDLoc(N00), VT, N00, N1); // N00 = ~N00 + N01 = DAG.getNode(ISD::XOR, SDLoc(N01), VT, N01, N1); // N01 = ~N01 + AddToWorklist(N00.getNode()); AddToWorklist(N01.getNode()); + return DAG.getNode(NewOpcode, DL, VT, N00, N01); + } + } + + // fold (not (neg x)) -> (add X, -1) + // FIXME: This can be generalized to (not (sub Y, X)) -> (add X, ~Y) if + // Y is a constant or the subtract has a single use. + if (isAllOnesConstant(N1) && N0.getOpcode() == ISD::SUB && + isNullConstant(N0.getOperand(0))) { + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(1), + DAG.getAllOnesConstant(DL, VT)); + } + + // fold (not (add X, -1)) -> (neg X) + if (isAllOnesConstant(N1) && N0.getOpcode() == ISD::ADD && + isAllOnesOrAllOnesSplat(N0.getOperand(1))) { + return DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), + N0.getOperand(0)); + } + + // fold (xor (and x, y), y) -> (and (not x), y) + if (N0Opcode == ISD::AND && N0.hasOneUse() && N0->getOperand(1) == N1) { + SDValue X = N0.getOperand(0); + SDValue NotX = DAG.getNOT(SDLoc(X), X, VT); + AddToWorklist(NotX.getNode()); + return DAG.getNode(ISD::AND, DL, VT, NotX, N1); + } + + if ((N0Opcode == ISD::SRL || N0Opcode == ISD::SHL) && N0.hasOneUse()) { + ConstantSDNode *XorC = isConstOrConstSplat(N1); + ConstantSDNode *ShiftC = isConstOrConstSplat(N0.getOperand(1)); + unsigned BitWidth = VT.getScalarSizeInBits(); + if (XorC && ShiftC) { + // Don't crash on an oversized shift. We can not guarantee that a bogus + // shift has been simplified to undef. + uint64_t ShiftAmt = ShiftC->getLimitedValue(); + if (ShiftAmt < BitWidth) { + APInt Ones = APInt::getAllOnesValue(BitWidth); + Ones = N0Opcode == ISD::SHL ? Ones.shl(ShiftAmt) : Ones.lshr(ShiftAmt); + if (XorC->getAPIntValue() == Ones) { + // If the xor constant is a shifted -1, do a 'not' before the shift: + // xor (X << ShiftC), XorC --> (not X) << ShiftC + // xor (X >> ShiftC), XorC --> (not X) >> ShiftC + SDValue Not = DAG.getNOT(DL, N0.getOperand(0), VT); + return DAG.getNode(N0Opcode, DL, VT, Not, N0.getOperand(1)); + } + } + } + } + + // fold Y = sra (X, size(X)-1); xor (add (X, Y), Y) -> (abs X) + if (TLI.isOperationLegalOrCustom(ISD::ABS, VT)) { + SDValue A = N0Opcode == ISD::ADD ? N0 : N1; + SDValue S = N0Opcode == ISD::SRA ? N0 : N1; + if (A.getOpcode() == ISD::ADD && S.getOpcode() == ISD::SRA) { + SDValue A0 = A.getOperand(0), A1 = A.getOperand(1); + SDValue S0 = S.getOperand(0); + if ((A0 == S && A1 == S0) || (A1 == S && A0 == S0)) + if (ConstantSDNode *C = isConstOrConstSplat(S.getOperand(1))) + if (C->getAPIntValue() == (VT.getScalarSizeInBits() - 1)) + return DAG.getNode(ISD::ABS, DL, VT, S0); + } + } + + // fold (xor x, x) -> 0 + if (N0 == N1) + return tryFoldToZero(DL, TLI, VT, DAG, LegalOperations); + + // fold (xor (shl 1, x), -1) -> (rotl ~1, x) + // Here is a concrete example of this equivalence: + // i16 x == 14 + // i16 shl == 1 << 14 == 16384 == 0b0100000000000000 + // i16 xor == ~(1 << 14) == 49151 == 0b1011111111111111 + // + // => + // + // i16 ~1 == 0b1111111111111110 + // i16 rol(~1, 14) == 0b1011111111111111 + // + // Some additional tips to help conceptualize this transform: + // - Try to see the operation as placing a single zero in a value of all ones. + // - There exists no value for x which would allow the result to contain zero. + // - Values of x larger than the bitwidth are undefined and do not require a + // consistent result. + // - Pushing the zero left requires shifting one bits in from the right. + // A rotate left of ~1 is a nice way of achieving the desired result. + if (TLI.isOperationLegalOrCustom(ISD::ROTL, VT) && N0Opcode == ISD::SHL && + isAllOnesConstant(N1) && isOneConstant(N0.getOperand(0))) { + return DAG.getNode(ISD::ROTL, DL, VT, DAG.getConstant(~1, DL, VT), + N0.getOperand(1)); + } + + // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) + if (N0Opcode == N1.getOpcode()) + if (SDValue V = hoistLogicOpWithSameOpcodeHands(N)) + return V; + + // Unfold ((x ^ y) & m) ^ y into (x & m) | (y & ~m) if profitable + if (SDValue MM = unfoldMaskedMerge(N)) + return MM; + + // Simplify the expression using non-local knowledge. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + if (SDValue Combined = combineCarryDiamond(*this, DAG, TLI, N0, N1, N)) + return Combined; + + return SDValue(); +} + +/// If we have a shift-by-constant of a bitwise logic op that itself has a +/// shift-by-constant operand with identical opcode, we may be able to convert +/// that into 2 independent shifts followed by the logic op. This is a +/// throughput improvement. +static SDValue combineShiftOfShiftedLogic(SDNode *Shift, SelectionDAG &DAG) { + // Match a one-use bitwise logic op. + SDValue LogicOp = Shift->getOperand(0); + if (!LogicOp.hasOneUse()) + return SDValue(); + + unsigned LogicOpcode = LogicOp.getOpcode(); + if (LogicOpcode != ISD::AND && LogicOpcode != ISD::OR && + LogicOpcode != ISD::XOR) + return SDValue(); + + // Find a matching one-use shift by constant. + unsigned ShiftOpcode = Shift->getOpcode(); + SDValue C1 = Shift->getOperand(1); + ConstantSDNode *C1Node = isConstOrConstSplat(C1); + assert(C1Node && "Expected a shift with constant operand"); + const APInt &C1Val = C1Node->getAPIntValue(); + auto matchFirstShift = [&](SDValue V, SDValue &ShiftOp, + const APInt *&ShiftAmtVal) { + if (V.getOpcode() != ShiftOpcode || !V.hasOneUse()) + return false; + + ConstantSDNode *ShiftCNode = isConstOrConstSplat(V.getOperand(1)); + if (!ShiftCNode) + return false; + + // Capture the shifted operand and shift amount value. + ShiftOp = V.getOperand(0); + ShiftAmtVal = &ShiftCNode->getAPIntValue(); + + // Shift amount types do not have to match their operand type, so check that + // the constants are the same width. + if (ShiftAmtVal->getBitWidth() != C1Val.getBitWidth()) + return false; + + // The fold is not valid if the sum of the shift values exceeds bitwidth. + if ((*ShiftAmtVal + C1Val).uge(V.getScalarValueSizeInBits())) + return false; + + return true; + }; + + // Logic ops are commutative, so check each operand for a match. + SDValue X, Y; + const APInt *C0Val; + if (matchFirstShift(LogicOp.getOperand(0), X, C0Val)) + Y = LogicOp.getOperand(1); + else if (matchFirstShift(LogicOp.getOperand(1), X, C0Val)) + Y = LogicOp.getOperand(0); + else + return SDValue(); + + // shift (logic (shift X, C0), Y), C1 -> logic (shift X, C0+C1), (shift Y, C1) + SDLoc DL(Shift); + EVT VT = Shift->getValueType(0); + EVT ShiftAmtVT = Shift->getOperand(1).getValueType(); + SDValue ShiftSumC = DAG.getConstant(*C0Val + C1Val, DL, ShiftAmtVT); + SDValue NewShift1 = DAG.getNode(ShiftOpcode, DL, VT, X, ShiftSumC); + SDValue NewShift2 = DAG.getNode(ShiftOpcode, DL, VT, Y, C1); + return DAG.getNode(LogicOpcode, DL, VT, NewShift1, NewShift2); +} + +/// Handle transforms common to the three shifts, when the shift amount is a +/// constant. +/// We are looking for: (shift being one of shl/sra/srl) +/// shift (binop X, C0), C1 +/// And want to transform into: +/// binop (shift X, C1), (shift C0, C1) +SDValue DAGCombiner::visitShiftByConstant(SDNode *N) { + assert(isConstOrConstSplat(N->getOperand(1)) && "Expected constant operand"); + + // Do not turn a 'not' into a regular xor. + if (isBitwiseNot(N->getOperand(0))) + return SDValue(); + + // The inner binop must be one-use, since we want to replace it. + SDValue LHS = N->getOperand(0); + if (!LHS.hasOneUse() || !TLI.isDesirableToCommuteWithShift(N, Level)) + return SDValue(); + + // TODO: This is limited to early combining because it may reveal regressions + // otherwise. But since we just checked a target hook to see if this is + // desirable, that should have filtered out cases where this interferes + // with some other pattern matching. + if (!LegalTypes) + if (SDValue R = combineShiftOfShiftedLogic(N, DAG)) + return R; + + // We want to pull some binops through shifts, so that we have (and (shift)) + // instead of (shift (and)), likewise for add, or, xor, etc. This sort of + // thing happens with address calculations, so it's important to canonicalize + // it. + switch (LHS.getOpcode()) { + default: + return SDValue(); + case ISD::OR: + case ISD::XOR: + case ISD::AND: + break; + case ISD::ADD: + if (N->getOpcode() != ISD::SHL) + return SDValue(); // only shl(add) not sr[al](add). + break; + } + + // We require the RHS of the binop to be a constant and not opaque as well. + ConstantSDNode *BinOpCst = getAsNonOpaqueConstant(LHS.getOperand(1)); + if (!BinOpCst) + return SDValue(); + + // FIXME: disable this unless the input to the binop is a shift by a constant + // or is copy/select. Enable this in other cases when figure out it's exactly + // profitable. + SDValue BinOpLHSVal = LHS.getOperand(0); + bool IsShiftByConstant = (BinOpLHSVal.getOpcode() == ISD::SHL || + BinOpLHSVal.getOpcode() == ISD::SRA || + BinOpLHSVal.getOpcode() == ISD::SRL) && + isa<ConstantSDNode>(BinOpLHSVal.getOperand(1)); + bool IsCopyOrSelect = BinOpLHSVal.getOpcode() == ISD::CopyFromReg || + BinOpLHSVal.getOpcode() == ISD::SELECT; + + if (!IsShiftByConstant && !IsCopyOrSelect) + return SDValue(); + + if (IsCopyOrSelect && N->hasOneUse()) + return SDValue(); + + // Fold the constants, shifting the binop RHS by the shift amount. + SDLoc DL(N); + EVT VT = N->getValueType(0); + SDValue NewRHS = DAG.getNode(N->getOpcode(), DL, VT, LHS.getOperand(1), + N->getOperand(1)); + assert(isa<ConstantSDNode>(NewRHS) && "Folding was not successful!"); + + SDValue NewShift = DAG.getNode(N->getOpcode(), DL, VT, LHS.getOperand(0), + N->getOperand(1)); + return DAG.getNode(LHS.getOpcode(), DL, VT, NewShift, NewRHS); +} + +SDValue DAGCombiner::distributeTruncateThroughAnd(SDNode *N) { + assert(N->getOpcode() == ISD::TRUNCATE); + assert(N->getOperand(0).getOpcode() == ISD::AND); + + // (truncate:TruncVT (and N00, N01C)) -> (and (truncate:TruncVT N00), TruncC) + EVT TruncVT = N->getValueType(0); + if (N->hasOneUse() && N->getOperand(0).hasOneUse() && + TLI.isTypeDesirableForOp(ISD::AND, TruncVT)) { + SDValue N01 = N->getOperand(0).getOperand(1); + if (isConstantOrConstantVector(N01, /* NoOpaques */ true)) { + SDLoc DL(N); + SDValue N00 = N->getOperand(0).getOperand(0); + SDValue Trunc00 = DAG.getNode(ISD::TRUNCATE, DL, TruncVT, N00); + SDValue Trunc01 = DAG.getNode(ISD::TRUNCATE, DL, TruncVT, N01); + AddToWorklist(Trunc00.getNode()); + AddToWorklist(Trunc01.getNode()); + return DAG.getNode(ISD::AND, DL, TruncVT, Trunc00, Trunc01); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitRotate(SDNode *N) { + SDLoc dl(N); + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + unsigned Bitsize = VT.getScalarSizeInBits(); + + // fold (rot x, 0) -> x + if (isNullOrNullSplat(N1)) + return N0; + + // fold (rot x, c) -> x iff (c % BitSize) == 0 + if (isPowerOf2_32(Bitsize) && Bitsize > 1) { + APInt ModuloMask(N1.getScalarValueSizeInBits(), Bitsize - 1); + if (DAG.MaskedValueIsZero(N1, ModuloMask)) + return N0; + } + + // fold (rot x, c) -> (rot x, c % BitSize) + bool OutOfRange = false; + auto MatchOutOfRange = [Bitsize, &OutOfRange](ConstantSDNode *C) { + OutOfRange |= C->getAPIntValue().uge(Bitsize); + return true; + }; + if (ISD::matchUnaryPredicate(N1, MatchOutOfRange) && OutOfRange) { + EVT AmtVT = N1.getValueType(); + SDValue Bits = DAG.getConstant(Bitsize, dl, AmtVT); + if (SDValue Amt = + DAG.FoldConstantArithmetic(ISD::UREM, dl, AmtVT, {N1, Bits})) + return DAG.getNode(N->getOpcode(), dl, VT, N0, Amt); + } + + // rot i16 X, 8 --> bswap X + auto *RotAmtC = isConstOrConstSplat(N1); + if (RotAmtC && RotAmtC->getAPIntValue() == 8 && + VT.getScalarSizeInBits() == 16 && hasOperation(ISD::BSWAP, VT)) + return DAG.getNode(ISD::BSWAP, dl, VT, N0); + + // Simplify the operands using demanded-bits information. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // fold (rot* x, (trunc (and y, c))) -> (rot* x, (and (trunc y), (trunc c))). + if (N1.getOpcode() == ISD::TRUNCATE && + N1.getOperand(0).getOpcode() == ISD::AND) { + if (SDValue NewOp1 = distributeTruncateThroughAnd(N1.getNode())) + return DAG.getNode(N->getOpcode(), dl, VT, N0, NewOp1); + } + + unsigned NextOp = N0.getOpcode(); + // fold (rot* (rot* x, c2), c1) -> (rot* x, c1 +- c2 % bitsize) + if (NextOp == ISD::ROTL || NextOp == ISD::ROTR) { + SDNode *C1 = DAG.isConstantIntBuildVectorOrConstantInt(N1); + SDNode *C2 = DAG.isConstantIntBuildVectorOrConstantInt(N0.getOperand(1)); + if (C1 && C2 && C1->getValueType(0) == C2->getValueType(0)) { + EVT ShiftVT = C1->getValueType(0); + bool SameSide = (N->getOpcode() == NextOp); + unsigned CombineOp = SameSide ? ISD::ADD : ISD::SUB; + if (SDValue CombinedShift = DAG.FoldConstantArithmetic( + CombineOp, dl, ShiftVT, {N1, N0.getOperand(1)})) { + SDValue BitsizeC = DAG.getConstant(Bitsize, dl, ShiftVT); + SDValue CombinedShiftNorm = DAG.FoldConstantArithmetic( + ISD::SREM, dl, ShiftVT, {CombinedShift, BitsizeC}); + return DAG.getNode(N->getOpcode(), dl, VT, N0->getOperand(0), + CombinedShiftNorm); + } + } + } + return SDValue(); +} + +SDValue DAGCombiner::visitSHL(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + if (SDValue V = DAG.simplifyShift(N0, N1)) + return V; + + EVT VT = N0.getValueType(); + EVT ShiftVT = N1.getValueType(); + unsigned OpSizeInBits = VT.getScalarSizeInBits(); + + // fold vector ops + if (VT.isVector()) { + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + BuildVectorSDNode *N1CV = dyn_cast<BuildVectorSDNode>(N1); + // If setcc produces all-one true value then: + // (shl (and (setcc) N01CV) N1CV) -> (and (setcc) N01CV<<N1CV) + if (N1CV && N1CV->isConstant()) { + if (N0.getOpcode() == ISD::AND) { + SDValue N00 = N0->getOperand(0); + SDValue N01 = N0->getOperand(1); + BuildVectorSDNode *N01CV = dyn_cast<BuildVectorSDNode>(N01); + + if (N01CV && N01CV->isConstant() && N00.getOpcode() == ISD::SETCC && + TLI.getBooleanContents(N00.getOperand(0).getValueType()) == + TargetLowering::ZeroOrNegativeOneBooleanContent) { + if (SDValue C = + DAG.FoldConstantArithmetic(ISD::SHL, SDLoc(N), VT, {N01, N1})) + return DAG.getNode(ISD::AND, SDLoc(N), VT, N00, C); + } + } + } + } + + ConstantSDNode *N1C = isConstOrConstSplat(N1); + + // fold (shl c1, c2) -> c1<<c2 + if (SDValue C = DAG.FoldConstantArithmetic(ISD::SHL, SDLoc(N), VT, {N0, N1})) + return C; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // if (shl x, c) is known to be zero, return 0 + if (DAG.MaskedValueIsZero(SDValue(N, 0), + APInt::getAllOnesValue(OpSizeInBits))) + return DAG.getConstant(0, SDLoc(N), VT); + + // fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), (trunc c))). + if (N1.getOpcode() == ISD::TRUNCATE && + N1.getOperand(0).getOpcode() == ISD::AND) { + if (SDValue NewOp1 = distributeTruncateThroughAnd(N1.getNode())) + return DAG.getNode(ISD::SHL, SDLoc(N), VT, N0, NewOp1); + } + + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // fold (shl (shl x, c1), c2) -> 0 or (shl x, (add c1, c2)) + if (N0.getOpcode() == ISD::SHL) { + auto MatchOutOfRange = [OpSizeInBits](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + return (c1 + c2).uge(OpSizeInBits); + }; + if (ISD::matchBinaryPredicate(N1, N0.getOperand(1), MatchOutOfRange)) + return DAG.getConstant(0, SDLoc(N), VT); + + auto MatchInRange = [OpSizeInBits](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + return (c1 + c2).ult(OpSizeInBits); + }; + if (ISD::matchBinaryPredicate(N1, N0.getOperand(1), MatchInRange)) { + SDLoc DL(N); + SDValue Sum = DAG.getNode(ISD::ADD, DL, ShiftVT, N1, N0.getOperand(1)); + return DAG.getNode(ISD::SHL, DL, VT, N0.getOperand(0), Sum); + } + } + + // fold (shl (ext (shl x, c1)), c2) -> (shl (ext x), (add c1, c2)) + // For this to be valid, the second form must not preserve any of the bits + // that are shifted out by the inner shift in the first form. This means + // the outer shift size must be >= the number of bits added by the ext. + // As a corollary, we don't care what kind of ext it is. + if ((N0.getOpcode() == ISD::ZERO_EXTEND || + N0.getOpcode() == ISD::ANY_EXTEND || + N0.getOpcode() == ISD::SIGN_EXTEND) && + N0.getOperand(0).getOpcode() == ISD::SHL) { + SDValue N0Op0 = N0.getOperand(0); + SDValue InnerShiftAmt = N0Op0.getOperand(1); + EVT InnerVT = N0Op0.getValueType(); + uint64_t InnerBitwidth = InnerVT.getScalarSizeInBits(); + + auto MatchOutOfRange = [OpSizeInBits, InnerBitwidth](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + return c2.uge(OpSizeInBits - InnerBitwidth) && + (c1 + c2).uge(OpSizeInBits); + }; + if (ISD::matchBinaryPredicate(InnerShiftAmt, N1, MatchOutOfRange, + /*AllowUndefs*/ false, + /*AllowTypeMismatch*/ true)) + return DAG.getConstant(0, SDLoc(N), VT); + + auto MatchInRange = [OpSizeInBits, InnerBitwidth](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + return c2.uge(OpSizeInBits - InnerBitwidth) && + (c1 + c2).ult(OpSizeInBits); + }; + if (ISD::matchBinaryPredicate(InnerShiftAmt, N1, MatchInRange, + /*AllowUndefs*/ false, + /*AllowTypeMismatch*/ true)) { + SDLoc DL(N); + SDValue Ext = DAG.getNode(N0.getOpcode(), DL, VT, N0Op0.getOperand(0)); + SDValue Sum = DAG.getZExtOrTrunc(InnerShiftAmt, DL, ShiftVT); + Sum = DAG.getNode(ISD::ADD, DL, ShiftVT, Sum, N1); + return DAG.getNode(ISD::SHL, DL, VT, Ext, Sum); + } + } + + // fold (shl (zext (srl x, C)), C) -> (zext (shl (srl x, C), C)) + // Only fold this if the inner zext has no other uses to avoid increasing + // the total number of instructions. + if (N0.getOpcode() == ISD::ZERO_EXTEND && N0.hasOneUse() && + N0.getOperand(0).getOpcode() == ISD::SRL) { + SDValue N0Op0 = N0.getOperand(0); + SDValue InnerShiftAmt = N0Op0.getOperand(1); + + auto MatchEqual = [VT](ConstantSDNode *LHS, ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2); + return c1.ult(VT.getScalarSizeInBits()) && (c1 == c2); + }; + if (ISD::matchBinaryPredicate(InnerShiftAmt, N1, MatchEqual, + /*AllowUndefs*/ false, + /*AllowTypeMismatch*/ true)) { + SDLoc DL(N); + EVT InnerShiftAmtVT = N0Op0.getOperand(1).getValueType(); + SDValue NewSHL = DAG.getZExtOrTrunc(N1, DL, InnerShiftAmtVT); + NewSHL = DAG.getNode(ISD::SHL, DL, N0Op0.getValueType(), N0Op0, NewSHL); + AddToWorklist(NewSHL.getNode()); + return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N0), VT, NewSHL); + } + } + + // fold (shl (sr[la] exact X, C1), C2) -> (shl X, (C2-C1)) if C1 <= C2 + // fold (shl (sr[la] exact X, C1), C2) -> (sr[la] X, (C2-C1)) if C1 > C2 + // TODO - support non-uniform vector shift amounts. + if (N1C && (N0.getOpcode() == ISD::SRL || N0.getOpcode() == ISD::SRA) && + N0->getFlags().hasExact()) { + if (ConstantSDNode *N0C1 = isConstOrConstSplat(N0.getOperand(1))) { + uint64_t C1 = N0C1->getZExtValue(); + uint64_t C2 = N1C->getZExtValue(); + SDLoc DL(N); + if (C1 <= C2) + return DAG.getNode(ISD::SHL, DL, VT, N0.getOperand(0), + DAG.getConstant(C2 - C1, DL, ShiftVT)); + return DAG.getNode(N0.getOpcode(), DL, VT, N0.getOperand(0), + DAG.getConstant(C1 - C2, DL, ShiftVT)); + } + } + + // fold (shl (srl x, c1), c2) -> (and (shl x, (sub c2, c1), MASK) or + // (and (srl x, (sub c1, c2), MASK) + // Only fold this if the inner shift has no other uses -- if it does, folding + // this will increase the total number of instructions. + // TODO - drop hasOneUse requirement if c1 == c2? + // TODO - support non-uniform vector shift amounts. + if (N1C && N0.getOpcode() == ISD::SRL && N0.hasOneUse() && + TLI.shouldFoldConstantShiftPairToMask(N, Level)) { + if (ConstantSDNode *N0C1 = isConstOrConstSplat(N0.getOperand(1))) { + if (N0C1->getAPIntValue().ult(OpSizeInBits)) { + uint64_t c1 = N0C1->getZExtValue(); + uint64_t c2 = N1C->getZExtValue(); + APInt Mask = APInt::getHighBitsSet(OpSizeInBits, OpSizeInBits - c1); + SDValue Shift; + if (c2 > c1) { + Mask <<= c2 - c1; + SDLoc DL(N); + Shift = DAG.getNode(ISD::SHL, DL, VT, N0.getOperand(0), + DAG.getConstant(c2 - c1, DL, ShiftVT)); + } else { + Mask.lshrInPlace(c1 - c2); + SDLoc DL(N); + Shift = DAG.getNode(ISD::SRL, DL, VT, N0.getOperand(0), + DAG.getConstant(c1 - c2, DL, ShiftVT)); + } + SDLoc DL(N0); + return DAG.getNode(ISD::AND, DL, VT, Shift, + DAG.getConstant(Mask, DL, VT)); + } + } + } + + // fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1)) + if (N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1) && + isConstantOrConstantVector(N1, /* No Opaques */ true)) { + SDLoc DL(N); + SDValue AllBits = DAG.getAllOnesConstant(DL, VT); + SDValue HiBitsMask = DAG.getNode(ISD::SHL, DL, VT, AllBits, N1); + return DAG.getNode(ISD::AND, DL, VT, N0.getOperand(0), HiBitsMask); + } + + // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1 << c2) + // fold (shl (or x, c1), c2) -> (or (shl x, c2), c1 << c2) + // Variant of version done on multiply, except mul by a power of 2 is turned + // into a shift. + if ((N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::OR) && + N0.getNode()->hasOneUse() && + isConstantOrConstantVector(N1, /* No Opaques */ true) && + isConstantOrConstantVector(N0.getOperand(1), /* No Opaques */ true) && + TLI.isDesirableToCommuteWithShift(N, Level)) { + SDValue Shl0 = DAG.getNode(ISD::SHL, SDLoc(N0), VT, N0.getOperand(0), N1); + SDValue Shl1 = DAG.getNode(ISD::SHL, SDLoc(N1), VT, N0.getOperand(1), N1); + AddToWorklist(Shl0.getNode()); + AddToWorklist(Shl1.getNode()); + return DAG.getNode(N0.getOpcode(), SDLoc(N), VT, Shl0, Shl1); + } + + // fold (shl (mul x, c1), c2) -> (mul x, c1 << c2) + if (N0.getOpcode() == ISD::MUL && N0.getNode()->hasOneUse() && + isConstantOrConstantVector(N1, /* No Opaques */ true) && + isConstantOrConstantVector(N0.getOperand(1), /* No Opaques */ true)) { + SDValue Shl = DAG.getNode(ISD::SHL, SDLoc(N1), VT, N0.getOperand(1), N1); + if (isConstantOrConstantVector(Shl)) + return DAG.getNode(ISD::MUL, SDLoc(N), VT, N0.getOperand(0), Shl); + } + + if (N1C && !N1C->isOpaque()) + if (SDValue NewSHL = visitShiftByConstant(N)) + return NewSHL; + + // Fold (shl (vscale * C0), C1) to (vscale * (C0 << C1)). + if (N0.getOpcode() == ISD::VSCALE) + if (ConstantSDNode *NC1 = isConstOrConstSplat(N->getOperand(1))) { + const APInt &C0 = N0.getConstantOperandAPInt(0); + const APInt &C1 = NC1->getAPIntValue(); + return DAG.getVScale(SDLoc(N), VT, C0 << C1); + } + + return SDValue(); +} + +// Transform a right shift of a multiply into a multiply-high. +// Examples: +// (srl (mul (zext i32:$a to i64), (zext i32:$a to i64)), 32) -> (mulhu $a, $b) +// (sra (mul (sext i32:$a to i64), (sext i32:$a to i64)), 32) -> (mulhs $a, $b) +static SDValue combineShiftToMULH(SDNode *N, SelectionDAG &DAG, + const TargetLowering &TLI) { + assert((N->getOpcode() == ISD::SRL || N->getOpcode() == ISD::SRA) && + "SRL or SRA node is required here!"); + + // Check the shift amount. Proceed with the transformation if the shift + // amount is constant. + ConstantSDNode *ShiftAmtSrc = isConstOrConstSplat(N->getOperand(1)); + if (!ShiftAmtSrc) + return SDValue(); + + SDLoc DL(N); + + // The operation feeding into the shift must be a multiply. + SDValue ShiftOperand = N->getOperand(0); + if (ShiftOperand.getOpcode() != ISD::MUL) + return SDValue(); + + // Both operands must be equivalent extend nodes. + SDValue LeftOp = ShiftOperand.getOperand(0); + SDValue RightOp = ShiftOperand.getOperand(1); + bool IsSignExt = LeftOp.getOpcode() == ISD::SIGN_EXTEND; + bool IsZeroExt = LeftOp.getOpcode() == ISD::ZERO_EXTEND; + + if ((!(IsSignExt || IsZeroExt)) || LeftOp.getOpcode() != RightOp.getOpcode()) + return SDValue(); + + EVT WideVT1 = LeftOp.getValueType(); + EVT WideVT2 = RightOp.getValueType(); + (void)WideVT2; + // Proceed with the transformation if the wide types match. + assert((WideVT1 == WideVT2) && + "Cannot have a multiply node with two different operand types."); + + EVT NarrowVT = LeftOp.getOperand(0).getValueType(); + // Check that the two extend nodes are the same type. + if (NarrowVT != RightOp.getOperand(0).getValueType()) + return SDValue(); + + // Proceed with the transformation if the wide type is twice as large + // as the narrow type. + unsigned NarrowVTSize = NarrowVT.getScalarSizeInBits(); + if (WideVT1.getScalarSizeInBits() != 2 * NarrowVTSize) + return SDValue(); + + // Check the shift amount with the narrow type size. + // Proceed with the transformation if the shift amount is the width + // of the narrow type. + unsigned ShiftAmt = ShiftAmtSrc->getZExtValue(); + if (ShiftAmt != NarrowVTSize) + return SDValue(); + + // If the operation feeding into the MUL is a sign extend (sext), + // we use mulhs. Othewise, zero extends (zext) use mulhu. + unsigned MulhOpcode = IsSignExt ? ISD::MULHS : ISD::MULHU; + + // Combine to mulh if mulh is legal/custom for the narrow type on the target. + if (!TLI.isOperationLegalOrCustom(MulhOpcode, NarrowVT)) + return SDValue(); + + SDValue Result = DAG.getNode(MulhOpcode, DL, NarrowVT, LeftOp.getOperand(0), + RightOp.getOperand(0)); + return (N->getOpcode() == ISD::SRA ? DAG.getSExtOrTrunc(Result, DL, WideVT1) + : DAG.getZExtOrTrunc(Result, DL, WideVT1)); +} + +SDValue DAGCombiner::visitSRA(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + if (SDValue V = DAG.simplifyShift(N0, N1)) + return V; + + EVT VT = N0.getValueType(); + unsigned OpSizeInBits = VT.getScalarSizeInBits(); + + // Arithmetic shifting an all-sign-bit value is a no-op. + // fold (sra 0, x) -> 0 + // fold (sra -1, x) -> -1 + if (DAG.ComputeNumSignBits(N0) == OpSizeInBits) + return N0; + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + ConstantSDNode *N1C = isConstOrConstSplat(N1); + + // fold (sra c1, c2) -> (sra c1, c2) + if (SDValue C = DAG.FoldConstantArithmetic(ISD::SRA, SDLoc(N), VT, {N0, N1})) + return C; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports + // sext_inreg. + if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { + unsigned LowBits = OpSizeInBits - (unsigned)N1C->getZExtValue(); + EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), LowBits); + if (VT.isVector()) + ExtVT = EVT::getVectorVT(*DAG.getContext(), + ExtVT, VT.getVectorNumElements()); + if (!LegalOperations || + TLI.getOperationAction(ISD::SIGN_EXTEND_INREG, ExtVT) == + TargetLowering::Legal) + return DAG.getNode(ISD::SIGN_EXTEND_INREG, SDLoc(N), VT, + N0.getOperand(0), DAG.getValueType(ExtVT)); + } + + // fold (sra (sra x, c1), c2) -> (sra x, (add c1, c2)) + // clamp (add c1, c2) to max shift. + if (N0.getOpcode() == ISD::SRA) { + SDLoc DL(N); + EVT ShiftVT = N1.getValueType(); + EVT ShiftSVT = ShiftVT.getScalarType(); + SmallVector<SDValue, 16> ShiftValues; + + auto SumOfShifts = [&](ConstantSDNode *LHS, ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + APInt Sum = c1 + c2; + unsigned ShiftSum = + Sum.uge(OpSizeInBits) ? (OpSizeInBits - 1) : Sum.getZExtValue(); + ShiftValues.push_back(DAG.getConstant(ShiftSum, DL, ShiftSVT)); + return true; + }; + if (ISD::matchBinaryPredicate(N1, N0.getOperand(1), SumOfShifts)) { + SDValue ShiftValue; + if (VT.isVector()) + ShiftValue = DAG.getBuildVector(ShiftVT, DL, ShiftValues); + else + ShiftValue = ShiftValues[0]; + return DAG.getNode(ISD::SRA, DL, VT, N0.getOperand(0), ShiftValue); + } + } + + // fold (sra (shl X, m), (sub result_size, n)) + // -> (sign_extend (trunc (shl X, (sub (sub result_size, n), m)))) for + // result_size - n != m. + // If truncate is free for the target sext(shl) is likely to result in better + // code. + if (N0.getOpcode() == ISD::SHL && N1C) { + // Get the two constanst of the shifts, CN0 = m, CN = n. + const ConstantSDNode *N01C = isConstOrConstSplat(N0.getOperand(1)); + if (N01C) { + LLVMContext &Ctx = *DAG.getContext(); + // Determine what the truncate's result bitsize and type would be. + EVT TruncVT = EVT::getIntegerVT(Ctx, OpSizeInBits - N1C->getZExtValue()); + + if (VT.isVector()) + TruncVT = EVT::getVectorVT(Ctx, TruncVT, VT.getVectorNumElements()); + + // Determine the residual right-shift amount. + int ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue(); + + // If the shift is not a no-op (in which case this should be just a sign + // extend already), the truncated to type is legal, sign_extend is legal + // on that type, and the truncate to that type is both legal and free, + // perform the transform. + if ((ShiftAmt > 0) && + TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) && + TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) && + TLI.isTruncateFree(VT, TruncVT)) { + SDLoc DL(N); + SDValue Amt = DAG.getConstant(ShiftAmt, DL, + getShiftAmountTy(N0.getOperand(0).getValueType())); + SDValue Shift = DAG.getNode(ISD::SRL, DL, VT, + N0.getOperand(0), Amt); + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, DL, TruncVT, + Shift); + return DAG.getNode(ISD::SIGN_EXTEND, DL, + N->getValueType(0), Trunc); + } + } + } + + // We convert trunc/ext to opposing shifts in IR, but casts may be cheaper. + // sra (add (shl X, N1C), AddC), N1C --> + // sext (add (trunc X to (width - N1C)), AddC') + if (N0.getOpcode() == ISD::ADD && N0.hasOneUse() && N1C && + N0.getOperand(0).getOpcode() == ISD::SHL && + N0.getOperand(0).getOperand(1) == N1 && N0.getOperand(0).hasOneUse()) { + if (ConstantSDNode *AddC = isConstOrConstSplat(N0.getOperand(1))) { + SDValue Shl = N0.getOperand(0); + // Determine what the truncate's type would be and ask the target if that + // is a free operation. + LLVMContext &Ctx = *DAG.getContext(); + unsigned ShiftAmt = N1C->getZExtValue(); + EVT TruncVT = EVT::getIntegerVT(Ctx, OpSizeInBits - ShiftAmt); + if (VT.isVector()) + TruncVT = EVT::getVectorVT(Ctx, TruncVT, VT.getVectorNumElements()); + + // TODO: The simple type check probably belongs in the default hook + // implementation and/or target-specific overrides (because + // non-simple types likely require masking when legalized), but that + // restriction may conflict with other transforms. + if (TruncVT.isSimple() && isTypeLegal(TruncVT) && + TLI.isTruncateFree(VT, TruncVT)) { + SDLoc DL(N); + SDValue Trunc = DAG.getZExtOrTrunc(Shl.getOperand(0), DL, TruncVT); + SDValue ShiftC = DAG.getConstant(AddC->getAPIntValue().lshr(ShiftAmt). + trunc(TruncVT.getScalarSizeInBits()), DL, TruncVT); + SDValue Add = DAG.getNode(ISD::ADD, DL, TruncVT, Trunc, ShiftC); + return DAG.getSExtOrTrunc(Add, DL, VT); + } + } + } + + // fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), (trunc c))). + if (N1.getOpcode() == ISD::TRUNCATE && + N1.getOperand(0).getOpcode() == ISD::AND) { + if (SDValue NewOp1 = distributeTruncateThroughAnd(N1.getNode())) + return DAG.getNode(ISD::SRA, SDLoc(N), VT, N0, NewOp1); + } + + // fold (sra (trunc (sra x, c1)), c2) -> (trunc (sra x, c1 + c2)) + // fold (sra (trunc (srl x, c1)), c2) -> (trunc (sra x, c1 + c2)) + // if c1 is equal to the number of bits the trunc removes + // TODO - support non-uniform vector shift amounts. + if (N0.getOpcode() == ISD::TRUNCATE && + (N0.getOperand(0).getOpcode() == ISD::SRL || + N0.getOperand(0).getOpcode() == ISD::SRA) && + N0.getOperand(0).hasOneUse() && + N0.getOperand(0).getOperand(1).hasOneUse() && N1C) { + SDValue N0Op0 = N0.getOperand(0); + if (ConstantSDNode *LargeShift = isConstOrConstSplat(N0Op0.getOperand(1))) { + EVT LargeVT = N0Op0.getValueType(); + unsigned TruncBits = LargeVT.getScalarSizeInBits() - OpSizeInBits; + if (LargeShift->getAPIntValue() == TruncBits) { + SDLoc DL(N); + SDValue Amt = DAG.getConstant(N1C->getZExtValue() + TruncBits, DL, + getShiftAmountTy(LargeVT)); + SDValue SRA = + DAG.getNode(ISD::SRA, DL, LargeVT, N0Op0.getOperand(0), Amt); + return DAG.getNode(ISD::TRUNCATE, DL, VT, SRA); + } + } + } + + // Simplify, based on bits shifted out of the LHS. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // If the sign bit is known to be zero, switch this to a SRL. + if (DAG.SignBitIsZero(N0)) + return DAG.getNode(ISD::SRL, SDLoc(N), VT, N0, N1); + + if (N1C && !N1C->isOpaque()) + if (SDValue NewSRA = visitShiftByConstant(N)) + return NewSRA; + + // Try to transform this shift into a multiply-high if + // it matches the appropriate pattern detected in combineShiftToMULH. + if (SDValue MULH = combineShiftToMULH(N, DAG, TLI)) + return MULH; + + return SDValue(); +} + +SDValue DAGCombiner::visitSRL(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + if (SDValue V = DAG.simplifyShift(N0, N1)) + return V; + + EVT VT = N0.getValueType(); + unsigned OpSizeInBits = VT.getScalarSizeInBits(); + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + ConstantSDNode *N1C = isConstOrConstSplat(N1); + + // fold (srl c1, c2) -> c1 >>u c2 + if (SDValue C = DAG.FoldConstantArithmetic(ISD::SRL, SDLoc(N), VT, {N0, N1})) + return C; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // if (srl x, c) is known to be zero, return 0 + if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0), + APInt::getAllOnesValue(OpSizeInBits))) + return DAG.getConstant(0, SDLoc(N), VT); + + // fold (srl (srl x, c1), c2) -> 0 or (srl x, (add c1, c2)) + if (N0.getOpcode() == ISD::SRL) { + auto MatchOutOfRange = [OpSizeInBits](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + return (c1 + c2).uge(OpSizeInBits); + }; + if (ISD::matchBinaryPredicate(N1, N0.getOperand(1), MatchOutOfRange)) + return DAG.getConstant(0, SDLoc(N), VT); + + auto MatchInRange = [OpSizeInBits](ConstantSDNode *LHS, + ConstantSDNode *RHS) { + APInt c1 = LHS->getAPIntValue(); + APInt c2 = RHS->getAPIntValue(); + zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */); + return (c1 + c2).ult(OpSizeInBits); + }; + if (ISD::matchBinaryPredicate(N1, N0.getOperand(1), MatchInRange)) { + SDLoc DL(N); + EVT ShiftVT = N1.getValueType(); + SDValue Sum = DAG.getNode(ISD::ADD, DL, ShiftVT, N1, N0.getOperand(1)); + return DAG.getNode(ISD::SRL, DL, VT, N0.getOperand(0), Sum); + } + } + + if (N1C && N0.getOpcode() == ISD::TRUNCATE && + N0.getOperand(0).getOpcode() == ISD::SRL) { + SDValue InnerShift = N0.getOperand(0); + // TODO - support non-uniform vector shift amounts. + if (auto *N001C = isConstOrConstSplat(InnerShift.getOperand(1))) { + uint64_t c1 = N001C->getZExtValue(); + uint64_t c2 = N1C->getZExtValue(); + EVT InnerShiftVT = InnerShift.getValueType(); + EVT ShiftAmtVT = InnerShift.getOperand(1).getValueType(); + uint64_t InnerShiftSize = InnerShiftVT.getScalarSizeInBits(); + // srl (trunc (srl x, c1)), c2 --> 0 or (trunc (srl x, (add c1, c2))) + // This is only valid if the OpSizeInBits + c1 = size of inner shift. + if (c1 + OpSizeInBits == InnerShiftSize) { + SDLoc DL(N); + if (c1 + c2 >= InnerShiftSize) + return DAG.getConstant(0, DL, VT); + SDValue NewShiftAmt = DAG.getConstant(c1 + c2, DL, ShiftAmtVT); + SDValue NewShift = DAG.getNode(ISD::SRL, DL, InnerShiftVT, + InnerShift.getOperand(0), NewShiftAmt); + return DAG.getNode(ISD::TRUNCATE, DL, VT, NewShift); + } + // In the more general case, we can clear the high bits after the shift: + // srl (trunc (srl x, c1)), c2 --> trunc (and (srl x, (c1+c2)), Mask) + if (N0.hasOneUse() && InnerShift.hasOneUse() && + c1 + c2 < InnerShiftSize) { + SDLoc DL(N); + SDValue NewShiftAmt = DAG.getConstant(c1 + c2, DL, ShiftAmtVT); + SDValue NewShift = DAG.getNode(ISD::SRL, DL, InnerShiftVT, + InnerShift.getOperand(0), NewShiftAmt); + SDValue Mask = DAG.getConstant(APInt::getLowBitsSet(InnerShiftSize, + OpSizeInBits - c2), + DL, InnerShiftVT); + SDValue And = DAG.getNode(ISD::AND, DL, InnerShiftVT, NewShift, Mask); + return DAG.getNode(ISD::TRUNCATE, DL, VT, And); + } + } + } + + // fold (srl (shl x, c), c) -> (and x, cst2) + // TODO - (srl (shl x, c1), c2). + if (N0.getOpcode() == ISD::SHL && N0.getOperand(1) == N1 && + isConstantOrConstantVector(N1, /* NoOpaques */ true)) { + SDLoc DL(N); + SDValue Mask = + DAG.getNode(ISD::SRL, DL, VT, DAG.getAllOnesConstant(DL, VT), N1); + AddToWorklist(Mask.getNode()); + return DAG.getNode(ISD::AND, DL, VT, N0.getOperand(0), Mask); + } + + // fold (srl (anyextend x), c) -> (and (anyextend (srl x, c)), mask) + // TODO - support non-uniform vector shift amounts. + if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { + // Shifting in all undef bits? + EVT SmallVT = N0.getOperand(0).getValueType(); + unsigned BitSize = SmallVT.getScalarSizeInBits(); + if (N1C->getAPIntValue().uge(BitSize)) + return DAG.getUNDEF(VT); + + if (!LegalTypes || TLI.isTypeDesirableForOp(ISD::SRL, SmallVT)) { + uint64_t ShiftAmt = N1C->getZExtValue(); + SDLoc DL0(N0); + SDValue SmallShift = DAG.getNode(ISD::SRL, DL0, SmallVT, + N0.getOperand(0), + DAG.getConstant(ShiftAmt, DL0, + getShiftAmountTy(SmallVT))); + AddToWorklist(SmallShift.getNode()); + APInt Mask = APInt::getLowBitsSet(OpSizeInBits, OpSizeInBits - ShiftAmt); + SDLoc DL(N); + return DAG.getNode(ISD::AND, DL, VT, + DAG.getNode(ISD::ANY_EXTEND, DL, VT, SmallShift), + DAG.getConstant(Mask, DL, VT)); + } + } + + // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign + // bit, which is unmodified by sra. + if (N1C && N1C->getAPIntValue() == (OpSizeInBits - 1)) { + if (N0.getOpcode() == ISD::SRA) + return DAG.getNode(ISD::SRL, SDLoc(N), VT, N0.getOperand(0), N1); + } + + // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). + if (N1C && N0.getOpcode() == ISD::CTLZ && + N1C->getAPIntValue() == Log2_32(OpSizeInBits)) { + KnownBits Known = DAG.computeKnownBits(N0.getOperand(0)); + + // If any of the input bits are KnownOne, then the input couldn't be all + // zeros, thus the result of the srl will always be zero. + if (Known.One.getBoolValue()) return DAG.getConstant(0, SDLoc(N0), VT); + + // If all of the bits input the to ctlz node are known to be zero, then + // the result of the ctlz is "32" and the result of the shift is one. + APInt UnknownBits = ~Known.Zero; + if (UnknownBits == 0) return DAG.getConstant(1, SDLoc(N0), VT); + + // Otherwise, check to see if there is exactly one bit input to the ctlz. + if (UnknownBits.isPowerOf2()) { + // Okay, we know that only that the single bit specified by UnknownBits + // could be set on input to the CTLZ node. If this bit is set, the SRL + // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair + // to an SRL/XOR pair, which is likely to simplify more. + unsigned ShAmt = UnknownBits.countTrailingZeros(); + SDValue Op = N0.getOperand(0); + + if (ShAmt) { + SDLoc DL(N0); + Op = DAG.getNode(ISD::SRL, DL, VT, Op, + DAG.getConstant(ShAmt, DL, + getShiftAmountTy(Op.getValueType()))); + AddToWorklist(Op.getNode()); + } + + SDLoc DL(N); + return DAG.getNode(ISD::XOR, DL, VT, + Op, DAG.getConstant(1, DL, VT)); + } + } + + // fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), (trunc c))). + if (N1.getOpcode() == ISD::TRUNCATE && + N1.getOperand(0).getOpcode() == ISD::AND) { + if (SDValue NewOp1 = distributeTruncateThroughAnd(N1.getNode())) + return DAG.getNode(ISD::SRL, SDLoc(N), VT, N0, NewOp1); + } + + // fold operands of srl based on knowledge that the low bits are not + // demanded. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + if (N1C && !N1C->isOpaque()) + if (SDValue NewSRL = visitShiftByConstant(N)) + return NewSRL; + + // Attempt to convert a srl of a load into a narrower zero-extending load. + if (SDValue NarrowLoad = ReduceLoadWidth(N)) + return NarrowLoad; + + // Here is a common situation. We want to optimize: + // + // %a = ... + // %b = and i32 %a, 2 + // %c = srl i32 %b, 1 + // brcond i32 %c ... + // + // into + // + // %a = ... + // %b = and %a, 2 + // %c = setcc eq %b, 0 + // brcond %c ... + // + // However when after the source operand of SRL is optimized into AND, the SRL + // itself may not be optimized further. Look for it and add the BRCOND into + // the worklist. + if (N->hasOneUse()) { + SDNode *Use = *N->use_begin(); + if (Use->getOpcode() == ISD::BRCOND) + AddToWorklist(Use); + else if (Use->getOpcode() == ISD::TRUNCATE && Use->hasOneUse()) { + // Also look pass the truncate. + Use = *Use->use_begin(); + if (Use->getOpcode() == ISD::BRCOND) + AddToWorklist(Use); + } + } + + // Try to transform this shift into a multiply-high if + // it matches the appropriate pattern detected in combineShiftToMULH. + if (SDValue MULH = combineShiftToMULH(N, DAG, TLI)) + return MULH; + + return SDValue(); +} + +SDValue DAGCombiner::visitFunnelShift(SDNode *N) { + EVT VT = N->getValueType(0); + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + bool IsFSHL = N->getOpcode() == ISD::FSHL; + unsigned BitWidth = VT.getScalarSizeInBits(); + + // fold (fshl N0, N1, 0) -> N0 + // fold (fshr N0, N1, 0) -> N1 + if (isPowerOf2_32(BitWidth)) + if (DAG.MaskedValueIsZero( + N2, APInt(N2.getScalarValueSizeInBits(), BitWidth - 1))) + return IsFSHL ? N0 : N1; + + auto IsUndefOrZero = [](SDValue V) { + return V.isUndef() || isNullOrNullSplat(V, /*AllowUndefs*/ true); + }; + + // TODO - support non-uniform vector shift amounts. + if (ConstantSDNode *Cst = isConstOrConstSplat(N2)) { + EVT ShAmtTy = N2.getValueType(); + + // fold (fsh* N0, N1, c) -> (fsh* N0, N1, c % BitWidth) + if (Cst->getAPIntValue().uge(BitWidth)) { + uint64_t RotAmt = Cst->getAPIntValue().urem(BitWidth); + return DAG.getNode(N->getOpcode(), SDLoc(N), VT, N0, N1, + DAG.getConstant(RotAmt, SDLoc(N), ShAmtTy)); + } + + unsigned ShAmt = Cst->getZExtValue(); + if (ShAmt == 0) + return IsFSHL ? N0 : N1; + + // fold fshl(undef_or_zero, N1, C) -> lshr(N1, BW-C) + // fold fshr(undef_or_zero, N1, C) -> lshr(N1, C) + // fold fshl(N0, undef_or_zero, C) -> shl(N0, C) + // fold fshr(N0, undef_or_zero, C) -> shl(N0, BW-C) + if (IsUndefOrZero(N0)) + return DAG.getNode(ISD::SRL, SDLoc(N), VT, N1, + DAG.getConstant(IsFSHL ? BitWidth - ShAmt : ShAmt, + SDLoc(N), ShAmtTy)); + if (IsUndefOrZero(N1)) + return DAG.getNode(ISD::SHL, SDLoc(N), VT, N0, + DAG.getConstant(IsFSHL ? ShAmt : BitWidth - ShAmt, + SDLoc(N), ShAmtTy)); + + // fold (fshl ld1, ld0, c) -> (ld0[ofs]) iff ld0 and ld1 are consecutive. + // fold (fshr ld1, ld0, c) -> (ld0[ofs]) iff ld0 and ld1 are consecutive. + // TODO - bigendian support once we have test coverage. + // TODO - can we merge this with CombineConseutiveLoads/MatchLoadCombine? + // TODO - permit LHS EXTLOAD if extensions are shifted out. + if ((BitWidth % 8) == 0 && (ShAmt % 8) == 0 && !VT.isVector() && + !DAG.getDataLayout().isBigEndian()) { + auto *LHS = dyn_cast<LoadSDNode>(N0); + auto *RHS = dyn_cast<LoadSDNode>(N1); + if (LHS && RHS && LHS->isSimple() && RHS->isSimple() && + LHS->getAddressSpace() == RHS->getAddressSpace() && + (LHS->hasOneUse() || RHS->hasOneUse()) && ISD::isNON_EXTLoad(RHS) && + ISD::isNON_EXTLoad(LHS)) { + if (DAG.areNonVolatileConsecutiveLoads(LHS, RHS, BitWidth / 8, 1)) { + SDLoc DL(RHS); + uint64_t PtrOff = + IsFSHL ? (((BitWidth - ShAmt) % BitWidth) / 8) : (ShAmt / 8); + Align NewAlign = commonAlignment(RHS->getAlign(), PtrOff); + bool Fast = false; + if (TLI.allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(), VT, + RHS->getAddressSpace(), NewAlign, + RHS->getMemOperand()->getFlags(), &Fast) && + Fast) { + SDValue NewPtr = DAG.getMemBasePlusOffset( + RHS->getBasePtr(), TypeSize::Fixed(PtrOff), DL); + AddToWorklist(NewPtr.getNode()); + SDValue Load = DAG.getLoad( + VT, DL, RHS->getChain(), NewPtr, + RHS->getPointerInfo().getWithOffset(PtrOff), NewAlign, + RHS->getMemOperand()->getFlags(), RHS->getAAInfo()); + // Replace the old load's chain with the new load's chain. + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(N1.getValue(1), Load.getValue(1)); + return Load; + } + } + } + } + } + + // fold fshr(undef_or_zero, N1, N2) -> lshr(N1, N2) + // fold fshl(N0, undef_or_zero, N2) -> shl(N0, N2) + // iff We know the shift amount is in range. + // TODO: when is it worth doing SUB(BW, N2) as well? + if (isPowerOf2_32(BitWidth)) { + APInt ModuloBits(N2.getScalarValueSizeInBits(), BitWidth - 1); + if (IsUndefOrZero(N0) && !IsFSHL && DAG.MaskedValueIsZero(N2, ~ModuloBits)) + return DAG.getNode(ISD::SRL, SDLoc(N), VT, N1, N2); + if (IsUndefOrZero(N1) && IsFSHL && DAG.MaskedValueIsZero(N2, ~ModuloBits)) + return DAG.getNode(ISD::SHL, SDLoc(N), VT, N0, N2); + } + + // fold (fshl N0, N0, N2) -> (rotl N0, N2) + // fold (fshr N0, N0, N2) -> (rotr N0, N2) + // TODO: Investigate flipping this rotate if only one is legal, if funnel shift + // is legal as well we might be better off avoiding non-constant (BW - N2). + unsigned RotOpc = IsFSHL ? ISD::ROTL : ISD::ROTR; + if (N0 == N1 && hasOperation(RotOpc, VT)) + return DAG.getNode(RotOpc, SDLoc(N), VT, N0, N2); + + // Simplify, based on bits shifted out of N0/N1. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + return SDValue(); +} + +SDValue DAGCombiner::visitABS(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (abs c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::ABS, SDLoc(N), VT, N0); + // fold (abs (abs x)) -> (abs x) + if (N0.getOpcode() == ISD::ABS) + return N0; + // fold (abs x) -> x iff not-negative + if (DAG.SignBitIsZero(N0)) + return N0; + return SDValue(); +} + +SDValue DAGCombiner::visitBSWAP(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (bswap c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::BSWAP, SDLoc(N), VT, N0); + // fold (bswap (bswap x)) -> x + if (N0.getOpcode() == ISD::BSWAP) + return N0->getOperand(0); + return SDValue(); +} + +SDValue DAGCombiner::visitBITREVERSE(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (bitreverse c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::BITREVERSE, SDLoc(N), VT, N0); + // fold (bitreverse (bitreverse x)) -> x + if (N0.getOpcode() == ISD::BITREVERSE) + return N0.getOperand(0); + return SDValue(); +} + +SDValue DAGCombiner::visitCTLZ(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (ctlz c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::CTLZ, SDLoc(N), VT, N0); + + // If the value is known never to be zero, switch to the undef version. + if (!LegalOperations || TLI.isOperationLegal(ISD::CTLZ_ZERO_UNDEF, VT)) { + if (DAG.isKnownNeverZero(N0)) + return DAG.getNode(ISD::CTLZ_ZERO_UNDEF, SDLoc(N), VT, N0); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitCTLZ_ZERO_UNDEF(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (ctlz_zero_undef c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::CTLZ_ZERO_UNDEF, SDLoc(N), VT, N0); + return SDValue(); +} + +SDValue DAGCombiner::visitCTTZ(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (cttz c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::CTTZ, SDLoc(N), VT, N0); + + // If the value is known never to be zero, switch to the undef version. + if (!LegalOperations || TLI.isOperationLegal(ISD::CTTZ_ZERO_UNDEF, VT)) { + if (DAG.isKnownNeverZero(N0)) + return DAG.getNode(ISD::CTTZ_ZERO_UNDEF, SDLoc(N), VT, N0); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitCTTZ_ZERO_UNDEF(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (cttz_zero_undef c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::CTTZ_ZERO_UNDEF, SDLoc(N), VT, N0); + return SDValue(); +} + +SDValue DAGCombiner::visitCTPOP(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (ctpop c1) -> c2 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::CTPOP, SDLoc(N), VT, N0); + return SDValue(); +} + +// FIXME: This should be checking for no signed zeros on individual operands, as +// well as no nans. +static bool isLegalToCombineMinNumMaxNum(SelectionDAG &DAG, SDValue LHS, + SDValue RHS, + const TargetLowering &TLI) { + const TargetOptions &Options = DAG.getTarget().Options; + EVT VT = LHS.getValueType(); + + return Options.NoSignedZerosFPMath && VT.isFloatingPoint() && + TLI.isProfitableToCombineMinNumMaxNum(VT) && + DAG.isKnownNeverNaN(LHS) && DAG.isKnownNeverNaN(RHS); +} + +/// Generate Min/Max node +static SDValue combineMinNumMaxNum(const SDLoc &DL, EVT VT, SDValue LHS, + SDValue RHS, SDValue True, SDValue False, + ISD::CondCode CC, const TargetLowering &TLI, + SelectionDAG &DAG) { + if (!(LHS == True && RHS == False) && !(LHS == False && RHS == True)) + return SDValue(); + + EVT TransformVT = TLI.getTypeToTransformTo(*DAG.getContext(), VT); + switch (CC) { + case ISD::SETOLT: + case ISD::SETOLE: + case ISD::SETLT: + case ISD::SETLE: + case ISD::SETULT: + case ISD::SETULE: { + // Since it's known never nan to get here already, either fminnum or + // fminnum_ieee are OK. Try the ieee version first, since it's fminnum is + // expanded in terms of it. + unsigned IEEEOpcode = (LHS == True) ? ISD::FMINNUM_IEEE : ISD::FMAXNUM_IEEE; + if (TLI.isOperationLegalOrCustom(IEEEOpcode, VT)) + return DAG.getNode(IEEEOpcode, DL, VT, LHS, RHS); + + unsigned Opcode = (LHS == True) ? ISD::FMINNUM : ISD::FMAXNUM; + if (TLI.isOperationLegalOrCustom(Opcode, TransformVT)) + return DAG.getNode(Opcode, DL, VT, LHS, RHS); + return SDValue(); + } + case ISD::SETOGT: + case ISD::SETOGE: + case ISD::SETGT: + case ISD::SETGE: + case ISD::SETUGT: + case ISD::SETUGE: { + unsigned IEEEOpcode = (LHS == True) ? ISD::FMAXNUM_IEEE : ISD::FMINNUM_IEEE; + if (TLI.isOperationLegalOrCustom(IEEEOpcode, VT)) + return DAG.getNode(IEEEOpcode, DL, VT, LHS, RHS); + + unsigned Opcode = (LHS == True) ? ISD::FMAXNUM : ISD::FMINNUM; + if (TLI.isOperationLegalOrCustom(Opcode, TransformVT)) + return DAG.getNode(Opcode, DL, VT, LHS, RHS); + return SDValue(); + } + default: + return SDValue(); + } +} + +/// If a (v)select has a condition value that is a sign-bit test, try to smear +/// the condition operand sign-bit across the value width and use it as a mask. +static SDValue foldSelectOfConstantsUsingSra(SDNode *N, SelectionDAG &DAG) { + SDValue Cond = N->getOperand(0); + SDValue C1 = N->getOperand(1); + SDValue C2 = N->getOperand(2); + assert(isConstantOrConstantVector(C1) && isConstantOrConstantVector(C2) && + "Expected select-of-constants"); + + EVT VT = N->getValueType(0); + if (Cond.getOpcode() != ISD::SETCC || !Cond.hasOneUse() || + VT != Cond.getOperand(0).getValueType()) + return SDValue(); + + // The inverted-condition + commuted-select variants of these patterns are + // canonicalized to these forms in IR. + SDValue X = Cond.getOperand(0); + SDValue CondC = Cond.getOperand(1); + ISD::CondCode CC = cast<CondCodeSDNode>(Cond.getOperand(2))->get(); + if (CC == ISD::SETGT && isAllOnesOrAllOnesSplat(CondC) && + isAllOnesOrAllOnesSplat(C2)) { + // i32 X > -1 ? C1 : -1 --> (X >>s 31) | C1 + SDLoc DL(N); + SDValue ShAmtC = DAG.getConstant(X.getScalarValueSizeInBits() - 1, DL, VT); + SDValue Sra = DAG.getNode(ISD::SRA, DL, VT, X, ShAmtC); + return DAG.getNode(ISD::OR, DL, VT, Sra, C1); + } + if (CC == ISD::SETLT && isNullOrNullSplat(CondC) && isNullOrNullSplat(C2)) { + // i8 X < 0 ? C1 : 0 --> (X >>s 7) & C1 + SDLoc DL(N); + SDValue ShAmtC = DAG.getConstant(X.getScalarValueSizeInBits() - 1, DL, VT); + SDValue Sra = DAG.getNode(ISD::SRA, DL, VT, X, ShAmtC); + return DAG.getNode(ISD::AND, DL, VT, Sra, C1); + } + return SDValue(); +} + +SDValue DAGCombiner::foldSelectOfConstants(SDNode *N) { + SDValue Cond = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + EVT VT = N->getValueType(0); + EVT CondVT = Cond.getValueType(); + SDLoc DL(N); + + if (!VT.isInteger()) + return SDValue(); + + auto *C1 = dyn_cast<ConstantSDNode>(N1); + auto *C2 = dyn_cast<ConstantSDNode>(N2); + if (!C1 || !C2) + return SDValue(); + + // Only do this before legalization to avoid conflicting with target-specific + // transforms in the other direction (create a select from a zext/sext). There + // is also a target-independent combine here in DAGCombiner in the other + // direction for (select Cond, -1, 0) when the condition is not i1. + if (CondVT == MVT::i1 && !LegalOperations) { + if (C1->isNullValue() && C2->isOne()) { + // select Cond, 0, 1 --> zext (!Cond) + SDValue NotCond = DAG.getNOT(DL, Cond, MVT::i1); + if (VT != MVT::i1) + NotCond = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, NotCond); + return NotCond; + } + if (C1->isNullValue() && C2->isAllOnesValue()) { + // select Cond, 0, -1 --> sext (!Cond) + SDValue NotCond = DAG.getNOT(DL, Cond, MVT::i1); + if (VT != MVT::i1) + NotCond = DAG.getNode(ISD::SIGN_EXTEND, DL, VT, NotCond); + return NotCond; + } + if (C1->isOne() && C2->isNullValue()) { + // select Cond, 1, 0 --> zext (Cond) + if (VT != MVT::i1) + Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Cond); + return Cond; + } + if (C1->isAllOnesValue() && C2->isNullValue()) { + // select Cond, -1, 0 --> sext (Cond) + if (VT != MVT::i1) + Cond = DAG.getNode(ISD::SIGN_EXTEND, DL, VT, Cond); + return Cond; + } + + // Use a target hook because some targets may prefer to transform in the + // other direction. + if (TLI.convertSelectOfConstantsToMath(VT)) { + // For any constants that differ by 1, we can transform the select into an + // extend and add. + const APInt &C1Val = C1->getAPIntValue(); + const APInt &C2Val = C2->getAPIntValue(); + if (C1Val - 1 == C2Val) { + // select Cond, C1, C1-1 --> add (zext Cond), C1-1 + if (VT != MVT::i1) + Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Cond); + return DAG.getNode(ISD::ADD, DL, VT, Cond, N2); + } + if (C1Val + 1 == C2Val) { + // select Cond, C1, C1+1 --> add (sext Cond), C1+1 + if (VT != MVT::i1) + Cond = DAG.getNode(ISD::SIGN_EXTEND, DL, VT, Cond); + return DAG.getNode(ISD::ADD, DL, VT, Cond, N2); + } + + // select Cond, Pow2, 0 --> (zext Cond) << log2(Pow2) + if (C1Val.isPowerOf2() && C2Val.isNullValue()) { + if (VT != MVT::i1) + Cond = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Cond); + SDValue ShAmtC = DAG.getConstant(C1Val.exactLogBase2(), DL, VT); + return DAG.getNode(ISD::SHL, DL, VT, Cond, ShAmtC); + } + + if (SDValue V = foldSelectOfConstantsUsingSra(N, DAG)) + return V; + } + + return SDValue(); + } + + // fold (select Cond, 0, 1) -> (xor Cond, 1) + // We can't do this reliably if integer based booleans have different contents + // to floating point based booleans. This is because we can't tell whether we + // have an integer-based boolean or a floating-point-based boolean unless we + // can find the SETCC that produced it and inspect its operands. This is + // fairly easy if C is the SETCC node, but it can potentially be + // undiscoverable (or not reasonably discoverable). For example, it could be + // in another basic block or it could require searching a complicated + // expression. + if (CondVT.isInteger() && + TLI.getBooleanContents(/*isVec*/false, /*isFloat*/true) == + TargetLowering::ZeroOrOneBooleanContent && + TLI.getBooleanContents(/*isVec*/false, /*isFloat*/false) == + TargetLowering::ZeroOrOneBooleanContent && + C1->isNullValue() && C2->isOne()) { + SDValue NotCond = + DAG.getNode(ISD::XOR, DL, CondVT, Cond, DAG.getConstant(1, DL, CondVT)); + if (VT.bitsEq(CondVT)) + return NotCond; + return DAG.getZExtOrTrunc(NotCond, DL, VT); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitSELECT(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + EVT VT = N->getValueType(0); + EVT VT0 = N0.getValueType(); + SDLoc DL(N); + SDNodeFlags Flags = N->getFlags(); + + if (SDValue V = DAG.simplifySelect(N0, N1, N2)) + return V; + + // fold (select X, X, Y) -> (or X, Y) + // fold (select X, 1, Y) -> (or C, Y) + if (VT == VT0 && VT == MVT::i1 && (N0 == N1 || isOneConstant(N1))) + return DAG.getNode(ISD::OR, DL, VT, N0, N2); + + if (SDValue V = foldSelectOfConstants(N)) + return V; + + // fold (select C, 0, X) -> (and (not C), X) + if (VT == VT0 && VT == MVT::i1 && isNullConstant(N1)) { + SDValue NOTNode = DAG.getNOT(SDLoc(N0), N0, VT); + AddToWorklist(NOTNode.getNode()); + return DAG.getNode(ISD::AND, DL, VT, NOTNode, N2); + } + // fold (select C, X, 1) -> (or (not C), X) + if (VT == VT0 && VT == MVT::i1 && isOneConstant(N2)) { + SDValue NOTNode = DAG.getNOT(SDLoc(N0), N0, VT); + AddToWorklist(NOTNode.getNode()); + return DAG.getNode(ISD::OR, DL, VT, NOTNode, N1); + } + // fold (select X, Y, X) -> (and X, Y) + // fold (select X, Y, 0) -> (and X, Y) + if (VT == VT0 && VT == MVT::i1 && (N0 == N2 || isNullConstant(N2))) + return DAG.getNode(ISD::AND, DL, VT, N0, N1); + + // If we can fold this based on the true/false value, do so. + if (SimplifySelectOps(N, N1, N2)) + return SDValue(N, 0); // Don't revisit N. + + if (VT0 == MVT::i1) { + // The code in this block deals with the following 2 equivalences: + // select(C0|C1, x, y) <=> select(C0, x, select(C1, x, y)) + // select(C0&C1, x, y) <=> select(C0, select(C1, x, y), y) + // The target can specify its preferred form with the + // shouldNormalizeToSelectSequence() callback. However we always transform + // to the right anyway if we find the inner select exists in the DAG anyway + // and we always transform to the left side if we know that we can further + // optimize the combination of the conditions. + bool normalizeToSequence = + TLI.shouldNormalizeToSelectSequence(*DAG.getContext(), VT); + // select (and Cond0, Cond1), X, Y + // -> select Cond0, (select Cond1, X, Y), Y + if (N0->getOpcode() == ISD::AND && N0->hasOneUse()) { + SDValue Cond0 = N0->getOperand(0); + SDValue Cond1 = N0->getOperand(1); + SDValue InnerSelect = + DAG.getNode(ISD::SELECT, DL, N1.getValueType(), Cond1, N1, N2, Flags); + if (normalizeToSequence || !InnerSelect.use_empty()) + return DAG.getNode(ISD::SELECT, DL, N1.getValueType(), Cond0, + InnerSelect, N2, Flags); + // Cleanup on failure. + if (InnerSelect.use_empty()) + recursivelyDeleteUnusedNodes(InnerSelect.getNode()); + } + // select (or Cond0, Cond1), X, Y -> select Cond0, X, (select Cond1, X, Y) + if (N0->getOpcode() == ISD::OR && N0->hasOneUse()) { + SDValue Cond0 = N0->getOperand(0); + SDValue Cond1 = N0->getOperand(1); + SDValue InnerSelect = DAG.getNode(ISD::SELECT, DL, N1.getValueType(), + Cond1, N1, N2, Flags); + if (normalizeToSequence || !InnerSelect.use_empty()) + return DAG.getNode(ISD::SELECT, DL, N1.getValueType(), Cond0, N1, + InnerSelect, Flags); + // Cleanup on failure. + if (InnerSelect.use_empty()) + recursivelyDeleteUnusedNodes(InnerSelect.getNode()); + } + + // select Cond0, (select Cond1, X, Y), Y -> select (and Cond0, Cond1), X, Y + if (N1->getOpcode() == ISD::SELECT && N1->hasOneUse()) { + SDValue N1_0 = N1->getOperand(0); + SDValue N1_1 = N1->getOperand(1); + SDValue N1_2 = N1->getOperand(2); + if (N1_2 == N2 && N0.getValueType() == N1_0.getValueType()) { + // Create the actual and node if we can generate good code for it. + if (!normalizeToSequence) { + SDValue And = DAG.getNode(ISD::AND, DL, N0.getValueType(), N0, N1_0); + return DAG.getNode(ISD::SELECT, DL, N1.getValueType(), And, N1_1, + N2, Flags); + } + // Otherwise see if we can optimize the "and" to a better pattern. + if (SDValue Combined = visitANDLike(N0, N1_0, N)) { + return DAG.getNode(ISD::SELECT, DL, N1.getValueType(), Combined, N1_1, + N2, Flags); + } + } + } + // select Cond0, X, (select Cond1, X, Y) -> select (or Cond0, Cond1), X, Y + if (N2->getOpcode() == ISD::SELECT && N2->hasOneUse()) { + SDValue N2_0 = N2->getOperand(0); + SDValue N2_1 = N2->getOperand(1); + SDValue N2_2 = N2->getOperand(2); + if (N2_1 == N1 && N0.getValueType() == N2_0.getValueType()) { + // Create the actual or node if we can generate good code for it. + if (!normalizeToSequence) { + SDValue Or = DAG.getNode(ISD::OR, DL, N0.getValueType(), N0, N2_0); + return DAG.getNode(ISD::SELECT, DL, N1.getValueType(), Or, N1, + N2_2, Flags); + } + // Otherwise see if we can optimize to a better pattern. + if (SDValue Combined = visitORLike(N0, N2_0, N)) + return DAG.getNode(ISD::SELECT, DL, N1.getValueType(), Combined, N1, + N2_2, Flags); + } + } + } + + // select (not Cond), N1, N2 -> select Cond, N2, N1 + if (SDValue F = extractBooleanFlip(N0, DAG, TLI, false)) { + SDValue SelectOp = DAG.getSelect(DL, VT, F, N2, N1); + SelectOp->setFlags(Flags); + return SelectOp; + } + + // Fold selects based on a setcc into other things, such as min/max/abs. + if (N0.getOpcode() == ISD::SETCC) { + SDValue Cond0 = N0.getOperand(0), Cond1 = N0.getOperand(1); + ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get(); + + // select (fcmp lt x, y), x, y -> fminnum x, y + // select (fcmp gt x, y), x, y -> fmaxnum x, y + // + // This is OK if we don't care what happens if either operand is a NaN. + if (N0.hasOneUse() && isLegalToCombineMinNumMaxNum(DAG, N1, N2, TLI)) + if (SDValue FMinMax = combineMinNumMaxNum(DL, VT, Cond0, Cond1, N1, N2, + CC, TLI, DAG)) + return FMinMax; + + // Use 'unsigned add with overflow' to optimize an unsigned saturating add. + // This is conservatively limited to pre-legal-operations to give targets + // a chance to reverse the transform if they want to do that. Also, it is + // unlikely that the pattern would be formed late, so it's probably not + // worth going through the other checks. + if (!LegalOperations && TLI.isOperationLegalOrCustom(ISD::UADDO, VT) && + CC == ISD::SETUGT && N0.hasOneUse() && isAllOnesConstant(N1) && + N2.getOpcode() == ISD::ADD && Cond0 == N2.getOperand(0)) { + auto *C = dyn_cast<ConstantSDNode>(N2.getOperand(1)); + auto *NotC = dyn_cast<ConstantSDNode>(Cond1); + if (C && NotC && C->getAPIntValue() == ~NotC->getAPIntValue()) { + // select (setcc Cond0, ~C, ugt), -1, (add Cond0, C) --> + // uaddo Cond0, C; select uaddo.1, -1, uaddo.0 + // + // The IR equivalent of this transform would have this form: + // %a = add %x, C + // %c = icmp ugt %x, ~C + // %r = select %c, -1, %a + // => + // %u = call {iN,i1} llvm.uadd.with.overflow(%x, C) + // %u0 = extractvalue %u, 0 + // %u1 = extractvalue %u, 1 + // %r = select %u1, -1, %u0 + SDVTList VTs = DAG.getVTList(VT, VT0); + SDValue UAO = DAG.getNode(ISD::UADDO, DL, VTs, Cond0, N2.getOperand(1)); + return DAG.getSelect(DL, VT, UAO.getValue(1), N1, UAO.getValue(0)); + } + } + + if (TLI.isOperationLegal(ISD::SELECT_CC, VT) || + (!LegalOperations && + TLI.isOperationLegalOrCustom(ISD::SELECT_CC, VT))) { + // Any flags available in a select/setcc fold will be on the setcc as they + // migrated from fcmp + Flags = N0.getNode()->getFlags(); + SDValue SelectNode = DAG.getNode(ISD::SELECT_CC, DL, VT, Cond0, Cond1, N1, + N2, N0.getOperand(2)); + SelectNode->setFlags(Flags); + return SelectNode; + } + + return SimplifySelect(DL, N0, N1, N2); + } + + return SDValue(); +} + +// This function assumes all the vselect's arguments are CONCAT_VECTOR +// nodes and that the condition is a BV of ConstantSDNodes (or undefs). +static SDValue ConvertSelectToConcatVector(SDNode *N, SelectionDAG &DAG) { + SDLoc DL(N); + SDValue Cond = N->getOperand(0); + SDValue LHS = N->getOperand(1); + SDValue RHS = N->getOperand(2); + EVT VT = N->getValueType(0); + int NumElems = VT.getVectorNumElements(); + assert(LHS.getOpcode() == ISD::CONCAT_VECTORS && + RHS.getOpcode() == ISD::CONCAT_VECTORS && + Cond.getOpcode() == ISD::BUILD_VECTOR); + + // CONCAT_VECTOR can take an arbitrary number of arguments. We only care about + // binary ones here. + if (LHS->getNumOperands() != 2 || RHS->getNumOperands() != 2) + return SDValue(); + + // We're sure we have an even number of elements due to the + // concat_vectors we have as arguments to vselect. + // Skip BV elements until we find one that's not an UNDEF + // After we find an UNDEF element, keep looping until we get to half the + // length of the BV and see if all the non-undef nodes are the same. + ConstantSDNode *BottomHalf = nullptr; + for (int i = 0; i < NumElems / 2; ++i) { + if (Cond->getOperand(i)->isUndef()) + continue; + + if (BottomHalf == nullptr) + BottomHalf = cast<ConstantSDNode>(Cond.getOperand(i)); + else if (Cond->getOperand(i).getNode() != BottomHalf) + return SDValue(); + } + + // Do the same for the second half of the BuildVector + ConstantSDNode *TopHalf = nullptr; + for (int i = NumElems / 2; i < NumElems; ++i) { + if (Cond->getOperand(i)->isUndef()) + continue; + + if (TopHalf == nullptr) + TopHalf = cast<ConstantSDNode>(Cond.getOperand(i)); + else if (Cond->getOperand(i).getNode() != TopHalf) + return SDValue(); + } + + assert(TopHalf && BottomHalf && + "One half of the selector was all UNDEFs and the other was all the " + "same value. This should have been addressed before this function."); + return DAG.getNode( + ISD::CONCAT_VECTORS, DL, VT, + BottomHalf->isNullValue() ? RHS->getOperand(0) : LHS->getOperand(0), + TopHalf->isNullValue() ? RHS->getOperand(1) : LHS->getOperand(1)); +} + +bool refineUniformBase(SDValue &BasePtr, SDValue &Index, SelectionDAG &DAG) { + if (!isNullConstant(BasePtr) || Index.getOpcode() != ISD::ADD) + return false; + + // For now we check only the LHS of the add. + SDValue LHS = Index.getOperand(0); + SDValue SplatVal = DAG.getSplatValue(LHS); + if (!SplatVal) + return false; + + BasePtr = SplatVal; + Index = Index.getOperand(1); + return true; +} + +// Fold sext/zext of index into index type. +bool refineIndexType(MaskedGatherScatterSDNode *MGS, SDValue &Index, + bool Scaled, SelectionDAG &DAG) { + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + + if (Index.getOpcode() == ISD::ZERO_EXTEND) { + SDValue Op = Index.getOperand(0); + MGS->setIndexType(Scaled ? ISD::UNSIGNED_SCALED : ISD::UNSIGNED_UNSCALED); + if (TLI.shouldRemoveExtendFromGSIndex(Op.getValueType())) { + Index = Op; + return true; + } + } + + if (Index.getOpcode() == ISD::SIGN_EXTEND) { + SDValue Op = Index.getOperand(0); + MGS->setIndexType(Scaled ? ISD::SIGNED_SCALED : ISD::SIGNED_UNSCALED); + if (TLI.shouldRemoveExtendFromGSIndex(Op.getValueType())) { + Index = Op; + return true; + } + } + + return false; +} + +SDValue DAGCombiner::visitMSCATTER(SDNode *N) { + MaskedScatterSDNode *MSC = cast<MaskedScatterSDNode>(N); + SDValue Mask = MSC->getMask(); + SDValue Chain = MSC->getChain(); + SDValue Index = MSC->getIndex(); + SDValue Scale = MSC->getScale(); + SDValue StoreVal = MSC->getValue(); + SDValue BasePtr = MSC->getBasePtr(); + SDLoc DL(N); + + // Zap scatters with a zero mask. + if (ISD::isBuildVectorAllZeros(Mask.getNode())) + return Chain; + + if (refineUniformBase(BasePtr, Index, DAG)) { + SDValue Ops[] = {Chain, StoreVal, Mask, BasePtr, Index, Scale}; + return DAG.getMaskedScatter( + DAG.getVTList(MVT::Other), StoreVal.getValueType(), DL, Ops, + MSC->getMemOperand(), MSC->getIndexType(), MSC->isTruncatingStore()); + } + + if (refineIndexType(MSC, Index, MSC->isIndexScaled(), DAG)) { + SDValue Ops[] = {Chain, StoreVal, Mask, BasePtr, Index, Scale}; + return DAG.getMaskedScatter( + DAG.getVTList(MVT::Other), StoreVal.getValueType(), DL, Ops, + MSC->getMemOperand(), MSC->getIndexType(), MSC->isTruncatingStore()); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitMSTORE(SDNode *N) { + MaskedStoreSDNode *MST = cast<MaskedStoreSDNode>(N); + SDValue Mask = MST->getMask(); + SDValue Chain = MST->getChain(); + SDLoc DL(N); + + // Zap masked stores with a zero mask. + if (ISD::isBuildVectorAllZeros(Mask.getNode())) + return Chain; + + // If this is a masked load with an all ones mask, we can use a unmasked load. + // FIXME: Can we do this for indexed, compressing, or truncating stores? + if (ISD::isBuildVectorAllOnes(Mask.getNode()) && + MST->isUnindexed() && !MST->isCompressingStore() && + !MST->isTruncatingStore()) + return DAG.getStore(MST->getChain(), SDLoc(N), MST->getValue(), + MST->getBasePtr(), MST->getMemOperand()); + + // Try transforming N to an indexed store. + if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) + return SDValue(N, 0); + + return SDValue(); +} + +SDValue DAGCombiner::visitMGATHER(SDNode *N) { + MaskedGatherSDNode *MGT = cast<MaskedGatherSDNode>(N); + SDValue Mask = MGT->getMask(); + SDValue Chain = MGT->getChain(); + SDValue Index = MGT->getIndex(); + SDValue Scale = MGT->getScale(); + SDValue PassThru = MGT->getPassThru(); + SDValue BasePtr = MGT->getBasePtr(); + SDLoc DL(N); + + // Zap gathers with a zero mask. + if (ISD::isBuildVectorAllZeros(Mask.getNode())) + return CombineTo(N, PassThru, MGT->getChain()); + + if (refineUniformBase(BasePtr, Index, DAG)) { + SDValue Ops[] = {Chain, PassThru, Mask, BasePtr, Index, Scale}; + return DAG.getMaskedGather(DAG.getVTList(N->getValueType(0), MVT::Other), + PassThru.getValueType(), DL, Ops, + MGT->getMemOperand(), MGT->getIndexType(), + MGT->getExtensionType()); + } + + if (refineIndexType(MGT, Index, MGT->isIndexScaled(), DAG)) { + SDValue Ops[] = {Chain, PassThru, Mask, BasePtr, Index, Scale}; + return DAG.getMaskedGather(DAG.getVTList(N->getValueType(0), MVT::Other), + PassThru.getValueType(), DL, Ops, + MGT->getMemOperand(), MGT->getIndexType(), + MGT->getExtensionType()); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitMLOAD(SDNode *N) { + MaskedLoadSDNode *MLD = cast<MaskedLoadSDNode>(N); + SDValue Mask = MLD->getMask(); + SDLoc DL(N); + + // Zap masked loads with a zero mask. + if (ISD::isBuildVectorAllZeros(Mask.getNode())) + return CombineTo(N, MLD->getPassThru(), MLD->getChain()); + + // If this is a masked load with an all ones mask, we can use a unmasked load. + // FIXME: Can we do this for indexed, expanding, or extending loads? + if (ISD::isBuildVectorAllOnes(Mask.getNode()) && + MLD->isUnindexed() && !MLD->isExpandingLoad() && + MLD->getExtensionType() == ISD::NON_EXTLOAD) { + SDValue NewLd = DAG.getLoad(N->getValueType(0), SDLoc(N), MLD->getChain(), + MLD->getBasePtr(), MLD->getMemOperand()); + return CombineTo(N, NewLd, NewLd.getValue(1)); + } + + // Try transforming N to an indexed load. + if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) + return SDValue(N, 0); + + return SDValue(); +} + +/// A vector select of 2 constant vectors can be simplified to math/logic to +/// avoid a variable select instruction and possibly avoid constant loads. +SDValue DAGCombiner::foldVSelectOfConstants(SDNode *N) { + SDValue Cond = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + EVT VT = N->getValueType(0); + if (!Cond.hasOneUse() || Cond.getScalarValueSizeInBits() != 1 || + !TLI.convertSelectOfConstantsToMath(VT) || + !ISD::isBuildVectorOfConstantSDNodes(N1.getNode()) || + !ISD::isBuildVectorOfConstantSDNodes(N2.getNode())) + return SDValue(); + + // Check if we can use the condition value to increment/decrement a single + // constant value. This simplifies a select to an add and removes a constant + // load/materialization from the general case. + bool AllAddOne = true; + bool AllSubOne = true; + unsigned Elts = VT.getVectorNumElements(); + for (unsigned i = 0; i != Elts; ++i) { + SDValue N1Elt = N1.getOperand(i); + SDValue N2Elt = N2.getOperand(i); + if (N1Elt.isUndef() || N2Elt.isUndef()) + continue; + if (N1Elt.getValueType() != N2Elt.getValueType()) + continue; + + const APInt &C1 = cast<ConstantSDNode>(N1Elt)->getAPIntValue(); + const APInt &C2 = cast<ConstantSDNode>(N2Elt)->getAPIntValue(); + if (C1 != C2 + 1) + AllAddOne = false; + if (C1 != C2 - 1) + AllSubOne = false; + } + + // Further simplifications for the extra-special cases where the constants are + // all 0 or all -1 should be implemented as folds of these patterns. + SDLoc DL(N); + if (AllAddOne || AllSubOne) { + // vselect <N x i1> Cond, C+1, C --> add (zext Cond), C + // vselect <N x i1> Cond, C-1, C --> add (sext Cond), C + auto ExtendOpcode = AllAddOne ? ISD::ZERO_EXTEND : ISD::SIGN_EXTEND; + SDValue ExtendedCond = DAG.getNode(ExtendOpcode, DL, VT, Cond); + return DAG.getNode(ISD::ADD, DL, VT, ExtendedCond, N2); + } + + // select Cond, Pow2C, 0 --> (zext Cond) << log2(Pow2C) + APInt Pow2C; + if (ISD::isConstantSplatVector(N1.getNode(), Pow2C) && Pow2C.isPowerOf2() && + isNullOrNullSplat(N2)) { + SDValue ZextCond = DAG.getZExtOrTrunc(Cond, DL, VT); + SDValue ShAmtC = DAG.getConstant(Pow2C.exactLogBase2(), DL, VT); + return DAG.getNode(ISD::SHL, DL, VT, ZextCond, ShAmtC); + } + + if (SDValue V = foldSelectOfConstantsUsingSra(N, DAG)) + return V; + + // The general case for select-of-constants: + // vselect <N x i1> Cond, C1, C2 --> xor (and (sext Cond), (C1^C2)), C2 + // ...but that only makes sense if a vselect is slower than 2 logic ops, so + // leave that to a machine-specific pass. + return SDValue(); +} + +SDValue DAGCombiner::visitVSELECT(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + EVT VT = N->getValueType(0); + SDLoc DL(N); + + if (SDValue V = DAG.simplifySelect(N0, N1, N2)) + return V; + + // vselect (not Cond), N1, N2 -> vselect Cond, N2, N1 + if (SDValue F = extractBooleanFlip(N0, DAG, TLI, false)) + return DAG.getSelect(DL, VT, F, N2, N1); + + // Canonicalize integer abs. + // vselect (setg[te] X, 0), X, -X -> + // vselect (setgt X, -1), X, -X -> + // vselect (setl[te] X, 0), -X, X -> + // Y = sra (X, size(X)-1); xor (add (X, Y), Y) + if (N0.getOpcode() == ISD::SETCC) { + SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); + ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get(); + bool isAbs = false; + bool RHSIsAllZeros = ISD::isBuildVectorAllZeros(RHS.getNode()); + + if (((RHSIsAllZeros && (CC == ISD::SETGT || CC == ISD::SETGE)) || + (ISD::isBuildVectorAllOnes(RHS.getNode()) && CC == ISD::SETGT)) && + N1 == LHS && N2.getOpcode() == ISD::SUB && N1 == N2.getOperand(1)) + isAbs = ISD::isBuildVectorAllZeros(N2.getOperand(0).getNode()); + else if ((RHSIsAllZeros && (CC == ISD::SETLT || CC == ISD::SETLE)) && + N2 == LHS && N1.getOpcode() == ISD::SUB && N2 == N1.getOperand(1)) + isAbs = ISD::isBuildVectorAllZeros(N1.getOperand(0).getNode()); + + if (isAbs) { + if (TLI.isOperationLegalOrCustom(ISD::ABS, VT)) + return DAG.getNode(ISD::ABS, DL, VT, LHS); + + SDValue Shift = DAG.getNode(ISD::SRA, DL, VT, LHS, + DAG.getConstant(VT.getScalarSizeInBits() - 1, + DL, getShiftAmountTy(VT))); + SDValue Add = DAG.getNode(ISD::ADD, DL, VT, LHS, Shift); + AddToWorklist(Shift.getNode()); + AddToWorklist(Add.getNode()); + return DAG.getNode(ISD::XOR, DL, VT, Add, Shift); + } + + // vselect x, y (fcmp lt x, y) -> fminnum x, y + // vselect x, y (fcmp gt x, y) -> fmaxnum x, y + // + // This is OK if we don't care about what happens if either operand is a + // NaN. + // + if (N0.hasOneUse() && isLegalToCombineMinNumMaxNum(DAG, LHS, RHS, TLI)) { + if (SDValue FMinMax = + combineMinNumMaxNum(DL, VT, LHS, RHS, N1, N2, CC, TLI, DAG)) + return FMinMax; + } + + // If this select has a condition (setcc) with narrower operands than the + // select, try to widen the compare to match the select width. + // TODO: This should be extended to handle any constant. + // TODO: This could be extended to handle non-loading patterns, but that + // requires thorough testing to avoid regressions. + if (isNullOrNullSplat(RHS)) { + EVT NarrowVT = LHS.getValueType(); + EVT WideVT = N1.getValueType().changeVectorElementTypeToInteger(); + EVT SetCCVT = getSetCCResultType(LHS.getValueType()); + unsigned SetCCWidth = SetCCVT.getScalarSizeInBits(); + unsigned WideWidth = WideVT.getScalarSizeInBits(); + bool IsSigned = isSignedIntSetCC(CC); + auto LoadExtOpcode = IsSigned ? ISD::SEXTLOAD : ISD::ZEXTLOAD; + if (LHS.getOpcode() == ISD::LOAD && LHS.hasOneUse() && + SetCCWidth != 1 && SetCCWidth < WideWidth && + TLI.isLoadExtLegalOrCustom(LoadExtOpcode, WideVT, NarrowVT) && + TLI.isOperationLegalOrCustom(ISD::SETCC, WideVT)) { + // Both compare operands can be widened for free. The LHS can use an + // extended load, and the RHS is a constant: + // vselect (ext (setcc load(X), C)), N1, N2 --> + // vselect (setcc extload(X), C'), N1, N2 + auto ExtOpcode = IsSigned ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND; + SDValue WideLHS = DAG.getNode(ExtOpcode, DL, WideVT, LHS); + SDValue WideRHS = DAG.getNode(ExtOpcode, DL, WideVT, RHS); + EVT WideSetCCVT = getSetCCResultType(WideVT); + SDValue WideSetCC = DAG.getSetCC(DL, WideSetCCVT, WideLHS, WideRHS, CC); + return DAG.getSelect(DL, N1.getValueType(), WideSetCC, N1, N2); + } + } + + // Match VSELECTs into add with unsigned saturation. + if (hasOperation(ISD::UADDSAT, VT)) { + // Check if one of the arms of the VSELECT is vector with all bits set. + // If it's on the left side invert the predicate to simplify logic below. + SDValue Other; + ISD::CondCode SatCC = CC; + if (ISD::isBuildVectorAllOnes(N1.getNode())) { + Other = N2; + SatCC = ISD::getSetCCInverse(SatCC, VT.getScalarType()); + } else if (ISD::isBuildVectorAllOnes(N2.getNode())) { + Other = N1; + } + + if (Other && Other.getOpcode() == ISD::ADD) { + SDValue CondLHS = LHS, CondRHS = RHS; + SDValue OpLHS = Other.getOperand(0), OpRHS = Other.getOperand(1); + + // Canonicalize condition operands. + if (SatCC == ISD::SETUGE) { + std::swap(CondLHS, CondRHS); + SatCC = ISD::SETULE; + } + + // We can test against either of the addition operands. + // x <= x+y ? x+y : ~0 --> uaddsat x, y + // x+y >= x ? x+y : ~0 --> uaddsat x, y + if (SatCC == ISD::SETULE && Other == CondRHS && + (OpLHS == CondLHS || OpRHS == CondLHS)) + return DAG.getNode(ISD::UADDSAT, DL, VT, OpLHS, OpRHS); + + if (isa<BuildVectorSDNode>(OpRHS) && isa<BuildVectorSDNode>(CondRHS) && + CondLHS == OpLHS) { + // If the RHS is a constant we have to reverse the const + // canonicalization. + // x >= ~C ? x+C : ~0 --> uaddsat x, C + auto MatchUADDSAT = [](ConstantSDNode *Op, ConstantSDNode *Cond) { + return Cond->getAPIntValue() == ~Op->getAPIntValue(); + }; + if (SatCC == ISD::SETULE && + ISD::matchBinaryPredicate(OpRHS, CondRHS, MatchUADDSAT)) + return DAG.getNode(ISD::UADDSAT, DL, VT, OpLHS, OpRHS); + } + } + } + + // Match VSELECTs into sub with unsigned saturation. + if (hasOperation(ISD::USUBSAT, VT)) { + // Check if one of the arms of the VSELECT is a zero vector. If it's on + // the left side invert the predicate to simplify logic below. + SDValue Other; + ISD::CondCode SatCC = CC; + if (ISD::isBuildVectorAllZeros(N1.getNode())) { + Other = N2; + SatCC = ISD::getSetCCInverse(SatCC, VT.getScalarType()); + } else if (ISD::isBuildVectorAllZeros(N2.getNode())) { + Other = N1; + } + + if (Other && Other.getNumOperands() == 2 && Other.getOperand(0) == LHS) { + SDValue CondRHS = RHS; + SDValue OpLHS = Other.getOperand(0), OpRHS = Other.getOperand(1); + + // Look for a general sub with unsigned saturation first. + // x >= y ? x-y : 0 --> usubsat x, y + // x > y ? x-y : 0 --> usubsat x, y + if ((SatCC == ISD::SETUGE || SatCC == ISD::SETUGT) && + Other.getOpcode() == ISD::SUB && OpRHS == CondRHS) + return DAG.getNode(ISD::USUBSAT, DL, VT, OpLHS, OpRHS); + + if (auto *OpRHSBV = dyn_cast<BuildVectorSDNode>(OpRHS)) { + if (isa<BuildVectorSDNode>(CondRHS)) { + // If the RHS is a constant we have to reverse the const + // canonicalization. + // x > C-1 ? x+-C : 0 --> usubsat x, C + auto MatchUSUBSAT = [](ConstantSDNode *Op, ConstantSDNode *Cond) { + return (!Op && !Cond) || + (Op && Cond && + Cond->getAPIntValue() == (-Op->getAPIntValue() - 1)); + }; + if (SatCC == ISD::SETUGT && Other.getOpcode() == ISD::ADD && + ISD::matchBinaryPredicate(OpRHS, CondRHS, MatchUSUBSAT, + /*AllowUndefs*/ true)) { + OpRHS = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), + OpRHS); + return DAG.getNode(ISD::USUBSAT, DL, VT, OpLHS, OpRHS); + } + + // Another special case: If C was a sign bit, the sub has been + // canonicalized into a xor. + // FIXME: Would it be better to use computeKnownBits to determine + // whether it's safe to decanonicalize the xor? + // x s< 0 ? x^C : 0 --> usubsat x, C + if (auto *OpRHSConst = OpRHSBV->getConstantSplatNode()) { + if (SatCC == ISD::SETLT && Other.getOpcode() == ISD::XOR && + ISD::isBuildVectorAllZeros(CondRHS.getNode()) && + OpRHSConst->getAPIntValue().isSignMask()) { + // Note that we have to rebuild the RHS constant here to ensure + // we don't rely on particular values of undef lanes. + OpRHS = DAG.getConstant(OpRHSConst->getAPIntValue(), DL, VT); + return DAG.getNode(ISD::USUBSAT, DL, VT, OpLHS, OpRHS); + } + } + } + } + } + } + } + + if (SimplifySelectOps(N, N1, N2)) + return SDValue(N, 0); // Don't revisit N. + + // Fold (vselect (build_vector all_ones), N1, N2) -> N1 + if (ISD::isBuildVectorAllOnes(N0.getNode())) + return N1; + // Fold (vselect (build_vector all_zeros), N1, N2) -> N2 + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N2; + + // The ConvertSelectToConcatVector function is assuming both the above + // checks for (vselect (build_vector all{ones,zeros) ...) have been made + // and addressed. + if (N1.getOpcode() == ISD::CONCAT_VECTORS && + N2.getOpcode() == ISD::CONCAT_VECTORS && + ISD::isBuildVectorOfConstantSDNodes(N0.getNode())) { + if (SDValue CV = ConvertSelectToConcatVector(N, DAG)) + return CV; + } + + if (SDValue V = foldVSelectOfConstants(N)) + return V; + + return SDValue(); +} + +SDValue DAGCombiner::visitSELECT_CC(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + SDValue N3 = N->getOperand(3); + SDValue N4 = N->getOperand(4); + ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get(); + + // fold select_cc lhs, rhs, x, x, cc -> x + if (N2 == N3) + return N2; + + // Determine if the condition we're dealing with is constant + if (SDValue SCC = SimplifySetCC(getSetCCResultType(N0.getValueType()), N0, N1, + CC, SDLoc(N), false)) { + AddToWorklist(SCC.getNode()); + + if (ConstantSDNode *SCCC = dyn_cast<ConstantSDNode>(SCC.getNode())) { + if (!SCCC->isNullValue()) + return N2; // cond always true -> true val + else + return N3; // cond always false -> false val + } else if (SCC->isUndef()) { + // When the condition is UNDEF, just return the first operand. This is + // coherent the DAG creation, no setcc node is created in this case + return N2; + } else if (SCC.getOpcode() == ISD::SETCC) { + // Fold to a simpler select_cc + SDValue SelectOp = DAG.getNode( + ISD::SELECT_CC, SDLoc(N), N2.getValueType(), SCC.getOperand(0), + SCC.getOperand(1), N2, N3, SCC.getOperand(2)); + SelectOp->setFlags(SCC->getFlags()); + return SelectOp; + } + } + + // If we can fold this based on the true/false value, do so. + if (SimplifySelectOps(N, N2, N3)) + return SDValue(N, 0); // Don't revisit N. + + // fold select_cc into other things, such as min/max/abs + return SimplifySelectCC(SDLoc(N), N0, N1, N2, N3, CC); +} + +SDValue DAGCombiner::visitSETCC(SDNode *N) { + // setcc is very commonly used as an argument to brcond. This pattern + // also lend itself to numerous combines and, as a result, it is desired + // we keep the argument to a brcond as a setcc as much as possible. + bool PreferSetCC = + N->hasOneUse() && N->use_begin()->getOpcode() == ISD::BRCOND; + + SDValue Combined = SimplifySetCC( + N->getValueType(0), N->getOperand(0), N->getOperand(1), + cast<CondCodeSDNode>(N->getOperand(2))->get(), SDLoc(N), !PreferSetCC); + + if (!Combined) + return SDValue(); + + // If we prefer to have a setcc, and we don't, we'll try our best to + // recreate one using rebuildSetCC. + if (PreferSetCC && Combined.getOpcode() != ISD::SETCC) { + SDValue NewSetCC = rebuildSetCC(Combined); + + // We don't have anything interesting to combine to. + if (NewSetCC.getNode() == N) + return SDValue(); + + if (NewSetCC) + return NewSetCC; + } + + return Combined; +} + +SDValue DAGCombiner::visitSETCCCARRY(SDNode *N) { + SDValue LHS = N->getOperand(0); + SDValue RHS = N->getOperand(1); + SDValue Carry = N->getOperand(2); + SDValue Cond = N->getOperand(3); + + // If Carry is false, fold to a regular SETCC. + if (isNullConstant(Carry)) + return DAG.getNode(ISD::SETCC, SDLoc(N), N->getVTList(), LHS, RHS, Cond); + + return SDValue(); +} + +/// Try to fold a sext/zext/aext dag node into a ConstantSDNode or +/// a build_vector of constants. +/// This function is called by the DAGCombiner when visiting sext/zext/aext +/// dag nodes (see for example method DAGCombiner::visitSIGN_EXTEND). +/// Vector extends are not folded if operations are legal; this is to +/// avoid introducing illegal build_vector dag nodes. +static SDValue tryToFoldExtendOfConstant(SDNode *N, const TargetLowering &TLI, + SelectionDAG &DAG, bool LegalTypes) { + unsigned Opcode = N->getOpcode(); + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + SDLoc DL(N); + + assert((Opcode == ISD::SIGN_EXTEND || Opcode == ISD::ZERO_EXTEND || + Opcode == ISD::ANY_EXTEND || Opcode == ISD::SIGN_EXTEND_VECTOR_INREG || + Opcode == ISD::ZERO_EXTEND_VECTOR_INREG) + && "Expected EXTEND dag node in input!"); + + // fold (sext c1) -> c1 + // fold (zext c1) -> c1 + // fold (aext c1) -> c1 + if (isa<ConstantSDNode>(N0)) + return DAG.getNode(Opcode, DL, VT, N0); + + // fold (sext (select cond, c1, c2)) -> (select cond, sext c1, sext c2) + // fold (zext (select cond, c1, c2)) -> (select cond, zext c1, zext c2) + // fold (aext (select cond, c1, c2)) -> (select cond, sext c1, sext c2) + if (N0->getOpcode() == ISD::SELECT) { + SDValue Op1 = N0->getOperand(1); + SDValue Op2 = N0->getOperand(2); + if (isa<ConstantSDNode>(Op1) && isa<ConstantSDNode>(Op2) && + (Opcode != ISD::ZERO_EXTEND || !TLI.isZExtFree(N0.getValueType(), VT))) { + // For any_extend, choose sign extension of the constants to allow a + // possible further transform to sign_extend_inreg.i.e. + // + // t1: i8 = select t0, Constant:i8<-1>, Constant:i8<0> + // t2: i64 = any_extend t1 + // --> + // t3: i64 = select t0, Constant:i64<-1>, Constant:i64<0> + // --> + // t4: i64 = sign_extend_inreg t3 + unsigned FoldOpc = Opcode; + if (FoldOpc == ISD::ANY_EXTEND) + FoldOpc = ISD::SIGN_EXTEND; + return DAG.getSelect(DL, VT, N0->getOperand(0), + DAG.getNode(FoldOpc, DL, VT, Op1), + DAG.getNode(FoldOpc, DL, VT, Op2)); + } + } + + // fold (sext (build_vector AllConstants) -> (build_vector AllConstants) + // fold (zext (build_vector AllConstants) -> (build_vector AllConstants) + // fold (aext (build_vector AllConstants) -> (build_vector AllConstants) + EVT SVT = VT.getScalarType(); + if (!(VT.isVector() && (!LegalTypes || TLI.isTypeLegal(SVT)) && + ISD::isBuildVectorOfConstantSDNodes(N0.getNode()))) + return SDValue(); + + // We can fold this node into a build_vector. + unsigned VTBits = SVT.getSizeInBits(); + unsigned EVTBits = N0->getValueType(0).getScalarSizeInBits(); + SmallVector<SDValue, 8> Elts; + unsigned NumElts = VT.getVectorNumElements(); + + // For zero-extensions, UNDEF elements still guarantee to have the upper + // bits set to zero. + bool IsZext = + Opcode == ISD::ZERO_EXTEND || Opcode == ISD::ZERO_EXTEND_VECTOR_INREG; + + for (unsigned i = 0; i != NumElts; ++i) { + SDValue Op = N0.getOperand(i); + if (Op.isUndef()) { + Elts.push_back(IsZext ? DAG.getConstant(0, DL, SVT) : DAG.getUNDEF(SVT)); + continue; + } + + SDLoc DL(Op); + // Get the constant value and if needed trunc it to the size of the type. + // Nodes like build_vector might have constants wider than the scalar type. + APInt C = cast<ConstantSDNode>(Op)->getAPIntValue().zextOrTrunc(EVTBits); + if (Opcode == ISD::SIGN_EXTEND || Opcode == ISD::SIGN_EXTEND_VECTOR_INREG) + Elts.push_back(DAG.getConstant(C.sext(VTBits), DL, SVT)); + else + Elts.push_back(DAG.getConstant(C.zext(VTBits), DL, SVT)); + } + + return DAG.getBuildVector(VT, DL, Elts); +} + +// ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this: +// "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))" +// transformation. Returns true if extension are possible and the above +// mentioned transformation is profitable. +static bool ExtendUsesToFormExtLoad(EVT VT, SDNode *N, SDValue N0, + unsigned ExtOpc, + SmallVectorImpl<SDNode *> &ExtendNodes, + const TargetLowering &TLI) { + bool HasCopyToRegUses = false; + bool isTruncFree = TLI.isTruncateFree(VT, N0.getValueType()); + for (SDNode::use_iterator UI = N0.getNode()->use_begin(), + UE = N0.getNode()->use_end(); + UI != UE; ++UI) { + SDNode *User = *UI; + if (User == N) + continue; + if (UI.getUse().getResNo() != N0.getResNo()) + continue; + // FIXME: Only extend SETCC N, N and SETCC N, c for now. + if (ExtOpc != ISD::ANY_EXTEND && User->getOpcode() == ISD::SETCC) { + ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get(); + if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC)) + // Sign bits will be lost after a zext. + return false; + bool Add = false; + for (unsigned i = 0; i != 2; ++i) { + SDValue UseOp = User->getOperand(i); + if (UseOp == N0) + continue; + if (!isa<ConstantSDNode>(UseOp)) + return false; + Add = true; + } + if (Add) + ExtendNodes.push_back(User); + continue; + } + // If truncates aren't free and there are users we can't + // extend, it isn't worthwhile. + if (!isTruncFree) + return false; + // Remember if this value is live-out. + if (User->getOpcode() == ISD::CopyToReg) + HasCopyToRegUses = true; + } + + if (HasCopyToRegUses) { + bool BothLiveOut = false; + for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); + UI != UE; ++UI) { + SDUse &Use = UI.getUse(); + if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) { + BothLiveOut = true; + break; + } + } + if (BothLiveOut) + // Both unextended and extended values are live out. There had better be + // a good reason for the transformation. + return ExtendNodes.size(); + } + return true; +} + +void DAGCombiner::ExtendSetCCUses(const SmallVectorImpl<SDNode *> &SetCCs, + SDValue OrigLoad, SDValue ExtLoad, + ISD::NodeType ExtType) { + // Extend SetCC uses if necessary. + SDLoc DL(ExtLoad); + for (SDNode *SetCC : SetCCs) { + SmallVector<SDValue, 4> Ops; + + for (unsigned j = 0; j != 2; ++j) { + SDValue SOp = SetCC->getOperand(j); + if (SOp == OrigLoad) + Ops.push_back(ExtLoad); + else + Ops.push_back(DAG.getNode(ExtType, DL, ExtLoad->getValueType(0), SOp)); + } + + Ops.push_back(SetCC->getOperand(2)); + CombineTo(SetCC, DAG.getNode(ISD::SETCC, DL, SetCC->getValueType(0), Ops)); + } +} + +// FIXME: Bring more similar combines here, common to sext/zext (maybe aext?). +SDValue DAGCombiner::CombineExtLoad(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT DstVT = N->getValueType(0); + EVT SrcVT = N0.getValueType(); + + assert((N->getOpcode() == ISD::SIGN_EXTEND || + N->getOpcode() == ISD::ZERO_EXTEND) && + "Unexpected node type (not an extend)!"); + + // fold (sext (load x)) to multiple smaller sextloads; same for zext. + // For example, on a target with legal v4i32, but illegal v8i32, turn: + // (v8i32 (sext (v8i16 (load x)))) + // into: + // (v8i32 (concat_vectors (v4i32 (sextload x)), + // (v4i32 (sextload (x + 16))))) + // Where uses of the original load, i.e.: + // (v8i16 (load x)) + // are replaced with: + // (v8i16 (truncate + // (v8i32 (concat_vectors (v4i32 (sextload x)), + // (v4i32 (sextload (x + 16))))))) + // + // This combine is only applicable to illegal, but splittable, vectors. + // All legal types, and illegal non-vector types, are handled elsewhere. + // This combine is controlled by TargetLowering::isVectorLoadExtDesirable. + // + if (N0->getOpcode() != ISD::LOAD) + return SDValue(); + + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + + if (!ISD::isNON_EXTLoad(LN0) || !ISD::isUNINDEXEDLoad(LN0) || + !N0.hasOneUse() || !LN0->isSimple() || + !DstVT.isVector() || !DstVT.isPow2VectorType() || + !TLI.isVectorLoadExtDesirable(SDValue(N, 0))) + return SDValue(); + + SmallVector<SDNode *, 4> SetCCs; + if (!ExtendUsesToFormExtLoad(DstVT, N, N0, N->getOpcode(), SetCCs, TLI)) + return SDValue(); + + ISD::LoadExtType ExtType = + N->getOpcode() == ISD::SIGN_EXTEND ? ISD::SEXTLOAD : ISD::ZEXTLOAD; + + // Try to split the vector types to get down to legal types. + EVT SplitSrcVT = SrcVT; + EVT SplitDstVT = DstVT; + while (!TLI.isLoadExtLegalOrCustom(ExtType, SplitDstVT, SplitSrcVT) && + SplitSrcVT.getVectorNumElements() > 1) { + SplitDstVT = DAG.GetSplitDestVTs(SplitDstVT).first; + SplitSrcVT = DAG.GetSplitDestVTs(SplitSrcVT).first; + } + + if (!TLI.isLoadExtLegalOrCustom(ExtType, SplitDstVT, SplitSrcVT)) + return SDValue(); + + assert(!DstVT.isScalableVector() && "Unexpected scalable vector type"); + + SDLoc DL(N); + const unsigned NumSplits = + DstVT.getVectorNumElements() / SplitDstVT.getVectorNumElements(); + const unsigned Stride = SplitSrcVT.getStoreSize(); + SmallVector<SDValue, 4> Loads; + SmallVector<SDValue, 4> Chains; + + SDValue BasePtr = LN0->getBasePtr(); + for (unsigned Idx = 0; Idx < NumSplits; Idx++) { + const unsigned Offset = Idx * Stride; + const Align Align = commonAlignment(LN0->getAlign(), Offset); + + SDValue SplitLoad = DAG.getExtLoad( + ExtType, SDLoc(LN0), SplitDstVT, LN0->getChain(), BasePtr, + LN0->getPointerInfo().getWithOffset(Offset), SplitSrcVT, Align, + LN0->getMemOperand()->getFlags(), LN0->getAAInfo()); + + BasePtr = DAG.getMemBasePlusOffset(BasePtr, TypeSize::Fixed(Stride), DL); + + Loads.push_back(SplitLoad.getValue(0)); + Chains.push_back(SplitLoad.getValue(1)); + } + + SDValue NewChain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Chains); + SDValue NewValue = DAG.getNode(ISD::CONCAT_VECTORS, DL, DstVT, Loads); + + // Simplify TF. + AddToWorklist(NewChain.getNode()); + + CombineTo(N, NewValue); + + // Replace uses of the original load (before extension) + // with a truncate of the concatenated sextloaded vectors. + SDValue Trunc = + DAG.getNode(ISD::TRUNCATE, SDLoc(N0), N0.getValueType(), NewValue); + ExtendSetCCUses(SetCCs, N0, NewValue, (ISD::NodeType)N->getOpcode()); + CombineTo(N0.getNode(), Trunc, NewChain); + return SDValue(N, 0); // Return N so it doesn't get rechecked! +} + +// fold (zext (and/or/xor (shl/shr (load x), cst), cst)) -> +// (and/or/xor (shl/shr (zextload x), (zext cst)), (zext cst)) +SDValue DAGCombiner::CombineZExtLogicopShiftLoad(SDNode *N) { + assert(N->getOpcode() == ISD::ZERO_EXTEND); + EVT VT = N->getValueType(0); + EVT OrigVT = N->getOperand(0).getValueType(); + if (TLI.isZExtFree(OrigVT, VT)) + return SDValue(); + + // and/or/xor + SDValue N0 = N->getOperand(0); + if (!(N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR || + N0.getOpcode() == ISD::XOR) || + N0.getOperand(1).getOpcode() != ISD::Constant || + (LegalOperations && !TLI.isOperationLegal(N0.getOpcode(), VT))) + return SDValue(); + + // shl/shr + SDValue N1 = N0->getOperand(0); + if (!(N1.getOpcode() == ISD::SHL || N1.getOpcode() == ISD::SRL) || + N1.getOperand(1).getOpcode() != ISD::Constant || + (LegalOperations && !TLI.isOperationLegal(N1.getOpcode(), VT))) + return SDValue(); + + // load + if (!isa<LoadSDNode>(N1.getOperand(0))) + return SDValue(); + LoadSDNode *Load = cast<LoadSDNode>(N1.getOperand(0)); + EVT MemVT = Load->getMemoryVT(); + if (!TLI.isLoadExtLegal(ISD::ZEXTLOAD, VT, MemVT) || + Load->getExtensionType() == ISD::SEXTLOAD || Load->isIndexed()) + return SDValue(); + + + // If the shift op is SHL, the logic op must be AND, otherwise the result + // will be wrong. + if (N1.getOpcode() == ISD::SHL && N0.getOpcode() != ISD::AND) + return SDValue(); + + if (!N0.hasOneUse() || !N1.hasOneUse()) + return SDValue(); + + SmallVector<SDNode*, 4> SetCCs; + if (!ExtendUsesToFormExtLoad(VT, N1.getNode(), N1.getOperand(0), + ISD::ZERO_EXTEND, SetCCs, TLI)) + return SDValue(); + + // Actually do the transformation. + SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, SDLoc(Load), VT, + Load->getChain(), Load->getBasePtr(), + Load->getMemoryVT(), Load->getMemOperand()); + + SDLoc DL1(N1); + SDValue Shift = DAG.getNode(N1.getOpcode(), DL1, VT, ExtLoad, + N1.getOperand(1)); + + APInt Mask = N0.getConstantOperandAPInt(1).zext(VT.getSizeInBits()); + SDLoc DL0(N0); + SDValue And = DAG.getNode(N0.getOpcode(), DL0, VT, Shift, + DAG.getConstant(Mask, DL0, VT)); + + ExtendSetCCUses(SetCCs, N1.getOperand(0), ExtLoad, ISD::ZERO_EXTEND); + CombineTo(N, And); + if (SDValue(Load, 0).hasOneUse()) { + DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), ExtLoad.getValue(1)); + } else { + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(Load), + Load->getValueType(0), ExtLoad); + CombineTo(Load, Trunc, ExtLoad.getValue(1)); + } + + // N0 is dead at this point. + recursivelyDeleteUnusedNodes(N0.getNode()); + + return SDValue(N,0); // Return N so it doesn't get rechecked! +} + +/// If we're narrowing or widening the result of a vector select and the final +/// size is the same size as a setcc (compare) feeding the select, then try to +/// apply the cast operation to the select's operands because matching vector +/// sizes for a select condition and other operands should be more efficient. +SDValue DAGCombiner::matchVSelectOpSizesWithSetCC(SDNode *Cast) { + unsigned CastOpcode = Cast->getOpcode(); + assert((CastOpcode == ISD::SIGN_EXTEND || CastOpcode == ISD::ZERO_EXTEND || + CastOpcode == ISD::TRUNCATE || CastOpcode == ISD::FP_EXTEND || + CastOpcode == ISD::FP_ROUND) && + "Unexpected opcode for vector select narrowing/widening"); + + // We only do this transform before legal ops because the pattern may be + // obfuscated by target-specific operations after legalization. Do not create + // an illegal select op, however, because that may be difficult to lower. + EVT VT = Cast->getValueType(0); + if (LegalOperations || !TLI.isOperationLegalOrCustom(ISD::VSELECT, VT)) + return SDValue(); + + SDValue VSel = Cast->getOperand(0); + if (VSel.getOpcode() != ISD::VSELECT || !VSel.hasOneUse() || + VSel.getOperand(0).getOpcode() != ISD::SETCC) + return SDValue(); + + // Does the setcc have the same vector size as the casted select? + SDValue SetCC = VSel.getOperand(0); + EVT SetCCVT = getSetCCResultType(SetCC.getOperand(0).getValueType()); + if (SetCCVT.getSizeInBits() != VT.getSizeInBits()) + return SDValue(); + + // cast (vsel (setcc X), A, B) --> vsel (setcc X), (cast A), (cast B) + SDValue A = VSel.getOperand(1); + SDValue B = VSel.getOperand(2); + SDValue CastA, CastB; + SDLoc DL(Cast); + if (CastOpcode == ISD::FP_ROUND) { + // FP_ROUND (fptrunc) has an extra flag operand to pass along. + CastA = DAG.getNode(CastOpcode, DL, VT, A, Cast->getOperand(1)); + CastB = DAG.getNode(CastOpcode, DL, VT, B, Cast->getOperand(1)); + } else { + CastA = DAG.getNode(CastOpcode, DL, VT, A); + CastB = DAG.getNode(CastOpcode, DL, VT, B); + } + return DAG.getNode(ISD::VSELECT, DL, VT, SetCC, CastA, CastB); +} + +// fold ([s|z]ext ([s|z]extload x)) -> ([s|z]ext (truncate ([s|z]extload x))) +// fold ([s|z]ext ( extload x)) -> ([s|z]ext (truncate ([s|z]extload x))) +static SDValue tryToFoldExtOfExtload(SelectionDAG &DAG, DAGCombiner &Combiner, + const TargetLowering &TLI, EVT VT, + bool LegalOperations, SDNode *N, + SDValue N0, ISD::LoadExtType ExtLoadType) { + SDNode *N0Node = N0.getNode(); + bool isAExtLoad = (ExtLoadType == ISD::SEXTLOAD) ? ISD::isSEXTLoad(N0Node) + : ISD::isZEXTLoad(N0Node); + if ((!isAExtLoad && !ISD::isEXTLoad(N0Node)) || + !ISD::isUNINDEXEDLoad(N0Node) || !N0.hasOneUse()) + return SDValue(); + + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + EVT MemVT = LN0->getMemoryVT(); + if ((LegalOperations || !LN0->isSimple() || + VT.isVector()) && + !TLI.isLoadExtLegal(ExtLoadType, VT, MemVT)) + return SDValue(); + + SDValue ExtLoad = + DAG.getExtLoad(ExtLoadType, SDLoc(LN0), VT, LN0->getChain(), + LN0->getBasePtr(), MemVT, LN0->getMemOperand()); + Combiner.CombineTo(N, ExtLoad); + DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1)); + if (LN0->use_empty()) + Combiner.recursivelyDeleteUnusedNodes(LN0); + return SDValue(N, 0); // Return N so it doesn't get rechecked! +} + +// fold ([s|z]ext (load x)) -> ([s|z]ext (truncate ([s|z]extload x))) +// Only generate vector extloads when 1) they're legal, and 2) they are +// deemed desirable by the target. +static SDValue tryToFoldExtOfLoad(SelectionDAG &DAG, DAGCombiner &Combiner, + const TargetLowering &TLI, EVT VT, + bool LegalOperations, SDNode *N, SDValue N0, + ISD::LoadExtType ExtLoadType, + ISD::NodeType ExtOpc) { + if (!ISD::isNON_EXTLoad(N0.getNode()) || + !ISD::isUNINDEXEDLoad(N0.getNode()) || + ((LegalOperations || VT.isVector() || + !cast<LoadSDNode>(N0)->isSimple()) && + !TLI.isLoadExtLegal(ExtLoadType, VT, N0.getValueType()))) + return {}; + + bool DoXform = true; + SmallVector<SDNode *, 4> SetCCs; + if (!N0.hasOneUse()) + DoXform = ExtendUsesToFormExtLoad(VT, N, N0, ExtOpc, SetCCs, TLI); + if (VT.isVector()) + DoXform &= TLI.isVectorLoadExtDesirable(SDValue(N, 0)); + if (!DoXform) + return {}; + + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ExtLoadType, SDLoc(LN0), VT, LN0->getChain(), + LN0->getBasePtr(), N0.getValueType(), + LN0->getMemOperand()); + Combiner.ExtendSetCCUses(SetCCs, N0, ExtLoad, ExtOpc); + // If the load value is used only by N, replace it via CombineTo N. + bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse(); + Combiner.CombineTo(N, ExtLoad); + if (NoReplaceTrunc) { + DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1)); + Combiner.recursivelyDeleteUnusedNodes(LN0); + } else { + SDValue Trunc = + DAG.getNode(ISD::TRUNCATE, SDLoc(N0), N0.getValueType(), ExtLoad); + Combiner.CombineTo(LN0, Trunc, ExtLoad.getValue(1)); + } + return SDValue(N, 0); // Return N so it doesn't get rechecked! +} + +static SDValue tryToFoldExtOfMaskedLoad(SelectionDAG &DAG, + const TargetLowering &TLI, EVT VT, + SDNode *N, SDValue N0, + ISD::LoadExtType ExtLoadType, + ISD::NodeType ExtOpc) { + if (!N0.hasOneUse()) + return SDValue(); + + MaskedLoadSDNode *Ld = dyn_cast<MaskedLoadSDNode>(N0); + if (!Ld || Ld->getExtensionType() != ISD::NON_EXTLOAD) + return SDValue(); + + if (!TLI.isLoadExtLegal(ExtLoadType, VT, Ld->getValueType(0))) + return SDValue(); + + if (!TLI.isVectorLoadExtDesirable(SDValue(N, 0))) + return SDValue(); + + SDLoc dl(Ld); + SDValue PassThru = DAG.getNode(ExtOpc, dl, VT, Ld->getPassThru()); + SDValue NewLoad = DAG.getMaskedLoad( + VT, dl, Ld->getChain(), Ld->getBasePtr(), Ld->getOffset(), Ld->getMask(), + PassThru, Ld->getMemoryVT(), Ld->getMemOperand(), Ld->getAddressingMode(), + ExtLoadType, Ld->isExpandingLoad()); + DAG.ReplaceAllUsesOfValueWith(SDValue(Ld, 1), SDValue(NewLoad.getNode(), 1)); + return NewLoad; +} + +static SDValue foldExtendedSignBitTest(SDNode *N, SelectionDAG &DAG, + bool LegalOperations) { + assert((N->getOpcode() == ISD::SIGN_EXTEND || + N->getOpcode() == ISD::ZERO_EXTEND) && "Expected sext or zext"); + + SDValue SetCC = N->getOperand(0); + if (LegalOperations || SetCC.getOpcode() != ISD::SETCC || + !SetCC.hasOneUse() || SetCC.getValueType() != MVT::i1) + return SDValue(); + + SDValue X = SetCC.getOperand(0); + SDValue Ones = SetCC.getOperand(1); + ISD::CondCode CC = cast<CondCodeSDNode>(SetCC.getOperand(2))->get(); + EVT VT = N->getValueType(0); + EVT XVT = X.getValueType(); + // setge X, C is canonicalized to setgt, so we do not need to match that + // pattern. The setlt sibling is folded in SimplifySelectCC() because it does + // not require the 'not' op. + if (CC == ISD::SETGT && isAllOnesConstant(Ones) && VT == XVT) { + // Invert and smear/shift the sign bit: + // sext i1 (setgt iN X, -1) --> sra (not X), (N - 1) + // zext i1 (setgt iN X, -1) --> srl (not X), (N - 1) + SDLoc DL(N); + unsigned ShCt = VT.getSizeInBits() - 1; + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + if (!TLI.shouldAvoidTransformToShift(VT, ShCt)) { + SDValue NotX = DAG.getNOT(DL, X, VT); + SDValue ShiftAmount = DAG.getConstant(ShCt, DL, VT); + auto ShiftOpcode = + N->getOpcode() == ISD::SIGN_EXTEND ? ISD::SRA : ISD::SRL; + return DAG.getNode(ShiftOpcode, DL, VT, NotX, ShiftAmount); + } + } + return SDValue(); +} + +SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + SDLoc DL(N); + + if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes)) + return Res; + + // fold (sext (sext x)) -> (sext x) + // fold (sext (aext x)) -> (sext x) + if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) + return DAG.getNode(ISD::SIGN_EXTEND, DL, VT, N0.getOperand(0)); + + if (N0.getOpcode() == ISD::TRUNCATE) { + // fold (sext (truncate (load x))) -> (sext (smaller load x)) + // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n))) + if (SDValue NarrowLoad = ReduceLoadWidth(N0.getNode())) { + SDNode *oye = N0.getOperand(0).getNode(); + if (NarrowLoad.getNode() != N0.getNode()) { + CombineTo(N0.getNode(), NarrowLoad); + // CombineTo deleted the truncate, if needed, but not what's under it. + AddToWorklist(oye); + } + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + + // See if the value being truncated is already sign extended. If so, just + // eliminate the trunc/sext pair. + SDValue Op = N0.getOperand(0); + unsigned OpBits = Op.getScalarValueSizeInBits(); + unsigned MidBits = N0.getScalarValueSizeInBits(); + unsigned DestBits = VT.getScalarSizeInBits(); + unsigned NumSignBits = DAG.ComputeNumSignBits(Op); + + if (OpBits == DestBits) { + // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign + // bits, it is already ready. + if (NumSignBits > DestBits-MidBits) + return Op; + } else if (OpBits < DestBits) { + // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign + // bits, just sext from i32. + if (NumSignBits > OpBits-MidBits) + return DAG.getNode(ISD::SIGN_EXTEND, DL, VT, Op); + } else { + // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign + // bits, just truncate to i32. + if (NumSignBits > OpBits-MidBits) + return DAG.getNode(ISD::TRUNCATE, DL, VT, Op); + } + + // fold (sext (truncate x)) -> (sextinreg x). + if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, + N0.getValueType())) { + if (OpBits < DestBits) + Op = DAG.getNode(ISD::ANY_EXTEND, SDLoc(N0), VT, Op); + else if (OpBits > DestBits) + Op = DAG.getNode(ISD::TRUNCATE, SDLoc(N0), VT, Op); + return DAG.getNode(ISD::SIGN_EXTEND_INREG, DL, VT, Op, + DAG.getValueType(N0.getValueType())); + } + } + + // Try to simplify (sext (load x)). + if (SDValue foldedExt = + tryToFoldExtOfLoad(DAG, *this, TLI, VT, LegalOperations, N, N0, + ISD::SEXTLOAD, ISD::SIGN_EXTEND)) + return foldedExt; + + if (SDValue foldedExt = + tryToFoldExtOfMaskedLoad(DAG, TLI, VT, N, N0, ISD::SEXTLOAD, + ISD::SIGN_EXTEND)) + return foldedExt; + + // fold (sext (load x)) to multiple smaller sextloads. + // Only on illegal but splittable vectors. + if (SDValue ExtLoad = CombineExtLoad(N)) + return ExtLoad; + + // Try to simplify (sext (sextload x)). + if (SDValue foldedExt = tryToFoldExtOfExtload( + DAG, *this, TLI, VT, LegalOperations, N, N0, ISD::SEXTLOAD)) + return foldedExt; + + // fold (sext (and/or/xor (load x), cst)) -> + // (and/or/xor (sextload x), (sext cst)) + if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR || + N0.getOpcode() == ISD::XOR) && + isa<LoadSDNode>(N0.getOperand(0)) && + N0.getOperand(1).getOpcode() == ISD::Constant && + (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) { + LoadSDNode *LN00 = cast<LoadSDNode>(N0.getOperand(0)); + EVT MemVT = LN00->getMemoryVT(); + if (TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, MemVT) && + LN00->getExtensionType() != ISD::ZEXTLOAD && LN00->isUnindexed()) { + SmallVector<SDNode*, 4> SetCCs; + bool DoXform = ExtendUsesToFormExtLoad(VT, N0.getNode(), N0.getOperand(0), + ISD::SIGN_EXTEND, SetCCs, TLI); + if (DoXform) { + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, SDLoc(LN00), VT, + LN00->getChain(), LN00->getBasePtr(), + LN00->getMemoryVT(), + LN00->getMemOperand()); + APInt Mask = N0.getConstantOperandAPInt(1).sext(VT.getSizeInBits()); + SDValue And = DAG.getNode(N0.getOpcode(), DL, VT, + ExtLoad, DAG.getConstant(Mask, DL, VT)); + ExtendSetCCUses(SetCCs, N0.getOperand(0), ExtLoad, ISD::SIGN_EXTEND); + bool NoReplaceTruncAnd = !N0.hasOneUse(); + bool NoReplaceTrunc = SDValue(LN00, 0).hasOneUse(); + CombineTo(N, And); + // If N0 has multiple uses, change other uses as well. + if (NoReplaceTruncAnd) { + SDValue TruncAnd = + DAG.getNode(ISD::TRUNCATE, DL, N0.getValueType(), And); + CombineTo(N0.getNode(), TruncAnd); + } + if (NoReplaceTrunc) { + DAG.ReplaceAllUsesOfValueWith(SDValue(LN00, 1), ExtLoad.getValue(1)); + } else { + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(LN00), + LN00->getValueType(0), ExtLoad); + CombineTo(LN00, Trunc, ExtLoad.getValue(1)); + } + return SDValue(N,0); // Return N so it doesn't get rechecked! + } + } + } + + if (SDValue V = foldExtendedSignBitTest(N, DAG, LegalOperations)) + return V; + + if (N0.getOpcode() == ISD::SETCC) { + SDValue N00 = N0.getOperand(0); + SDValue N01 = N0.getOperand(1); + ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get(); + EVT N00VT = N00.getValueType(); + + // sext(setcc) -> sext_in_reg(vsetcc) for vectors. + // Only do this before legalize for now. + if (VT.isVector() && !LegalOperations && + TLI.getBooleanContents(N00VT) == + TargetLowering::ZeroOrNegativeOneBooleanContent) { + // On some architectures (such as SSE/NEON/etc) the SETCC result type is + // of the same size as the compared operands. Only optimize sext(setcc()) + // if this is the case. + EVT SVT = getSetCCResultType(N00VT); + + // If we already have the desired type, don't change it. + if (SVT != N0.getValueType()) { + // We know that the # elements of the results is the same as the + // # elements of the compare (and the # elements of the compare result + // for that matter). Check to see that they are the same size. If so, + // we know that the element size of the sext'd result matches the + // element size of the compare operands. + if (VT.getSizeInBits() == SVT.getSizeInBits()) + return DAG.getSetCC(DL, VT, N00, N01, CC); + + // If the desired elements are smaller or larger than the source + // elements, we can use a matching integer vector type and then + // truncate/sign extend. + EVT MatchingVecType = N00VT.changeVectorElementTypeToInteger(); + if (SVT == MatchingVecType) { + SDValue VsetCC = DAG.getSetCC(DL, MatchingVecType, N00, N01, CC); + return DAG.getSExtOrTrunc(VsetCC, DL, VT); + } + } + } + + // sext(setcc x, y, cc) -> (select (setcc x, y, cc), T, 0) + // Here, T can be 1 or -1, depending on the type of the setcc and + // getBooleanContents(). + unsigned SetCCWidth = N0.getScalarValueSizeInBits(); + + // To determine the "true" side of the select, we need to know the high bit + // of the value returned by the setcc if it evaluates to true. + // If the type of the setcc is i1, then the true case of the select is just + // sext(i1 1), that is, -1. + // If the type of the setcc is larger (say, i8) then the value of the high + // bit depends on getBooleanContents(), so ask TLI for a real "true" value + // of the appropriate width. + SDValue ExtTrueVal = (SetCCWidth == 1) + ? DAG.getAllOnesConstant(DL, VT) + : DAG.getBoolConstant(true, DL, VT, N00VT); + SDValue Zero = DAG.getConstant(0, DL, VT); + if (SDValue SCC = + SimplifySelectCC(DL, N00, N01, ExtTrueVal, Zero, CC, true)) + return SCC; + + if (!VT.isVector() && !TLI.convertSelectOfConstantsToMath(VT)) { + EVT SetCCVT = getSetCCResultType(N00VT); + // Don't do this transform for i1 because there's a select transform + // that would reverse it. + // TODO: We should not do this transform at all without a target hook + // because a sext is likely cheaper than a select? + if (SetCCVT.getScalarSizeInBits() != 1 && + (!LegalOperations || TLI.isOperationLegal(ISD::SETCC, N00VT))) { + SDValue SetCC = DAG.getSetCC(DL, SetCCVT, N00, N01, CC); + return DAG.getSelect(DL, VT, SetCC, ExtTrueVal, Zero); + } + } + } + + // fold (sext x) -> (zext x) if the sign bit is known zero. + if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) && + DAG.SignBitIsZero(N0)) + return DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0); + + if (SDValue NewVSel = matchVSelectOpSizesWithSetCC(N)) + return NewVSel; + + // Eliminate this sign extend by doing a negation in the destination type: + // sext i32 (0 - (zext i8 X to i32)) to i64 --> 0 - (zext i8 X to i64) + if (N0.getOpcode() == ISD::SUB && N0.hasOneUse() && + isNullOrNullSplat(N0.getOperand(0)) && + N0.getOperand(1).getOpcode() == ISD::ZERO_EXTEND && + TLI.isOperationLegalOrCustom(ISD::SUB, VT)) { + SDValue Zext = DAG.getZExtOrTrunc(N0.getOperand(1).getOperand(0), DL, VT); + return DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), Zext); + } + // Eliminate this sign extend by doing a decrement in the destination type: + // sext i32 ((zext i8 X to i32) + (-1)) to i64 --> (zext i8 X to i64) + (-1) + if (N0.getOpcode() == ISD::ADD && N0.hasOneUse() && + isAllOnesOrAllOnesSplat(N0.getOperand(1)) && + N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND && + TLI.isOperationLegalOrCustom(ISD::ADD, VT)) { + SDValue Zext = DAG.getZExtOrTrunc(N0.getOperand(0).getOperand(0), DL, VT); + return DAG.getNode(ISD::ADD, DL, VT, Zext, DAG.getAllOnesConstant(DL, VT)); + } + + // fold sext (not i1 X) -> add (zext i1 X), -1 + // TODO: This could be extended to handle bool vectors. + if (N0.getValueType() == MVT::i1 && isBitwiseNot(N0) && N0.hasOneUse() && + (!LegalOperations || (TLI.isOperationLegal(ISD::ZERO_EXTEND, VT) && + TLI.isOperationLegal(ISD::ADD, VT)))) { + // If we can eliminate the 'not', the sext form should be better + if (SDValue NewXor = visitXOR(N0.getNode())) { + // Returning N0 is a form of in-visit replacement that may have + // invalidated N0. + if (NewXor.getNode() == N0.getNode()) { + // Return SDValue here as the xor should have already been replaced in + // this sext. + return SDValue(); + } else { + // Return a new sext with the new xor. + return DAG.getNode(ISD::SIGN_EXTEND, DL, VT, NewXor); + } + } + + SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)); + return DAG.getNode(ISD::ADD, DL, VT, Zext, DAG.getAllOnesConstant(DL, VT)); + } + + return SDValue(); +} + +// isTruncateOf - If N is a truncate of some other value, return true, record +// the value being truncated in Op and which of Op's bits are zero/one in Known. +// This function computes KnownBits to avoid a duplicated call to +// computeKnownBits in the caller. +static bool isTruncateOf(SelectionDAG &DAG, SDValue N, SDValue &Op, + KnownBits &Known) { + if (N->getOpcode() == ISD::TRUNCATE) { + Op = N->getOperand(0); + Known = DAG.computeKnownBits(Op); + return true; + } + + if (N.getOpcode() != ISD::SETCC || + N.getValueType().getScalarType() != MVT::i1 || + cast<CondCodeSDNode>(N.getOperand(2))->get() != ISD::SETNE) + return false; + + SDValue Op0 = N->getOperand(0); + SDValue Op1 = N->getOperand(1); + assert(Op0.getValueType() == Op1.getValueType()); + + if (isNullOrNullSplat(Op0)) + Op = Op1; + else if (isNullOrNullSplat(Op1)) + Op = Op0; + else + return false; + + Known = DAG.computeKnownBits(Op); + + return (Known.Zero | 1).isAllOnesValue(); +} + +/// Given an extending node with a pop-count operand, if the target does not +/// support a pop-count in the narrow source type but does support it in the +/// destination type, widen the pop-count to the destination type. +static SDValue widenCtPop(SDNode *Extend, SelectionDAG &DAG) { + assert((Extend->getOpcode() == ISD::ZERO_EXTEND || + Extend->getOpcode() == ISD::ANY_EXTEND) && "Expected extend op"); + + SDValue CtPop = Extend->getOperand(0); + if (CtPop.getOpcode() != ISD::CTPOP || !CtPop.hasOneUse()) + return SDValue(); + + EVT VT = Extend->getValueType(0); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + if (TLI.isOperationLegalOrCustom(ISD::CTPOP, CtPop.getValueType()) || + !TLI.isOperationLegalOrCustom(ISD::CTPOP, VT)) + return SDValue(); + + // zext (ctpop X) --> ctpop (zext X) + SDLoc DL(Extend); + SDValue NewZext = DAG.getZExtOrTrunc(CtPop.getOperand(0), DL, VT); + return DAG.getNode(ISD::CTPOP, DL, VT, NewZext); +} + +SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes)) + return Res; + + // fold (zext (zext x)) -> (zext x) + // fold (zext (aext x)) -> (zext x) + if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) + return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N), VT, + N0.getOperand(0)); + + // fold (zext (truncate x)) -> (zext x) or + // (zext (truncate x)) -> (truncate x) + // This is valid when the truncated bits of x are already zero. + SDValue Op; + KnownBits Known; + if (isTruncateOf(DAG, N0, Op, Known)) { + APInt TruncatedBits = + (Op.getScalarValueSizeInBits() == N0.getScalarValueSizeInBits()) ? + APInt(Op.getScalarValueSizeInBits(), 0) : + APInt::getBitsSet(Op.getScalarValueSizeInBits(), + N0.getScalarValueSizeInBits(), + std::min(Op.getScalarValueSizeInBits(), + VT.getScalarSizeInBits())); + if (TruncatedBits.isSubsetOf(Known.Zero)) + return DAG.getZExtOrTrunc(Op, SDLoc(N), VT); + } + + // fold (zext (truncate x)) -> (and x, mask) + if (N0.getOpcode() == ISD::TRUNCATE) { + // fold (zext (truncate (load x))) -> (zext (smaller load x)) + // fold (zext (truncate (srl (load x), c))) -> (zext (smaller load (x+c/n))) + if (SDValue NarrowLoad = ReduceLoadWidth(N0.getNode())) { + SDNode *oye = N0.getOperand(0).getNode(); + if (NarrowLoad.getNode() != N0.getNode()) { + CombineTo(N0.getNode(), NarrowLoad); + // CombineTo deleted the truncate, if needed, but not what's under it. + AddToWorklist(oye); + } + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + + EVT SrcVT = N0.getOperand(0).getValueType(); + EVT MinVT = N0.getValueType(); + + // Try to mask before the extension to avoid having to generate a larger mask, + // possibly over several sub-vectors. + if (SrcVT.bitsLT(VT) && VT.isVector()) { + if (!LegalOperations || (TLI.isOperationLegal(ISD::AND, SrcVT) && + TLI.isOperationLegal(ISD::ZERO_EXTEND, VT))) { + SDValue Op = N0.getOperand(0); + Op = DAG.getZeroExtendInReg(Op, SDLoc(N), MinVT); + AddToWorklist(Op.getNode()); + SDValue ZExtOrTrunc = DAG.getZExtOrTrunc(Op, SDLoc(N), VT); + // Transfer the debug info; the new node is equivalent to N0. + DAG.transferDbgValues(N0, ZExtOrTrunc); + return ZExtOrTrunc; + } + } + + if (!LegalOperations || TLI.isOperationLegal(ISD::AND, VT)) { + SDValue Op = DAG.getAnyExtOrTrunc(N0.getOperand(0), SDLoc(N), VT); + AddToWorklist(Op.getNode()); + SDValue And = DAG.getZeroExtendInReg(Op, SDLoc(N), MinVT); + // We may safely transfer the debug info describing the truncate node over + // to the equivalent and operation. + DAG.transferDbgValues(N0, And); + return And; + } + } + + // Fold (zext (and (trunc x), cst)) -> (and x, cst), + // if either of the casts is not free. + if (N0.getOpcode() == ISD::AND && + N0.getOperand(0).getOpcode() == ISD::TRUNCATE && + N0.getOperand(1).getOpcode() == ISD::Constant && + (!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), + N0.getValueType()) || + !TLI.isZExtFree(N0.getValueType(), VT))) { + SDValue X = N0.getOperand(0).getOperand(0); + X = DAG.getAnyExtOrTrunc(X, SDLoc(X), VT); + APInt Mask = N0.getConstantOperandAPInt(1).zext(VT.getSizeInBits()); + SDLoc DL(N); + return DAG.getNode(ISD::AND, DL, VT, + X, DAG.getConstant(Mask, DL, VT)); + } + + // Try to simplify (zext (load x)). + if (SDValue foldedExt = + tryToFoldExtOfLoad(DAG, *this, TLI, VT, LegalOperations, N, N0, + ISD::ZEXTLOAD, ISD::ZERO_EXTEND)) + return foldedExt; + + if (SDValue foldedExt = + tryToFoldExtOfMaskedLoad(DAG, TLI, VT, N, N0, ISD::ZEXTLOAD, + ISD::ZERO_EXTEND)) + return foldedExt; + + // fold (zext (load x)) to multiple smaller zextloads. + // Only on illegal but splittable vectors. + if (SDValue ExtLoad = CombineExtLoad(N)) + return ExtLoad; + + // fold (zext (and/or/xor (load x), cst)) -> + // (and/or/xor (zextload x), (zext cst)) + // Unless (and (load x) cst) will match as a zextload already and has + // additional users. + if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR || + N0.getOpcode() == ISD::XOR) && + isa<LoadSDNode>(N0.getOperand(0)) && + N0.getOperand(1).getOpcode() == ISD::Constant && + (!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) { + LoadSDNode *LN00 = cast<LoadSDNode>(N0.getOperand(0)); + EVT MemVT = LN00->getMemoryVT(); + if (TLI.isLoadExtLegal(ISD::ZEXTLOAD, VT, MemVT) && + LN00->getExtensionType() != ISD::SEXTLOAD && LN00->isUnindexed()) { + bool DoXform = true; + SmallVector<SDNode*, 4> SetCCs; + if (!N0.hasOneUse()) { + if (N0.getOpcode() == ISD::AND) { + auto *AndC = cast<ConstantSDNode>(N0.getOperand(1)); + EVT LoadResultTy = AndC->getValueType(0); + EVT ExtVT; + if (isAndLoadExtLoad(AndC, LN00, LoadResultTy, ExtVT)) + DoXform = false; + } + } + if (DoXform) + DoXform = ExtendUsesToFormExtLoad(VT, N0.getNode(), N0.getOperand(0), + ISD::ZERO_EXTEND, SetCCs, TLI); + if (DoXform) { + SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, SDLoc(LN00), VT, + LN00->getChain(), LN00->getBasePtr(), + LN00->getMemoryVT(), + LN00->getMemOperand()); + APInt Mask = N0.getConstantOperandAPInt(1).zext(VT.getSizeInBits()); + SDLoc DL(N); + SDValue And = DAG.getNode(N0.getOpcode(), DL, VT, + ExtLoad, DAG.getConstant(Mask, DL, VT)); + ExtendSetCCUses(SetCCs, N0.getOperand(0), ExtLoad, ISD::ZERO_EXTEND); + bool NoReplaceTruncAnd = !N0.hasOneUse(); + bool NoReplaceTrunc = SDValue(LN00, 0).hasOneUse(); + CombineTo(N, And); + // If N0 has multiple uses, change other uses as well. + if (NoReplaceTruncAnd) { + SDValue TruncAnd = + DAG.getNode(ISD::TRUNCATE, DL, N0.getValueType(), And); + CombineTo(N0.getNode(), TruncAnd); + } + if (NoReplaceTrunc) { + DAG.ReplaceAllUsesOfValueWith(SDValue(LN00, 1), ExtLoad.getValue(1)); + } else { + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(LN00), + LN00->getValueType(0), ExtLoad); + CombineTo(LN00, Trunc, ExtLoad.getValue(1)); + } + return SDValue(N,0); // Return N so it doesn't get rechecked! + } + } + } + + // fold (zext (and/or/xor (shl/shr (load x), cst), cst)) -> + // (and/or/xor (shl/shr (zextload x), (zext cst)), (zext cst)) + if (SDValue ZExtLoad = CombineZExtLogicopShiftLoad(N)) + return ZExtLoad; + + // Try to simplify (zext (zextload x)). + if (SDValue foldedExt = tryToFoldExtOfExtload( + DAG, *this, TLI, VT, LegalOperations, N, N0, ISD::ZEXTLOAD)) + return foldedExt; + + if (SDValue V = foldExtendedSignBitTest(N, DAG, LegalOperations)) + return V; + + if (N0.getOpcode() == ISD::SETCC) { + // Only do this before legalize for now. + if (!LegalOperations && VT.isVector() && + N0.getValueType().getVectorElementType() == MVT::i1) { + EVT N00VT = N0.getOperand(0).getValueType(); + if (getSetCCResultType(N00VT) == N0.getValueType()) + return SDValue(); + + // We know that the # elements of the results is the same as the # + // elements of the compare (and the # elements of the compare result for + // that matter). Check to see that they are the same size. If so, we know + // that the element size of the sext'd result matches the element size of + // the compare operands. + SDLoc DL(N); + if (VT.getSizeInBits() == N00VT.getSizeInBits()) { + // zext(setcc) -> zext_in_reg(vsetcc) for vectors. + SDValue VSetCC = DAG.getNode(ISD::SETCC, DL, VT, N0.getOperand(0), + N0.getOperand(1), N0.getOperand(2)); + return DAG.getZeroExtendInReg(VSetCC, DL, N0.getValueType()); + } + + // If the desired elements are smaller or larger than the source + // elements we can use a matching integer vector type and then + // truncate/any extend followed by zext_in_reg. + EVT MatchingVectorType = N00VT.changeVectorElementTypeToInteger(); + SDValue VsetCC = + DAG.getNode(ISD::SETCC, DL, MatchingVectorType, N0.getOperand(0), + N0.getOperand(1), N0.getOperand(2)); + return DAG.getZeroExtendInReg(DAG.getAnyExtOrTrunc(VsetCC, DL, VT), DL, + N0.getValueType()); + } + + // zext(setcc x,y,cc) -> zext(select x, y, true, false, cc) + SDLoc DL(N); + EVT N0VT = N0.getValueType(); + EVT N00VT = N0.getOperand(0).getValueType(); + if (SDValue SCC = SimplifySelectCC( + DL, N0.getOperand(0), N0.getOperand(1), + DAG.getBoolConstant(true, DL, N0VT, N00VT), + DAG.getBoolConstant(false, DL, N0VT, N00VT), + cast<CondCodeSDNode>(N0.getOperand(2))->get(), true)) + return DAG.getNode(ISD::ZERO_EXTEND, DL, VT, SCC); + } + + // (zext (shl (zext x), cst)) -> (shl (zext x), cst) + if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL) && + isa<ConstantSDNode>(N0.getOperand(1)) && + N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND && + N0.hasOneUse()) { + SDValue ShAmt = N0.getOperand(1); + if (N0.getOpcode() == ISD::SHL) { + SDValue InnerZExt = N0.getOperand(0); + // If the original shl may be shifting out bits, do not perform this + // transformation. + unsigned KnownZeroBits = InnerZExt.getValueSizeInBits() - + InnerZExt.getOperand(0).getValueSizeInBits(); + if (cast<ConstantSDNode>(ShAmt)->getAPIntValue().ugt(KnownZeroBits)) + return SDValue(); + } + + SDLoc DL(N); + + // Ensure that the shift amount is wide enough for the shifted value. + if (Log2_32_Ceil(VT.getSizeInBits()) > ShAmt.getValueSizeInBits()) + ShAmt = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, ShAmt); + + return DAG.getNode(N0.getOpcode(), DL, VT, + DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)), + ShAmt); + } + + if (SDValue NewVSel = matchVSelectOpSizesWithSetCC(N)) + return NewVSel; + + if (SDValue NewCtPop = widenCtPop(N, DAG)) + return NewCtPop; + + return SDValue(); +} + +SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes)) + return Res; + + // fold (aext (aext x)) -> (aext x) + // fold (aext (zext x)) -> (zext x) + // fold (aext (sext x)) -> (sext x) + if (N0.getOpcode() == ISD::ANY_EXTEND || + N0.getOpcode() == ISD::ZERO_EXTEND || + N0.getOpcode() == ISD::SIGN_EXTEND) + return DAG.getNode(N0.getOpcode(), SDLoc(N), VT, N0.getOperand(0)); + + // fold (aext (truncate (load x))) -> (aext (smaller load x)) + // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n))) + if (N0.getOpcode() == ISD::TRUNCATE) { + if (SDValue NarrowLoad = ReduceLoadWidth(N0.getNode())) { + SDNode *oye = N0.getOperand(0).getNode(); + if (NarrowLoad.getNode() != N0.getNode()) { + CombineTo(N0.getNode(), NarrowLoad); + // CombineTo deleted the truncate, if needed, but not what's under it. + AddToWorklist(oye); + } + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // fold (aext (truncate x)) + if (N0.getOpcode() == ISD::TRUNCATE) + return DAG.getAnyExtOrTrunc(N0.getOperand(0), SDLoc(N), VT); + + // Fold (aext (and (trunc x), cst)) -> (and x, cst) + // if the trunc is not free. + if (N0.getOpcode() == ISD::AND && + N0.getOperand(0).getOpcode() == ISD::TRUNCATE && + N0.getOperand(1).getOpcode() == ISD::Constant && + !TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(), + N0.getValueType())) { + SDLoc DL(N); + SDValue X = N0.getOperand(0).getOperand(0); + X = DAG.getAnyExtOrTrunc(X, DL, VT); + APInt Mask = N0.getConstantOperandAPInt(1).zext(VT.getSizeInBits()); + return DAG.getNode(ISD::AND, DL, VT, + X, DAG.getConstant(Mask, DL, VT)); + } + + // fold (aext (load x)) -> (aext (truncate (extload x))) + // None of the supported targets knows how to perform load and any_ext + // on vectors in one instruction, so attempt to fold to zext instead. + if (VT.isVector()) { + // Try to simplify (zext (load x)). + if (SDValue foldedExt = + tryToFoldExtOfLoad(DAG, *this, TLI, VT, LegalOperations, N, N0, + ISD::ZEXTLOAD, ISD::ZERO_EXTEND)) + return foldedExt; + } else if (ISD::isNON_EXTLoad(N0.getNode()) && + ISD::isUNINDEXEDLoad(N0.getNode()) && + TLI.isLoadExtLegal(ISD::EXTLOAD, VT, N0.getValueType())) { + bool DoXform = true; + SmallVector<SDNode *, 4> SetCCs; + if (!N0.hasOneUse()) + DoXform = + ExtendUsesToFormExtLoad(VT, N, N0, ISD::ANY_EXTEND, SetCCs, TLI); + if (DoXform) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, SDLoc(N), VT, + LN0->getChain(), LN0->getBasePtr(), + N0.getValueType(), LN0->getMemOperand()); + ExtendSetCCUses(SetCCs, N0, ExtLoad, ISD::ANY_EXTEND); + // If the load value is used only by N, replace it via CombineTo N. + bool NoReplaceTrunc = N0.hasOneUse(); + CombineTo(N, ExtLoad); + if (NoReplaceTrunc) { + DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1)); + recursivelyDeleteUnusedNodes(LN0); + } else { + SDValue Trunc = + DAG.getNode(ISD::TRUNCATE, SDLoc(N0), N0.getValueType(), ExtLoad); + CombineTo(LN0, Trunc, ExtLoad.getValue(1)); + } + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // fold (aext (zextload x)) -> (aext (truncate (zextload x))) + // fold (aext (sextload x)) -> (aext (truncate (sextload x))) + // fold (aext ( extload x)) -> (aext (truncate (extload x))) + if (N0.getOpcode() == ISD::LOAD && !ISD::isNON_EXTLoad(N0.getNode()) && + ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + ISD::LoadExtType ExtType = LN0->getExtensionType(); + EVT MemVT = LN0->getMemoryVT(); + if (!LegalOperations || TLI.isLoadExtLegal(ExtType, VT, MemVT)) { + SDValue ExtLoad = DAG.getExtLoad(ExtType, SDLoc(N), + VT, LN0->getChain(), LN0->getBasePtr(), + MemVT, LN0->getMemOperand()); + CombineTo(N, ExtLoad); + DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1)); + recursivelyDeleteUnusedNodes(LN0); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + if (N0.getOpcode() == ISD::SETCC) { + // For vectors: + // aext(setcc) -> vsetcc + // aext(setcc) -> truncate(vsetcc) + // aext(setcc) -> aext(vsetcc) + // Only do this before legalize for now. + if (VT.isVector() && !LegalOperations) { + EVT N00VT = N0.getOperand(0).getValueType(); + if (getSetCCResultType(N00VT) == N0.getValueType()) + return SDValue(); + + // We know that the # elements of the results is the same as the + // # elements of the compare (and the # elements of the compare result + // for that matter). Check to see that they are the same size. If so, + // we know that the element size of the sext'd result matches the + // element size of the compare operands. + if (VT.getSizeInBits() == N00VT.getSizeInBits()) + return DAG.getSetCC(SDLoc(N), VT, N0.getOperand(0), + N0.getOperand(1), + cast<CondCodeSDNode>(N0.getOperand(2))->get()); + + // If the desired elements are smaller or larger than the source + // elements we can use a matching integer vector type and then + // truncate/any extend + EVT MatchingVectorType = N00VT.changeVectorElementTypeToInteger(); + SDValue VsetCC = + DAG.getSetCC(SDLoc(N), MatchingVectorType, N0.getOperand(0), + N0.getOperand(1), + cast<CondCodeSDNode>(N0.getOperand(2))->get()); + return DAG.getAnyExtOrTrunc(VsetCC, SDLoc(N), VT); + } + + // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc + SDLoc DL(N); + if (SDValue SCC = SimplifySelectCC( + DL, N0.getOperand(0), N0.getOperand(1), DAG.getConstant(1, DL, VT), + DAG.getConstant(0, DL, VT), + cast<CondCodeSDNode>(N0.getOperand(2))->get(), true)) + return SCC; + } + + if (SDValue NewCtPop = widenCtPop(N, DAG)) + return NewCtPop; + + return SDValue(); +} + +SDValue DAGCombiner::visitAssertExt(SDNode *N) { + unsigned Opcode = N->getOpcode(); + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT AssertVT = cast<VTSDNode>(N1)->getVT(); + + // fold (assert?ext (assert?ext x, vt), vt) -> (assert?ext x, vt) + if (N0.getOpcode() == Opcode && + AssertVT == cast<VTSDNode>(N0.getOperand(1))->getVT()) + return N0; + + if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() && + N0.getOperand(0).getOpcode() == Opcode) { + // We have an assert, truncate, assert sandwich. Make one stronger assert + // by asserting on the smallest asserted type to the larger source type. + // This eliminates the later assert: + // assert (trunc (assert X, i8) to iN), i1 --> trunc (assert X, i1) to iN + // assert (trunc (assert X, i1) to iN), i8 --> trunc (assert X, i1) to iN + SDValue BigA = N0.getOperand(0); + EVT BigA_AssertVT = cast<VTSDNode>(BigA.getOperand(1))->getVT(); + assert(BigA_AssertVT.bitsLE(N0.getValueType()) && + "Asserting zero/sign-extended bits to a type larger than the " + "truncated destination does not provide information"); + + SDLoc DL(N); + EVT MinAssertVT = AssertVT.bitsLT(BigA_AssertVT) ? AssertVT : BigA_AssertVT; + SDValue MinAssertVTVal = DAG.getValueType(MinAssertVT); + SDValue NewAssert = DAG.getNode(Opcode, DL, BigA.getValueType(), + BigA.getOperand(0), MinAssertVTVal); + return DAG.getNode(ISD::TRUNCATE, DL, N->getValueType(0), NewAssert); + } + + // If we have (AssertZext (truncate (AssertSext X, iX)), iY) and Y is smaller + // than X. Just move the AssertZext in front of the truncate and drop the + // AssertSExt. + if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() && + N0.getOperand(0).getOpcode() == ISD::AssertSext && + Opcode == ISD::AssertZext) { + SDValue BigA = N0.getOperand(0); + EVT BigA_AssertVT = cast<VTSDNode>(BigA.getOperand(1))->getVT(); + assert(BigA_AssertVT.bitsLE(N0.getValueType()) && + "Asserting zero/sign-extended bits to a type larger than the " + "truncated destination does not provide information"); + + if (AssertVT.bitsLT(BigA_AssertVT)) { + SDLoc DL(N); + SDValue NewAssert = DAG.getNode(Opcode, DL, BigA.getValueType(), + BigA.getOperand(0), N1); + return DAG.getNode(ISD::TRUNCATE, DL, N->getValueType(0), NewAssert); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitAssertAlign(SDNode *N) { + SDLoc DL(N); + + Align AL = cast<AssertAlignSDNode>(N)->getAlign(); + SDValue N0 = N->getOperand(0); + + // Fold (assertalign (assertalign x, AL0), AL1) -> + // (assertalign x, max(AL0, AL1)) + if (auto *AAN = dyn_cast<AssertAlignSDNode>(N0)) + return DAG.getAssertAlign(DL, N0.getOperand(0), + std::max(AL, AAN->getAlign())); + + // In rare cases, there are trivial arithmetic ops in source operands. Sink + // this assert down to source operands so that those arithmetic ops could be + // exposed to the DAG combining. + switch (N0.getOpcode()) { + default: + break; + case ISD::ADD: + case ISD::SUB: { + unsigned AlignShift = Log2(AL); + SDValue LHS = N0.getOperand(0); + SDValue RHS = N0.getOperand(1); + unsigned LHSAlignShift = DAG.computeKnownBits(LHS).countMinTrailingZeros(); + unsigned RHSAlignShift = DAG.computeKnownBits(RHS).countMinTrailingZeros(); + if (LHSAlignShift >= AlignShift || RHSAlignShift >= AlignShift) { + if (LHSAlignShift < AlignShift) + LHS = DAG.getAssertAlign(DL, LHS, AL); + if (RHSAlignShift < AlignShift) + RHS = DAG.getAssertAlign(DL, RHS, AL); + return DAG.getNode(N0.getOpcode(), DL, N0.getValueType(), LHS, RHS); + } + break; + } + } + + return SDValue(); +} + +/// If the result of a wider load is shifted to right of N bits and then +/// truncated to a narrower type and where N is a multiple of number of bits of +/// the narrower type, transform it to a narrower load from address + N / num of +/// bits of new type. Also narrow the load if the result is masked with an AND +/// to effectively produce a smaller type. If the result is to be extended, also +/// fold the extension to form a extending load. +SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) { + unsigned Opc = N->getOpcode(); + + ISD::LoadExtType ExtType = ISD::NON_EXTLOAD; + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + EVT ExtVT = VT; + + // This transformation isn't valid for vector loads. + if (VT.isVector()) + return SDValue(); + + unsigned ShAmt = 0; + bool HasShiftedOffset = false; + // Special case: SIGN_EXTEND_INREG is basically truncating to ExtVT then + // extended to VT. + if (Opc == ISD::SIGN_EXTEND_INREG) { + ExtType = ISD::SEXTLOAD; + ExtVT = cast<VTSDNode>(N->getOperand(1))->getVT(); + } else if (Opc == ISD::SRL) { + // Another special-case: SRL is basically zero-extending a narrower value, + // or it maybe shifting a higher subword, half or byte into the lowest + // bits. + ExtType = ISD::ZEXTLOAD; + N0 = SDValue(N, 0); + + auto *LN0 = dyn_cast<LoadSDNode>(N0.getOperand(0)); + auto *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1)); + if (!N01 || !LN0) + return SDValue(); + + uint64_t ShiftAmt = N01->getZExtValue(); + uint64_t MemoryWidth = LN0->getMemoryVT().getScalarSizeInBits(); + if (LN0->getExtensionType() != ISD::SEXTLOAD && MemoryWidth > ShiftAmt) + ExtVT = EVT::getIntegerVT(*DAG.getContext(), MemoryWidth - ShiftAmt); + else + ExtVT = EVT::getIntegerVT(*DAG.getContext(), + VT.getScalarSizeInBits() - ShiftAmt); + } else if (Opc == ISD::AND) { + // An AND with a constant mask is the same as a truncate + zero-extend. + auto AndC = dyn_cast<ConstantSDNode>(N->getOperand(1)); + if (!AndC) + return SDValue(); + + const APInt &Mask = AndC->getAPIntValue(); + unsigned ActiveBits = 0; + if (Mask.isMask()) { + ActiveBits = Mask.countTrailingOnes(); + } else if (Mask.isShiftedMask()) { + ShAmt = Mask.countTrailingZeros(); + APInt ShiftedMask = Mask.lshr(ShAmt); + ActiveBits = ShiftedMask.countTrailingOnes(); + HasShiftedOffset = true; + } else + return SDValue(); + + ExtType = ISD::ZEXTLOAD; + ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits); + } + + if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) { + SDValue SRL = N0; + if (auto *ConstShift = dyn_cast<ConstantSDNode>(SRL.getOperand(1))) { + ShAmt = ConstShift->getZExtValue(); + unsigned EVTBits = ExtVT.getScalarSizeInBits(); + // Is the shift amount a multiple of size of VT? + if ((ShAmt & (EVTBits-1)) == 0) { + N0 = N0.getOperand(0); + // Is the load width a multiple of size of VT? + if ((N0.getScalarValueSizeInBits() & (EVTBits - 1)) != 0) + return SDValue(); + } + + // At this point, we must have a load or else we can't do the transform. + auto *LN0 = dyn_cast<LoadSDNode>(N0); + if (!LN0) return SDValue(); + + // Because a SRL must be assumed to *need* to zero-extend the high bits + // (as opposed to anyext the high bits), we can't combine the zextload + // lowering of SRL and an sextload. + if (LN0->getExtensionType() == ISD::SEXTLOAD) + return SDValue(); + + // If the shift amount is larger than the input type then we're not + // accessing any of the loaded bytes. If the load was a zextload/extload + // then the result of the shift+trunc is zero/undef (handled elsewhere). + if (ShAmt >= LN0->getMemoryVT().getSizeInBits()) + return SDValue(); + + // If the SRL is only used by a masking AND, we may be able to adjust + // the ExtVT to make the AND redundant. + SDNode *Mask = *(SRL->use_begin()); + if (Mask->getOpcode() == ISD::AND && + isa<ConstantSDNode>(Mask->getOperand(1))) { + const APInt& ShiftMask = Mask->getConstantOperandAPInt(1); + if (ShiftMask.isMask()) { + EVT MaskedVT = EVT::getIntegerVT(*DAG.getContext(), + ShiftMask.countTrailingOnes()); + // If the mask is smaller, recompute the type. + if ((ExtVT.getScalarSizeInBits() > MaskedVT.getScalarSizeInBits()) && + TLI.isLoadExtLegal(ExtType, N0.getValueType(), MaskedVT)) + ExtVT = MaskedVT; + } + } + } + } + + // If the load is shifted left (and the result isn't shifted back right), + // we can fold the truncate through the shift. + unsigned ShLeftAmt = 0; + if (ShAmt == 0 && N0.getOpcode() == ISD::SHL && N0.hasOneUse() && + ExtVT == VT && TLI.isNarrowingProfitable(N0.getValueType(), VT)) { + if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { + ShLeftAmt = N01->getZExtValue(); + N0 = N0.getOperand(0); + } + } + + // If we haven't found a load, we can't narrow it. + if (!isa<LoadSDNode>(N0)) + return SDValue(); + + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + // Reducing the width of a volatile load is illegal. For atomics, we may be + // able to reduce the width provided we never widen again. (see D66309) + if (!LN0->isSimple() || + !isLegalNarrowLdSt(LN0, ExtType, ExtVT, ShAmt)) + return SDValue(); + + auto AdjustBigEndianShift = [&](unsigned ShAmt) { + unsigned LVTStoreBits = + LN0->getMemoryVT().getStoreSizeInBits().getFixedSize(); + unsigned EVTStoreBits = ExtVT.getStoreSizeInBits().getFixedSize(); + return LVTStoreBits - EVTStoreBits - ShAmt; + }; + + // For big endian targets, we need to adjust the offset to the pointer to + // load the correct bytes. + if (DAG.getDataLayout().isBigEndian()) + ShAmt = AdjustBigEndianShift(ShAmt); + + uint64_t PtrOff = ShAmt / 8; + Align NewAlign = commonAlignment(LN0->getAlign(), PtrOff); + SDLoc DL(LN0); + // The original load itself didn't wrap, so an offset within it doesn't. + SDNodeFlags Flags; + Flags.setNoUnsignedWrap(true); + SDValue NewPtr = DAG.getMemBasePlusOffset(LN0->getBasePtr(), + TypeSize::Fixed(PtrOff), DL, Flags); + AddToWorklist(NewPtr.getNode()); + + SDValue Load; + if (ExtType == ISD::NON_EXTLOAD) + Load = DAG.getLoad(VT, DL, LN0->getChain(), NewPtr, + LN0->getPointerInfo().getWithOffset(PtrOff), NewAlign, + LN0->getMemOperand()->getFlags(), LN0->getAAInfo()); + else + Load = DAG.getExtLoad(ExtType, DL, VT, LN0->getChain(), NewPtr, + LN0->getPointerInfo().getWithOffset(PtrOff), ExtVT, + NewAlign, LN0->getMemOperand()->getFlags(), + LN0->getAAInfo()); + + // Replace the old load's chain with the new load's chain. + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1)); + + // Shift the result left, if we've swallowed a left shift. + SDValue Result = Load; + if (ShLeftAmt != 0) { + EVT ShImmTy = getShiftAmountTy(Result.getValueType()); + if (!isUIntN(ShImmTy.getScalarSizeInBits(), ShLeftAmt)) + ShImmTy = VT; + // If the shift amount is as large as the result size (but, presumably, + // no larger than the source) then the useful bits of the result are + // zero; we can't simply return the shortened shift, because the result + // of that operation is undefined. + if (ShLeftAmt >= VT.getScalarSizeInBits()) + Result = DAG.getConstant(0, DL, VT); + else + Result = DAG.getNode(ISD::SHL, DL, VT, + Result, DAG.getConstant(ShLeftAmt, DL, ShImmTy)); + } + + if (HasShiftedOffset) { + // Recalculate the shift amount after it has been altered to calculate + // the offset. + if (DAG.getDataLayout().isBigEndian()) + ShAmt = AdjustBigEndianShift(ShAmt); + + // We're using a shifted mask, so the load now has an offset. This means + // that data has been loaded into the lower bytes than it would have been + // before, so we need to shl the loaded data into the correct position in the + // register. + SDValue ShiftC = DAG.getConstant(ShAmt, DL, VT); + Result = DAG.getNode(ISD::SHL, DL, VT, Result, ShiftC); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result); + } + + // Return the new loaded value. + return Result; +} + +SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + EVT ExtVT = cast<VTSDNode>(N1)->getVT(); + unsigned VTBits = VT.getScalarSizeInBits(); + unsigned ExtVTBits = ExtVT.getScalarSizeInBits(); + + // sext_vector_inreg(undef) = 0 because the top bit will all be the same. + if (N0.isUndef()) + return DAG.getConstant(0, SDLoc(N), VT); + + // fold (sext_in_reg c1) -> c1 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) + return DAG.getNode(ISD::SIGN_EXTEND_INREG, SDLoc(N), VT, N0, N1); + + // If the input is already sign extended, just drop the extension. + if (DAG.ComputeNumSignBits(N0) >= (VTBits - ExtVTBits + 1)) + return N0; + + // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 + if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && + ExtVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) + return DAG.getNode(ISD::SIGN_EXTEND_INREG, SDLoc(N), VT, N0.getOperand(0), + N1); + + // fold (sext_in_reg (sext x)) -> (sext x) + // fold (sext_in_reg (aext x)) -> (sext x) + // if x is small enough or if we know that x has more than 1 sign bit and the + // sign_extend_inreg is extending from one of them. + if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) { + SDValue N00 = N0.getOperand(0); + unsigned N00Bits = N00.getScalarValueSizeInBits(); + if ((N00Bits <= ExtVTBits || + (N00Bits - DAG.ComputeNumSignBits(N00)) < ExtVTBits) && + (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND, VT))) + return DAG.getNode(ISD::SIGN_EXTEND, SDLoc(N), VT, N00); + } + + // fold (sext_in_reg (*_extend_vector_inreg x)) -> (sext_vector_inreg x) + if ((N0.getOpcode() == ISD::ANY_EXTEND_VECTOR_INREG || + N0.getOpcode() == ISD::SIGN_EXTEND_VECTOR_INREG || + N0.getOpcode() == ISD::ZERO_EXTEND_VECTOR_INREG) && + N0.getOperand(0).getScalarValueSizeInBits() == ExtVTBits) { + if (!LegalOperations || + TLI.isOperationLegal(ISD::SIGN_EXTEND_VECTOR_INREG, VT)) + return DAG.getNode(ISD::SIGN_EXTEND_VECTOR_INREG, SDLoc(N), VT, + N0.getOperand(0)); + } + + // fold (sext_in_reg (zext x)) -> (sext x) + // iff we are extending the source sign bit. + if (N0.getOpcode() == ISD::ZERO_EXTEND) { + SDValue N00 = N0.getOperand(0); + if (N00.getScalarValueSizeInBits() == ExtVTBits && + (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND, VT))) + return DAG.getNode(ISD::SIGN_EXTEND, SDLoc(N), VT, N00, N1); + } + + // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero. + if (DAG.MaskedValueIsZero(N0, APInt::getOneBitSet(VTBits, ExtVTBits - 1))) + return DAG.getZeroExtendInReg(N0, SDLoc(N), ExtVT); + + // fold operands of sext_in_reg based on knowledge that the top bits are not + // demanded. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // fold (sext_in_reg (load x)) -> (smaller sextload x) + // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits)) + if (SDValue NarrowLoad = ReduceLoadWidth(N)) + return NarrowLoad; + + // fold (sext_in_reg (srl X, 24), i8) -> (sra X, 24) + // fold (sext_in_reg (srl X, 23), i8) -> (sra X, 23) iff possible. + // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. + if (N0.getOpcode() == ISD::SRL) { + if (auto *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1))) + if (ShAmt->getAPIntValue().ule(VTBits - ExtVTBits)) { + // We can turn this into an SRA iff the input to the SRL is already sign + // extended enough. + unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0)); + if (((VTBits - ExtVTBits) - ShAmt->getZExtValue()) < InSignBits) + return DAG.getNode(ISD::SRA, SDLoc(N), VT, N0.getOperand(0), + N0.getOperand(1)); + } + } + + // fold (sext_inreg (extload x)) -> (sextload x) + // If sextload is not supported by target, we can only do the combine when + // load has one use. Doing otherwise can block folding the extload with other + // extends that the target does support. + if (ISD::isEXTLoad(N0.getNode()) && + ISD::isUNINDEXEDLoad(N0.getNode()) && + ExtVT == cast<LoadSDNode>(N0)->getMemoryVT() && + ((!LegalOperations && cast<LoadSDNode>(N0)->isSimple() && + N0.hasOneUse()) || + TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, ExtVT))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, SDLoc(N), VT, + LN0->getChain(), + LN0->getBasePtr(), ExtVT, + LN0->getMemOperand()); + CombineTo(N, ExtLoad); + CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); + AddToWorklist(ExtLoad.getNode()); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use + if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) && + N0.hasOneUse() && + ExtVT == cast<LoadSDNode>(N0)->getMemoryVT() && + ((!LegalOperations && cast<LoadSDNode>(N0)->isSimple()) && + TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, ExtVT))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, SDLoc(N), VT, + LN0->getChain(), + LN0->getBasePtr(), ExtVT, + LN0->getMemOperand()); + CombineTo(N, ExtLoad); + CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + + // fold (sext_inreg (masked_load x)) -> (sext_masked_load x) + // ignore it if the masked load is already sign extended + if (MaskedLoadSDNode *Ld = dyn_cast<MaskedLoadSDNode>(N0)) { + if (ExtVT == Ld->getMemoryVT() && N0.hasOneUse() && + Ld->getExtensionType() != ISD::LoadExtType::NON_EXTLOAD && + TLI.isLoadExtLegal(ISD::SEXTLOAD, VT, ExtVT)) { + SDValue ExtMaskedLoad = DAG.getMaskedLoad( + VT, SDLoc(N), Ld->getChain(), Ld->getBasePtr(), Ld->getOffset(), + Ld->getMask(), Ld->getPassThru(), ExtVT, Ld->getMemOperand(), + Ld->getAddressingMode(), ISD::SEXTLOAD, Ld->isExpandingLoad()); + CombineTo(N, ExtMaskedLoad); + CombineTo(N0.getNode(), ExtMaskedLoad, ExtMaskedLoad.getValue(1)); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // fold (sext_inreg (masked_gather x)) -> (sext_masked_gather x) + if (auto *GN0 = dyn_cast<MaskedGatherSDNode>(N0)) { + if (SDValue(GN0, 0).hasOneUse() && + ExtVT == GN0->getMemoryVT() && + TLI.isVectorLoadExtDesirable(SDValue(SDValue(GN0, 0)))) { + SDValue Ops[] = {GN0->getChain(), GN0->getPassThru(), GN0->getMask(), + GN0->getBasePtr(), GN0->getIndex(), GN0->getScale()}; + + SDValue ExtLoad = DAG.getMaskedGather( + DAG.getVTList(VT, MVT::Other), ExtVT, SDLoc(N), Ops, + GN0->getMemOperand(), GN0->getIndexType(), ISD::SEXTLOAD); + + CombineTo(N, ExtLoad); + CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1)); + AddToWorklist(ExtLoad.getNode()); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + + // Form (sext_inreg (bswap >> 16)) or (sext_inreg (rotl (bswap) 16)) + if (ExtVTBits <= 16 && N0.getOpcode() == ISD::OR) { + if (SDValue BSwap = MatchBSwapHWordLow(N0.getNode(), N0.getOperand(0), + N0.getOperand(1), false)) + return DAG.getNode(ISD::SIGN_EXTEND_INREG, SDLoc(N), VT, BSwap, N1); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitSIGN_EXTEND_VECTOR_INREG(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // sext_vector_inreg(undef) = 0 because the top bit will all be the same. + if (N0.isUndef()) + return DAG.getConstant(0, SDLoc(N), VT); + + if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes)) + return Res; + + if (SimplifyDemandedVectorElts(SDValue(N, 0))) + return SDValue(N, 0); + + return SDValue(); +} + +SDValue DAGCombiner::visitZERO_EXTEND_VECTOR_INREG(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // zext_vector_inreg(undef) = 0 because the top bits will be zero. + if (N0.isUndef()) + return DAG.getConstant(0, SDLoc(N), VT); + + if (SDValue Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes)) + return Res; + + if (SimplifyDemandedVectorElts(SDValue(N, 0))) + return SDValue(N, 0); + + return SDValue(); +} + +SDValue DAGCombiner::visitTRUNCATE(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + EVT SrcVT = N0.getValueType(); + bool isLE = DAG.getDataLayout().isLittleEndian(); + + // noop truncate + if (SrcVT == VT) + return N0; + + // fold (truncate (truncate x)) -> (truncate x) + if (N0.getOpcode() == ISD::TRUNCATE) + return DAG.getNode(ISD::TRUNCATE, SDLoc(N), VT, N0.getOperand(0)); + + // fold (truncate c1) -> c1 + if (DAG.isConstantIntBuildVectorOrConstantInt(N0)) { + SDValue C = DAG.getNode(ISD::TRUNCATE, SDLoc(N), VT, N0); + if (C.getNode() != N) + return C; + } + + // fold (truncate (ext x)) -> (ext x) or (truncate x) or x + if (N0.getOpcode() == ISD::ZERO_EXTEND || + N0.getOpcode() == ISD::SIGN_EXTEND || + N0.getOpcode() == ISD::ANY_EXTEND) { + // if the source is smaller than the dest, we still need an extend. + if (N0.getOperand(0).getValueType().bitsLT(VT)) + return DAG.getNode(N0.getOpcode(), SDLoc(N), VT, N0.getOperand(0)); + // if the source is larger than the dest, than we just need the truncate. + if (N0.getOperand(0).getValueType().bitsGT(VT)) + return DAG.getNode(ISD::TRUNCATE, SDLoc(N), VT, N0.getOperand(0)); + // if the source and dest are the same type, we can drop both the extend + // and the truncate. + return N0.getOperand(0); + } + + // If this is anyext(trunc), don't fold it, allow ourselves to be folded. + if (N->hasOneUse() && (N->use_begin()->getOpcode() == ISD::ANY_EXTEND)) + return SDValue(); + + // Fold extract-and-trunc into a narrow extract. For example: + // i64 x = EXTRACT_VECTOR_ELT(v2i64 val, i32 1) + // i32 y = TRUNCATE(i64 x) + // -- becomes -- + // v16i8 b = BITCAST (v2i64 val) + // i8 x = EXTRACT_VECTOR_ELT(v16i8 b, i32 8) + // + // Note: We only run this optimization after type legalization (which often + // creates this pattern) and before operation legalization after which + // we need to be more careful about the vector instructions that we generate. + if (N0.getOpcode() == ISD::EXTRACT_VECTOR_ELT && + LegalTypes && !LegalOperations && N0->hasOneUse() && VT != MVT::i1) { + EVT VecTy = N0.getOperand(0).getValueType(); + EVT ExTy = N0.getValueType(); + EVT TrTy = N->getValueType(0); + + auto EltCnt = VecTy.getVectorElementCount(); + unsigned SizeRatio = ExTy.getSizeInBits()/TrTy.getSizeInBits(); + auto NewEltCnt = EltCnt * SizeRatio; + + EVT NVT = EVT::getVectorVT(*DAG.getContext(), TrTy, NewEltCnt); + assert(NVT.getSizeInBits() == VecTy.getSizeInBits() && "Invalid Size"); + + SDValue EltNo = N0->getOperand(1); + if (isa<ConstantSDNode>(EltNo) && isTypeLegal(NVT)) { + int Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); + int Index = isLE ? (Elt*SizeRatio) : (Elt*SizeRatio + (SizeRatio-1)); + + SDLoc DL(N); + return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, TrTy, + DAG.getBitcast(NVT, N0.getOperand(0)), + DAG.getVectorIdxConstant(Index, DL)); + } + } + + // trunc (select c, a, b) -> select c, (trunc a), (trunc b) + if (N0.getOpcode() == ISD::SELECT && N0.hasOneUse()) { + if ((!LegalOperations || TLI.isOperationLegal(ISD::SELECT, SrcVT)) && + TLI.isTruncateFree(SrcVT, VT)) { + SDLoc SL(N0); + SDValue Cond = N0.getOperand(0); + SDValue TruncOp0 = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(1)); + SDValue TruncOp1 = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(2)); + return DAG.getNode(ISD::SELECT, SDLoc(N), VT, Cond, TruncOp0, TruncOp1); + } + } + + // trunc (shl x, K) -> shl (trunc x), K => K < VT.getScalarSizeInBits() + if (N0.getOpcode() == ISD::SHL && N0.hasOneUse() && + (!LegalOperations || TLI.isOperationLegal(ISD::SHL, VT)) && + TLI.isTypeDesirableForOp(ISD::SHL, VT)) { + SDValue Amt = N0.getOperand(1); + KnownBits Known = DAG.computeKnownBits(Amt); + unsigned Size = VT.getScalarSizeInBits(); + if (Known.getBitWidth() - Known.countMinLeadingZeros() <= Log2_32(Size)) { + SDLoc SL(N); + EVT AmtVT = TLI.getShiftAmountTy(VT, DAG.getDataLayout()); + + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(0)); + if (AmtVT != Amt.getValueType()) { + Amt = DAG.getZExtOrTrunc(Amt, SL, AmtVT); + AddToWorklist(Amt.getNode()); + } + return DAG.getNode(ISD::SHL, SL, VT, Trunc, Amt); + } + } + + // Attempt to pre-truncate BUILD_VECTOR sources. + if (N0.getOpcode() == ISD::BUILD_VECTOR && !LegalOperations && + TLI.isTruncateFree(SrcVT.getScalarType(), VT.getScalarType()) && + // Avoid creating illegal types if running after type legalizer. + (!LegalTypes || TLI.isTypeLegal(VT.getScalarType()))) { + SDLoc DL(N); + EVT SVT = VT.getScalarType(); + SmallVector<SDValue, 8> TruncOps; + for (const SDValue &Op : N0->op_values()) { + SDValue TruncOp = DAG.getNode(ISD::TRUNCATE, DL, SVT, Op); + TruncOps.push_back(TruncOp); + } + return DAG.getBuildVector(VT, DL, TruncOps); + } + + // Fold a series of buildvector, bitcast, and truncate if possible. + // For example fold + // (2xi32 trunc (bitcast ((4xi32)buildvector x, x, y, y) 2xi64)) to + // (2xi32 (buildvector x, y)). + if (Level == AfterLegalizeVectorOps && VT.isVector() && + N0.getOpcode() == ISD::BITCAST && N0.hasOneUse() && + N0.getOperand(0).getOpcode() == ISD::BUILD_VECTOR && + N0.getOperand(0).hasOneUse()) { + SDValue BuildVect = N0.getOperand(0); + EVT BuildVectEltTy = BuildVect.getValueType().getVectorElementType(); + EVT TruncVecEltTy = VT.getVectorElementType(); + + // Check that the element types match. + if (BuildVectEltTy == TruncVecEltTy) { + // Now we only need to compute the offset of the truncated elements. + unsigned BuildVecNumElts = BuildVect.getNumOperands(); + unsigned TruncVecNumElts = VT.getVectorNumElements(); + unsigned TruncEltOffset = BuildVecNumElts / TruncVecNumElts; + + assert((BuildVecNumElts % TruncVecNumElts) == 0 && + "Invalid number of elements"); + + SmallVector<SDValue, 8> Opnds; + for (unsigned i = 0, e = BuildVecNumElts; i != e; i += TruncEltOffset) + Opnds.push_back(BuildVect.getOperand(i)); + + return DAG.getBuildVector(VT, SDLoc(N), Opnds); + } + } + + // See if we can simplify the input to this truncate through knowledge that + // only the low bits are being used. + // For example "trunc (or (shl x, 8), y)" // -> trunc y + // Currently we only perform this optimization on scalars because vectors + // may have different active low bits. + if (!VT.isVector()) { + APInt Mask = + APInt::getLowBitsSet(N0.getValueSizeInBits(), VT.getSizeInBits()); + if (SDValue Shorter = DAG.GetDemandedBits(N0, Mask)) + return DAG.getNode(ISD::TRUNCATE, SDLoc(N), VT, Shorter); + } + + // fold (truncate (load x)) -> (smaller load x) + // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) + if (!LegalTypes || TLI.isTypeDesirableForOp(N0.getOpcode(), VT)) { + if (SDValue Reduced = ReduceLoadWidth(N)) + return Reduced; + + // Handle the case where the load remains an extending load even + // after truncation. + if (N0.hasOneUse() && ISD::isUNINDEXEDLoad(N0.getNode())) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + if (LN0->isSimple() && LN0->getMemoryVT().bitsLT(VT)) { + SDValue NewLoad = DAG.getExtLoad(LN0->getExtensionType(), SDLoc(LN0), + VT, LN0->getChain(), LN0->getBasePtr(), + LN0->getMemoryVT(), + LN0->getMemOperand()); + DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLoad.getValue(1)); + return NewLoad; + } + } + } + + // fold (trunc (concat ... x ...)) -> (concat ..., (trunc x), ...)), + // where ... are all 'undef'. + if (N0.getOpcode() == ISD::CONCAT_VECTORS && !LegalTypes) { + SmallVector<EVT, 8> VTs; + SDValue V; + unsigned Idx = 0; + unsigned NumDefs = 0; + + for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) { + SDValue X = N0.getOperand(i); + if (!X.isUndef()) { + V = X; + Idx = i; + NumDefs++; + } + // Stop if more than one members are non-undef. + if (NumDefs > 1) + break; + + VTs.push_back(EVT::getVectorVT(*DAG.getContext(), + VT.getVectorElementType(), + X.getValueType().getVectorElementCount())); + } + + if (NumDefs == 0) + return DAG.getUNDEF(VT); + + if (NumDefs == 1) { + assert(V.getNode() && "The single defined operand is empty!"); + SmallVector<SDValue, 8> Opnds; + for (unsigned i = 0, e = VTs.size(); i != e; ++i) { + if (i != Idx) { + Opnds.push_back(DAG.getUNDEF(VTs[i])); + continue; + } + SDValue NV = DAG.getNode(ISD::TRUNCATE, SDLoc(V), VTs[i], V); + AddToWorklist(NV.getNode()); + Opnds.push_back(NV); + } + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, Opnds); + } + } + + // Fold truncate of a bitcast of a vector to an extract of the low vector + // element. + // + // e.g. trunc (i64 (bitcast v2i32:x)) -> extract_vector_elt v2i32:x, idx + if (N0.getOpcode() == ISD::BITCAST && !VT.isVector()) { + SDValue VecSrc = N0.getOperand(0); + EVT VecSrcVT = VecSrc.getValueType(); + if (VecSrcVT.isVector() && VecSrcVT.getScalarType() == VT && + (!LegalOperations || + TLI.isOperationLegal(ISD::EXTRACT_VECTOR_ELT, VecSrcVT))) { + SDLoc SL(N); + + unsigned Idx = isLE ? 0 : VecSrcVT.getVectorNumElements() - 1; + return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, VT, VecSrc, + DAG.getVectorIdxConstant(Idx, SL)); + } + } + + // Simplify the operands using demanded-bits information. + if (SimplifyDemandedBits(SDValue(N, 0))) + return SDValue(N, 0); + + // (trunc adde(X, Y, Carry)) -> (adde trunc(X), trunc(Y), Carry) + // (trunc addcarry(X, Y, Carry)) -> (addcarry trunc(X), trunc(Y), Carry) + // When the adde's carry is not used. + if ((N0.getOpcode() == ISD::ADDE || N0.getOpcode() == ISD::ADDCARRY) && + N0.hasOneUse() && !N0.getNode()->hasAnyUseOfValue(1) && + // We only do for addcarry before legalize operation + ((!LegalOperations && N0.getOpcode() == ISD::ADDCARRY) || + TLI.isOperationLegal(N0.getOpcode(), VT))) { + SDLoc SL(N); + auto X = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(0)); + auto Y = DAG.getNode(ISD::TRUNCATE, SL, VT, N0.getOperand(1)); + auto VTs = DAG.getVTList(VT, N0->getValueType(1)); + return DAG.getNode(N0.getOpcode(), SL, VTs, X, Y, N0.getOperand(2)); + } + + // fold (truncate (extract_subvector(ext x))) -> + // (extract_subvector x) + // TODO: This can be generalized to cover cases where the truncate and extract + // do not fully cancel each other out. + if (!LegalTypes && N0.getOpcode() == ISD::EXTRACT_SUBVECTOR) { + SDValue N00 = N0.getOperand(0); + if (N00.getOpcode() == ISD::SIGN_EXTEND || + N00.getOpcode() == ISD::ZERO_EXTEND || + N00.getOpcode() == ISD::ANY_EXTEND) { + if (N00.getOperand(0)->getValueType(0).getVectorElementType() == + VT.getVectorElementType()) + return DAG.getNode(ISD::EXTRACT_SUBVECTOR, SDLoc(N0->getOperand(0)), VT, + N00.getOperand(0), N0.getOperand(1)); + } + } + + if (SDValue NewVSel = matchVSelectOpSizesWithSetCC(N)) + return NewVSel; + + // Narrow a suitable binary operation with a non-opaque constant operand by + // moving it ahead of the truncate. This is limited to pre-legalization + // because targets may prefer a wider type during later combines and invert + // this transform. + switch (N0.getOpcode()) { + case ISD::ADD: + case ISD::SUB: + case ISD::MUL: + case ISD::AND: + case ISD::OR: + case ISD::XOR: + if (!LegalOperations && N0.hasOneUse() && + (isConstantOrConstantVector(N0.getOperand(0), true) || + isConstantOrConstantVector(N0.getOperand(1), true))) { + // TODO: We already restricted this to pre-legalization, but for vectors + // we are extra cautious to not create an unsupported operation. + // Target-specific changes are likely needed to avoid regressions here. + if (VT.isScalarInteger() || TLI.isOperationLegal(N0.getOpcode(), VT)) { + SDLoc DL(N); + SDValue NarrowL = DAG.getNode(ISD::TRUNCATE, DL, VT, N0.getOperand(0)); + SDValue NarrowR = DAG.getNode(ISD::TRUNCATE, DL, VT, N0.getOperand(1)); + return DAG.getNode(N0.getOpcode(), DL, VT, NarrowL, NarrowR); + } + } + } + + return SDValue(); +} + +static SDNode *getBuildPairElt(SDNode *N, unsigned i) { + SDValue Elt = N->getOperand(i); + if (Elt.getOpcode() != ISD::MERGE_VALUES) + return Elt.getNode(); + return Elt.getOperand(Elt.getResNo()).getNode(); +} + +/// build_pair (load, load) -> load +/// if load locations are consecutive. +SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) { + assert(N->getOpcode() == ISD::BUILD_PAIR); + + LoadSDNode *LD1 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 0)); + LoadSDNode *LD2 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 1)); + + // A BUILD_PAIR is always having the least significant part in elt 0 and the + // most significant part in elt 1. So when combining into one large load, we + // need to consider the endianness. + if (DAG.getDataLayout().isBigEndian()) + std::swap(LD1, LD2); + + if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse() || + LD1->getAddressSpace() != LD2->getAddressSpace()) + return SDValue(); + EVT LD1VT = LD1->getValueType(0); + unsigned LD1Bytes = LD1VT.getStoreSize(); + if (ISD::isNON_EXTLoad(LD2) && LD2->hasOneUse() && + DAG.areNonVolatileConsecutiveLoads(LD2, LD1, LD1Bytes, 1)) { + Align Alignment = LD1->getAlign(); + Align NewAlign = DAG.getDataLayout().getABITypeAlign( + VT.getTypeForEVT(*DAG.getContext())); + + if (NewAlign <= Alignment && + (!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) + return DAG.getLoad(VT, SDLoc(N), LD1->getChain(), LD1->getBasePtr(), + LD1->getPointerInfo(), Alignment); + } + + return SDValue(); +} + +static unsigned getPPCf128HiElementSelector(const SelectionDAG &DAG) { + // On little-endian machines, bitcasting from ppcf128 to i128 does swap the Hi + // and Lo parts; on big-endian machines it doesn't. + return DAG.getDataLayout().isBigEndian() ? 1 : 0; +} + +static SDValue foldBitcastedFPLogic(SDNode *N, SelectionDAG &DAG, + const TargetLowering &TLI) { + // If this is not a bitcast to an FP type or if the target doesn't have + // IEEE754-compliant FP logic, we're done. + EVT VT = N->getValueType(0); + if (!VT.isFloatingPoint() || !TLI.hasBitPreservingFPLogic(VT)) + return SDValue(); + + // TODO: Handle cases where the integer constant is a different scalar + // bitwidth to the FP. + SDValue N0 = N->getOperand(0); + EVT SourceVT = N0.getValueType(); + if (VT.getScalarSizeInBits() != SourceVT.getScalarSizeInBits()) + return SDValue(); + + unsigned FPOpcode; + APInt SignMask; + switch (N0.getOpcode()) { + case ISD::AND: + FPOpcode = ISD::FABS; + SignMask = ~APInt::getSignMask(SourceVT.getScalarSizeInBits()); + break; + case ISD::XOR: + FPOpcode = ISD::FNEG; + SignMask = APInt::getSignMask(SourceVT.getScalarSizeInBits()); + break; + case ISD::OR: + FPOpcode = ISD::FABS; + SignMask = APInt::getSignMask(SourceVT.getScalarSizeInBits()); + break; + default: + return SDValue(); + } + + // Fold (bitcast int (and (bitcast fp X to int), 0x7fff...) to fp) -> fabs X + // Fold (bitcast int (xor (bitcast fp X to int), 0x8000...) to fp) -> fneg X + // Fold (bitcast int (or (bitcast fp X to int), 0x8000...) to fp) -> + // fneg (fabs X) + SDValue LogicOp0 = N0.getOperand(0); + ConstantSDNode *LogicOp1 = isConstOrConstSplat(N0.getOperand(1), true); + if (LogicOp1 && LogicOp1->getAPIntValue() == SignMask && + LogicOp0.getOpcode() == ISD::BITCAST && + LogicOp0.getOperand(0).getValueType() == VT) { + SDValue FPOp = DAG.getNode(FPOpcode, SDLoc(N), VT, LogicOp0.getOperand(0)); + NumFPLogicOpsConv++; + if (N0.getOpcode() == ISD::OR) + return DAG.getNode(ISD::FNEG, SDLoc(N), VT, FPOp); + return FPOp; + } + + return SDValue(); +} + +SDValue DAGCombiner::visitBITCAST(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + if (N0.isUndef()) + return DAG.getUNDEF(VT); + + // If the input is a BUILD_VECTOR with all constant elements, fold this now. + // Only do this before legalize types, unless both types are integer and the + // scalar type is legal. Only do this before legalize ops, since the target + // maybe depending on the bitcast. + // First check to see if this is all constant. + // TODO: Support FP bitcasts after legalize types. + if (VT.isVector() && + (!LegalTypes || + (!LegalOperations && VT.isInteger() && N0.getValueType().isInteger() && + TLI.isTypeLegal(VT.getVectorElementType()))) && + N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() && + cast<BuildVectorSDNode>(N0)->isConstant()) + return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(), + VT.getVectorElementType()); + + // If the input is a constant, let getNode fold it. + if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { + // If we can't allow illegal operations, we need to check that this is just + // a fp -> int or int -> conversion and that the resulting operation will + // be legal. + if (!LegalOperations || + (isa<ConstantSDNode>(N0) && VT.isFloatingPoint() && !VT.isVector() && + TLI.isOperationLegal(ISD::ConstantFP, VT)) || + (isa<ConstantFPSDNode>(N0) && VT.isInteger() && !VT.isVector() && + TLI.isOperationLegal(ISD::Constant, VT))) { + SDValue C = DAG.getBitcast(VT, N0); + if (C.getNode() != N) + return C; + } + } + + // (conv (conv x, t1), t2) -> (conv x, t2) + if (N0.getOpcode() == ISD::BITCAST) + return DAG.getBitcast(VT, N0.getOperand(0)); + + // fold (conv (load x)) -> (load (conv*)x) + // If the resultant load doesn't need a higher alignment than the original! + if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && + // Do not remove the cast if the types differ in endian layout. + TLI.hasBigEndianPartOrdering(N0.getValueType(), DAG.getDataLayout()) == + TLI.hasBigEndianPartOrdering(VT, DAG.getDataLayout()) && + // If the load is volatile, we only want to change the load type if the + // resulting load is legal. Otherwise we might increase the number of + // memory accesses. We don't care if the original type was legal or not + // as we assume software couldn't rely on the number of accesses of an + // illegal type. + ((!LegalOperations && cast<LoadSDNode>(N0)->isSimple()) || + TLI.isOperationLegal(ISD::LOAD, VT))) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + + if (TLI.isLoadBitCastBeneficial(N0.getValueType(), VT, DAG, + *LN0->getMemOperand())) { + SDValue Load = + DAG.getLoad(VT, SDLoc(N), LN0->getChain(), LN0->getBasePtr(), + LN0->getPointerInfo(), LN0->getAlign(), + LN0->getMemOperand()->getFlags(), LN0->getAAInfo()); + DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1)); + return Load; + } + } + + if (SDValue V = foldBitcastedFPLogic(N, DAG, TLI)) + return V; + + // fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit) + // fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit)) + // + // For ppc_fp128: + // fold (bitcast (fneg x)) -> + // flipbit = signbit + // (xor (bitcast x) (build_pair flipbit, flipbit)) + // + // fold (bitcast (fabs x)) -> + // flipbit = (and (extract_element (bitcast x), 0), signbit) + // (xor (bitcast x) (build_pair flipbit, flipbit)) + // This often reduces constant pool loads. + if (((N0.getOpcode() == ISD::FNEG && !TLI.isFNegFree(N0.getValueType())) || + (N0.getOpcode() == ISD::FABS && !TLI.isFAbsFree(N0.getValueType()))) && + N0.getNode()->hasOneUse() && VT.isInteger() && + !VT.isVector() && !N0.getValueType().isVector()) { + SDValue NewConv = DAG.getBitcast(VT, N0.getOperand(0)); + AddToWorklist(NewConv.getNode()); + + SDLoc DL(N); + if (N0.getValueType() == MVT::ppcf128 && !LegalTypes) { + assert(VT.getSizeInBits() == 128); + SDValue SignBit = DAG.getConstant( + APInt::getSignMask(VT.getSizeInBits() / 2), SDLoc(N0), MVT::i64); + SDValue FlipBit; + if (N0.getOpcode() == ISD::FNEG) { + FlipBit = SignBit; + AddToWorklist(FlipBit.getNode()); + } else { + assert(N0.getOpcode() == ISD::FABS); + SDValue Hi = + DAG.getNode(ISD::EXTRACT_ELEMENT, SDLoc(NewConv), MVT::i64, NewConv, + DAG.getIntPtrConstant(getPPCf128HiElementSelector(DAG), + SDLoc(NewConv))); + AddToWorklist(Hi.getNode()); + FlipBit = DAG.getNode(ISD::AND, SDLoc(N0), MVT::i64, Hi, SignBit); + AddToWorklist(FlipBit.getNode()); + } + SDValue FlipBits = + DAG.getNode(ISD::BUILD_PAIR, SDLoc(N0), VT, FlipBit, FlipBit); + AddToWorklist(FlipBits.getNode()); + return DAG.getNode(ISD::XOR, DL, VT, NewConv, FlipBits); + } + APInt SignBit = APInt::getSignMask(VT.getSizeInBits()); + if (N0.getOpcode() == ISD::FNEG) + return DAG.getNode(ISD::XOR, DL, VT, + NewConv, DAG.getConstant(SignBit, DL, VT)); + assert(N0.getOpcode() == ISD::FABS); + return DAG.getNode(ISD::AND, DL, VT, + NewConv, DAG.getConstant(~SignBit, DL, VT)); + } + + // fold (bitconvert (fcopysign cst, x)) -> + // (or (and (bitconvert x), sign), (and cst, (not sign))) + // Note that we don't handle (copysign x, cst) because this can always be + // folded to an fneg or fabs. + // + // For ppc_fp128: + // fold (bitcast (fcopysign cst, x)) -> + // flipbit = (and (extract_element + // (xor (bitcast cst), (bitcast x)), 0), + // signbit) + // (xor (bitcast cst) (build_pair flipbit, flipbit)) + if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() && + isa<ConstantFPSDNode>(N0.getOperand(0)) && + VT.isInteger() && !VT.isVector()) { + unsigned OrigXWidth = N0.getOperand(1).getValueSizeInBits(); + EVT IntXVT = EVT::getIntegerVT(*DAG.getContext(), OrigXWidth); + if (isTypeLegal(IntXVT)) { + SDValue X = DAG.getBitcast(IntXVT, N0.getOperand(1)); + AddToWorklist(X.getNode()); + + // If X has a different width than the result/lhs, sext it or truncate it. + unsigned VTWidth = VT.getSizeInBits(); + if (OrigXWidth < VTWidth) { + X = DAG.getNode(ISD::SIGN_EXTEND, SDLoc(N), VT, X); + AddToWorklist(X.getNode()); + } else if (OrigXWidth > VTWidth) { + // To get the sign bit in the right place, we have to shift it right + // before truncating. + SDLoc DL(X); + X = DAG.getNode(ISD::SRL, DL, + X.getValueType(), X, + DAG.getConstant(OrigXWidth-VTWidth, DL, + X.getValueType())); + AddToWorklist(X.getNode()); + X = DAG.getNode(ISD::TRUNCATE, SDLoc(X), VT, X); + AddToWorklist(X.getNode()); + } + + if (N0.getValueType() == MVT::ppcf128 && !LegalTypes) { + APInt SignBit = APInt::getSignMask(VT.getSizeInBits() / 2); + SDValue Cst = DAG.getBitcast(VT, N0.getOperand(0)); + AddToWorklist(Cst.getNode()); + SDValue X = DAG.getBitcast(VT, N0.getOperand(1)); + AddToWorklist(X.getNode()); + SDValue XorResult = DAG.getNode(ISD::XOR, SDLoc(N0), VT, Cst, X); + AddToWorklist(XorResult.getNode()); + SDValue XorResult64 = DAG.getNode( + ISD::EXTRACT_ELEMENT, SDLoc(XorResult), MVT::i64, XorResult, + DAG.getIntPtrConstant(getPPCf128HiElementSelector(DAG), + SDLoc(XorResult))); + AddToWorklist(XorResult64.getNode()); + SDValue FlipBit = + DAG.getNode(ISD::AND, SDLoc(XorResult64), MVT::i64, XorResult64, + DAG.getConstant(SignBit, SDLoc(XorResult64), MVT::i64)); + AddToWorklist(FlipBit.getNode()); + SDValue FlipBits = + DAG.getNode(ISD::BUILD_PAIR, SDLoc(N0), VT, FlipBit, FlipBit); + AddToWorklist(FlipBits.getNode()); + return DAG.getNode(ISD::XOR, SDLoc(N), VT, Cst, FlipBits); + } + APInt SignBit = APInt::getSignMask(VT.getSizeInBits()); + X = DAG.getNode(ISD::AND, SDLoc(X), VT, + X, DAG.getConstant(SignBit, SDLoc(X), VT)); + AddToWorklist(X.getNode()); + + SDValue Cst = DAG.getBitcast(VT, N0.getOperand(0)); + Cst = DAG.getNode(ISD::AND, SDLoc(Cst), VT, + Cst, DAG.getConstant(~SignBit, SDLoc(Cst), VT)); + AddToWorklist(Cst.getNode()); + + return DAG.getNode(ISD::OR, SDLoc(N), VT, X, Cst); + } + } + + // bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive. + if (N0.getOpcode() == ISD::BUILD_PAIR) + if (SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT)) + return CombineLD; + + // Remove double bitcasts from shuffles - this is often a legacy of + // XformToShuffleWithZero being used to combine bitmaskings (of + // float vectors bitcast to integer vectors) into shuffles. + // bitcast(shuffle(bitcast(s0),bitcast(s1))) -> shuffle(s0,s1) + if (Level < AfterLegalizeDAG && TLI.isTypeLegal(VT) && VT.isVector() && + N0->getOpcode() == ISD::VECTOR_SHUFFLE && N0.hasOneUse() && + VT.getVectorNumElements() >= N0.getValueType().getVectorNumElements() && + !(VT.getVectorNumElements() % N0.getValueType().getVectorNumElements())) { + ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N0); + + // If operands are a bitcast, peek through if it casts the original VT. + // If operands are a constant, just bitcast back to original VT. + auto PeekThroughBitcast = [&](SDValue Op) { + if (Op.getOpcode() == ISD::BITCAST && + Op.getOperand(0).getValueType() == VT) + return SDValue(Op.getOperand(0)); + if (Op.isUndef() || ISD::isBuildVectorOfConstantSDNodes(Op.getNode()) || + ISD::isBuildVectorOfConstantFPSDNodes(Op.getNode())) + return DAG.getBitcast(VT, Op); + return SDValue(); + }; + + // FIXME: If either input vector is bitcast, try to convert the shuffle to + // the result type of this bitcast. This would eliminate at least one + // bitcast. See the transform in InstCombine. + SDValue SV0 = PeekThroughBitcast(N0->getOperand(0)); + SDValue SV1 = PeekThroughBitcast(N0->getOperand(1)); + if (!(SV0 && SV1)) + return SDValue(); + + int MaskScale = + VT.getVectorNumElements() / N0.getValueType().getVectorNumElements(); + SmallVector<int, 8> NewMask; + for (int M : SVN->getMask()) + for (int i = 0; i != MaskScale; ++i) + NewMask.push_back(M < 0 ? -1 : M * MaskScale + i); + + SDValue LegalShuffle = + TLI.buildLegalVectorShuffle(VT, SDLoc(N), SV0, SV1, NewMask, DAG); + if (LegalShuffle) + return LegalShuffle; + } + + return SDValue(); +} + +SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) { + EVT VT = N->getValueType(0); + return CombineConsecutiveLoads(N, VT); +} + +SDValue DAGCombiner::visitFREEZE(SDNode *N) { + SDValue N0 = N->getOperand(0); + + // (freeze (freeze x)) -> (freeze x) + if (N0.getOpcode() == ISD::FREEZE) + return N0; + + // If the input is a constant, return it. + if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) + return N0; + + return SDValue(); +} + +/// We know that BV is a build_vector node with Constant, ConstantFP or Undef +/// operands. DstEltVT indicates the destination element value type. +SDValue DAGCombiner:: +ConstantFoldBITCASTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) { + EVT SrcEltVT = BV->getValueType(0).getVectorElementType(); + + // If this is already the right type, we're done. + if (SrcEltVT == DstEltVT) return SDValue(BV, 0); + + unsigned SrcBitSize = SrcEltVT.getSizeInBits(); + unsigned DstBitSize = DstEltVT.getSizeInBits(); + + // If this is a conversion of N elements of one type to N elements of another + // type, convert each element. This handles FP<->INT cases. + if (SrcBitSize == DstBitSize) { + SmallVector<SDValue, 8> Ops; + for (SDValue Op : BV->op_values()) { + // If the vector element type is not legal, the BUILD_VECTOR operands + // are promoted and implicitly truncated. Make that explicit here. + if (Op.getValueType() != SrcEltVT) + Op = DAG.getNode(ISD::TRUNCATE, SDLoc(BV), SrcEltVT, Op); + Ops.push_back(DAG.getBitcast(DstEltVT, Op)); + AddToWorklist(Ops.back().getNode()); + } + EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, + BV->getValueType(0).getVectorNumElements()); + return DAG.getBuildVector(VT, SDLoc(BV), Ops); + } + + // Otherwise, we're growing or shrinking the elements. To avoid having to + // handle annoying details of growing/shrinking FP values, we convert them to + // int first. + if (SrcEltVT.isFloatingPoint()) { + // Convert the input float vector to a int vector where the elements are the + // same sizes. + EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), SrcEltVT.getSizeInBits()); + BV = ConstantFoldBITCASTofBUILD_VECTOR(BV, IntVT).getNode(); + SrcEltVT = IntVT; + } + + // Now we know the input is an integer vector. If the output is a FP type, + // convert to integer first, then to FP of the right size. + if (DstEltVT.isFloatingPoint()) { + EVT TmpVT = EVT::getIntegerVT(*DAG.getContext(), DstEltVT.getSizeInBits()); + SDNode *Tmp = ConstantFoldBITCASTofBUILD_VECTOR(BV, TmpVT).getNode(); + + // Next, convert to FP elements of the same size. + return ConstantFoldBITCASTofBUILD_VECTOR(Tmp, DstEltVT); + } + + SDLoc DL(BV); + + // Okay, we know the src/dst types are both integers of differing types. + // Handling growing first. + assert(SrcEltVT.isInteger() && DstEltVT.isInteger()); + if (SrcBitSize < DstBitSize) { + unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; + + SmallVector<SDValue, 8> Ops; + for (unsigned i = 0, e = BV->getNumOperands(); i != e; + i += NumInputsPerOutput) { + bool isLE = DAG.getDataLayout().isLittleEndian(); + APInt NewBits = APInt(DstBitSize, 0); + bool EltIsUndef = true; + for (unsigned j = 0; j != NumInputsPerOutput; ++j) { + // Shift the previously computed bits over. + NewBits <<= SrcBitSize; + SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); + if (Op.isUndef()) continue; + EltIsUndef = false; + + NewBits |= cast<ConstantSDNode>(Op)->getAPIntValue(). + zextOrTrunc(SrcBitSize).zext(DstBitSize); + } + + if (EltIsUndef) + Ops.push_back(DAG.getUNDEF(DstEltVT)); + else + Ops.push_back(DAG.getConstant(NewBits, DL, DstEltVT)); + } + + EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, Ops.size()); + return DAG.getBuildVector(VT, DL, Ops); + } + + // Finally, this must be the case where we are shrinking elements: each input + // turns into multiple outputs. + unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; + EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, + NumOutputsPerInput*BV->getNumOperands()); + SmallVector<SDValue, 8> Ops; + + for (const SDValue &Op : BV->op_values()) { + if (Op.isUndef()) { + Ops.append(NumOutputsPerInput, DAG.getUNDEF(DstEltVT)); + continue; + } + + APInt OpVal = cast<ConstantSDNode>(Op)-> + getAPIntValue().zextOrTrunc(SrcBitSize); + + for (unsigned j = 0; j != NumOutputsPerInput; ++j) { + APInt ThisVal = OpVal.trunc(DstBitSize); + Ops.push_back(DAG.getConstant(ThisVal, DL, DstEltVT)); + OpVal.lshrInPlace(DstBitSize); + } + + // For big endian targets, swap the order of the pieces of each element. + if (DAG.getDataLayout().isBigEndian()) + std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); + } + + return DAG.getBuildVector(VT, DL, Ops); +} + +static bool isContractable(SDNode *N) { + SDNodeFlags F = N->getFlags(); + return F.hasAllowContract() || F.hasAllowReassociation(); +} + +/// Try to perform FMA combining on a given FADD node. +SDValue DAGCombiner::visitFADDForFMACombine(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + SDLoc SL(N); + + const TargetOptions &Options = DAG.getTarget().Options; + + // Floating-point multiply-add with intermediate rounding. + bool HasFMAD = (LegalOperations && TLI.isFMADLegal(DAG, N)); + + // Floating-point multiply-add without intermediate rounding. + bool HasFMA = + TLI.isFMAFasterThanFMulAndFAdd(DAG.getMachineFunction(), VT) && + (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FMA, VT)); + + // No valid opcode, do not combine. + if (!HasFMAD && !HasFMA) + return SDValue(); + + bool CanFuse = Options.UnsafeFPMath || isContractable(N); + bool CanReassociate = + Options.UnsafeFPMath || N->getFlags().hasAllowReassociation(); + bool AllowFusionGlobally = (Options.AllowFPOpFusion == FPOpFusion::Fast || + CanFuse || HasFMAD); + // If the addition is not contractable, do not combine. + if (!AllowFusionGlobally && !isContractable(N)) + return SDValue(); + + if (STI && STI->generateFMAsInMachineCombiner(OptLevel)) + return SDValue(); + + // Always prefer FMAD to FMA for precision. + unsigned PreferredFusedOpcode = HasFMAD ? ISD::FMAD : ISD::FMA; + bool Aggressive = TLI.enableAggressiveFMAFusion(VT); + + // Is the node an FMUL and contractable either due to global flags or + // SDNodeFlags. + auto isContractableFMUL = [AllowFusionGlobally](SDValue N) { + if (N.getOpcode() != ISD::FMUL) + return false; + return AllowFusionGlobally || isContractable(N.getNode()); + }; + // If we have two choices trying to fold (fadd (fmul u, v), (fmul x, y)), + // prefer to fold the multiply with fewer uses. + if (Aggressive && isContractableFMUL(N0) && isContractableFMUL(N1)) { + if (N0.getNode()->use_size() > N1.getNode()->use_size()) + std::swap(N0, N1); + } + + // fold (fadd (fmul x, y), z) -> (fma x, y, z) + if (isContractableFMUL(N0) && (Aggressive || N0->hasOneUse())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, N0.getOperand(0), + N0.getOperand(1), N1); + } + + // fold (fadd x, (fmul y, z)) -> (fma y, z, x) + // Note: Commutes FADD operands. + if (isContractableFMUL(N1) && (Aggressive || N1->hasOneUse())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, N1.getOperand(0), + N1.getOperand(1), N0); + } + + // fadd (fma A, B, (fmul C, D)), E --> fma A, B, (fma C, D, E) + // fadd E, (fma A, B, (fmul C, D)) --> fma A, B, (fma C, D, E) + // This requires reassociation because it changes the order of operations. + SDValue FMA, E; + if (CanReassociate && N0.getOpcode() == PreferredFusedOpcode && + N0.getOperand(2).getOpcode() == ISD::FMUL && N0.hasOneUse() && + N0.getOperand(2).hasOneUse()) { + FMA = N0; + E = N1; + } else if (CanReassociate && N1.getOpcode() == PreferredFusedOpcode && + N1.getOperand(2).getOpcode() == ISD::FMUL && N1.hasOneUse() && + N1.getOperand(2).hasOneUse()) { + FMA = N1; + E = N0; + } + if (FMA && E) { + SDValue A = FMA.getOperand(0); + SDValue B = FMA.getOperand(1); + SDValue C = FMA.getOperand(2).getOperand(0); + SDValue D = FMA.getOperand(2).getOperand(1); + SDValue CDE = DAG.getNode(PreferredFusedOpcode, SL, VT, C, D, E); + return DAG.getNode(PreferredFusedOpcode, SL, VT, A, B, CDE); + } + + // Look through FP_EXTEND nodes to do more combining. + + // fold (fadd (fpext (fmul x, y)), z) -> (fma (fpext x), (fpext y), z) + if (N0.getOpcode() == ISD::FP_EXTEND) { + SDValue N00 = N0.getOperand(0); + if (isContractableFMUL(N00) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N00.getValueType())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N00.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N00.getOperand(1)), + N1); + } + } + + // fold (fadd x, (fpext (fmul y, z))) -> (fma (fpext y), (fpext z), x) + // Note: Commutes FADD operands. + if (N1.getOpcode() == ISD::FP_EXTEND) { + SDValue N10 = N1.getOperand(0); + if (isContractableFMUL(N10) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N10.getValueType())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N10.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N10.getOperand(1)), + N0); + } + } + + // More folding opportunities when target permits. + if (Aggressive) { + // fold (fadd (fma x, y, (fpext (fmul u, v))), z) + // -> (fma x, y, (fma (fpext u), (fpext v), z)) + auto FoldFAddFMAFPExtFMul = [&](SDValue X, SDValue Y, SDValue U, SDValue V, + SDValue Z) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, X, Y, + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, U), + DAG.getNode(ISD::FP_EXTEND, SL, VT, V), + Z)); + }; + if (N0.getOpcode() == PreferredFusedOpcode) { + SDValue N02 = N0.getOperand(2); + if (N02.getOpcode() == ISD::FP_EXTEND) { + SDValue N020 = N02.getOperand(0); + if (isContractableFMUL(N020) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N020.getValueType())) { + return FoldFAddFMAFPExtFMul(N0.getOperand(0), N0.getOperand(1), + N020.getOperand(0), N020.getOperand(1), + N1); + } + } + } + + // fold (fadd (fpext (fma x, y, (fmul u, v))), z) + // -> (fma (fpext x), (fpext y), (fma (fpext u), (fpext v), z)) + // FIXME: This turns two single-precision and one double-precision + // operation into two double-precision operations, which might not be + // interesting for all targets, especially GPUs. + auto FoldFAddFPExtFMAFMul = [&](SDValue X, SDValue Y, SDValue U, SDValue V, + SDValue Z) { + return DAG.getNode( + PreferredFusedOpcode, SL, VT, DAG.getNode(ISD::FP_EXTEND, SL, VT, X), + DAG.getNode(ISD::FP_EXTEND, SL, VT, Y), + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, U), + DAG.getNode(ISD::FP_EXTEND, SL, VT, V), Z)); + }; + if (N0.getOpcode() == ISD::FP_EXTEND) { + SDValue N00 = N0.getOperand(0); + if (N00.getOpcode() == PreferredFusedOpcode) { + SDValue N002 = N00.getOperand(2); + if (isContractableFMUL(N002) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N00.getValueType())) { + return FoldFAddFPExtFMAFMul(N00.getOperand(0), N00.getOperand(1), + N002.getOperand(0), N002.getOperand(1), + N1); + } + } + } + + // fold (fadd x, (fma y, z, (fpext (fmul u, v))) + // -> (fma y, z, (fma (fpext u), (fpext v), x)) + if (N1.getOpcode() == PreferredFusedOpcode) { + SDValue N12 = N1.getOperand(2); + if (N12.getOpcode() == ISD::FP_EXTEND) { + SDValue N120 = N12.getOperand(0); + if (isContractableFMUL(N120) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N120.getValueType())) { + return FoldFAddFMAFPExtFMul(N1.getOperand(0), N1.getOperand(1), + N120.getOperand(0), N120.getOperand(1), + N0); + } + } + } + + // fold (fadd x, (fpext (fma y, z, (fmul u, v))) + // -> (fma (fpext y), (fpext z), (fma (fpext u), (fpext v), x)) + // FIXME: This turns two single-precision and one double-precision + // operation into two double-precision operations, which might not be + // interesting for all targets, especially GPUs. + if (N1.getOpcode() == ISD::FP_EXTEND) { + SDValue N10 = N1.getOperand(0); + if (N10.getOpcode() == PreferredFusedOpcode) { + SDValue N102 = N10.getOperand(2); + if (isContractableFMUL(N102) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N10.getValueType())) { + return FoldFAddFPExtFMAFMul(N10.getOperand(0), N10.getOperand(1), + N102.getOperand(0), N102.getOperand(1), + N0); + } + } + } + } + + return SDValue(); +} + +/// Try to perform FMA combining on a given FSUB node. +SDValue DAGCombiner::visitFSUBForFMACombine(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + SDLoc SL(N); + + const TargetOptions &Options = DAG.getTarget().Options; + // Floating-point multiply-add with intermediate rounding. + bool HasFMAD = (LegalOperations && TLI.isFMADLegal(DAG, N)); + + // Floating-point multiply-add without intermediate rounding. + bool HasFMA = + TLI.isFMAFasterThanFMulAndFAdd(DAG.getMachineFunction(), VT) && + (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FMA, VT)); + + // No valid opcode, do not combine. + if (!HasFMAD && !HasFMA) + return SDValue(); + + const SDNodeFlags Flags = N->getFlags(); + bool CanFuse = Options.UnsafeFPMath || isContractable(N); + bool AllowFusionGlobally = (Options.AllowFPOpFusion == FPOpFusion::Fast || + CanFuse || HasFMAD); + + // If the subtraction is not contractable, do not combine. + if (!AllowFusionGlobally && !isContractable(N)) + return SDValue(); + + if (STI && STI->generateFMAsInMachineCombiner(OptLevel)) + return SDValue(); + + // Always prefer FMAD to FMA for precision. + unsigned PreferredFusedOpcode = HasFMAD ? ISD::FMAD : ISD::FMA; + bool Aggressive = TLI.enableAggressiveFMAFusion(VT); + bool NoSignedZero = Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros(); + + // Is the node an FMUL and contractable either due to global flags or + // SDNodeFlags. + auto isContractableFMUL = [AllowFusionGlobally](SDValue N) { + if (N.getOpcode() != ISD::FMUL) + return false; + return AllowFusionGlobally || isContractable(N.getNode()); + }; + + // fold (fsub (fmul x, y), z) -> (fma x, y, (fneg z)) + auto tryToFoldXYSubZ = [&](SDValue XY, SDValue Z) { + if (isContractableFMUL(XY) && (Aggressive || XY->hasOneUse())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, XY.getOperand(0), + XY.getOperand(1), DAG.getNode(ISD::FNEG, SL, VT, Z)); + } + return SDValue(); + }; + + // fold (fsub x, (fmul y, z)) -> (fma (fneg y), z, x) + // Note: Commutes FSUB operands. + auto tryToFoldXSubYZ = [&](SDValue X, SDValue YZ) { + if (isContractableFMUL(YZ) && (Aggressive || YZ->hasOneUse())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, YZ.getOperand(0)), + YZ.getOperand(1), X); + } + return SDValue(); + }; + + // If we have two choices trying to fold (fsub (fmul u, v), (fmul x, y)), + // prefer to fold the multiply with fewer uses. + if (isContractableFMUL(N0) && isContractableFMUL(N1) && + (N0.getNode()->use_size() > N1.getNode()->use_size())) { + // fold (fsub (fmul a, b), (fmul c, d)) -> (fma (fneg c), d, (fmul a, b)) + if (SDValue V = tryToFoldXSubYZ(N0, N1)) + return V; + // fold (fsub (fmul a, b), (fmul c, d)) -> (fma a, b, (fneg (fmul c, d))) + if (SDValue V = tryToFoldXYSubZ(N0, N1)) + return V; + } else { + // fold (fsub (fmul x, y), z) -> (fma x, y, (fneg z)) + if (SDValue V = tryToFoldXYSubZ(N0, N1)) + return V; + // fold (fsub x, (fmul y, z)) -> (fma (fneg y), z, x) + if (SDValue V = tryToFoldXSubYZ(N0, N1)) + return V; + } + + // fold (fsub (fneg (fmul, x, y)), z) -> (fma (fneg x), y, (fneg z)) + if (N0.getOpcode() == ISD::FNEG && isContractableFMUL(N0.getOperand(0)) && + (Aggressive || (N0->hasOneUse() && N0.getOperand(0).hasOneUse()))) { + SDValue N00 = N0.getOperand(0).getOperand(0); + SDValue N01 = N0.getOperand(0).getOperand(1); + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, N00), N01, + DAG.getNode(ISD::FNEG, SL, VT, N1)); + } + + // Look through FP_EXTEND nodes to do more combining. + + // fold (fsub (fpext (fmul x, y)), z) + // -> (fma (fpext x), (fpext y), (fneg z)) + if (N0.getOpcode() == ISD::FP_EXTEND) { + SDValue N00 = N0.getOperand(0); + if (isContractableFMUL(N00) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N00.getValueType())) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N00.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N00.getOperand(1)), + DAG.getNode(ISD::FNEG, SL, VT, N1)); + } + } + + // fold (fsub x, (fpext (fmul y, z))) + // -> (fma (fneg (fpext y)), (fpext z), x) + // Note: Commutes FSUB operands. + if (N1.getOpcode() == ISD::FP_EXTEND) { + SDValue N10 = N1.getOperand(0); + if (isContractableFMUL(N10) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N10.getValueType())) { + return DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N10.getOperand(0))), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N10.getOperand(1)), N0); + } + } + + // fold (fsub (fpext (fneg (fmul, x, y))), z) + // -> (fneg (fma (fpext x), (fpext y), z)) + // Note: This could be removed with appropriate canonicalization of the + // input expression into (fneg (fadd (fpext (fmul, x, y)), z). However, the + // orthogonal flags -fp-contract=fast and -enable-unsafe-fp-math prevent + // from implementing the canonicalization in visitFSUB. + if (N0.getOpcode() == ISD::FP_EXTEND) { + SDValue N00 = N0.getOperand(0); + if (N00.getOpcode() == ISD::FNEG) { + SDValue N000 = N00.getOperand(0); + if (isContractableFMUL(N000) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N00.getValueType())) { + return DAG.getNode( + ISD::FNEG, SL, VT, + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N000.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N000.getOperand(1)), + N1)); + } + } + } + + // fold (fsub (fneg (fpext (fmul, x, y))), z) + // -> (fneg (fma (fpext x)), (fpext y), z) + // Note: This could be removed with appropriate canonicalization of the + // input expression into (fneg (fadd (fpext (fmul, x, y)), z). However, the + // orthogonal flags -fp-contract=fast and -enable-unsafe-fp-math prevent + // from implementing the canonicalization in visitFSUB. + if (N0.getOpcode() == ISD::FNEG) { + SDValue N00 = N0.getOperand(0); + if (N00.getOpcode() == ISD::FP_EXTEND) { + SDValue N000 = N00.getOperand(0); + if (isContractableFMUL(N000) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N000.getValueType())) { + return DAG.getNode( + ISD::FNEG, SL, VT, + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N000.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N000.getOperand(1)), + N1)); + } + } + } + + // More folding opportunities when target permits. + if (Aggressive) { + // fold (fsub (fma x, y, (fmul u, v)), z) + // -> (fma x, y (fma u, v, (fneg z))) + if (CanFuse && N0.getOpcode() == PreferredFusedOpcode && + isContractableFMUL(N0.getOperand(2)) && N0->hasOneUse() && + N0.getOperand(2)->hasOneUse()) { + return DAG.getNode(PreferredFusedOpcode, SL, VT, N0.getOperand(0), + N0.getOperand(1), + DAG.getNode(PreferredFusedOpcode, SL, VT, + N0.getOperand(2).getOperand(0), + N0.getOperand(2).getOperand(1), + DAG.getNode(ISD::FNEG, SL, VT, N1))); + } + + // fold (fsub x, (fma y, z, (fmul u, v))) + // -> (fma (fneg y), z, (fma (fneg u), v, x)) + if (CanFuse && N1.getOpcode() == PreferredFusedOpcode && + isContractableFMUL(N1.getOperand(2)) && + N1->hasOneUse() && NoSignedZero) { + SDValue N20 = N1.getOperand(2).getOperand(0); + SDValue N21 = N1.getOperand(2).getOperand(1); + return DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, N1.getOperand(0)), N1.getOperand(1), + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, N20), N21, N0)); + } + + + // fold (fsub (fma x, y, (fpext (fmul u, v))), z) + // -> (fma x, y (fma (fpext u), (fpext v), (fneg z))) + if (N0.getOpcode() == PreferredFusedOpcode && + N0->hasOneUse()) { + SDValue N02 = N0.getOperand(2); + if (N02.getOpcode() == ISD::FP_EXTEND) { + SDValue N020 = N02.getOperand(0); + if (isContractableFMUL(N020) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N020.getValueType())) { + return DAG.getNode( + PreferredFusedOpcode, SL, VT, N0.getOperand(0), N0.getOperand(1), + DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N020.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N020.getOperand(1)), + DAG.getNode(ISD::FNEG, SL, VT, N1))); + } + } + } + + // fold (fsub (fpext (fma x, y, (fmul u, v))), z) + // -> (fma (fpext x), (fpext y), + // (fma (fpext u), (fpext v), (fneg z))) + // FIXME: This turns two single-precision and one double-precision + // operation into two double-precision operations, which might not be + // interesting for all targets, especially GPUs. + if (N0.getOpcode() == ISD::FP_EXTEND) { + SDValue N00 = N0.getOperand(0); + if (N00.getOpcode() == PreferredFusedOpcode) { + SDValue N002 = N00.getOperand(2); + if (isContractableFMUL(N002) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N00.getValueType())) { + return DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N00.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N00.getOperand(1)), + DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N002.getOperand(0)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N002.getOperand(1)), + DAG.getNode(ISD::FNEG, SL, VT, N1))); + } + } + } + + // fold (fsub x, (fma y, z, (fpext (fmul u, v)))) + // -> (fma (fneg y), z, (fma (fneg (fpext u)), (fpext v), x)) + if (N1.getOpcode() == PreferredFusedOpcode && + N1.getOperand(2).getOpcode() == ISD::FP_EXTEND && + N1->hasOneUse()) { + SDValue N120 = N1.getOperand(2).getOperand(0); + if (isContractableFMUL(N120) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + N120.getValueType())) { + SDValue N1200 = N120.getOperand(0); + SDValue N1201 = N120.getOperand(1); + return DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, N1.getOperand(0)), N1.getOperand(1), + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N1200)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N1201), N0)); + } + } + + // fold (fsub x, (fpext (fma y, z, (fmul u, v)))) + // -> (fma (fneg (fpext y)), (fpext z), + // (fma (fneg (fpext u)), (fpext v), x)) + // FIXME: This turns two single-precision and one double-precision + // operation into two double-precision operations, which might not be + // interesting for all targets, especially GPUs. + if (N1.getOpcode() == ISD::FP_EXTEND && + N1.getOperand(0).getOpcode() == PreferredFusedOpcode) { + SDValue CvtSrc = N1.getOperand(0); + SDValue N100 = CvtSrc.getOperand(0); + SDValue N101 = CvtSrc.getOperand(1); + SDValue N102 = CvtSrc.getOperand(2); + if (isContractableFMUL(N102) && + TLI.isFPExtFoldable(DAG, PreferredFusedOpcode, VT, + CvtSrc.getValueType())) { + SDValue N1020 = N102.getOperand(0); + SDValue N1021 = N102.getOperand(1); + return DAG.getNode( + PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N100)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N101), + DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, + DAG.getNode(ISD::FP_EXTEND, SL, VT, N1020)), + DAG.getNode(ISD::FP_EXTEND, SL, VT, N1021), N0)); + } + } + } + + return SDValue(); +} + +/// Try to perform FMA combining on a given FMUL node based on the distributive +/// law x * (y + 1) = x * y + x and variants thereof (commuted versions, +/// subtraction instead of addition). +SDValue DAGCombiner::visitFMULForFMADistributiveCombine(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + SDLoc SL(N); + + assert(N->getOpcode() == ISD::FMUL && "Expected FMUL Operation"); + + const TargetOptions &Options = DAG.getTarget().Options; + + // The transforms below are incorrect when x == 0 and y == inf, because the + // intermediate multiplication produces a nan. + if (!Options.NoInfsFPMath) + return SDValue(); + + // Floating-point multiply-add without intermediate rounding. + bool HasFMA = + (Options.AllowFPOpFusion == FPOpFusion::Fast || Options.UnsafeFPMath) && + TLI.isFMAFasterThanFMulAndFAdd(DAG.getMachineFunction(), VT) && + (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FMA, VT)); + + // Floating-point multiply-add with intermediate rounding. This can result + // in a less precise result due to the changed rounding order. + bool HasFMAD = Options.UnsafeFPMath && + (LegalOperations && TLI.isFMADLegal(DAG, N)); + + // No valid opcode, do not combine. + if (!HasFMAD && !HasFMA) + return SDValue(); + + // Always prefer FMAD to FMA for precision. + unsigned PreferredFusedOpcode = HasFMAD ? ISD::FMAD : ISD::FMA; + bool Aggressive = TLI.enableAggressiveFMAFusion(VT); + + // fold (fmul (fadd x0, +1.0), y) -> (fma x0, y, y) + // fold (fmul (fadd x0, -1.0), y) -> (fma x0, y, (fneg y)) + auto FuseFADD = [&](SDValue X, SDValue Y) { + if (X.getOpcode() == ISD::FADD && (Aggressive || X->hasOneUse())) { + if (auto *C = isConstOrConstSplatFP(X.getOperand(1), true)) { + if (C->isExactlyValue(+1.0)) + return DAG.getNode(PreferredFusedOpcode, SL, VT, X.getOperand(0), Y, + Y); + if (C->isExactlyValue(-1.0)) + return DAG.getNode(PreferredFusedOpcode, SL, VT, X.getOperand(0), Y, + DAG.getNode(ISD::FNEG, SL, VT, Y)); + } + } + return SDValue(); + }; + + if (SDValue FMA = FuseFADD(N0, N1)) + return FMA; + if (SDValue FMA = FuseFADD(N1, N0)) + return FMA; + + // fold (fmul (fsub +1.0, x1), y) -> (fma (fneg x1), y, y) + // fold (fmul (fsub -1.0, x1), y) -> (fma (fneg x1), y, (fneg y)) + // fold (fmul (fsub x0, +1.0), y) -> (fma x0, y, (fneg y)) + // fold (fmul (fsub x0, -1.0), y) -> (fma x0, y, y) + auto FuseFSUB = [&](SDValue X, SDValue Y) { + if (X.getOpcode() == ISD::FSUB && (Aggressive || X->hasOneUse())) { + if (auto *C0 = isConstOrConstSplatFP(X.getOperand(0), true)) { + if (C0->isExactlyValue(+1.0)) + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, X.getOperand(1)), Y, + Y); + if (C0->isExactlyValue(-1.0)) + return DAG.getNode(PreferredFusedOpcode, SL, VT, + DAG.getNode(ISD::FNEG, SL, VT, X.getOperand(1)), Y, + DAG.getNode(ISD::FNEG, SL, VT, Y)); + } + if (auto *C1 = isConstOrConstSplatFP(X.getOperand(1), true)) { + if (C1->isExactlyValue(+1.0)) + return DAG.getNode(PreferredFusedOpcode, SL, VT, X.getOperand(0), Y, + DAG.getNode(ISD::FNEG, SL, VT, Y)); + if (C1->isExactlyValue(-1.0)) + return DAG.getNode(PreferredFusedOpcode, SL, VT, X.getOperand(0), Y, + Y); + } + } + return SDValue(); + }; + + if (SDValue FMA = FuseFSUB(N0, N1)) + return FMA; + if (SDValue FMA = FuseFSUB(N1, N0)) + return FMA; + + return SDValue(); +} + +SDValue DAGCombiner::visitFADD(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + bool N0CFP = DAG.isConstantFPBuildVectorOrConstantFP(N0); + bool N1CFP = DAG.isConstantFPBuildVectorOrConstantFP(N1); + EVT VT = N->getValueType(0); + SDLoc DL(N); + const TargetOptions &Options = DAG.getTarget().Options; + SDNodeFlags Flags = N->getFlags(); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + if (SDValue R = DAG.simplifyFPBinop(N->getOpcode(), N0, N1, Flags)) + return R; + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (fadd c1, c2) -> c1 + c2 + if (N0CFP && N1CFP) + return DAG.getNode(ISD::FADD, DL, VT, N0, N1); + + // canonicalize constant to RHS + if (N0CFP && !N1CFP) + return DAG.getNode(ISD::FADD, DL, VT, N1, N0); + + // N0 + -0.0 --> N0 (also allowed with +0.0 and fast-math) + ConstantFPSDNode *N1C = isConstOrConstSplatFP(N1, true); + if (N1C && N1C->isZero()) + if (N1C->isNegative() || Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros()) + return N0; + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // fold (fadd A, (fneg B)) -> (fsub A, B) + if (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FSUB, VT)) + if (SDValue NegN1 = TLI.getCheaperNegatedExpression( + N1, DAG, LegalOperations, ForCodeSize)) + return DAG.getNode(ISD::FSUB, DL, VT, N0, NegN1); + + // fold (fadd (fneg A), B) -> (fsub B, A) + if (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::FSUB, VT)) + if (SDValue NegN0 = TLI.getCheaperNegatedExpression( + N0, DAG, LegalOperations, ForCodeSize)) + return DAG.getNode(ISD::FSUB, DL, VT, N1, NegN0); + + auto isFMulNegTwo = [](SDValue FMul) { + if (!FMul.hasOneUse() || FMul.getOpcode() != ISD::FMUL) + return false; + auto *C = isConstOrConstSplatFP(FMul.getOperand(1), true); + return C && C->isExactlyValue(-2.0); + }; + + // fadd (fmul B, -2.0), A --> fsub A, (fadd B, B) + if (isFMulNegTwo(N0)) { + SDValue B = N0.getOperand(0); + SDValue Add = DAG.getNode(ISD::FADD, DL, VT, B, B); + return DAG.getNode(ISD::FSUB, DL, VT, N1, Add); + } + // fadd A, (fmul B, -2.0) --> fsub A, (fadd B, B) + if (isFMulNegTwo(N1)) { + SDValue B = N1.getOperand(0); + SDValue Add = DAG.getNode(ISD::FADD, DL, VT, B, B); + return DAG.getNode(ISD::FSUB, DL, VT, N0, Add); + } + + // No FP constant should be created after legalization as Instruction + // Selection pass has a hard time dealing with FP constants. + bool AllowNewConst = (Level < AfterLegalizeDAG); + + // If nnan is enabled, fold lots of things. + if ((Options.NoNaNsFPMath || Flags.hasNoNaNs()) && AllowNewConst) { + // If allowed, fold (fadd (fneg x), x) -> 0.0 + if (N0.getOpcode() == ISD::FNEG && N0.getOperand(0) == N1) + return DAG.getConstantFP(0.0, DL, VT); + + // If allowed, fold (fadd x, (fneg x)) -> 0.0 + if (N1.getOpcode() == ISD::FNEG && N1.getOperand(0) == N0) + return DAG.getConstantFP(0.0, DL, VT); + } + + // If 'unsafe math' or reassoc and nsz, fold lots of things. + // TODO: break out portions of the transformations below for which Unsafe is + // considered and which do not require both nsz and reassoc + if (((Options.UnsafeFPMath && Options.NoSignedZerosFPMath) || + (Flags.hasAllowReassociation() && Flags.hasNoSignedZeros())) && + AllowNewConst) { + // fadd (fadd x, c1), c2 -> fadd x, c1 + c2 + if (N1CFP && N0.getOpcode() == ISD::FADD && + DAG.isConstantFPBuildVectorOrConstantFP(N0.getOperand(1))) { + SDValue NewC = DAG.getNode(ISD::FADD, DL, VT, N0.getOperand(1), N1); + return DAG.getNode(ISD::FADD, DL, VT, N0.getOperand(0), NewC); + } + + // We can fold chains of FADD's of the same value into multiplications. + // This transform is not safe in general because we are reducing the number + // of rounding steps. + if (TLI.isOperationLegalOrCustom(ISD::FMUL, VT) && !N0CFP && !N1CFP) { + if (N0.getOpcode() == ISD::FMUL) { + bool CFP00 = DAG.isConstantFPBuildVectorOrConstantFP(N0.getOperand(0)); + bool CFP01 = DAG.isConstantFPBuildVectorOrConstantFP(N0.getOperand(1)); + + // (fadd (fmul x, c), x) -> (fmul x, c+1) + if (CFP01 && !CFP00 && N0.getOperand(0) == N1) { + SDValue NewCFP = DAG.getNode(ISD::FADD, DL, VT, N0.getOperand(1), + DAG.getConstantFP(1.0, DL, VT)); + return DAG.getNode(ISD::FMUL, DL, VT, N1, NewCFP); + } + + // (fadd (fmul x, c), (fadd x, x)) -> (fmul x, c+2) + if (CFP01 && !CFP00 && N1.getOpcode() == ISD::FADD && + N1.getOperand(0) == N1.getOperand(1) && + N0.getOperand(0) == N1.getOperand(0)) { + SDValue NewCFP = DAG.getNode(ISD::FADD, DL, VT, N0.getOperand(1), + DAG.getConstantFP(2.0, DL, VT)); + return DAG.getNode(ISD::FMUL, DL, VT, N0.getOperand(0), NewCFP); + } + } + + if (N1.getOpcode() == ISD::FMUL) { + bool CFP10 = DAG.isConstantFPBuildVectorOrConstantFP(N1.getOperand(0)); + bool CFP11 = DAG.isConstantFPBuildVectorOrConstantFP(N1.getOperand(1)); + + // (fadd x, (fmul x, c)) -> (fmul x, c+1) + if (CFP11 && !CFP10 && N1.getOperand(0) == N0) { + SDValue NewCFP = DAG.getNode(ISD::FADD, DL, VT, N1.getOperand(1), + DAG.getConstantFP(1.0, DL, VT)); + return DAG.getNode(ISD::FMUL, DL, VT, N0, NewCFP); + } + + // (fadd (fadd x, x), (fmul x, c)) -> (fmul x, c+2) + if (CFP11 && !CFP10 && N0.getOpcode() == ISD::FADD && + N0.getOperand(0) == N0.getOperand(1) && + N1.getOperand(0) == N0.getOperand(0)) { + SDValue NewCFP = DAG.getNode(ISD::FADD, DL, VT, N1.getOperand(1), + DAG.getConstantFP(2.0, DL, VT)); + return DAG.getNode(ISD::FMUL, DL, VT, N1.getOperand(0), NewCFP); + } + } + + if (N0.getOpcode() == ISD::FADD) { + bool CFP00 = DAG.isConstantFPBuildVectorOrConstantFP(N0.getOperand(0)); + // (fadd (fadd x, x), x) -> (fmul x, 3.0) + if (!CFP00 && N0.getOperand(0) == N0.getOperand(1) && + (N0.getOperand(0) == N1)) { + return DAG.getNode(ISD::FMUL, DL, VT, N1, + DAG.getConstantFP(3.0, DL, VT)); + } + } + + if (N1.getOpcode() == ISD::FADD) { + bool CFP10 = DAG.isConstantFPBuildVectorOrConstantFP(N1.getOperand(0)); + // (fadd x, (fadd x, x)) -> (fmul x, 3.0) + if (!CFP10 && N1.getOperand(0) == N1.getOperand(1) && + N1.getOperand(0) == N0) { + return DAG.getNode(ISD::FMUL, DL, VT, N0, + DAG.getConstantFP(3.0, DL, VT)); + } + } + + // (fadd (fadd x, x), (fadd x, x)) -> (fmul x, 4.0) + if (N0.getOpcode() == ISD::FADD && N1.getOpcode() == ISD::FADD && + N0.getOperand(0) == N0.getOperand(1) && + N1.getOperand(0) == N1.getOperand(1) && + N0.getOperand(0) == N1.getOperand(0)) { + return DAG.getNode(ISD::FMUL, DL, VT, N0.getOperand(0), + DAG.getConstantFP(4.0, DL, VT)); + } + } + } // enable-unsafe-fp-math + + // FADD -> FMA combines: + if (SDValue Fused = visitFADDForFMACombine(N)) { + AddToWorklist(Fused.getNode()); + return Fused; + } + return SDValue(); +} + +SDValue DAGCombiner::visitSTRICT_FADD(SDNode *N) { + SDValue Chain = N->getOperand(0); + SDValue N0 = N->getOperand(1); + SDValue N1 = N->getOperand(2); + EVT VT = N->getValueType(0); + EVT ChainVT = N->getValueType(1); + SDLoc DL(N); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + // fold (strict_fadd A, (fneg B)) -> (strict_fsub A, B) + if (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::STRICT_FSUB, VT)) + if (SDValue NegN1 = TLI.getCheaperNegatedExpression( + N1, DAG, LegalOperations, ForCodeSize)) { + return DAG.getNode(ISD::STRICT_FSUB, DL, DAG.getVTList(VT, ChainVT), + {Chain, N0, NegN1}); + } + + // fold (strict_fadd (fneg A), B) -> (strict_fsub B, A) + if (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::STRICT_FSUB, VT)) + if (SDValue NegN0 = TLI.getCheaperNegatedExpression( + N0, DAG, LegalOperations, ForCodeSize)) { + return DAG.getNode(ISD::STRICT_FSUB, DL, DAG.getVTList(VT, ChainVT), + {Chain, N1, NegN0}); + } + return SDValue(); +} + +SDValue DAGCombiner::visitFSUB(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantFPSDNode *N0CFP = isConstOrConstSplatFP(N0, true); + ConstantFPSDNode *N1CFP = isConstOrConstSplatFP(N1, true); + EVT VT = N->getValueType(0); + SDLoc DL(N); + const TargetOptions &Options = DAG.getTarget().Options; + const SDNodeFlags Flags = N->getFlags(); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + if (SDValue R = DAG.simplifyFPBinop(N->getOpcode(), N0, N1, Flags)) + return R; + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (fsub c1, c2) -> c1-c2 + if (N0CFP && N1CFP) + return DAG.getNode(ISD::FSUB, DL, VT, N0, N1); + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + // (fsub A, 0) -> A + if (N1CFP && N1CFP->isZero()) { + if (!N1CFP->isNegative() || Options.NoSignedZerosFPMath || + Flags.hasNoSignedZeros()) { + return N0; + } + } + + if (N0 == N1) { + // (fsub x, x) -> 0.0 + if (Options.NoNaNsFPMath || Flags.hasNoNaNs()) + return DAG.getConstantFP(0.0f, DL, VT); + } + + // (fsub -0.0, N1) -> -N1 + if (N0CFP && N0CFP->isZero()) { + if (N0CFP->isNegative() || + (Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros())) { + // We cannot replace an FSUB(+-0.0,X) with FNEG(X) when denormals are + // flushed to zero, unless all users treat denorms as zero (DAZ). + // FIXME: This transform will change the sign of a NaN and the behavior + // of a signaling NaN. It is only valid when a NoNaN flag is present. + DenormalMode DenormMode = DAG.getDenormalMode(VT); + if (DenormMode == DenormalMode::getIEEE()) { + if (SDValue NegN1 = + TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize)) + return NegN1; + if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) + return DAG.getNode(ISD::FNEG, DL, VT, N1); + } + } + } + + if (((Options.UnsafeFPMath && Options.NoSignedZerosFPMath) || + (Flags.hasAllowReassociation() && Flags.hasNoSignedZeros())) && + N1.getOpcode() == ISD::FADD) { + // X - (X + Y) -> -Y + if (N0 == N1->getOperand(0)) + return DAG.getNode(ISD::FNEG, DL, VT, N1->getOperand(1)); + // X - (Y + X) -> -Y + if (N0 == N1->getOperand(1)) + return DAG.getNode(ISD::FNEG, DL, VT, N1->getOperand(0)); + } + + // fold (fsub A, (fneg B)) -> (fadd A, B) + if (SDValue NegN1 = + TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize)) + return DAG.getNode(ISD::FADD, DL, VT, N0, NegN1); + + // FSUB -> FMA combines: + if (SDValue Fused = visitFSUBForFMACombine(N)) { + AddToWorklist(Fused.getNode()); + return Fused; + } + + return SDValue(); +} + +SDValue DAGCombiner::visitFMUL(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantFPSDNode *N0CFP = isConstOrConstSplatFP(N0, true); + ConstantFPSDNode *N1CFP = isConstOrConstSplatFP(N1, true); + EVT VT = N->getValueType(0); + SDLoc DL(N); + const TargetOptions &Options = DAG.getTarget().Options; + const SDNodeFlags Flags = N->getFlags(); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + if (SDValue R = DAG.simplifyFPBinop(N->getOpcode(), N0, N1, Flags)) + return R; + + // fold vector ops + if (VT.isVector()) { + // This just handles C1 * C2 for vectors. Other vector folds are below. + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + } + + // fold (fmul c1, c2) -> c1*c2 + if (N0CFP && N1CFP) + return DAG.getNode(ISD::FMUL, DL, VT, N0, N1); + + // canonicalize constant to RHS + if (DAG.isConstantFPBuildVectorOrConstantFP(N0) && + !DAG.isConstantFPBuildVectorOrConstantFP(N1)) + return DAG.getNode(ISD::FMUL, DL, VT, N1, N0); + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + if (Options.UnsafeFPMath || Flags.hasAllowReassociation()) { + // fmul (fmul X, C1), C2 -> fmul X, C1 * C2 + if (DAG.isConstantFPBuildVectorOrConstantFP(N1) && + N0.getOpcode() == ISD::FMUL) { + SDValue N00 = N0.getOperand(0); + SDValue N01 = N0.getOperand(1); + // Avoid an infinite loop by making sure that N00 is not a constant + // (the inner multiply has not been constant folded yet). + if (DAG.isConstantFPBuildVectorOrConstantFP(N01) && + !DAG.isConstantFPBuildVectorOrConstantFP(N00)) { + SDValue MulConsts = DAG.getNode(ISD::FMUL, DL, VT, N01, N1); + return DAG.getNode(ISD::FMUL, DL, VT, N00, MulConsts); + } + } + + // Match a special-case: we convert X * 2.0 into fadd. + // fmul (fadd X, X), C -> fmul X, 2.0 * C + if (N0.getOpcode() == ISD::FADD && N0.hasOneUse() && + N0.getOperand(0) == N0.getOperand(1)) { + const SDValue Two = DAG.getConstantFP(2.0, DL, VT); + SDValue MulConsts = DAG.getNode(ISD::FMUL, DL, VT, Two, N1); + return DAG.getNode(ISD::FMUL, DL, VT, N0.getOperand(0), MulConsts); + } + } + + // fold (fmul X, 2.0) -> (fadd X, X) + if (N1CFP && N1CFP->isExactlyValue(+2.0)) + return DAG.getNode(ISD::FADD, DL, VT, N0, N0); + + // fold (fmul X, -1.0) -> (fneg X) + if (N1CFP && N1CFP->isExactlyValue(-1.0)) + if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) + return DAG.getNode(ISD::FNEG, DL, VT, N0); + + // -N0 * -N1 --> N0 * N1 + TargetLowering::NegatibleCost CostN0 = + TargetLowering::NegatibleCost::Expensive; + TargetLowering::NegatibleCost CostN1 = + TargetLowering::NegatibleCost::Expensive; + SDValue NegN0 = + TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize, CostN0); + SDValue NegN1 = + TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize, CostN1); + if (NegN0 && NegN1 && + (CostN0 == TargetLowering::NegatibleCost::Cheaper || + CostN1 == TargetLowering::NegatibleCost::Cheaper)) + return DAG.getNode(ISD::FMUL, DL, VT, NegN0, NegN1); + + // fold (fmul X, (select (fcmp X > 0.0), -1.0, 1.0)) -> (fneg (fabs X)) + // fold (fmul X, (select (fcmp X > 0.0), 1.0, -1.0)) -> (fabs X) + if (Flags.hasNoNaNs() && Flags.hasNoSignedZeros() && + (N0.getOpcode() == ISD::SELECT || N1.getOpcode() == ISD::SELECT) && + TLI.isOperationLegal(ISD::FABS, VT)) { + SDValue Select = N0, X = N1; + if (Select.getOpcode() != ISD::SELECT) + std::swap(Select, X); + + SDValue Cond = Select.getOperand(0); + auto TrueOpnd = dyn_cast<ConstantFPSDNode>(Select.getOperand(1)); + auto FalseOpnd = dyn_cast<ConstantFPSDNode>(Select.getOperand(2)); + + if (TrueOpnd && FalseOpnd && + Cond.getOpcode() == ISD::SETCC && Cond.getOperand(0) == X && + isa<ConstantFPSDNode>(Cond.getOperand(1)) && + cast<ConstantFPSDNode>(Cond.getOperand(1))->isExactlyValue(0.0)) { + ISD::CondCode CC = cast<CondCodeSDNode>(Cond.getOperand(2))->get(); + switch (CC) { + default: break; + case ISD::SETOLT: + case ISD::SETULT: + case ISD::SETOLE: + case ISD::SETULE: + case ISD::SETLT: + case ISD::SETLE: + std::swap(TrueOpnd, FalseOpnd); + LLVM_FALLTHROUGH; + case ISD::SETOGT: + case ISD::SETUGT: + case ISD::SETOGE: + case ISD::SETUGE: + case ISD::SETGT: + case ISD::SETGE: + if (TrueOpnd->isExactlyValue(-1.0) && FalseOpnd->isExactlyValue(1.0) && + TLI.isOperationLegal(ISD::FNEG, VT)) + return DAG.getNode(ISD::FNEG, DL, VT, + DAG.getNode(ISD::FABS, DL, VT, X)); + if (TrueOpnd->isExactlyValue(1.0) && FalseOpnd->isExactlyValue(-1.0)) + return DAG.getNode(ISD::FABS, DL, VT, X); + + break; + } + } + } + + // FMUL -> FMA combines: + if (SDValue Fused = visitFMULForFMADistributiveCombine(N)) { + AddToWorklist(Fused.getNode()); + return Fused; + } + + return SDValue(); +} + +SDValue DAGCombiner::visitFMA(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); + EVT VT = N->getValueType(0); + SDLoc DL(N); + const TargetOptions &Options = DAG.getTarget().Options; + // FMA nodes have flags that propagate to the created nodes. + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + bool UnsafeFPMath = + Options.UnsafeFPMath || N->getFlags().hasAllowReassociation(); + + // Constant fold FMA. + if (isa<ConstantFPSDNode>(N0) && + isa<ConstantFPSDNode>(N1) && + isa<ConstantFPSDNode>(N2)) { + return DAG.getNode(ISD::FMA, DL, VT, N0, N1, N2); + } + + // (-N0 * -N1) + N2 --> (N0 * N1) + N2 + TargetLowering::NegatibleCost CostN0 = + TargetLowering::NegatibleCost::Expensive; + TargetLowering::NegatibleCost CostN1 = + TargetLowering::NegatibleCost::Expensive; + SDValue NegN0 = + TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize, CostN0); + SDValue NegN1 = + TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize, CostN1); + if (NegN0 && NegN1 && + (CostN0 == TargetLowering::NegatibleCost::Cheaper || + CostN1 == TargetLowering::NegatibleCost::Cheaper)) + return DAG.getNode(ISD::FMA, DL, VT, NegN0, NegN1, N2); + + if (UnsafeFPMath) { + if (N0CFP && N0CFP->isZero()) + return N2; + if (N1CFP && N1CFP->isZero()) + return N2; + } + + if (N0CFP && N0CFP->isExactlyValue(1.0)) + return DAG.getNode(ISD::FADD, SDLoc(N), VT, N1, N2); + if (N1CFP && N1CFP->isExactlyValue(1.0)) + return DAG.getNode(ISD::FADD, SDLoc(N), VT, N0, N2); + + // Canonicalize (fma c, x, y) -> (fma x, c, y) + if (DAG.isConstantFPBuildVectorOrConstantFP(N0) && + !DAG.isConstantFPBuildVectorOrConstantFP(N1)) + return DAG.getNode(ISD::FMA, SDLoc(N), VT, N1, N0, N2); + + if (UnsafeFPMath) { + // (fma x, c1, (fmul x, c2)) -> (fmul x, c1+c2) + if (N2.getOpcode() == ISD::FMUL && N0 == N2.getOperand(0) && + DAG.isConstantFPBuildVectorOrConstantFP(N1) && + DAG.isConstantFPBuildVectorOrConstantFP(N2.getOperand(1))) { + return DAG.getNode(ISD::FMUL, DL, VT, N0, + DAG.getNode(ISD::FADD, DL, VT, N1, N2.getOperand(1))); + } + + // (fma (fmul x, c1), c2, y) -> (fma x, c1*c2, y) + if (N0.getOpcode() == ISD::FMUL && + DAG.isConstantFPBuildVectorOrConstantFP(N1) && + DAG.isConstantFPBuildVectorOrConstantFP(N0.getOperand(1))) { + return DAG.getNode(ISD::FMA, DL, VT, N0.getOperand(0), + DAG.getNode(ISD::FMUL, DL, VT, N1, N0.getOperand(1)), + N2); + } + } + + // (fma x, -1, y) -> (fadd (fneg x), y) + if (N1CFP) { + if (N1CFP->isExactlyValue(1.0)) + return DAG.getNode(ISD::FADD, DL, VT, N0, N2); + + if (N1CFP->isExactlyValue(-1.0) && + (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))) { + SDValue RHSNeg = DAG.getNode(ISD::FNEG, DL, VT, N0); + AddToWorklist(RHSNeg.getNode()); + return DAG.getNode(ISD::FADD, DL, VT, N2, RHSNeg); + } + + // fma (fneg x), K, y -> fma x -K, y + if (N0.getOpcode() == ISD::FNEG && + (TLI.isOperationLegal(ISD::ConstantFP, VT) || + (N1.hasOneUse() && !TLI.isFPImmLegal(N1CFP->getValueAPF(), VT, + ForCodeSize)))) { + return DAG.getNode(ISD::FMA, DL, VT, N0.getOperand(0), + DAG.getNode(ISD::FNEG, DL, VT, N1), N2); + } + } + + if (UnsafeFPMath) { + // (fma x, c, x) -> (fmul x, (c+1)) + if (N1CFP && N0 == N2) { + return DAG.getNode( + ISD::FMUL, DL, VT, N0, + DAG.getNode(ISD::FADD, DL, VT, N1, DAG.getConstantFP(1.0, DL, VT))); + } + + // (fma x, c, (fneg x)) -> (fmul x, (c-1)) + if (N1CFP && N2.getOpcode() == ISD::FNEG && N2.getOperand(0) == N0) { + return DAG.getNode( + ISD::FMUL, DL, VT, N0, + DAG.getNode(ISD::FADD, DL, VT, N1, DAG.getConstantFP(-1.0, DL, VT))); + } + } + + // fold ((fma (fneg X), Y, (fneg Z)) -> fneg (fma X, Y, Z)) + // fold ((fma X, (fneg Y), (fneg Z)) -> fneg (fma X, Y, Z)) + if (!TLI.isFNegFree(VT)) + if (SDValue Neg = TLI.getCheaperNegatedExpression( + SDValue(N, 0), DAG, LegalOperations, ForCodeSize)) + return DAG.getNode(ISD::FNEG, DL, VT, Neg); + return SDValue(); +} + +// Combine multiple FDIVs with the same divisor into multiple FMULs by the +// reciprocal. +// E.g., (a / D; b / D;) -> (recip = 1.0 / D; a * recip; b * recip) +// Notice that this is not always beneficial. One reason is different targets +// may have different costs for FDIV and FMUL, so sometimes the cost of two +// FDIVs may be lower than the cost of one FDIV and two FMULs. Another reason +// is the critical path is increased from "one FDIV" to "one FDIV + one FMUL". +SDValue DAGCombiner::combineRepeatedFPDivisors(SDNode *N) { + // TODO: Limit this transform based on optsize/minsize - it always creates at + // least 1 extra instruction. But the perf win may be substantial enough + // that only minsize should restrict this. + bool UnsafeMath = DAG.getTarget().Options.UnsafeFPMath; + const SDNodeFlags Flags = N->getFlags(); + if (LegalDAG || (!UnsafeMath && !Flags.hasAllowReciprocal())) + return SDValue(); + + // Skip if current node is a reciprocal/fneg-reciprocal. + SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); + ConstantFPSDNode *N0CFP = isConstOrConstSplatFP(N0, /* AllowUndefs */ true); + if (N0CFP && (N0CFP->isExactlyValue(1.0) || N0CFP->isExactlyValue(-1.0))) + return SDValue(); + + // Exit early if the target does not want this transform or if there can't + // possibly be enough uses of the divisor to make the transform worthwhile. + unsigned MinUses = TLI.combineRepeatedFPDivisors(); + + // For splat vectors, scale the number of uses by the splat factor. If we can + // convert the division into a scalar op, that will likely be much faster. + unsigned NumElts = 1; + EVT VT = N->getValueType(0); + if (VT.isVector() && DAG.isSplatValue(N1)) + NumElts = VT.getVectorNumElements(); + + if (!MinUses || (N1->use_size() * NumElts) < MinUses) + return SDValue(); + + // Find all FDIV users of the same divisor. + // Use a set because duplicates may be present in the user list. + SetVector<SDNode *> Users; + for (auto *U : N1->uses()) { + if (U->getOpcode() == ISD::FDIV && U->getOperand(1) == N1) { + // Skip X/sqrt(X) that has not been simplified to sqrt(X) yet. + if (U->getOperand(1).getOpcode() == ISD::FSQRT && + U->getOperand(0) == U->getOperand(1).getOperand(0) && + U->getFlags().hasAllowReassociation() && + U->getFlags().hasNoSignedZeros()) + continue; + + // This division is eligible for optimization only if global unsafe math + // is enabled or if this division allows reciprocal formation. + if (UnsafeMath || U->getFlags().hasAllowReciprocal()) + Users.insert(U); + } + } + + // Now that we have the actual number of divisor uses, make sure it meets + // the minimum threshold specified by the target. + if ((Users.size() * NumElts) < MinUses) + return SDValue(); + + SDLoc DL(N); + SDValue FPOne = DAG.getConstantFP(1.0, DL, VT); + SDValue Reciprocal = DAG.getNode(ISD::FDIV, DL, VT, FPOne, N1, Flags); + + // Dividend / Divisor -> Dividend * Reciprocal + for (auto *U : Users) { + SDValue Dividend = U->getOperand(0); + if (Dividend != FPOne) { + SDValue NewNode = DAG.getNode(ISD::FMUL, SDLoc(U), VT, Dividend, + Reciprocal, Flags); + CombineTo(U, NewNode); + } else if (U != Reciprocal.getNode()) { + // In the absence of fast-math-flags, this user node is always the + // same node as Reciprocal, but with FMF they may be different nodes. + CombineTo(U, Reciprocal); + } + } + return SDValue(N, 0); // N was replaced. +} + +SDValue DAGCombiner::visitFDIV(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); + EVT VT = N->getValueType(0); + SDLoc DL(N); + const TargetOptions &Options = DAG.getTarget().Options; + SDNodeFlags Flags = N->getFlags(); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + if (SDValue R = DAG.simplifyFPBinop(N->getOpcode(), N0, N1, Flags)) + return R; + + // fold vector ops + if (VT.isVector()) + if (SDValue FoldedVOp = SimplifyVBinOp(N)) + return FoldedVOp; + + // fold (fdiv c1, c2) -> c1/c2 + if (N0CFP && N1CFP) + return DAG.getNode(ISD::FDIV, SDLoc(N), VT, N0, N1); + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + if (SDValue V = combineRepeatedFPDivisors(N)) + return V; + + if (Options.UnsafeFPMath || Flags.hasAllowReciprocal()) { + // fold (fdiv X, c2) -> fmul X, 1/c2 if losing precision is acceptable. + if (N1CFP) { + // Compute the reciprocal 1.0 / c2. + const APFloat &N1APF = N1CFP->getValueAPF(); + APFloat Recip(N1APF.getSemantics(), 1); // 1.0 + APFloat::opStatus st = Recip.divide(N1APF, APFloat::rmNearestTiesToEven); + // Only do the transform if the reciprocal is a legal fp immediate that + // isn't too nasty (eg NaN, denormal, ...). + if ((st == APFloat::opOK || st == APFloat::opInexact) && // Not too nasty + (!LegalOperations || + // FIXME: custom lowering of ConstantFP might fail (see e.g. ARM + // backend)... we should handle this gracefully after Legalize. + // TLI.isOperationLegalOrCustom(ISD::ConstantFP, VT) || + TLI.isOperationLegal(ISD::ConstantFP, VT) || + TLI.isFPImmLegal(Recip, VT, ForCodeSize))) + return DAG.getNode(ISD::FMUL, DL, VT, N0, + DAG.getConstantFP(Recip, DL, VT)); + } + + // If this FDIV is part of a reciprocal square root, it may be folded + // into a target-specific square root estimate instruction. + if (N1.getOpcode() == ISD::FSQRT) { + if (SDValue RV = buildRsqrtEstimate(N1.getOperand(0), Flags)) + return DAG.getNode(ISD::FMUL, DL, VT, N0, RV); + } else if (N1.getOpcode() == ISD::FP_EXTEND && + N1.getOperand(0).getOpcode() == ISD::FSQRT) { + if (SDValue RV = + buildRsqrtEstimate(N1.getOperand(0).getOperand(0), Flags)) { + RV = DAG.getNode(ISD::FP_EXTEND, SDLoc(N1), VT, RV); + AddToWorklist(RV.getNode()); + return DAG.getNode(ISD::FMUL, DL, VT, N0, RV); + } + } else if (N1.getOpcode() == ISD::FP_ROUND && + N1.getOperand(0).getOpcode() == ISD::FSQRT) { + if (SDValue RV = + buildRsqrtEstimate(N1.getOperand(0).getOperand(0), Flags)) { + RV = DAG.getNode(ISD::FP_ROUND, SDLoc(N1), VT, RV, N1.getOperand(1)); + AddToWorklist(RV.getNode()); + return DAG.getNode(ISD::FMUL, DL, VT, N0, RV); + } + } else if (N1.getOpcode() == ISD::FMUL) { + // Look through an FMUL. Even though this won't remove the FDIV directly, + // it's still worthwhile to get rid of the FSQRT if possible. + SDValue Sqrt, Y; + if (N1.getOperand(0).getOpcode() == ISD::FSQRT) { + Sqrt = N1.getOperand(0); + Y = N1.getOperand(1); + } else if (N1.getOperand(1).getOpcode() == ISD::FSQRT) { + Sqrt = N1.getOperand(1); + Y = N1.getOperand(0); + } + if (Sqrt.getNode()) { + // If the other multiply operand is known positive, pull it into the + // sqrt. That will eliminate the division if we convert to an estimate. + if (Flags.hasAllowReassociation() && N1.hasOneUse() && + N1->getFlags().hasAllowReassociation() && Sqrt.hasOneUse()) { + SDValue A; + if (Y.getOpcode() == ISD::FABS && Y.hasOneUse()) + A = Y.getOperand(0); + else if (Y == Sqrt.getOperand(0)) + A = Y; + if (A) { + // X / (fabs(A) * sqrt(Z)) --> X / sqrt(A*A*Z) --> X * rsqrt(A*A*Z) + // X / (A * sqrt(A)) --> X / sqrt(A*A*A) --> X * rsqrt(A*A*A) + SDValue AA = DAG.getNode(ISD::FMUL, DL, VT, A, A); + SDValue AAZ = + DAG.getNode(ISD::FMUL, DL, VT, AA, Sqrt.getOperand(0)); + if (SDValue Rsqrt = buildRsqrtEstimate(AAZ, Flags)) + return DAG.getNode(ISD::FMUL, DL, VT, N0, Rsqrt); + + // Estimate creation failed. Clean up speculatively created nodes. + recursivelyDeleteUnusedNodes(AAZ.getNode()); + } + } + + // We found a FSQRT, so try to make this fold: + // X / (Y * sqrt(Z)) -> X * (rsqrt(Z) / Y) + if (SDValue Rsqrt = buildRsqrtEstimate(Sqrt.getOperand(0), Flags)) { + SDValue Div = DAG.getNode(ISD::FDIV, SDLoc(N1), VT, Rsqrt, Y); + AddToWorklist(Div.getNode()); + return DAG.getNode(ISD::FMUL, DL, VT, N0, Div); + } + } + } + + // Fold into a reciprocal estimate and multiply instead of a real divide. + if (Options.NoInfsFPMath || Flags.hasNoInfs()) + if (SDValue RV = BuildDivEstimate(N0, N1, Flags)) + return RV; + } + + // Fold X/Sqrt(X) -> Sqrt(X) + if ((Options.NoSignedZerosFPMath || Flags.hasNoSignedZeros()) && + (Options.UnsafeFPMath || Flags.hasAllowReassociation())) + if (N1.getOpcode() == ISD::FSQRT && N0 == N1.getOperand(0)) + return N1; + + // (fdiv (fneg X), (fneg Y)) -> (fdiv X, Y) + TargetLowering::NegatibleCost CostN0 = + TargetLowering::NegatibleCost::Expensive; + TargetLowering::NegatibleCost CostN1 = + TargetLowering::NegatibleCost::Expensive; + SDValue NegN0 = + TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize, CostN0); + SDValue NegN1 = + TLI.getNegatedExpression(N1, DAG, LegalOperations, ForCodeSize, CostN1); + if (NegN0 && NegN1 && + (CostN0 == TargetLowering::NegatibleCost::Cheaper || + CostN1 == TargetLowering::NegatibleCost::Cheaper)) + return DAG.getNode(ISD::FDIV, SDLoc(N), VT, NegN0, NegN1); + + return SDValue(); +} + +SDValue DAGCombiner::visitFREM(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); + ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); + EVT VT = N->getValueType(0); + SDNodeFlags Flags = N->getFlags(); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + if (SDValue R = DAG.simplifyFPBinop(N->getOpcode(), N0, N1, Flags)) + return R; + + // fold (frem c1, c2) -> fmod(c1,c2) + if (N0CFP && N1CFP) + return DAG.getNode(ISD::FREM, SDLoc(N), VT, N0, N1); + + if (SDValue NewSel = foldBinOpIntoSelect(N)) + return NewSel; + + return SDValue(); +} + +SDValue DAGCombiner::visitFSQRT(SDNode *N) { + SDNodeFlags Flags = N->getFlags(); + const TargetOptions &Options = DAG.getTarget().Options; + + // Require 'ninf' flag since sqrt(+Inf) = +Inf, but the estimation goes as: + // sqrt(+Inf) == rsqrt(+Inf) * +Inf = 0 * +Inf = NaN + if (!Flags.hasApproximateFuncs() || + (!Options.NoInfsFPMath && !Flags.hasNoInfs())) + return SDValue(); + + SDValue N0 = N->getOperand(0); + if (TLI.isFsqrtCheap(N0, DAG)) + return SDValue(); + + // FSQRT nodes have flags that propagate to the created nodes. + // TODO: If this is N0/sqrt(N0), and we reach this node before trying to + // transform the fdiv, we may produce a sub-optimal estimate sequence + // because the reciprocal calculation may not have to filter out a + // 0.0 input. + return buildSqrtEstimate(N0, Flags); +} + +/// copysign(x, fp_extend(y)) -> copysign(x, y) +/// copysign(x, fp_round(y)) -> copysign(x, y) +static inline bool CanCombineFCOPYSIGN_EXTEND_ROUND(SDNode *N) { + SDValue N1 = N->getOperand(1); + if ((N1.getOpcode() == ISD::FP_EXTEND || + N1.getOpcode() == ISD::FP_ROUND)) { + // Do not optimize out type conversion of f128 type yet. + // For some targets like x86_64, configuration is changed to keep one f128 + // value in one SSE register, but instruction selection cannot handle + // FCOPYSIGN on SSE registers yet. + EVT N1VT = N1->getValueType(0); + EVT N1Op0VT = N1->getOperand(0).getValueType(); + return (N1VT == N1Op0VT || N1Op0VT != MVT::f128); + } + return false; +} + +SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + bool N0CFP = DAG.isConstantFPBuildVectorOrConstantFP(N0); + bool N1CFP = DAG.isConstantFPBuildVectorOrConstantFP(N1); + EVT VT = N->getValueType(0); + + if (N0CFP && N1CFP) // Constant fold + return DAG.getNode(ISD::FCOPYSIGN, SDLoc(N), VT, N0, N1); + + if (ConstantFPSDNode *N1C = isConstOrConstSplatFP(N->getOperand(1))) { + const APFloat &V = N1C->getValueAPF(); + // copysign(x, c1) -> fabs(x) iff ispos(c1) + // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) + if (!V.isNegative()) { + if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT)) + return DAG.getNode(ISD::FABS, SDLoc(N), VT, N0); + } else { + if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT)) + return DAG.getNode(ISD::FNEG, SDLoc(N), VT, + DAG.getNode(ISD::FABS, SDLoc(N0), VT, N0)); + } + } + + // copysign(fabs(x), y) -> copysign(x, y) + // copysign(fneg(x), y) -> copysign(x, y) + // copysign(copysign(x,z), y) -> copysign(x, y) + if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || + N0.getOpcode() == ISD::FCOPYSIGN) + return DAG.getNode(ISD::FCOPYSIGN, SDLoc(N), VT, N0.getOperand(0), N1); + + // copysign(x, abs(y)) -> abs(x) + if (N1.getOpcode() == ISD::FABS) + return DAG.getNode(ISD::FABS, SDLoc(N), VT, N0); + + // copysign(x, copysign(y,z)) -> copysign(x, z) + if (N1.getOpcode() == ISD::FCOPYSIGN) + return DAG.getNode(ISD::FCOPYSIGN, SDLoc(N), VT, N0, N1.getOperand(1)); + + // copysign(x, fp_extend(y)) -> copysign(x, y) + // copysign(x, fp_round(y)) -> copysign(x, y) + if (CanCombineFCOPYSIGN_EXTEND_ROUND(N)) + return DAG.getNode(ISD::FCOPYSIGN, SDLoc(N), VT, N0, N1.getOperand(0)); + + return SDValue(); +} + +SDValue DAGCombiner::visitFPOW(SDNode *N) { + ConstantFPSDNode *ExponentC = isConstOrConstSplatFP(N->getOperand(1)); + if (!ExponentC) + return SDValue(); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + // Try to convert x ** (1/3) into cube root. + // TODO: Handle the various flavors of long double. + // TODO: Since we're approximating, we don't need an exact 1/3 exponent. + // Some range near 1/3 should be fine. + EVT VT = N->getValueType(0); + if ((VT == MVT::f32 && ExponentC->getValueAPF().isExactlyValue(1.0f/3.0f)) || + (VT == MVT::f64 && ExponentC->getValueAPF().isExactlyValue(1.0/3.0))) { + // pow(-0.0, 1/3) = +0.0; cbrt(-0.0) = -0.0. + // pow(-inf, 1/3) = +inf; cbrt(-inf) = -inf. + // pow(-val, 1/3) = nan; cbrt(-val) = -num. + // For regular numbers, rounding may cause the results to differ. + // Therefore, we require { nsz ninf nnan afn } for this transform. + // TODO: We could select out the special cases if we don't have nsz/ninf. + SDNodeFlags Flags = N->getFlags(); + if (!Flags.hasNoSignedZeros() || !Flags.hasNoInfs() || !Flags.hasNoNaNs() || + !Flags.hasApproximateFuncs()) + return SDValue(); + + // Do not create a cbrt() libcall if the target does not have it, and do not + // turn a pow that has lowering support into a cbrt() libcall. + if (!DAG.getLibInfo().has(LibFunc_cbrt) || + (!DAG.getTargetLoweringInfo().isOperationExpand(ISD::FPOW, VT) && + DAG.getTargetLoweringInfo().isOperationExpand(ISD::FCBRT, VT))) + return SDValue(); + + return DAG.getNode(ISD::FCBRT, SDLoc(N), VT, N->getOperand(0)); + } + + // Try to convert x ** (1/4) and x ** (3/4) into square roots. + // x ** (1/2) is canonicalized to sqrt, so we do not bother with that case. + // TODO: This could be extended (using a target hook) to handle smaller + // power-of-2 fractional exponents. + bool ExponentIs025 = ExponentC->getValueAPF().isExactlyValue(0.25); + bool ExponentIs075 = ExponentC->getValueAPF().isExactlyValue(0.75); + if (ExponentIs025 || ExponentIs075) { + // pow(-0.0, 0.25) = +0.0; sqrt(sqrt(-0.0)) = -0.0. + // pow(-inf, 0.25) = +inf; sqrt(sqrt(-inf)) = NaN. + // pow(-0.0, 0.75) = +0.0; sqrt(-0.0) * sqrt(sqrt(-0.0)) = +0.0. + // pow(-inf, 0.75) = +inf; sqrt(-inf) * sqrt(sqrt(-inf)) = NaN. + // For regular numbers, rounding may cause the results to differ. + // Therefore, we require { nsz ninf afn } for this transform. + // TODO: We could select out the special cases if we don't have nsz/ninf. + SDNodeFlags Flags = N->getFlags(); + + // We only need no signed zeros for the 0.25 case. + if ((!Flags.hasNoSignedZeros() && ExponentIs025) || !Flags.hasNoInfs() || + !Flags.hasApproximateFuncs()) + return SDValue(); + + // Don't double the number of libcalls. We are trying to inline fast code. + if (!DAG.getTargetLoweringInfo().isOperationLegalOrCustom(ISD::FSQRT, VT)) + return SDValue(); + + // Assume that libcalls are the smallest code. + // TODO: This restriction should probably be lifted for vectors. + if (ForCodeSize) + return SDValue(); + + // pow(X, 0.25) --> sqrt(sqrt(X)) + SDLoc DL(N); + SDValue Sqrt = DAG.getNode(ISD::FSQRT, DL, VT, N->getOperand(0)); + SDValue SqrtSqrt = DAG.getNode(ISD::FSQRT, DL, VT, Sqrt); + if (ExponentIs025) + return SqrtSqrt; + // pow(X, 0.75) --> sqrt(X) * sqrt(sqrt(X)) + return DAG.getNode(ISD::FMUL, DL, VT, Sqrt, SqrtSqrt); + } + + return SDValue(); +} + +static SDValue foldFPToIntToFP(SDNode *N, SelectionDAG &DAG, + const TargetLowering &TLI) { + // This optimization is guarded by a function attribute because it may produce + // unexpected results. Ie, programs may be relying on the platform-specific + // undefined behavior when the float-to-int conversion overflows. + const Function &F = DAG.getMachineFunction().getFunction(); + Attribute StrictOverflow = F.getFnAttribute("strict-float-cast-overflow"); + if (StrictOverflow.getValueAsString().equals("false")) + return SDValue(); + + // We only do this if the target has legal ftrunc. Otherwise, we'd likely be + // replacing casts with a libcall. We also must be allowed to ignore -0.0 + // because FTRUNC will return -0.0 for (-1.0, -0.0), but using integer + // conversions would return +0.0. + // FIXME: We should be able to use node-level FMF here. + // TODO: If strict math, should we use FABS (+ range check for signed cast)? + EVT VT = N->getValueType(0); + if (!TLI.isOperationLegal(ISD::FTRUNC, VT) || + !DAG.getTarget().Options.NoSignedZerosFPMath) + return SDValue(); + + // fptosi/fptoui round towards zero, so converting from FP to integer and + // back is the same as an 'ftrunc': [us]itofp (fpto[us]i X) --> ftrunc X + SDValue N0 = N->getOperand(0); + if (N->getOpcode() == ISD::SINT_TO_FP && N0.getOpcode() == ISD::FP_TO_SINT && + N0.getOperand(0).getValueType() == VT) + return DAG.getNode(ISD::FTRUNC, SDLoc(N), VT, N0.getOperand(0)); + + if (N->getOpcode() == ISD::UINT_TO_FP && N0.getOpcode() == ISD::FP_TO_UINT && + N0.getOperand(0).getValueType() == VT) + return DAG.getNode(ISD::FTRUNC, SDLoc(N), VT, N0.getOperand(0)); + + return SDValue(); +} + +SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + EVT OpVT = N0.getValueType(); + + // [us]itofp(undef) = 0, because the result value is bounded. + if (N0.isUndef()) + return DAG.getConstantFP(0.0, SDLoc(N), VT); + + // fold (sint_to_fp c1) -> c1fp + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + // ...but only if the target supports immediate floating-point values + (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::ConstantFP, VT))) + return DAG.getNode(ISD::SINT_TO_FP, SDLoc(N), VT, N0); + + // If the input is a legal type, and SINT_TO_FP is not legal on this target, + // but UINT_TO_FP is legal on this target, try to convert. + if (!hasOperation(ISD::SINT_TO_FP, OpVT) && + hasOperation(ISD::UINT_TO_FP, OpVT)) { + // If the sign bit is known to be zero, we can change this to UINT_TO_FP. + if (DAG.SignBitIsZero(N0)) + return DAG.getNode(ISD::UINT_TO_FP, SDLoc(N), VT, N0); + } + + // The next optimizations are desirable only if SELECT_CC can be lowered. + // fold (sint_to_fp (setcc x, y, cc)) -> (select (setcc x, y, cc), -1.0, 0.0) + if (N0.getOpcode() == ISD::SETCC && N0.getValueType() == MVT::i1 && + !VT.isVector() && + (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::ConstantFP, VT))) { + SDLoc DL(N); + return DAG.getSelect(DL, VT, N0, DAG.getConstantFP(-1.0, DL, VT), + DAG.getConstantFP(0.0, DL, VT)); + } + + // fold (sint_to_fp (zext (setcc x, y, cc))) -> + // (select (setcc x, y, cc), 1.0, 0.0) + if (N0.getOpcode() == ISD::ZERO_EXTEND && + N0.getOperand(0).getOpcode() == ISD::SETCC && !VT.isVector() && + (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::ConstantFP, VT))) { + SDLoc DL(N); + return DAG.getSelect(DL, VT, N0.getOperand(0), + DAG.getConstantFP(1.0, DL, VT), + DAG.getConstantFP(0.0, DL, VT)); + } + + if (SDValue FTrunc = foldFPToIntToFP(N, DAG, TLI)) + return FTrunc; + + return SDValue(); +} + +SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + EVT OpVT = N0.getValueType(); + + // [us]itofp(undef) = 0, because the result value is bounded. + if (N0.isUndef()) + return DAG.getConstantFP(0.0, SDLoc(N), VT); + + // fold (uint_to_fp c1) -> c1fp + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && + // ...but only if the target supports immediate floating-point values + (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::ConstantFP, VT))) + return DAG.getNode(ISD::UINT_TO_FP, SDLoc(N), VT, N0); + + // If the input is a legal type, and UINT_TO_FP is not legal on this target, + // but SINT_TO_FP is legal on this target, try to convert. + if (!hasOperation(ISD::UINT_TO_FP, OpVT) && + hasOperation(ISD::SINT_TO_FP, OpVT)) { + // If the sign bit is known to be zero, we can change this to SINT_TO_FP. + if (DAG.SignBitIsZero(N0)) + return DAG.getNode(ISD::SINT_TO_FP, SDLoc(N), VT, N0); + } + + // fold (uint_to_fp (setcc x, y, cc)) -> (select (setcc x, y, cc), 1.0, 0.0) + if (N0.getOpcode() == ISD::SETCC && !VT.isVector() && + (!LegalOperations || TLI.isOperationLegalOrCustom(ISD::ConstantFP, VT))) { + SDLoc DL(N); + return DAG.getSelect(DL, VT, N0, DAG.getConstantFP(1.0, DL, VT), + DAG.getConstantFP(0.0, DL, VT)); + } + + if (SDValue FTrunc = foldFPToIntToFP(N, DAG, TLI)) + return FTrunc; + + return SDValue(); +} + +// Fold (fp_to_{s/u}int ({s/u}int_to_fpx)) -> zext x, sext x, trunc x, or x +static SDValue FoldIntToFPToInt(SDNode *N, SelectionDAG &DAG) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + if (N0.getOpcode() != ISD::UINT_TO_FP && N0.getOpcode() != ISD::SINT_TO_FP) + return SDValue(); + + SDValue Src = N0.getOperand(0); + EVT SrcVT = Src.getValueType(); + bool IsInputSigned = N0.getOpcode() == ISD::SINT_TO_FP; + bool IsOutputSigned = N->getOpcode() == ISD::FP_TO_SINT; + + // We can safely assume the conversion won't overflow the output range, + // because (for example) (uint8_t)18293.f is undefined behavior. + + // Since we can assume the conversion won't overflow, our decision as to + // whether the input will fit in the float should depend on the minimum + // of the input range and output range. + + // This means this is also safe for a signed input and unsigned output, since + // a negative input would lead to undefined behavior. + unsigned InputSize = (int)SrcVT.getScalarSizeInBits() - IsInputSigned; + unsigned OutputSize = (int)VT.getScalarSizeInBits() - IsOutputSigned; + unsigned ActualSize = std::min(InputSize, OutputSize); + const fltSemantics &sem = DAG.EVTToAPFloatSemantics(N0.getValueType()); + + // We can only fold away the float conversion if the input range can be + // represented exactly in the float range. + if (APFloat::semanticsPrecision(sem) >= ActualSize) { + if (VT.getScalarSizeInBits() > SrcVT.getScalarSizeInBits()) { + unsigned ExtOp = IsInputSigned && IsOutputSigned ? ISD::SIGN_EXTEND + : ISD::ZERO_EXTEND; + return DAG.getNode(ExtOp, SDLoc(N), VT, Src); + } + if (VT.getScalarSizeInBits() < SrcVT.getScalarSizeInBits()) + return DAG.getNode(ISD::TRUNCATE, SDLoc(N), VT, Src); + return DAG.getBitcast(VT, Src); + } + return SDValue(); +} + +SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (fp_to_sint undef) -> undef + if (N0.isUndef()) + return DAG.getUNDEF(VT); + + // fold (fp_to_sint c1fp) -> c1 + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FP_TO_SINT, SDLoc(N), VT, N0); + + return FoldIntToFPToInt(N, DAG); +} + +SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (fp_to_uint undef) -> undef + if (N0.isUndef()) + return DAG.getUNDEF(VT); + + // fold (fp_to_uint c1fp) -> c1 + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FP_TO_UINT, SDLoc(N), VT, N0); + + return FoldIntToFPToInt(N, DAG); +} + +SDValue DAGCombiner::visitFP_ROUND(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); + EVT VT = N->getValueType(0); + + // fold (fp_round c1fp) -> c1fp + if (N0CFP) + return DAG.getNode(ISD::FP_ROUND, SDLoc(N), VT, N0, N1); + + // fold (fp_round (fp_extend x)) -> x + if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) + return N0.getOperand(0); + + // fold (fp_round (fp_round x)) -> (fp_round x) + if (N0.getOpcode() == ISD::FP_ROUND) { + const bool NIsTrunc = N->getConstantOperandVal(1) == 1; + const bool N0IsTrunc = N0.getConstantOperandVal(1) == 1; + + // Skip this folding if it results in an fp_round from f80 to f16. + // + // f80 to f16 always generates an expensive (and as yet, unimplemented) + // libcall to __truncxfhf2 instead of selecting native f16 conversion + // instructions from f32 or f64. Moreover, the first (value-preserving) + // fp_round from f80 to either f32 or f64 may become a NOP in platforms like + // x86. + if (N0.getOperand(0).getValueType() == MVT::f80 && VT == MVT::f16) + return SDValue(); + + // If the first fp_round isn't a value preserving truncation, it might + // introduce a tie in the second fp_round, that wouldn't occur in the + // single-step fp_round we want to fold to. + // In other words, double rounding isn't the same as rounding. + // Also, this is a value preserving truncation iff both fp_round's are. + if (DAG.getTarget().Options.UnsafeFPMath || N0IsTrunc) { + SDLoc DL(N); + return DAG.getNode(ISD::FP_ROUND, DL, VT, N0.getOperand(0), + DAG.getIntPtrConstant(NIsTrunc && N0IsTrunc, DL)); + } + } + + // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) + if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) { + SDValue Tmp = DAG.getNode(ISD::FP_ROUND, SDLoc(N0), VT, + N0.getOperand(0), N1); + AddToWorklist(Tmp.getNode()); + return DAG.getNode(ISD::FCOPYSIGN, SDLoc(N), VT, + Tmp, N0.getOperand(1)); + } + + if (SDValue NewVSel = matchVSelectOpSizesWithSetCC(N)) + return NewVSel; + + return SDValue(); +} + +SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded. + if (N->hasOneUse() && + N->use_begin()->getOpcode() == ISD::FP_ROUND) + return SDValue(); + + // fold (fp_extend c1fp) -> c1fp + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FP_EXTEND, SDLoc(N), VT, N0); + + // fold (fp_extend (fp16_to_fp op)) -> (fp16_to_fp op) + if (N0.getOpcode() == ISD::FP16_TO_FP && + TLI.getOperationAction(ISD::FP16_TO_FP, VT) == TargetLowering::Legal) + return DAG.getNode(ISD::FP16_TO_FP, SDLoc(N), VT, N0.getOperand(0)); + + // Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the + // value of X. + if (N0.getOpcode() == ISD::FP_ROUND + && N0.getConstantOperandVal(1) == 1) { + SDValue In = N0.getOperand(0); + if (In.getValueType() == VT) return In; + if (VT.bitsLT(In.getValueType())) + return DAG.getNode(ISD::FP_ROUND, SDLoc(N), VT, + In, N0.getOperand(1)); + return DAG.getNode(ISD::FP_EXTEND, SDLoc(N), VT, In); + } + + // fold (fpext (load x)) -> (fpext (fptrunc (extload x))) + if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && + TLI.isLoadExtLegal(ISD::EXTLOAD, VT, N0.getValueType())) { + LoadSDNode *LN0 = cast<LoadSDNode>(N0); + SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, SDLoc(N), VT, + LN0->getChain(), + LN0->getBasePtr(), N0.getValueType(), + LN0->getMemOperand()); + CombineTo(N, ExtLoad); + CombineTo(N0.getNode(), + DAG.getNode(ISD::FP_ROUND, SDLoc(N0), + N0.getValueType(), ExtLoad, + DAG.getIntPtrConstant(1, SDLoc(N0))), + ExtLoad.getValue(1)); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + + if (SDValue NewVSel = matchVSelectOpSizesWithSetCC(N)) + return NewVSel; + + return SDValue(); +} + +SDValue DAGCombiner::visitFCEIL(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (fceil c1) -> fceil(c1) + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FCEIL, SDLoc(N), VT, N0); + + return SDValue(); +} + +SDValue DAGCombiner::visitFTRUNC(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (ftrunc c1) -> ftrunc(c1) + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FTRUNC, SDLoc(N), VT, N0); + + // fold ftrunc (known rounded int x) -> x + // ftrunc is a part of fptosi/fptoui expansion on some targets, so this is + // likely to be generated to extract integer from a rounded floating value. + switch (N0.getOpcode()) { + default: break; + case ISD::FRINT: + case ISD::FTRUNC: + case ISD::FNEARBYINT: + case ISD::FFLOOR: + case ISD::FCEIL: + return N0; + } + + return SDValue(); +} + +SDValue DAGCombiner::visitFFLOOR(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (ffloor c1) -> ffloor(c1) + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FFLOOR, SDLoc(N), VT, N0); + + return SDValue(); +} + +SDValue DAGCombiner::visitFNEG(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + // Constant fold FNEG. + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FNEG, SDLoc(N), VT, N0); + + if (SDValue NegN0 = + TLI.getNegatedExpression(N0, DAG, LegalOperations, ForCodeSize)) + return NegN0; + + // -(X-Y) -> (Y-X) is unsafe because when X==Y, -0.0 != +0.0 + // FIXME: This is duplicated in getNegatibleCost, but getNegatibleCost doesn't + // know it was called from a context with a nsz flag if the input fsub does + // not. + if (N0.getOpcode() == ISD::FSUB && + (DAG.getTarget().Options.NoSignedZerosFPMath || + N->getFlags().hasNoSignedZeros()) && N0.hasOneUse()) { + return DAG.getNode(ISD::FSUB, SDLoc(N), VT, N0.getOperand(1), + N0.getOperand(0)); + } + + if (SDValue Cast = foldSignChangeInBitcast(N)) + return Cast; + + return SDValue(); +} + +static SDValue visitFMinMax(SelectionDAG &DAG, SDNode *N, + APFloat (*Op)(const APFloat &, const APFloat &)) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + EVT VT = N->getValueType(0); + const ConstantFPSDNode *N0CFP = isConstOrConstSplatFP(N0); + const ConstantFPSDNode *N1CFP = isConstOrConstSplatFP(N1); + const SDNodeFlags Flags = N->getFlags(); + unsigned Opc = N->getOpcode(); + bool PropagatesNaN = Opc == ISD::FMINIMUM || Opc == ISD::FMAXIMUM; + bool IsMin = Opc == ISD::FMINNUM || Opc == ISD::FMINIMUM; + SelectionDAG::FlagInserter FlagsInserter(DAG, N); + + if (N0CFP && N1CFP) { + const APFloat &C0 = N0CFP->getValueAPF(); + const APFloat &C1 = N1CFP->getValueAPF(); + return DAG.getConstantFP(Op(C0, C1), SDLoc(N), VT); + } + + // Canonicalize to constant on RHS. + if (DAG.isConstantFPBuildVectorOrConstantFP(N0) && + !DAG.isConstantFPBuildVectorOrConstantFP(N1)) + return DAG.getNode(N->getOpcode(), SDLoc(N), VT, N1, N0); + + if (N1CFP) { + const APFloat &AF = N1CFP->getValueAPF(); + + // minnum(X, nan) -> X + // maxnum(X, nan) -> X + // minimum(X, nan) -> nan + // maximum(X, nan) -> nan + if (AF.isNaN()) + return PropagatesNaN ? N->getOperand(1) : N->getOperand(0); + + // In the following folds, inf can be replaced with the largest finite + // float, if the ninf flag is set. + if (AF.isInfinity() || (Flags.hasNoInfs() && AF.isLargest())) { + // minnum(X, -inf) -> -inf + // maxnum(X, +inf) -> +inf + // minimum(X, -inf) -> -inf if nnan + // maximum(X, +inf) -> +inf if nnan + if (IsMin == AF.isNegative() && (!PropagatesNaN || Flags.hasNoNaNs())) + return N->getOperand(1); + + // minnum(X, +inf) -> X if nnan + // maxnum(X, -inf) -> X if nnan + // minimum(X, +inf) -> X + // maximum(X, -inf) -> X + if (IsMin != AF.isNegative() && (PropagatesNaN || Flags.hasNoNaNs())) + return N->getOperand(0); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitFMINNUM(SDNode *N) { + return visitFMinMax(DAG, N, minnum); +} + +SDValue DAGCombiner::visitFMAXNUM(SDNode *N) { + return visitFMinMax(DAG, N, maxnum); +} + +SDValue DAGCombiner::visitFMINIMUM(SDNode *N) { + return visitFMinMax(DAG, N, minimum); +} + +SDValue DAGCombiner::visitFMAXIMUM(SDNode *N) { + return visitFMinMax(DAG, N, maximum); +} + +SDValue DAGCombiner::visitFABS(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + + // fold (fabs c1) -> fabs(c1) + if (DAG.isConstantFPBuildVectorOrConstantFP(N0)) + return DAG.getNode(ISD::FABS, SDLoc(N), VT, N0); + + // fold (fabs (fabs x)) -> (fabs x) + if (N0.getOpcode() == ISD::FABS) + return N->getOperand(0); + + // fold (fabs (fneg x)) -> (fabs x) + // fold (fabs (fcopysign x, y)) -> (fabs x) + if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) + return DAG.getNode(ISD::FABS, SDLoc(N), VT, N0.getOperand(0)); + + if (SDValue Cast = foldSignChangeInBitcast(N)) + return Cast; + + return SDValue(); +} + +SDValue DAGCombiner::visitBRCOND(SDNode *N) { + SDValue Chain = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + + // BRCOND(FREEZE(cond)) is equivalent to BRCOND(cond) (both are + // nondeterministic jumps). + if (N1->getOpcode() == ISD::FREEZE && N1.hasOneUse()) { + return DAG.getNode(ISD::BRCOND, SDLoc(N), MVT::Other, Chain, + N1->getOperand(0), N2); + } + + // If N is a constant we could fold this into a fallthrough or unconditional + // branch. However that doesn't happen very often in normal code, because + // Instcombine/SimplifyCFG should have handled the available opportunities. + // If we did this folding here, it would be necessary to update the + // MachineBasicBlock CFG, which is awkward. + + // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal + // on the target. + if (N1.getOpcode() == ISD::SETCC && + TLI.isOperationLegalOrCustom(ISD::BR_CC, + N1.getOperand(0).getValueType())) { + return DAG.getNode(ISD::BR_CC, SDLoc(N), MVT::Other, + Chain, N1.getOperand(2), + N1.getOperand(0), N1.getOperand(1), N2); + } + + if (N1.hasOneUse()) { + // rebuildSetCC calls visitXor which may change the Chain when there is a + // STRICT_FSETCC/STRICT_FSETCCS involved. Use a handle to track changes. + HandleSDNode ChainHandle(Chain); + if (SDValue NewN1 = rebuildSetCC(N1)) + return DAG.getNode(ISD::BRCOND, SDLoc(N), MVT::Other, + ChainHandle.getValue(), NewN1, N2); + } + + return SDValue(); +} + +SDValue DAGCombiner::rebuildSetCC(SDValue N) { + if (N.getOpcode() == ISD::SRL || + (N.getOpcode() == ISD::TRUNCATE && + (N.getOperand(0).hasOneUse() && + N.getOperand(0).getOpcode() == ISD::SRL))) { + // Look pass the truncate. + if (N.getOpcode() == ISD::TRUNCATE) + N = N.getOperand(0); + + // Match this pattern so that we can generate simpler code: + // + // %a = ... + // %b = and i32 %a, 2 + // %c = srl i32 %b, 1 + // brcond i32 %c ... + // + // into + // + // %a = ... + // %b = and i32 %a, 2 + // %c = setcc eq %b, 0 + // brcond %c ... + // + // This applies only when the AND constant value has one bit set and the + // SRL constant is equal to the log2 of the AND constant. The back-end is + // smart enough to convert the result into a TEST/JMP sequence. + SDValue Op0 = N.getOperand(0); + SDValue Op1 = N.getOperand(1); + + if (Op0.getOpcode() == ISD::AND && Op1.getOpcode() == ISD::Constant) { + SDValue AndOp1 = Op0.getOperand(1); + + if (AndOp1.getOpcode() == ISD::Constant) { + const APInt &AndConst = cast<ConstantSDNode>(AndOp1)->getAPIntValue(); + + if (AndConst.isPowerOf2() && + cast<ConstantSDNode>(Op1)->getAPIntValue() == AndConst.logBase2()) { + SDLoc DL(N); + return DAG.getSetCC(DL, getSetCCResultType(Op0.getValueType()), + Op0, DAG.getConstant(0, DL, Op0.getValueType()), + ISD::SETNE); + } + } + } + } + + // Transform (brcond (xor x, y)) -> (brcond (setcc, x, y, ne)) + // Transform (brcond (xor (xor x, y), -1)) -> (brcond (setcc, x, y, eq)) + if (N.getOpcode() == ISD::XOR) { + // Because we may call this on a speculatively constructed + // SimplifiedSetCC Node, we need to simplify this node first. + // Ideally this should be folded into SimplifySetCC and not + // here. For now, grab a handle to N so we don't lose it from + // replacements interal to the visit. + HandleSDNode XORHandle(N); + while (N.getOpcode() == ISD::XOR) { + SDValue Tmp = visitXOR(N.getNode()); + // No simplification done. + if (!Tmp.getNode()) + break; + // Returning N is form in-visit replacement that may invalidated + // N. Grab value from Handle. + if (Tmp.getNode() == N.getNode()) + N = XORHandle.getValue(); + else // Node simplified. Try simplifying again. + N = Tmp; + } + + if (N.getOpcode() != ISD::XOR) + return N; + + SDValue Op0 = N->getOperand(0); + SDValue Op1 = N->getOperand(1); + + if (Op0.getOpcode() != ISD::SETCC && Op1.getOpcode() != ISD::SETCC) { + bool Equal = false; + // (brcond (xor (xor x, y), -1)) -> (brcond (setcc x, y, eq)) + if (isBitwiseNot(N) && Op0.hasOneUse() && Op0.getOpcode() == ISD::XOR && + Op0.getValueType() == MVT::i1) { + N = Op0; + Op0 = N->getOperand(0); + Op1 = N->getOperand(1); + Equal = true; + } + + EVT SetCCVT = N.getValueType(); + if (LegalTypes) + SetCCVT = getSetCCResultType(SetCCVT); + // Replace the uses of XOR with SETCC + return DAG.getSetCC(SDLoc(N), SetCCVT, Op0, Op1, + Equal ? ISD::SETEQ : ISD::SETNE); + } + } + + return SDValue(); +} + +// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. +// +SDValue DAGCombiner::visitBR_CC(SDNode *N) { + CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1)); + SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); + + // If N is a constant we could fold this into a fallthrough or unconditional + // branch. However that doesn't happen very often in normal code, because + // Instcombine/SimplifyCFG should have handled the available opportunities. + // If we did this folding here, it would be necessary to update the + // MachineBasicBlock CFG, which is awkward. + + // Use SimplifySetCC to simplify SETCC's. + SDValue Simp = SimplifySetCC(getSetCCResultType(CondLHS.getValueType()), + CondLHS, CondRHS, CC->get(), SDLoc(N), + false); + if (Simp.getNode()) AddToWorklist(Simp.getNode()); + + // fold to a simpler setcc + if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC) + return DAG.getNode(ISD::BR_CC, SDLoc(N), MVT::Other, + N->getOperand(0), Simp.getOperand(2), + Simp.getOperand(0), Simp.getOperand(1), + N->getOperand(4)); + + return SDValue(); +} + +static bool getCombineLoadStoreParts(SDNode *N, unsigned Inc, unsigned Dec, + bool &IsLoad, bool &IsMasked, SDValue &Ptr, + const TargetLowering &TLI) { + if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { + if (LD->isIndexed()) + return false; + EVT VT = LD->getMemoryVT(); + if (!TLI.isIndexedLoadLegal(Inc, VT) && !TLI.isIndexedLoadLegal(Dec, VT)) + return false; + Ptr = LD->getBasePtr(); + } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { + if (ST->isIndexed()) + return false; + EVT VT = ST->getMemoryVT(); + if (!TLI.isIndexedStoreLegal(Inc, VT) && !TLI.isIndexedStoreLegal(Dec, VT)) + return false; + Ptr = ST->getBasePtr(); + IsLoad = false; + } else if (MaskedLoadSDNode *LD = dyn_cast<MaskedLoadSDNode>(N)) { + if (LD->isIndexed()) + return false; + EVT VT = LD->getMemoryVT(); + if (!TLI.isIndexedMaskedLoadLegal(Inc, VT) && + !TLI.isIndexedMaskedLoadLegal(Dec, VT)) + return false; + Ptr = LD->getBasePtr(); + IsMasked = true; + } else if (MaskedStoreSDNode *ST = dyn_cast<MaskedStoreSDNode>(N)) { + if (ST->isIndexed()) + return false; + EVT VT = ST->getMemoryVT(); + if (!TLI.isIndexedMaskedStoreLegal(Inc, VT) && + !TLI.isIndexedMaskedStoreLegal(Dec, VT)) + return false; + Ptr = ST->getBasePtr(); + IsLoad = false; + IsMasked = true; + } else { + return false; + } + return true; +} + +/// Try turning a load/store into a pre-indexed load/store when the base +/// pointer is an add or subtract and it has other uses besides the load/store. +/// After the transformation, the new indexed load/store has effectively folded +/// the add/subtract in and all of its other uses are redirected to the +/// new load/store. +bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) { + if (Level < AfterLegalizeDAG) + return false; + + bool IsLoad = true; + bool IsMasked = false; + SDValue Ptr; + if (!getCombineLoadStoreParts(N, ISD::PRE_INC, ISD::PRE_DEC, IsLoad, IsMasked, + Ptr, TLI)) + return false; + + // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail + // out. There is no reason to make this a preinc/predec. + if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) || + Ptr.getNode()->hasOneUse()) + return false; + + // Ask the target to do addressing mode selection. + SDValue BasePtr; + SDValue Offset; + ISD::MemIndexedMode AM = ISD::UNINDEXED; + if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG)) + return false; + + // Backends without true r+i pre-indexed forms may need to pass a + // constant base with a variable offset so that constant coercion + // will work with the patterns in canonical form. + bool Swapped = false; + if (isa<ConstantSDNode>(BasePtr)) { + std::swap(BasePtr, Offset); + Swapped = true; + } + + // Don't create a indexed load / store with zero offset. + if (isNullConstant(Offset)) + return false; + + // Try turning it into a pre-indexed load / store except when: + // 1) The new base ptr is a frame index. + // 2) If N is a store and the new base ptr is either the same as or is a + // predecessor of the value being stored. + // 3) Another use of old base ptr is a predecessor of N. If ptr is folded + // that would create a cycle. + // 4) All uses are load / store ops that use it as old base ptr. + + // Check #1. Preinc'ing a frame index would require copying the stack pointer + // (plus the implicit offset) to a register to preinc anyway. + if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) + return false; + + // Check #2. + if (!IsLoad) { + SDValue Val = IsMasked ? cast<MaskedStoreSDNode>(N)->getValue() + : cast<StoreSDNode>(N)->getValue(); + + // Would require a copy. + if (Val == BasePtr) + return false; + + // Would create a cycle. + if (Val == Ptr || Ptr->isPredecessorOf(Val.getNode())) + return false; + } + + // Caches for hasPredecessorHelper. + SmallPtrSet<const SDNode *, 32> Visited; + SmallVector<const SDNode *, 16> Worklist; + Worklist.push_back(N); + + // If the offset is a constant, there may be other adds of constants that + // can be folded with this one. We should do this to avoid having to keep + // a copy of the original base pointer. + SmallVector<SDNode *, 16> OtherUses; + if (isa<ConstantSDNode>(Offset)) + for (SDNode::use_iterator UI = BasePtr.getNode()->use_begin(), + UE = BasePtr.getNode()->use_end(); + UI != UE; ++UI) { + SDUse &Use = UI.getUse(); + // Skip the use that is Ptr and uses of other results from BasePtr's + // node (important for nodes that return multiple results). + if (Use.getUser() == Ptr.getNode() || Use != BasePtr) + continue; + + if (SDNode::hasPredecessorHelper(Use.getUser(), Visited, Worklist)) + continue; + + if (Use.getUser()->getOpcode() != ISD::ADD && + Use.getUser()->getOpcode() != ISD::SUB) { + OtherUses.clear(); + break; + } + + SDValue Op1 = Use.getUser()->getOperand((UI.getOperandNo() + 1) & 1); + if (!isa<ConstantSDNode>(Op1)) { + OtherUses.clear(); + break; + } + + // FIXME: In some cases, we can be smarter about this. + if (Op1.getValueType() != Offset.getValueType()) { + OtherUses.clear(); + break; + } + + OtherUses.push_back(Use.getUser()); + } + + if (Swapped) + std::swap(BasePtr, Offset); + + // Now check for #3 and #4. + bool RealUse = false; + + for (SDNode *Use : Ptr.getNode()->uses()) { + if (Use == N) + continue; + if (SDNode::hasPredecessorHelper(Use, Visited, Worklist)) + return false; + + // If Ptr may be folded in addressing mode of other use, then it's + // not profitable to do this transformation. + if (!canFoldInAddressingMode(Ptr.getNode(), Use, DAG, TLI)) + RealUse = true; + } + + if (!RealUse) + return false; + + SDValue Result; + if (!IsMasked) { + if (IsLoad) + Result = DAG.getIndexedLoad(SDValue(N, 0), SDLoc(N), BasePtr, Offset, AM); + else + Result = + DAG.getIndexedStore(SDValue(N, 0), SDLoc(N), BasePtr, Offset, AM); + } else { + if (IsLoad) + Result = DAG.getIndexedMaskedLoad(SDValue(N, 0), SDLoc(N), BasePtr, + Offset, AM); + else + Result = DAG.getIndexedMaskedStore(SDValue(N, 0), SDLoc(N), BasePtr, + Offset, AM); + } + ++PreIndexedNodes; + ++NodesCombined; + LLVM_DEBUG(dbgs() << "\nReplacing.4 "; N->dump(&DAG); dbgs() << "\nWith: "; + Result.getNode()->dump(&DAG); dbgs() << '\n'); + WorklistRemover DeadNodes(*this); + if (IsLoad) { + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0)); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2)); + } else { + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1)); + } + + // Finally, since the node is now dead, remove it from the graph. + deleteAndRecombine(N); + + if (Swapped) + std::swap(BasePtr, Offset); + + // Replace other uses of BasePtr that can be updated to use Ptr + for (unsigned i = 0, e = OtherUses.size(); i != e; ++i) { + unsigned OffsetIdx = 1; + if (OtherUses[i]->getOperand(OffsetIdx).getNode() == BasePtr.getNode()) + OffsetIdx = 0; + assert(OtherUses[i]->getOperand(!OffsetIdx).getNode() == + BasePtr.getNode() && "Expected BasePtr operand"); + + // We need to replace ptr0 in the following expression: + // x0 * offset0 + y0 * ptr0 = t0 + // knowing that + // x1 * offset1 + y1 * ptr0 = t1 (the indexed load/store) + // + // where x0, x1, y0 and y1 in {-1, 1} are given by the types of the + // indexed load/store and the expression that needs to be re-written. + // + // Therefore, we have: + // t0 = (x0 * offset0 - x1 * y0 * y1 *offset1) + (y0 * y1) * t1 + + auto *CN = cast<ConstantSDNode>(OtherUses[i]->getOperand(OffsetIdx)); + const APInt &Offset0 = CN->getAPIntValue(); + const APInt &Offset1 = cast<ConstantSDNode>(Offset)->getAPIntValue(); + int X0 = (OtherUses[i]->getOpcode() == ISD::SUB && OffsetIdx == 1) ? -1 : 1; + int Y0 = (OtherUses[i]->getOpcode() == ISD::SUB && OffsetIdx == 0) ? -1 : 1; + int X1 = (AM == ISD::PRE_DEC && !Swapped) ? -1 : 1; + int Y1 = (AM == ISD::PRE_DEC && Swapped) ? -1 : 1; + + unsigned Opcode = (Y0 * Y1 < 0) ? ISD::SUB : ISD::ADD; + + APInt CNV = Offset0; + if (X0 < 0) CNV = -CNV; + if (X1 * Y0 * Y1 < 0) CNV = CNV + Offset1; + else CNV = CNV - Offset1; + + SDLoc DL(OtherUses[i]); + + // We can now generate the new expression. + SDValue NewOp1 = DAG.getConstant(CNV, DL, CN->getValueType(0)); + SDValue NewOp2 = Result.getValue(IsLoad ? 1 : 0); + + SDValue NewUse = DAG.getNode(Opcode, + DL, + OtherUses[i]->getValueType(0), NewOp1, NewOp2); + DAG.ReplaceAllUsesOfValueWith(SDValue(OtherUses[i], 0), NewUse); + deleteAndRecombine(OtherUses[i]); + } + + // Replace the uses of Ptr with uses of the updated base value. + DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(IsLoad ? 1 : 0)); + deleteAndRecombine(Ptr.getNode()); + AddToWorklist(Result.getNode()); + + return true; +} + +static bool shouldCombineToPostInc(SDNode *N, SDValue Ptr, SDNode *PtrUse, + SDValue &BasePtr, SDValue &Offset, + ISD::MemIndexedMode &AM, + SelectionDAG &DAG, + const TargetLowering &TLI) { + if (PtrUse == N || + (PtrUse->getOpcode() != ISD::ADD && PtrUse->getOpcode() != ISD::SUB)) + return false; + + if (!TLI.getPostIndexedAddressParts(N, PtrUse, BasePtr, Offset, AM, DAG)) + return false; + + // Don't create a indexed load / store with zero offset. + if (isNullConstant(Offset)) + return false; + + if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr)) + return false; + + SmallPtrSet<const SDNode *, 32> Visited; + for (SDNode *Use : BasePtr.getNode()->uses()) { + if (Use == Ptr.getNode()) + continue; + + // No if there's a later user which could perform the index instead. + if (isa<MemSDNode>(Use)) { + bool IsLoad = true; + bool IsMasked = false; + SDValue OtherPtr; + if (getCombineLoadStoreParts(Use, ISD::POST_INC, ISD::POST_DEC, IsLoad, + IsMasked, OtherPtr, TLI)) { + SmallVector<const SDNode *, 2> Worklist; + Worklist.push_back(Use); + if (SDNode::hasPredecessorHelper(N, Visited, Worklist)) + return false; + } + } + + // If all the uses are load / store addresses, then don't do the + // transformation. + if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB) { + for (SDNode *UseUse : Use->uses()) + if (canFoldInAddressingMode(Use, UseUse, DAG, TLI)) + return false; + } + } + return true; +} + +static SDNode *getPostIndexedLoadStoreOp(SDNode *N, bool &IsLoad, + bool &IsMasked, SDValue &Ptr, + SDValue &BasePtr, SDValue &Offset, + ISD::MemIndexedMode &AM, + SelectionDAG &DAG, + const TargetLowering &TLI) { + if (!getCombineLoadStoreParts(N, ISD::POST_INC, ISD::POST_DEC, IsLoad, + IsMasked, Ptr, TLI) || + Ptr.getNode()->hasOneUse()) + return nullptr; + + // Try turning it into a post-indexed load / store except when + // 1) All uses are load / store ops that use it as base ptr (and + // it may be folded as addressing mmode). + // 2) Op must be independent of N, i.e. Op is neither a predecessor + // nor a successor of N. Otherwise, if Op is folded that would + // create a cycle. + for (SDNode *Op : Ptr->uses()) { + // Check for #1. + if (!shouldCombineToPostInc(N, Ptr, Op, BasePtr, Offset, AM, DAG, TLI)) + continue; + + // Check for #2. + SmallPtrSet<const SDNode *, 32> Visited; + SmallVector<const SDNode *, 8> Worklist; + // Ptr is predecessor to both N and Op. + Visited.insert(Ptr.getNode()); + Worklist.push_back(N); + Worklist.push_back(Op); + if (!SDNode::hasPredecessorHelper(N, Visited, Worklist) && + !SDNode::hasPredecessorHelper(Op, Visited, Worklist)) + return Op; + } + return nullptr; +} + +/// Try to combine a load/store with a add/sub of the base pointer node into a +/// post-indexed load/store. The transformation folded the add/subtract into the +/// new indexed load/store effectively and all of its uses are redirected to the +/// new load/store. +bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { + if (Level < AfterLegalizeDAG) + return false; + + bool IsLoad = true; + bool IsMasked = false; + SDValue Ptr; + SDValue BasePtr; + SDValue Offset; + ISD::MemIndexedMode AM = ISD::UNINDEXED; + SDNode *Op = getPostIndexedLoadStoreOp(N, IsLoad, IsMasked, Ptr, BasePtr, + Offset, AM, DAG, TLI); + if (!Op) + return false; + + SDValue Result; + if (!IsMasked) + Result = IsLoad ? DAG.getIndexedLoad(SDValue(N, 0), SDLoc(N), BasePtr, + Offset, AM) + : DAG.getIndexedStore(SDValue(N, 0), SDLoc(N), + BasePtr, Offset, AM); + else + Result = IsLoad ? DAG.getIndexedMaskedLoad(SDValue(N, 0), SDLoc(N), + BasePtr, Offset, AM) + : DAG.getIndexedMaskedStore(SDValue(N, 0), SDLoc(N), + BasePtr, Offset, AM); + ++PostIndexedNodes; + ++NodesCombined; + LLVM_DEBUG(dbgs() << "\nReplacing.5 "; N->dump(&DAG); + dbgs() << "\nWith: "; Result.getNode()->dump(&DAG); + dbgs() << '\n'); + WorklistRemover DeadNodes(*this); + if (IsLoad) { + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0)); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2)); + } else { + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1)); + } + + // Finally, since the node is now dead, remove it from the graph. + deleteAndRecombine(N); + + // Replace the uses of Use with uses of the updated base value. + DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0), + Result.getValue(IsLoad ? 1 : 0)); + deleteAndRecombine(Op); + return true; +} + +/// Return the base-pointer arithmetic from an indexed \p LD. +SDValue DAGCombiner::SplitIndexingFromLoad(LoadSDNode *LD) { + ISD::MemIndexedMode AM = LD->getAddressingMode(); + assert(AM != ISD::UNINDEXED); + SDValue BP = LD->getOperand(1); + SDValue Inc = LD->getOperand(2); + + // Some backends use TargetConstants for load offsets, but don't expect + // TargetConstants in general ADD nodes. We can convert these constants into + // regular Constants (if the constant is not opaque). + assert((Inc.getOpcode() != ISD::TargetConstant || + !cast<ConstantSDNode>(Inc)->isOpaque()) && + "Cannot split out indexing using opaque target constants"); + if (Inc.getOpcode() == ISD::TargetConstant) { + ConstantSDNode *ConstInc = cast<ConstantSDNode>(Inc); + Inc = DAG.getConstant(*ConstInc->getConstantIntValue(), SDLoc(Inc), + ConstInc->getValueType(0)); + } + + unsigned Opc = + (AM == ISD::PRE_INC || AM == ISD::POST_INC ? ISD::ADD : ISD::SUB); + return DAG.getNode(Opc, SDLoc(LD), BP.getSimpleValueType(), BP, Inc); +} + +static inline ElementCount numVectorEltsOrZero(EVT T) { + return T.isVector() ? T.getVectorElementCount() : ElementCount::getFixed(0); +} + +bool DAGCombiner::getTruncatedStoreValue(StoreSDNode *ST, SDValue &Val) { + Val = ST->getValue(); + EVT STType = Val.getValueType(); + EVT STMemType = ST->getMemoryVT(); + if (STType == STMemType) + return true; + if (isTypeLegal(STMemType)) + return false; // fail. + if (STType.isFloatingPoint() && STMemType.isFloatingPoint() && + TLI.isOperationLegal(ISD::FTRUNC, STMemType)) { + Val = DAG.getNode(ISD::FTRUNC, SDLoc(ST), STMemType, Val); + return true; + } + if (numVectorEltsOrZero(STType) == numVectorEltsOrZero(STMemType) && + STType.isInteger() && STMemType.isInteger()) { + Val = DAG.getNode(ISD::TRUNCATE, SDLoc(ST), STMemType, Val); + return true; + } + if (STType.getSizeInBits() == STMemType.getSizeInBits()) { + Val = DAG.getBitcast(STMemType, Val); + return true; + } + return false; // fail. +} + +bool DAGCombiner::extendLoadedValueToExtension(LoadSDNode *LD, SDValue &Val) { + EVT LDMemType = LD->getMemoryVT(); + EVT LDType = LD->getValueType(0); + assert(Val.getValueType() == LDMemType && + "Attempting to extend value of non-matching type"); + if (LDType == LDMemType) + return true; + if (LDMemType.isInteger() && LDType.isInteger()) { + switch (LD->getExtensionType()) { + case ISD::NON_EXTLOAD: + Val = DAG.getBitcast(LDType, Val); + return true; + case ISD::EXTLOAD: + Val = DAG.getNode(ISD::ANY_EXTEND, SDLoc(LD), LDType, Val); + return true; + case ISD::SEXTLOAD: + Val = DAG.getNode(ISD::SIGN_EXTEND, SDLoc(LD), LDType, Val); + return true; + case ISD::ZEXTLOAD: + Val = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(LD), LDType, Val); + return true; + } + } + return false; +} + +SDValue DAGCombiner::ForwardStoreValueToDirectLoad(LoadSDNode *LD) { + if (OptLevel == CodeGenOpt::None || !LD->isSimple()) + return SDValue(); + SDValue Chain = LD->getOperand(0); + StoreSDNode *ST = dyn_cast<StoreSDNode>(Chain.getNode()); + // TODO: Relax this restriction for unordered atomics (see D66309) + if (!ST || !ST->isSimple()) + return SDValue(); + + EVT LDType = LD->getValueType(0); + EVT LDMemType = LD->getMemoryVT(); + EVT STMemType = ST->getMemoryVT(); + EVT STType = ST->getValue().getValueType(); + + // There are two cases to consider here: + // 1. The store is fixed width and the load is scalable. In this case we + // don't know at compile time if the store completely envelops the load + // so we abandon the optimisation. + // 2. The store is scalable and the load is fixed width. We could + // potentially support a limited number of cases here, but there has been + // no cost-benefit analysis to prove it's worth it. + bool LdStScalable = LDMemType.isScalableVector(); + if (LdStScalable != STMemType.isScalableVector()) + return SDValue(); + + // If we are dealing with scalable vectors on a big endian platform the + // calculation of offsets below becomes trickier, since we do not know at + // compile time the absolute size of the vector. Until we've done more + // analysis on big-endian platforms it seems better to bail out for now. + if (LdStScalable && DAG.getDataLayout().isBigEndian()) + return SDValue(); + + BaseIndexOffset BasePtrLD = BaseIndexOffset::match(LD, DAG); + BaseIndexOffset BasePtrST = BaseIndexOffset::match(ST, DAG); + int64_t Offset; + if (!BasePtrST.equalBaseIndex(BasePtrLD, DAG, Offset)) + return SDValue(); + + // Normalize for Endianness. After this Offset=0 will denote that the least + // significant bit in the loaded value maps to the least significant bit in + // the stored value). With Offset=n (for n > 0) the loaded value starts at the + // n:th least significant byte of the stored value. + if (DAG.getDataLayout().isBigEndian()) + Offset = ((int64_t)STMemType.getStoreSizeInBits().getFixedSize() - + (int64_t)LDMemType.getStoreSizeInBits().getFixedSize()) / + 8 - + Offset; + + // Check that the stored value cover all bits that are loaded. + bool STCoversLD; + + TypeSize LdMemSize = LDMemType.getSizeInBits(); + TypeSize StMemSize = STMemType.getSizeInBits(); + if (LdStScalable) + STCoversLD = (Offset == 0) && LdMemSize == StMemSize; + else + STCoversLD = (Offset >= 0) && (Offset * 8 + LdMemSize.getFixedSize() <= + StMemSize.getFixedSize()); + + auto ReplaceLd = [&](LoadSDNode *LD, SDValue Val, SDValue Chain) -> SDValue { + if (LD->isIndexed()) { + // Cannot handle opaque target constants and we must respect the user's + // request not to split indexes from loads. + if (!canSplitIdx(LD)) + return SDValue(); + SDValue Idx = SplitIndexingFromLoad(LD); + SDValue Ops[] = {Val, Idx, Chain}; + return CombineTo(LD, Ops, 3); + } + return CombineTo(LD, Val, Chain); + }; + + if (!STCoversLD) + return SDValue(); + + // Memory as copy space (potentially masked). + if (Offset == 0 && LDType == STType && STMemType == LDMemType) { + // Simple case: Direct non-truncating forwarding + if (LDType.getSizeInBits() == LdMemSize) + return ReplaceLd(LD, ST->getValue(), Chain); + // Can we model the truncate and extension with an and mask? + if (STType.isInteger() && LDMemType.isInteger() && !STType.isVector() && + !LDMemType.isVector() && LD->getExtensionType() != ISD::SEXTLOAD) { + // Mask to size of LDMemType + auto Mask = + DAG.getConstant(APInt::getLowBitsSet(STType.getFixedSizeInBits(), + StMemSize.getFixedSize()), + SDLoc(ST), STType); + auto Val = DAG.getNode(ISD::AND, SDLoc(LD), LDType, ST->getValue(), Mask); + return ReplaceLd(LD, Val, Chain); + } + } + + // TODO: Deal with nonzero offset. + if (LD->getBasePtr().isUndef() || Offset != 0) + return SDValue(); + // Model necessary truncations / extenstions. + SDValue Val; + // Truncate Value To Stored Memory Size. + do { + if (!getTruncatedStoreValue(ST, Val)) + continue; + if (!isTypeLegal(LDMemType)) + continue; + if (STMemType != LDMemType) { + // TODO: Support vectors? This requires extract_subvector/bitcast. + if (!STMemType.isVector() && !LDMemType.isVector() && + STMemType.isInteger() && LDMemType.isInteger()) + Val = DAG.getNode(ISD::TRUNCATE, SDLoc(LD), LDMemType, Val); + else + continue; + } + if (!extendLoadedValueToExtension(LD, Val)) + continue; + return ReplaceLd(LD, Val, Chain); + } while (false); + + // On failure, cleanup dead nodes we may have created. + if (Val->use_empty()) + deleteAndRecombine(Val.getNode()); + return SDValue(); +} + +SDValue DAGCombiner::visitLOAD(SDNode *N) { + LoadSDNode *LD = cast<LoadSDNode>(N); + SDValue Chain = LD->getChain(); + SDValue Ptr = LD->getBasePtr(); + + // If load is not volatile and there are no uses of the loaded value (and + // the updated indexed value in case of indexed loads), change uses of the + // chain value into uses of the chain input (i.e. delete the dead load). + // TODO: Allow this for unordered atomics (see D66309) + if (LD->isSimple()) { + if (N->getValueType(1) == MVT::Other) { + // Unindexed loads. + if (!N->hasAnyUseOfValue(0)) { + // It's not safe to use the two value CombineTo variant here. e.g. + // v1, chain2 = load chain1, loc + // v2, chain3 = load chain2, loc + // v3 = add v2, c + // Now we replace use of chain2 with chain1. This makes the second load + // isomorphic to the one we are deleting, and thus makes this load live. + LLVM_DEBUG(dbgs() << "\nReplacing.6 "; N->dump(&DAG); + dbgs() << "\nWith chain: "; Chain.getNode()->dump(&DAG); + dbgs() << "\n"); + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain); + AddUsersToWorklist(Chain.getNode()); + if (N->use_empty()) + deleteAndRecombine(N); + + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } else { + // Indexed loads. + assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?"); + + // If this load has an opaque TargetConstant offset, then we cannot split + // the indexing into an add/sub directly (that TargetConstant may not be + // valid for a different type of node, and we cannot convert an opaque + // target constant into a regular constant). + bool CanSplitIdx = canSplitIdx(LD); + + if (!N->hasAnyUseOfValue(0) && (CanSplitIdx || !N->hasAnyUseOfValue(1))) { + SDValue Undef = DAG.getUNDEF(N->getValueType(0)); + SDValue Index; + if (N->hasAnyUseOfValue(1) && CanSplitIdx) { + Index = SplitIndexingFromLoad(LD); + // Try to fold the base pointer arithmetic into subsequent loads and + // stores. + AddUsersToWorklist(N); + } else + Index = DAG.getUNDEF(N->getValueType(1)); + LLVM_DEBUG(dbgs() << "\nReplacing.7 "; N->dump(&DAG); + dbgs() << "\nWith: "; Undef.getNode()->dump(&DAG); + dbgs() << " and 2 other values\n"); + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Index); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain); + deleteAndRecombine(N); + return SDValue(N, 0); // Return N so it doesn't get rechecked! + } + } + } + + // If this load is directly stored, replace the load value with the stored + // value. + if (auto V = ForwardStoreValueToDirectLoad(LD)) + return V; + + // Try to infer better alignment information than the load already has. + if (OptLevel != CodeGenOpt::None && LD->isUnindexed() && !LD->isAtomic()) { + if (MaybeAlign Alignment = DAG.InferPtrAlign(Ptr)) { + if (*Alignment > LD->getAlign() && + isAligned(*Alignment, LD->getSrcValueOffset())) { + SDValue NewLoad = DAG.getExtLoad( + LD->getExtensionType(), SDLoc(N), LD->getValueType(0), Chain, Ptr, + LD->getPointerInfo(), LD->getMemoryVT(), *Alignment, + LD->getMemOperand()->getFlags(), LD->getAAInfo()); + // NewLoad will always be N as we are only refining the alignment + assert(NewLoad.getNode() == N); + (void)NewLoad; + } + } + } + + if (LD->isUnindexed()) { + // Walk up chain skipping non-aliasing memory nodes. + SDValue BetterChain = FindBetterChain(LD, Chain); + + // If there is a better chain. + if (Chain != BetterChain) { + SDValue ReplLoad; + + // Replace the chain to void dependency. + if (LD->getExtensionType() == ISD::NON_EXTLOAD) { + ReplLoad = DAG.getLoad(N->getValueType(0), SDLoc(LD), + BetterChain, Ptr, LD->getMemOperand()); + } else { + ReplLoad = DAG.getExtLoad(LD->getExtensionType(), SDLoc(LD), + LD->getValueType(0), + BetterChain, Ptr, LD->getMemoryVT(), + LD->getMemOperand()); + } + + // Create token factor to keep old chain connected. + SDValue Token = DAG.getNode(ISD::TokenFactor, SDLoc(N), + MVT::Other, Chain, ReplLoad.getValue(1)); + + // Replace uses with load result and token factor + return CombineTo(N, ReplLoad.getValue(0), Token); + } + } + + // Try transforming N to an indexed load. + if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) + return SDValue(N, 0); + + // Try to slice up N to more direct loads if the slices are mapped to + // different register banks or pairing can take place. + if (SliceUpLoad(N)) + return SDValue(N, 0); + + return SDValue(); +} + +namespace { + +/// Helper structure used to slice a load in smaller loads. +/// Basically a slice is obtained from the following sequence: +/// Origin = load Ty1, Base +/// Shift = srl Ty1 Origin, CstTy Amount +/// Inst = trunc Shift to Ty2 +/// +/// Then, it will be rewritten into: +/// Slice = load SliceTy, Base + SliceOffset +/// [Inst = zext Slice to Ty2], only if SliceTy <> Ty2 +/// +/// SliceTy is deduced from the number of bits that are actually used to +/// build Inst. +struct LoadedSlice { + /// Helper structure used to compute the cost of a slice. + struct Cost { + /// Are we optimizing for code size. + bool ForCodeSize = false; + + /// Various cost. + unsigned Loads = 0; + unsigned Truncates = 0; + unsigned CrossRegisterBanksCopies = 0; + unsigned ZExts = 0; + unsigned Shift = 0; + + explicit Cost(bool ForCodeSize) : ForCodeSize(ForCodeSize) {} + + /// Get the cost of one isolated slice. + Cost(const LoadedSlice &LS, bool ForCodeSize) + : ForCodeSize(ForCodeSize), Loads(1) { + EVT TruncType = LS.Inst->getValueType(0); + EVT LoadedType = LS.getLoadedType(); + if (TruncType != LoadedType && + !LS.DAG->getTargetLoweringInfo().isZExtFree(LoadedType, TruncType)) + ZExts = 1; + } + + /// Account for slicing gain in the current cost. + /// Slicing provide a few gains like removing a shift or a + /// truncate. This method allows to grow the cost of the original + /// load with the gain from this slice. + void addSliceGain(const LoadedSlice &LS) { + // Each slice saves a truncate. + const TargetLowering &TLI = LS.DAG->getTargetLoweringInfo(); + if (!TLI.isTruncateFree(LS.Inst->getOperand(0).getValueType(), + LS.Inst->getValueType(0))) + ++Truncates; + // If there is a shift amount, this slice gets rid of it. + if (LS.Shift) + ++Shift; + // If this slice can merge a cross register bank copy, account for it. + if (LS.canMergeExpensiveCrossRegisterBankCopy()) + ++CrossRegisterBanksCopies; + } + + Cost &operator+=(const Cost &RHS) { + Loads += RHS.Loads; + Truncates += RHS.Truncates; + CrossRegisterBanksCopies += RHS.CrossRegisterBanksCopies; + ZExts += RHS.ZExts; + Shift += RHS.Shift; + return *this; + } + + bool operator==(const Cost &RHS) const { + return Loads == RHS.Loads && Truncates == RHS.Truncates && + CrossRegisterBanksCopies == RHS.CrossRegisterBanksCopies && + ZExts == RHS.ZExts && Shift == RHS.Shift; + } + + bool operator!=(const Cost &RHS) const { return !(*this == RHS); } + + bool operator<(const Cost &RHS) const { + // Assume cross register banks copies are as expensive as loads. + // FIXME: Do we want some more target hooks? + unsigned ExpensiveOpsLHS = Loads + CrossRegisterBanksCopies; + unsigned ExpensiveOpsRHS = RHS.Loads + RHS.CrossRegisterBanksCopies; + // Unless we are optimizing for code size, consider the + // expensive operation first. + if (!ForCodeSize && ExpensiveOpsLHS != ExpensiveOpsRHS) + return ExpensiveOpsLHS < ExpensiveOpsRHS; + return (Truncates + ZExts + Shift + ExpensiveOpsLHS) < + (RHS.Truncates + RHS.ZExts + RHS.Shift + ExpensiveOpsRHS); + } + + bool operator>(const Cost &RHS) const { return RHS < *this; } + + bool operator<=(const Cost &RHS) const { return !(RHS < *this); } + + bool operator>=(const Cost &RHS) const { return !(*this < RHS); } + }; + + // The last instruction that represent the slice. This should be a + // truncate instruction. + SDNode *Inst; + + // The original load instruction. + LoadSDNode *Origin; + + // The right shift amount in bits from the original load. + unsigned Shift; + + // The DAG from which Origin came from. + // This is used to get some contextual information about legal types, etc. + SelectionDAG *DAG; + + LoadedSlice(SDNode *Inst = nullptr, LoadSDNode *Origin = nullptr, + unsigned Shift = 0, SelectionDAG *DAG = nullptr) + : Inst(Inst), Origin(Origin), Shift(Shift), DAG(DAG) {} + + /// Get the bits used in a chunk of bits \p BitWidth large. + /// \return Result is \p BitWidth and has used bits set to 1 and + /// not used bits set to 0. + APInt getUsedBits() const { + // Reproduce the trunc(lshr) sequence: + // - Start from the truncated value. + // - Zero extend to the desired bit width. + // - Shift left. + assert(Origin && "No original load to compare against."); + unsigned BitWidth = Origin->getValueSizeInBits(0); + assert(Inst && "This slice is not bound to an instruction"); + assert(Inst->getValueSizeInBits(0) <= BitWidth && + "Extracted slice is bigger than the whole type!"); + APInt UsedBits(Inst->getValueSizeInBits(0), 0); + UsedBits.setAllBits(); + UsedBits = UsedBits.zext(BitWidth); + UsedBits <<= Shift; + return UsedBits; + } + + /// Get the size of the slice to be loaded in bytes. + unsigned getLoadedSize() const { + unsigned SliceSize = getUsedBits().countPopulation(); + assert(!(SliceSize & 0x7) && "Size is not a multiple of a byte."); + return SliceSize / 8; + } + + /// Get the type that will be loaded for this slice. + /// Note: This may not be the final type for the slice. + EVT getLoadedType() const { + assert(DAG && "Missing context"); + LLVMContext &Ctxt = *DAG->getContext(); + return EVT::getIntegerVT(Ctxt, getLoadedSize() * 8); + } + + /// Get the alignment of the load used for this slice. + Align getAlign() const { + Align Alignment = Origin->getAlign(); + uint64_t Offset = getOffsetFromBase(); + if (Offset != 0) + Alignment = commonAlignment(Alignment, Alignment.value() + Offset); + return Alignment; + } + + /// Check if this slice can be rewritten with legal operations. + bool isLegal() const { + // An invalid slice is not legal. + if (!Origin || !Inst || !DAG) + return false; + + // Offsets are for indexed load only, we do not handle that. + if (!Origin->getOffset().isUndef()) + return false; + + const TargetLowering &TLI = DAG->getTargetLoweringInfo(); + + // Check that the type is legal. + EVT SliceType = getLoadedType(); + if (!TLI.isTypeLegal(SliceType)) + return false; + + // Check that the load is legal for this type. + if (!TLI.isOperationLegal(ISD::LOAD, SliceType)) + return false; + + // Check that the offset can be computed. + // 1. Check its type. + EVT PtrType = Origin->getBasePtr().getValueType(); + if (PtrType == MVT::Untyped || PtrType.isExtended()) + return false; + + // 2. Check that it fits in the immediate. + if (!TLI.isLegalAddImmediate(getOffsetFromBase())) + return false; + + // 3. Check that the computation is legal. + if (!TLI.isOperationLegal(ISD::ADD, PtrType)) + return false; + + // Check that the zext is legal if it needs one. + EVT TruncateType = Inst->getValueType(0); + if (TruncateType != SliceType && + !TLI.isOperationLegal(ISD::ZERO_EXTEND, TruncateType)) + return false; + + return true; + } + + /// Get the offset in bytes of this slice in the original chunk of + /// bits. + /// \pre DAG != nullptr. + uint64_t getOffsetFromBase() const { + assert(DAG && "Missing context."); + bool IsBigEndian = DAG->getDataLayout().isBigEndian(); + assert(!(Shift & 0x7) && "Shifts not aligned on Bytes are not supported."); + uint64_t Offset = Shift / 8; + unsigned TySizeInBytes = Origin->getValueSizeInBits(0) / 8; + assert(!(Origin->getValueSizeInBits(0) & 0x7) && + "The size of the original loaded type is not a multiple of a" + " byte."); + // If Offset is bigger than TySizeInBytes, it means we are loading all + // zeros. This should have been optimized before in the process. + assert(TySizeInBytes > Offset && + "Invalid shift amount for given loaded size"); + if (IsBigEndian) + Offset = TySizeInBytes - Offset - getLoadedSize(); + return Offset; + } + + /// Generate the sequence of instructions to load the slice + /// represented by this object and redirect the uses of this slice to + /// this new sequence of instructions. + /// \pre this->Inst && this->Origin are valid Instructions and this + /// object passed the legal check: LoadedSlice::isLegal returned true. + /// \return The last instruction of the sequence used to load the slice. + SDValue loadSlice() const { + assert(Inst && Origin && "Unable to replace a non-existing slice."); + const SDValue &OldBaseAddr = Origin->getBasePtr(); + SDValue BaseAddr = OldBaseAddr; + // Get the offset in that chunk of bytes w.r.t. the endianness. + int64_t Offset = static_cast<int64_t>(getOffsetFromBase()); + assert(Offset >= 0 && "Offset too big to fit in int64_t!"); + if (Offset) { + // BaseAddr = BaseAddr + Offset. + EVT ArithType = BaseAddr.getValueType(); + SDLoc DL(Origin); + BaseAddr = DAG->getNode(ISD::ADD, DL, ArithType, BaseAddr, + DAG->getConstant(Offset, DL, ArithType)); + } + + // Create the type of the loaded slice according to its size. + EVT SliceType = getLoadedType(); + + // Create the load for the slice. + SDValue LastInst = + DAG->getLoad(SliceType, SDLoc(Origin), Origin->getChain(), BaseAddr, + Origin->getPointerInfo().getWithOffset(Offset), getAlign(), + Origin->getMemOperand()->getFlags()); + // If the final type is not the same as the loaded type, this means that + // we have to pad with zero. Create a zero extend for that. + EVT FinalType = Inst->getValueType(0); + if (SliceType != FinalType) + LastInst = + DAG->getNode(ISD::ZERO_EXTEND, SDLoc(LastInst), FinalType, LastInst); + return LastInst; + } + + /// Check if this slice can be merged with an expensive cross register + /// bank copy. E.g., + /// i = load i32 + /// f = bitcast i32 i to float + bool canMergeExpensiveCrossRegisterBankCopy() const { + if (!Inst || !Inst->hasOneUse()) + return false; + SDNode *Use = *Inst->use_begin(); + if (Use->getOpcode() != ISD::BITCAST) + return false; + assert(DAG && "Missing context"); + const TargetLowering &TLI = DAG->getTargetLoweringInfo(); + EVT ResVT = Use->getValueType(0); + const TargetRegisterClass *ResRC = + TLI.getRegClassFor(ResVT.getSimpleVT(), Use->isDivergent()); + const TargetRegisterClass *ArgRC = + TLI.getRegClassFor(Use->getOperand(0).getValueType().getSimpleVT(), + Use->getOperand(0)->isDivergent()); + if (ArgRC == ResRC || !TLI.isOperationLegal(ISD::LOAD, ResVT)) + return false; + + // At this point, we know that we perform a cross-register-bank copy. + // Check if it is expensive. + const TargetRegisterInfo *TRI = DAG->getSubtarget().getRegisterInfo(); + // Assume bitcasts are cheap, unless both register classes do not + // explicitly share a common sub class. + if (!TRI || TRI->getCommonSubClass(ArgRC, ResRC)) + return false; + + // Check if it will be merged with the load. + // 1. Check the alignment constraint. + Align RequiredAlignment = DAG->getDataLayout().getABITypeAlign( + ResVT.getTypeForEVT(*DAG->getContext())); + + if (RequiredAlignment > getAlign()) + return false; + + // 2. Check that the load is a legal operation for that type. + if (!TLI.isOperationLegal(ISD::LOAD, ResVT)) + return false; + + // 3. Check that we do not have a zext in the way. + if (Inst->getValueType(0) != getLoadedType()) + return false; + + return true; + } +}; + +} // end anonymous namespace + +/// Check that all bits set in \p UsedBits form a dense region, i.e., +/// \p UsedBits looks like 0..0 1..1 0..0. +static bool areUsedBitsDense(const APInt &UsedBits) { + // If all the bits are one, this is dense! + if (UsedBits.isAllOnesValue()) + return true; + + // Get rid of the unused bits on the right. + APInt NarrowedUsedBits = UsedBits.lshr(UsedBits.countTrailingZeros()); + // Get rid of the unused bits on the left. + if (NarrowedUsedBits.countLeadingZeros()) + NarrowedUsedBits = NarrowedUsedBits.trunc(NarrowedUsedBits.getActiveBits()); + // Check that the chunk of bits is completely used. + return NarrowedUsedBits.isAllOnesValue(); +} + +/// Check whether or not \p First and \p Second are next to each other +/// in memory. This means that there is no hole between the bits loaded +/// by \p First and the bits loaded by \p Second. +static bool areSlicesNextToEachOther(const LoadedSlice &First, + const LoadedSlice &Second) { + assert(First.Origin == Second.Origin && First.Origin && + "Unable to match different memory origins."); + APInt UsedBits = First.getUsedBits(); + assert((UsedBits & Second.getUsedBits()) == 0 && + "Slices are not supposed to overlap."); + UsedBits |= Second.getUsedBits(); + return areUsedBitsDense(UsedBits); +} + +/// Adjust the \p GlobalLSCost according to the target +/// paring capabilities and the layout of the slices. +/// \pre \p GlobalLSCost should account for at least as many loads as +/// there is in the slices in \p LoadedSlices. +static void adjustCostForPairing(SmallVectorImpl<LoadedSlice> &LoadedSlices, + LoadedSlice::Cost &GlobalLSCost) { + unsigned NumberOfSlices = LoadedSlices.size(); + // If there is less than 2 elements, no pairing is possible. + if (NumberOfSlices < 2) + return; + + // Sort the slices so that elements that are likely to be next to each + // other in memory are next to each other in the list. + llvm::sort(LoadedSlices, [](const LoadedSlice &LHS, const LoadedSlice &RHS) { + assert(LHS.Origin == RHS.Origin && "Different bases not implemented."); + return LHS.getOffsetFromBase() < RHS.getOffsetFromBase(); + }); + const TargetLowering &TLI = LoadedSlices[0].DAG->getTargetLoweringInfo(); + // First (resp. Second) is the first (resp. Second) potentially candidate + // to be placed in a paired load. + const LoadedSlice *First = nullptr; + const LoadedSlice *Second = nullptr; + for (unsigned CurrSlice = 0; CurrSlice < NumberOfSlices; ++CurrSlice, + // Set the beginning of the pair. + First = Second) { + Second = &LoadedSlices[CurrSlice]; + + // If First is NULL, it means we start a new pair. + // Get to the next slice. + if (!First) + continue; + + EVT LoadedType = First->getLoadedType(); + + // If the types of the slices are different, we cannot pair them. + if (LoadedType != Second->getLoadedType()) + continue; + + // Check if the target supplies paired loads for this type. + Align RequiredAlignment; + if (!TLI.hasPairedLoad(LoadedType, RequiredAlignment)) { + // move to the next pair, this type is hopeless. + Second = nullptr; + continue; + } + // Check if we meet the alignment requirement. + if (First->getAlign() < RequiredAlignment) + continue; + + // Check that both loads are next to each other in memory. + if (!areSlicesNextToEachOther(*First, *Second)) + continue; + + assert(GlobalLSCost.Loads > 0 && "We save more loads than we created!"); + --GlobalLSCost.Loads; + // Move to the next pair. + Second = nullptr; + } +} + +/// Check the profitability of all involved LoadedSlice. +/// Currently, it is considered profitable if there is exactly two +/// involved slices (1) which are (2) next to each other in memory, and +/// whose cost (\see LoadedSlice::Cost) is smaller than the original load (3). +/// +/// Note: The order of the elements in \p LoadedSlices may be modified, but not +/// the elements themselves. +/// +/// FIXME: When the cost model will be mature enough, we can relax +/// constraints (1) and (2). +static bool isSlicingProfitable(SmallVectorImpl<LoadedSlice> &LoadedSlices, + const APInt &UsedBits, bool ForCodeSize) { + unsigned NumberOfSlices = LoadedSlices.size(); + if (StressLoadSlicing) + return NumberOfSlices > 1; + + // Check (1). + if (NumberOfSlices != 2) + return false; + + // Check (2). + if (!areUsedBitsDense(UsedBits)) + return false; + + // Check (3). + LoadedSlice::Cost OrigCost(ForCodeSize), GlobalSlicingCost(ForCodeSize); + // The original code has one big load. + OrigCost.Loads = 1; + for (unsigned CurrSlice = 0; CurrSlice < NumberOfSlices; ++CurrSlice) { + const LoadedSlice &LS = LoadedSlices[CurrSlice]; + // Accumulate the cost of all the slices. + LoadedSlice::Cost SliceCost(LS, ForCodeSize); + GlobalSlicingCost += SliceCost; + + // Account as cost in the original configuration the gain obtained + // with the current slices. + OrigCost.addSliceGain(LS); + } + + // If the target supports paired load, adjust the cost accordingly. + adjustCostForPairing(LoadedSlices, GlobalSlicingCost); + return OrigCost > GlobalSlicingCost; +} + +/// If the given load, \p LI, is used only by trunc or trunc(lshr) +/// operations, split it in the various pieces being extracted. +/// +/// This sort of thing is introduced by SROA. +/// This slicing takes care not to insert overlapping loads. +/// \pre LI is a simple load (i.e., not an atomic or volatile load). +bool DAGCombiner::SliceUpLoad(SDNode *N) { + if (Level < AfterLegalizeDAG) + return false; + + LoadSDNode *LD = cast<LoadSDNode>(N); + if (!LD->isSimple() || !ISD::isNormalLoad(LD) || + !LD->getValueType(0).isInteger()) + return false; + + // The algorithm to split up a load of a scalable vector into individual + // elements currently requires knowing the length of the loaded type, + // so will need adjusting to work on scalable vectors. + if (LD->getValueType(0).isScalableVector()) + return false; + + // Keep track of already used bits to detect overlapping values. + // In that case, we will just abort the transformation. + APInt UsedBits(LD->getValueSizeInBits(0), 0); + + SmallVector<LoadedSlice, 4> LoadedSlices; + + // Check if this load is used as several smaller chunks of bits. + // Basically, look for uses in trunc or trunc(lshr) and record a new chain + // of computation for each trunc. + for (SDNode::use_iterator UI = LD->use_begin(), UIEnd = LD->use_end(); + UI != UIEnd; ++UI) { + // Skip the uses of the chain. + if (UI.getUse().getResNo() != 0) + continue; + + SDNode *User = *UI; + unsigned Shift = 0; + + // Check if this is a trunc(lshr). + if (User->getOpcode() == ISD::SRL && User->hasOneUse() && + isa<ConstantSDNode>(User->getOperand(1))) { + Shift = User->getConstantOperandVal(1); + User = *User->use_begin(); + } + + // At this point, User is a Truncate, iff we encountered, trunc or + // trunc(lshr). + if (User->getOpcode() != ISD::TRUNCATE) + return false; + + // The width of the type must be a power of 2 and greater than 8-bits. + // Otherwise the load cannot be represented in LLVM IR. + // Moreover, if we shifted with a non-8-bits multiple, the slice + // will be across several bytes. We do not support that. + unsigned Width = User->getValueSizeInBits(0); + if (Width < 8 || !isPowerOf2_32(Width) || (Shift & 0x7)) + return false; + + // Build the slice for this chain of computations. + LoadedSlice LS(User, LD, Shift, &DAG); + APInt CurrentUsedBits = LS.getUsedBits(); + + // Check if this slice overlaps with another. + if ((CurrentUsedBits & UsedBits) != 0) + return false; + // Update the bits used globally. + UsedBits |= CurrentUsedBits; + + // Check if the new slice would be legal. + if (!LS.isLegal()) + return false; + + // Record the slice. + LoadedSlices.push_back(LS); + } + + // Abort slicing if it does not seem to be profitable. + if (!isSlicingProfitable(LoadedSlices, UsedBits, ForCodeSize)) + return false; + + ++SlicedLoads; + + // Rewrite each chain to use an independent load. + // By construction, each chain can be represented by a unique load. + + // Prepare the argument for the new token factor for all the slices. + SmallVector<SDValue, 8> ArgChains; + for (SmallVectorImpl<LoadedSlice>::const_iterator + LSIt = LoadedSlices.begin(), + LSItEnd = LoadedSlices.end(); + LSIt != LSItEnd; ++LSIt) { + SDValue SliceInst = LSIt->loadSlice(); + CombineTo(LSIt->Inst, SliceInst, true); + if (SliceInst.getOpcode() != ISD::LOAD) + SliceInst = SliceInst.getOperand(0); + assert(SliceInst->getOpcode() == ISD::LOAD && + "It takes more than a zext to get to the loaded slice!!"); + ArgChains.push_back(SliceInst.getValue(1)); + } + + SDValue Chain = DAG.getNode(ISD::TokenFactor, SDLoc(LD), MVT::Other, + ArgChains); + DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain); + AddToWorklist(Chain.getNode()); + return true; +} + +/// Check to see if V is (and load (ptr), imm), where the load is having +/// specific bytes cleared out. If so, return the byte size being masked out +/// and the shift amount. +static std::pair<unsigned, unsigned> +CheckForMaskedLoad(SDValue V, SDValue Ptr, SDValue Chain) { + std::pair<unsigned, unsigned> Result(0, 0); + + // Check for the structure we're looking for. + if (V->getOpcode() != ISD::AND || + !isa<ConstantSDNode>(V->getOperand(1)) || + !ISD::isNormalLoad(V->getOperand(0).getNode())) + return Result; + + // Check the chain and pointer. + LoadSDNode *LD = cast<LoadSDNode>(V->getOperand(0)); + if (LD->getBasePtr() != Ptr) return Result; // Not from same pointer. + + // This only handles simple types. + if (V.getValueType() != MVT::i16 && + V.getValueType() != MVT::i32 && + V.getValueType() != MVT::i64) + return Result; + + // Check the constant mask. Invert it so that the bits being masked out are + // 0 and the bits being kept are 1. Use getSExtValue so that leading bits + // follow the sign bit for uniformity. + uint64_t NotMask = ~cast<ConstantSDNode>(V->getOperand(1))->getSExtValue(); + unsigned NotMaskLZ = countLeadingZeros(NotMask); + if (NotMaskLZ & 7) return Result; // Must be multiple of a byte. + unsigned NotMaskTZ = countTrailingZeros(NotMask); + if (NotMaskTZ & 7) return Result; // Must be multiple of a byte. + if (NotMaskLZ == 64) return Result; // All zero mask. + + // See if we have a continuous run of bits. If so, we have 0*1+0* + if (countTrailingOnes(NotMask >> NotMaskTZ) + NotMaskTZ + NotMaskLZ != 64) + return Result; + + // Adjust NotMaskLZ down to be from the actual size of the int instead of i64. + if (V.getValueType() != MVT::i64 && NotMaskLZ) + NotMaskLZ -= 64-V.getValueSizeInBits(); + + unsigned MaskedBytes = (V.getValueSizeInBits()-NotMaskLZ-NotMaskTZ)/8; + switch (MaskedBytes) { + case 1: + case 2: + case 4: break; + default: return Result; // All one mask, or 5-byte mask. + } + + // Verify that the first bit starts at a multiple of mask so that the access + // is aligned the same as the access width. + if (NotMaskTZ && NotMaskTZ/8 % MaskedBytes) return Result; + + // For narrowing to be valid, it must be the case that the load the + // immediately preceding memory operation before the store. + if (LD == Chain.getNode()) + ; // ok. + else if (Chain->getOpcode() == ISD::TokenFactor && + SDValue(LD, 1).hasOneUse()) { + // LD has only 1 chain use so they are no indirect dependencies. + if (!LD->isOperandOf(Chain.getNode())) + return Result; + } else + return Result; // Fail. + + Result.first = MaskedBytes; + Result.second = NotMaskTZ/8; + return Result; +} + +/// Check to see if IVal is something that provides a value as specified by +/// MaskInfo. If so, replace the specified store with a narrower store of +/// truncated IVal. +static SDValue +ShrinkLoadReplaceStoreWithStore(const std::pair<unsigned, unsigned> &MaskInfo, + SDValue IVal, StoreSDNode *St, + DAGCombiner *DC) { + unsigned NumBytes = MaskInfo.first; + unsigned ByteShift = MaskInfo.second; + SelectionDAG &DAG = DC->getDAG(); + + // Check to see if IVal is all zeros in the part being masked in by the 'or' + // that uses this. If not, this is not a replacement. + APInt Mask = ~APInt::getBitsSet(IVal.getValueSizeInBits(), + ByteShift*8, (ByteShift+NumBytes)*8); + if (!DAG.MaskedValueIsZero(IVal, Mask)) return SDValue(); + + // Check that it is legal on the target to do this. It is legal if the new + // VT we're shrinking to (i8/i16/i32) is legal or we're still before type + // legalization (and the target doesn't explicitly think this is a bad idea). + MVT VT = MVT::getIntegerVT(NumBytes * 8); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + if (!DC->isTypeLegal(VT)) + return SDValue(); + if (St->getMemOperand() && + !TLI.allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(), VT, + *St->getMemOperand())) + return SDValue(); + + // Okay, we can do this! Replace the 'St' store with a store of IVal that is + // shifted by ByteShift and truncated down to NumBytes. + if (ByteShift) { + SDLoc DL(IVal); + IVal = DAG.getNode(ISD::SRL, DL, IVal.getValueType(), IVal, + DAG.getConstant(ByteShift*8, DL, + DC->getShiftAmountTy(IVal.getValueType()))); + } + + // Figure out the offset for the store and the alignment of the access. + unsigned StOffset; + if (DAG.getDataLayout().isLittleEndian()) + StOffset = ByteShift; + else + StOffset = IVal.getValueType().getStoreSize() - ByteShift - NumBytes; + + SDValue Ptr = St->getBasePtr(); + if (StOffset) { + SDLoc DL(IVal); + Ptr = DAG.getMemBasePlusOffset(Ptr, TypeSize::Fixed(StOffset), DL); + } + + // Truncate down to the new size. + IVal = DAG.getNode(ISD::TRUNCATE, SDLoc(IVal), VT, IVal); + + ++OpsNarrowed; + return DAG + .getStore(St->getChain(), SDLoc(St), IVal, Ptr, + St->getPointerInfo().getWithOffset(StOffset), + St->getOriginalAlign()); +} + +/// Look for sequence of load / op / store where op is one of 'or', 'xor', and +/// 'and' of immediates. If 'op' is only touching some of the loaded bits, try +/// narrowing the load and store if it would end up being a win for performance +/// or code size. +SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) { + StoreSDNode *ST = cast<StoreSDNode>(N); + if (!ST->isSimple()) + return SDValue(); + + SDValue Chain = ST->getChain(); + SDValue Value = ST->getValue(); + SDValue Ptr = ST->getBasePtr(); + EVT VT = Value.getValueType(); + + if (ST->isTruncatingStore() || VT.isVector() || !Value.hasOneUse()) + return SDValue(); + + unsigned Opc = Value.getOpcode(); + + // If this is "store (or X, Y), P" and X is "(and (load P), cst)", where cst + // is a byte mask indicating a consecutive number of bytes, check to see if + // Y is known to provide just those bytes. If so, we try to replace the + // load + replace + store sequence with a single (narrower) store, which makes + // the load dead. + if (Opc == ISD::OR && EnableShrinkLoadReplaceStoreWithStore) { + std::pair<unsigned, unsigned> MaskedLoad; + MaskedLoad = CheckForMaskedLoad(Value.getOperand(0), Ptr, Chain); + if (MaskedLoad.first) + if (SDValue NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad, + Value.getOperand(1), ST,this)) + return NewST; + + // Or is commutative, so try swapping X and Y. + MaskedLoad = CheckForMaskedLoad(Value.getOperand(1), Ptr, Chain); + if (MaskedLoad.first) + if (SDValue NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad, + Value.getOperand(0), ST,this)) + return NewST; + } + + if (!EnableReduceLoadOpStoreWidth) + return SDValue(); + + if ((Opc != ISD::OR && Opc != ISD::XOR && Opc != ISD::AND) || + Value.getOperand(1).getOpcode() != ISD::Constant) + return SDValue(); + + SDValue N0 = Value.getOperand(0); + if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() && + Chain == SDValue(N0.getNode(), 1)) { + LoadSDNode *LD = cast<LoadSDNode>(N0); + if (LD->getBasePtr() != Ptr || + LD->getPointerInfo().getAddrSpace() != + ST->getPointerInfo().getAddrSpace()) + return SDValue(); + + // Find the type to narrow it the load / op / store to. + SDValue N1 = Value.getOperand(1); + unsigned BitWidth = N1.getValueSizeInBits(); + APInt Imm = cast<ConstantSDNode>(N1)->getAPIntValue(); + if (Opc == ISD::AND) + Imm ^= APInt::getAllOnesValue(BitWidth); + if (Imm == 0 || Imm.isAllOnesValue()) + return SDValue(); + unsigned ShAmt = Imm.countTrailingZeros(); + unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1; + unsigned NewBW = NextPowerOf2(MSB - ShAmt); + EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); + // The narrowing should be profitable, the load/store operation should be + // legal (or custom) and the store size should be equal to the NewVT width. + while (NewBW < BitWidth && + (NewVT.getStoreSizeInBits() != NewBW || + !TLI.isOperationLegalOrCustom(Opc, NewVT) || + !TLI.isNarrowingProfitable(VT, NewVT))) { + NewBW = NextPowerOf2(NewBW); + NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW); + } + if (NewBW >= BitWidth) + return SDValue(); + + // If the lsb changed does not start at the type bitwidth boundary, + // start at the previous one. + if (ShAmt % NewBW) + ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW; + APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, + std::min(BitWidth, ShAmt + NewBW)); + if ((Imm & Mask) == Imm) { + APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW); + if (Opc == ISD::AND) + NewImm ^= APInt::getAllOnesValue(NewBW); + uint64_t PtrOff = ShAmt / 8; + // For big endian targets, we need to adjust the offset to the pointer to + // load the correct bytes. + if (DAG.getDataLayout().isBigEndian()) + PtrOff = (BitWidth + 7 - NewBW) / 8 - PtrOff; + + Align NewAlign = commonAlignment(LD->getAlign(), PtrOff); + Type *NewVTTy = NewVT.getTypeForEVT(*DAG.getContext()); + if (NewAlign < DAG.getDataLayout().getABITypeAlign(NewVTTy)) + return SDValue(); + + SDValue NewPtr = + DAG.getMemBasePlusOffset(Ptr, TypeSize::Fixed(PtrOff), SDLoc(LD)); + SDValue NewLD = + DAG.getLoad(NewVT, SDLoc(N0), LD->getChain(), NewPtr, + LD->getPointerInfo().getWithOffset(PtrOff), NewAlign, + LD->getMemOperand()->getFlags(), LD->getAAInfo()); + SDValue NewVal = DAG.getNode(Opc, SDLoc(Value), NewVT, NewLD, + DAG.getConstant(NewImm, SDLoc(Value), + NewVT)); + SDValue NewST = + DAG.getStore(Chain, SDLoc(N), NewVal, NewPtr, + ST->getPointerInfo().getWithOffset(PtrOff), NewAlign); + + AddToWorklist(NewPtr.getNode()); + AddToWorklist(NewLD.getNode()); + AddToWorklist(NewVal.getNode()); + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLD.getValue(1)); + ++OpsNarrowed; + return NewST; + } + } + + return SDValue(); +} + +/// For a given floating point load / store pair, if the load value isn't used +/// by any other operations, then consider transforming the pair to integer +/// load / store operations if the target deems the transformation profitable. +SDValue DAGCombiner::TransformFPLoadStorePair(SDNode *N) { + StoreSDNode *ST = cast<StoreSDNode>(N); + SDValue Value = ST->getValue(); + if (ISD::isNormalStore(ST) && ISD::isNormalLoad(Value.getNode()) && + Value.hasOneUse()) { + LoadSDNode *LD = cast<LoadSDNode>(Value); + EVT VT = LD->getMemoryVT(); + if (!VT.isFloatingPoint() || + VT != ST->getMemoryVT() || + LD->isNonTemporal() || + ST->isNonTemporal() || + LD->getPointerInfo().getAddrSpace() != 0 || + ST->getPointerInfo().getAddrSpace() != 0) + return SDValue(); + + TypeSize VTSize = VT.getSizeInBits(); + + // We don't know the size of scalable types at compile time so we cannot + // create an integer of the equivalent size. + if (VTSize.isScalable()) + return SDValue(); + + EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), VTSize.getFixedSize()); + if (!TLI.isOperationLegal(ISD::LOAD, IntVT) || + !TLI.isOperationLegal(ISD::STORE, IntVT) || + !TLI.isDesirableToTransformToIntegerOp(ISD::LOAD, VT) || + !TLI.isDesirableToTransformToIntegerOp(ISD::STORE, VT)) + return SDValue(); + + Align LDAlign = LD->getAlign(); + Align STAlign = ST->getAlign(); + Type *IntVTTy = IntVT.getTypeForEVT(*DAG.getContext()); + Align ABIAlign = DAG.getDataLayout().getABITypeAlign(IntVTTy); + if (LDAlign < ABIAlign || STAlign < ABIAlign) + return SDValue(); + + SDValue NewLD = + DAG.getLoad(IntVT, SDLoc(Value), LD->getChain(), LD->getBasePtr(), + LD->getPointerInfo(), LDAlign); + + SDValue NewST = + DAG.getStore(ST->getChain(), SDLoc(N), NewLD, ST->getBasePtr(), + ST->getPointerInfo(), STAlign); + + AddToWorklist(NewLD.getNode()); + AddToWorklist(NewST.getNode()); + WorklistRemover DeadNodes(*this); + DAG.ReplaceAllUsesOfValueWith(Value.getValue(1), NewLD.getValue(1)); + ++LdStFP2Int; + return NewST; + } + + return SDValue(); +} + +// This is a helper function for visitMUL to check the profitability +// of folding (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2). +// MulNode is the original multiply, AddNode is (add x, c1), +// and ConstNode is c2. +// +// If the (add x, c1) has multiple uses, we could increase +// the number of adds if we make this transformation. +// It would only be worth doing this if we can remove a +// multiply in the process. Check for that here. +// To illustrate: +// (A + c1) * c3 +// (A + c2) * c3 +// We're checking for cases where we have common "c3 * A" expressions. +bool DAGCombiner::isMulAddWithConstProfitable(SDNode *MulNode, + SDValue &AddNode, + SDValue &ConstNode) { + APInt Val; + + // If the add only has one use, this would be OK to do. + if (AddNode.getNode()->hasOneUse()) + return true; + + // Walk all the users of the constant with which we're multiplying. + for (SDNode *Use : ConstNode->uses()) { + if (Use == MulNode) // This use is the one we're on right now. Skip it. + continue; + + if (Use->getOpcode() == ISD::MUL) { // We have another multiply use. + SDNode *OtherOp; + SDNode *MulVar = AddNode.getOperand(0).getNode(); + + // OtherOp is what we're multiplying against the constant. + if (Use->getOperand(0) == ConstNode) + OtherOp = Use->getOperand(1).getNode(); + else + OtherOp = Use->getOperand(0).getNode(); + + // Check to see if multiply is with the same operand of our "add". + // + // ConstNode = CONST + // Use = ConstNode * A <-- visiting Use. OtherOp is A. + // ... + // AddNode = (A + c1) <-- MulVar is A. + // = AddNode * ConstNode <-- current visiting instruction. + // + // If we make this transformation, we will have a common + // multiply (ConstNode * A) that we can save. + if (OtherOp == MulVar) + return true; + + // Now check to see if a future expansion will give us a common + // multiply. + // + // ConstNode = CONST + // AddNode = (A + c1) + // ... = AddNode * ConstNode <-- current visiting instruction. + // ... + // OtherOp = (A + c2) + // Use = OtherOp * ConstNode <-- visiting Use. + // + // If we make this transformation, we will have a common + // multiply (CONST * A) after we also do the same transformation + // to the "t2" instruction. + if (OtherOp->getOpcode() == ISD::ADD && + DAG.isConstantIntBuildVectorOrConstantInt(OtherOp->getOperand(1)) && + OtherOp->getOperand(0).getNode() == MulVar) + return true; + } + } + + // Didn't find a case where this would be profitable. + return false; +} + +SDValue DAGCombiner::getMergeStoreChains(SmallVectorImpl<MemOpLink> &StoreNodes, + unsigned NumStores) { + SmallVector<SDValue, 8> Chains; + SmallPtrSet<const SDNode *, 8> Visited; + SDLoc StoreDL(StoreNodes[0].MemNode); + + for (unsigned i = 0; i < NumStores; ++i) { + Visited.insert(StoreNodes[i].MemNode); + } + + // don't include nodes that are children or repeated nodes. + for (unsigned i = 0; i < NumStores; ++i) { + if (Visited.insert(StoreNodes[i].MemNode->getChain().getNode()).second) + Chains.push_back(StoreNodes[i].MemNode->getChain()); + } + + assert(Chains.size() > 0 && "Chain should have generated a chain"); + return DAG.getTokenFactor(StoreDL, Chains); +} + +bool DAGCombiner::mergeStoresOfConstantsOrVecElts( + SmallVectorImpl<MemOpLink> &StoreNodes, EVT MemVT, unsigned NumStores, + bool IsConstantSrc, bool UseVector, bool UseTrunc) { + // Make sure we have something to merge. + if (NumStores < 2) + return false; + + // The latest Node in the DAG. + SDLoc DL(StoreNodes[0].MemNode); + + TypeSize ElementSizeBits = MemVT.getStoreSizeInBits(); + unsigned SizeInBits = NumStores * ElementSizeBits; + unsigned NumMemElts = MemVT.isVector() ? MemVT.getVectorNumElements() : 1; + + EVT StoreTy; + if (UseVector) { + unsigned Elts = NumStores * NumMemElts; + // Get the type for the merged vector store. + StoreTy = EVT::getVectorVT(*DAG.getContext(), MemVT.getScalarType(), Elts); + } else + StoreTy = EVT::getIntegerVT(*DAG.getContext(), SizeInBits); + + SDValue StoredVal; + if (UseVector) { + if (IsConstantSrc) { + SmallVector<SDValue, 8> BuildVector; + for (unsigned I = 0; I != NumStores; ++I) { + StoreSDNode *St = cast<StoreSDNode>(StoreNodes[I].MemNode); + SDValue Val = St->getValue(); + // If constant is of the wrong type, convert it now. + if (MemVT != Val.getValueType()) { + Val = peekThroughBitcasts(Val); + // Deal with constants of wrong size. + if (ElementSizeBits != Val.getValueSizeInBits()) { + EVT IntMemVT = + EVT::getIntegerVT(*DAG.getContext(), MemVT.getSizeInBits()); + if (isa<ConstantFPSDNode>(Val)) { + // Not clear how to truncate FP values. + return false; + } else if (auto *C = dyn_cast<ConstantSDNode>(Val)) + Val = DAG.getConstant(C->getAPIntValue() + .zextOrTrunc(Val.getValueSizeInBits()) + .zextOrTrunc(ElementSizeBits), + SDLoc(C), IntMemVT); + } + // Make sure correctly size type is the correct type. + Val = DAG.getBitcast(MemVT, Val); + } + BuildVector.push_back(Val); + } + StoredVal = DAG.getNode(MemVT.isVector() ? ISD::CONCAT_VECTORS + : ISD::BUILD_VECTOR, + DL, StoreTy, BuildVector); + } else { + SmallVector<SDValue, 8> Ops; + for (unsigned i = 0; i < NumStores; ++i) { + StoreSDNode *St = cast<StoreSDNode>(StoreNodes[i].MemNode); + SDValue Val = peekThroughBitcasts(St->getValue()); + // All operands of BUILD_VECTOR / CONCAT_VECTOR must be of + // type MemVT. If the underlying value is not the correct + // type, but it is an extraction of an appropriate vector we + // can recast Val to be of the correct type. This may require + // converting between EXTRACT_VECTOR_ELT and + // EXTRACT_SUBVECTOR. + if ((MemVT != Val.getValueType()) && + (Val.getOpcode() == ISD::EXTRACT_VECTOR_ELT || + Val.getOpcode() == ISD::EXTRACT_SUBVECTOR)) { + EVT MemVTScalarTy = MemVT.getScalarType(); + // We may need to add a bitcast here to get types to line up. + if (MemVTScalarTy != Val.getValueType().getScalarType()) { + Val = DAG.getBitcast(MemVT, Val); + } else { + unsigned OpC = MemVT.isVector() ? ISD::EXTRACT_SUBVECTOR + : ISD::EXTRACT_VECTOR_ELT; + SDValue Vec = Val.getOperand(0); + SDValue Idx = Val.getOperand(1); + Val = DAG.getNode(OpC, SDLoc(Val), MemVT, Vec, Idx); + } + } + Ops.push_back(Val); + } + + // Build the extracted vector elements back into a vector. + StoredVal = DAG.getNode(MemVT.isVector() ? ISD::CONCAT_VECTORS + : ISD::BUILD_VECTOR, + DL, StoreTy, Ops); + } + } else { + // We should always use a vector store when merging extracted vector + // elements, so this path implies a store of constants. + assert(IsConstantSrc && "Merged vector elements should use vector store"); + + APInt StoreInt(SizeInBits, 0); + + // Construct a single integer constant which is made of the smaller + // constant inputs. + bool IsLE = DAG.getDataLayout().isLittleEndian(); + for (unsigned i = 0; i < NumStores; ++i) { + unsigned Idx = IsLE ? (NumStores - 1 - i) : i; + StoreSDNode *St = cast<StoreSDNode>(StoreNodes[Idx].MemNode); + + SDValue Val = St->getValue(); + Val = peekThroughBitcasts(Val); + StoreInt <<= ElementSizeBits; + if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val)) { + StoreInt |= C->getAPIntValue() + .zextOrTrunc(ElementSizeBits) + .zextOrTrunc(SizeInBits); + } else if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Val)) { + StoreInt |= C->getValueAPF() + .bitcastToAPInt() + .zextOrTrunc(ElementSizeBits) + .zextOrTrunc(SizeInBits); + // If fp truncation is necessary give up for now. + if (MemVT.getSizeInBits() != ElementSizeBits) + return false; + } else { + llvm_unreachable("Invalid constant element type"); + } + } + + // Create the new Load and Store operations. + StoredVal = DAG.getConstant(StoreInt, DL, StoreTy); + } + + LSBaseSDNode *FirstInChain = StoreNodes[0].MemNode; + SDValue NewChain = getMergeStoreChains(StoreNodes, NumStores); + + // make sure we use trunc store if it's necessary to be legal. + SDValue NewStore; + if (!UseTrunc) { + NewStore = + DAG.getStore(NewChain, DL, StoredVal, FirstInChain->getBasePtr(), + FirstInChain->getPointerInfo(), FirstInChain->getAlign()); + } else { // Must be realized as a trunc store + EVT LegalizedStoredValTy = + TLI.getTypeToTransformTo(*DAG.getContext(), StoredVal.getValueType()); + unsigned LegalizedStoreSize = LegalizedStoredValTy.getSizeInBits(); + ConstantSDNode *C = cast<ConstantSDNode>(StoredVal); + SDValue ExtendedStoreVal = + DAG.getConstant(C->getAPIntValue().zextOrTrunc(LegalizedStoreSize), DL, + LegalizedStoredValTy); + NewStore = DAG.getTruncStore( + NewChain, DL, ExtendedStoreVal, FirstInChain->getBasePtr(), + FirstInChain->getPointerInfo(), StoredVal.getValueType() /*TVT*/, + FirstInChain->getAlign(), FirstInChain->getMemOperand()->getFlags()); + } + + // Replace all merged stores with the new store. + for (unsigned i = 0; i < NumStores; ++i) + CombineTo(StoreNodes[i].MemNode, NewStore); + + AddToWorklist(NewChain.getNode()); + return true; +} + +void DAGCombiner::getStoreMergeCandidates( + StoreSDNode *St, SmallVectorImpl<MemOpLink> &StoreNodes, + SDNode *&RootNode) { + // This holds the base pointer, index, and the offset in bytes from the base + // pointer. We must have a base and an offset. Do not handle stores to undef + // base pointers. + BaseIndexOffset BasePtr = BaseIndexOffset::match(St, DAG); + if (!BasePtr.getBase().getNode() || BasePtr.getBase().isUndef()) + return; + + SDValue Val = peekThroughBitcasts(St->getValue()); + StoreSource StoreSrc = getStoreSource(Val); + assert(StoreSrc != StoreSource::Unknown && "Expected known source for store"); + + // Match on loadbaseptr if relevant. + EVT MemVT = St->getMemoryVT(); + BaseIndexOffset LBasePtr; + EVT LoadVT; + if (StoreSrc == StoreSource::Load) { + auto *Ld = cast<LoadSDNode>(Val); + LBasePtr = BaseIndexOffset::match(Ld, DAG); + LoadVT = Ld->getMemoryVT(); + // Load and store should be the same type. + if (MemVT != LoadVT) + return; + // Loads must only have one use. + if (!Ld->hasNUsesOfValue(1, 0)) + return; + // The memory operands must not be volatile/indexed/atomic. + // TODO: May be able to relax for unordered atomics (see D66309) + if (!Ld->isSimple() || Ld->isIndexed()) + return; + } + auto CandidateMatch = [&](StoreSDNode *Other, BaseIndexOffset &Ptr, + int64_t &Offset) -> bool { + // The memory operands must not be volatile/indexed/atomic. + // TODO: May be able to relax for unordered atomics (see D66309) + if (!Other->isSimple() || Other->isIndexed()) + return false; + // Don't mix temporal stores with non-temporal stores. + if (St->isNonTemporal() != Other->isNonTemporal()) + return false; + SDValue OtherBC = peekThroughBitcasts(Other->getValue()); + // Allow merging constants of different types as integers. + bool NoTypeMatch = (MemVT.isInteger()) ? !MemVT.bitsEq(Other->getMemoryVT()) + : Other->getMemoryVT() != MemVT; + switch (StoreSrc) { + case StoreSource::Load: { + if (NoTypeMatch) + return false; + // The Load's Base Ptr must also match. + auto *OtherLd = dyn_cast<LoadSDNode>(OtherBC); + if (!OtherLd) + return false; + BaseIndexOffset LPtr = BaseIndexOffset::match(OtherLd, DAG); + if (LoadVT != OtherLd->getMemoryVT()) + return false; + // Loads must only have one use. + if (!OtherLd->hasNUsesOfValue(1, 0)) + return false; + // The memory operands must not be volatile/indexed/atomic. + // TODO: May be able to relax for unordered atomics (see D66309) + if (!OtherLd->isSimple() || OtherLd->isIndexed()) + return false; + // Don't mix temporal loads with non-temporal loads. + if (cast<LoadSDNode>(Val)->isNonTemporal() != OtherLd->isNonTemporal()) + return false; + if (!(LBasePtr.equalBaseIndex(LPtr, DAG))) + return false; + break; + } + case StoreSource::Constant: + if (NoTypeMatch) + return false; + if (!(isa<ConstantSDNode>(OtherBC) || isa<ConstantFPSDNode>(OtherBC))) + return false; + break; + case StoreSource::Extract: + // Do not merge truncated stores here. + if (Other->isTruncatingStore()) + return false; + if (!MemVT.bitsEq(OtherBC.getValueType())) + return false; + if (OtherBC.getOpcode() != ISD::EXTRACT_VECTOR_ELT && + OtherBC.getOpcode() != ISD::EXTRACT_SUBVECTOR) + return false; + break; + default: + llvm_unreachable("Unhandled store source for merging"); + } + Ptr = BaseIndexOffset::match(Other, DAG); + return (BasePtr.equalBaseIndex(Ptr, DAG, Offset)); + }; + + // Check if the pair of StoreNode and the RootNode already bail out many + // times which is over the limit in dependence check. + auto OverLimitInDependenceCheck = [&](SDNode *StoreNode, + SDNode *RootNode) -> bool { + auto RootCount = StoreRootCountMap.find(StoreNode); + return RootCount != StoreRootCountMap.end() && + RootCount->second.first == RootNode && + RootCount->second.second > StoreMergeDependenceLimit; + }; + + auto TryToAddCandidate = [&](SDNode::use_iterator UseIter) { + // This must be a chain use. + if (UseIter.getOperandNo() != 0) + return; + if (auto *OtherStore = dyn_cast<StoreSDNode>(*UseIter)) { + BaseIndexOffset Ptr; + int64_t PtrDiff; + if (CandidateMatch(OtherStore, Ptr, PtrDiff) && + !OverLimitInDependenceCheck(OtherStore, RootNode)) + StoreNodes.push_back(MemOpLink(OtherStore, PtrDiff)); + } + }; + + // We looking for a root node which is an ancestor to all mergable + // stores. We search up through a load, to our root and then down + // through all children. For instance we will find Store{1,2,3} if + // St is Store1, Store2. or Store3 where the root is not a load + // which always true for nonvolatile ops. TODO: Expand + // the search to find all valid candidates through multiple layers of loads. + // + // Root + // |-------|-------| + // Load Load Store3 + // | | + // Store1 Store2 + // + // FIXME: We should be able to climb and + // descend TokenFactors to find candidates as well. + + RootNode = St->getChain().getNode(); + + unsigned NumNodesExplored = 0; + const unsigned MaxSearchNodes = 1024; + if (auto *Ldn = dyn_cast<LoadSDNode>(RootNode)) { + RootNode = Ldn->getChain().getNode(); + for (auto I = RootNode->use_begin(), E = RootNode->use_end(); + I != E && NumNodesExplored < MaxSearchNodes; ++I, ++NumNodesExplored) { + if (I.getOperandNo() == 0 && isa<LoadSDNode>(*I)) { // walk down chain + for (auto I2 = (*I)->use_begin(), E2 = (*I)->use_end(); I2 != E2; ++I2) + TryToAddCandidate(I2); + } + } + } else { + for (auto I = RootNode->use_begin(), E = RootNode->use_end(); + I != E && NumNodesExplored < MaxSearchNodes; ++I, ++NumNodesExplored) + TryToAddCandidate(I); + } +} + +// We need to check that merging these stores does not cause a loop in +// the DAG. Any store candidate may depend on another candidate +// indirectly through its operand (we already consider dependencies +// through the chain). Check in parallel by searching up from +// non-chain operands of candidates. +bool DAGCombiner::checkMergeStoreCandidatesForDependencies( + SmallVectorImpl<MemOpLink> &StoreNodes, unsigned NumStores, + SDNode *RootNode) { + // FIXME: We should be able to truncate a full search of + // predecessors by doing a BFS and keeping tabs the originating + // stores from which worklist nodes come from in a similar way to + // TokenFactor simplfication. + + SmallPtrSet<const SDNode *, 32> Visited; + SmallVector<const SDNode *, 8> Worklist; + + // RootNode is a predecessor to all candidates so we need not search + // past it. Add RootNode (peeking through TokenFactors). Do not count + // these towards size check. + + Worklist.push_back(RootNode); + while (!Worklist.empty()) { + auto N = Worklist.pop_back_val(); + if (!Visited.insert(N).second) + continue; // Already present in Visited. + if (N->getOpcode() == ISD::TokenFactor) { + for (SDValue Op : N->ops()) + Worklist.push_back(Op.getNode()); + } + } + + // Don't count pruning nodes towards max. + unsigned int Max = 1024 + Visited.size(); + // Search Ops of store candidates. + for (unsigned i = 0; i < NumStores; ++i) { + SDNode *N = StoreNodes[i].MemNode; + // Of the 4 Store Operands: + // * Chain (Op 0) -> We have already considered these + // in candidate selection and can be + // safely ignored + // * Value (Op 1) -> Cycles may happen (e.g. through load chains) + // * Address (Op 2) -> Merged addresses may only vary by a fixed constant, + // but aren't necessarily fromt the same base node, so + // cycles possible (e.g. via indexed store). + // * (Op 3) -> Represents the pre or post-indexing offset (or undef for + // non-indexed stores). Not constant on all targets (e.g. ARM) + // and so can participate in a cycle. + for (unsigned j = 1; j < N->getNumOperands(); ++j) + Worklist.push_back(N->getOperand(j).getNode()); + } + // Search through DAG. We can stop early if we find a store node. + for (unsigned i = 0; i < NumStores; ++i) + if (SDNode::hasPredecessorHelper(StoreNodes[i].MemNode, Visited, Worklist, + Max)) { + // If the searching bail out, record the StoreNode and RootNode in the + // StoreRootCountMap. If we have seen the pair many times over a limit, + // we won't add the StoreNode into StoreNodes set again. + if (Visited.size() >= Max) { + auto &RootCount = StoreRootCountMap[StoreNodes[i].MemNode]; + if (RootCount.first == RootNode) + RootCount.second++; + else + RootCount = {RootNode, 1}; + } + return false; + } + return true; +} + +unsigned +DAGCombiner::getConsecutiveStores(SmallVectorImpl<MemOpLink> &StoreNodes, + int64_t ElementSizeBytes) const { + while (true) { + // Find a store past the width of the first store. + size_t StartIdx = 0; + while ((StartIdx + 1 < StoreNodes.size()) && + StoreNodes[StartIdx].OffsetFromBase + ElementSizeBytes != + StoreNodes[StartIdx + 1].OffsetFromBase) + ++StartIdx; + + // Bail if we don't have enough candidates to merge. + if (StartIdx + 1 >= StoreNodes.size()) + return 0; + + // Trim stores that overlapped with the first store. + if (StartIdx) + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + StartIdx); + + // Scan the memory operations on the chain and find the first + // non-consecutive store memory address. + unsigned NumConsecutiveStores = 1; + int64_t StartAddress = StoreNodes[0].OffsetFromBase; + // Check that the addresses are consecutive starting from the second + // element in the list of stores. + for (unsigned i = 1, e = StoreNodes.size(); i < e; ++i) { + int64_t CurrAddress = StoreNodes[i].OffsetFromBase; + if (CurrAddress - StartAddress != (ElementSizeBytes * i)) + break; + NumConsecutiveStores = i + 1; + } + if (NumConsecutiveStores > 1) + return NumConsecutiveStores; + + // There are no consecutive stores at the start of the list. + // Remove the first store and try again. + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + 1); + } +} + +bool DAGCombiner::tryStoreMergeOfConstants( + SmallVectorImpl<MemOpLink> &StoreNodes, unsigned NumConsecutiveStores, + EVT MemVT, SDNode *RootNode, bool AllowVectors) { + LLVMContext &Context = *DAG.getContext(); + const DataLayout &DL = DAG.getDataLayout(); + int64_t ElementSizeBytes = MemVT.getStoreSize(); + unsigned NumMemElts = MemVT.isVector() ? MemVT.getVectorNumElements() : 1; + bool MadeChange = false; + + // Store the constants into memory as one consecutive store. + while (NumConsecutiveStores >= 2) { + LSBaseSDNode *FirstInChain = StoreNodes[0].MemNode; + unsigned FirstStoreAS = FirstInChain->getAddressSpace(); + unsigned FirstStoreAlign = FirstInChain->getAlignment(); + unsigned LastLegalType = 1; + unsigned LastLegalVectorType = 1; + bool LastIntegerTrunc = false; + bool NonZero = false; + unsigned FirstZeroAfterNonZero = NumConsecutiveStores; + for (unsigned i = 0; i < NumConsecutiveStores; ++i) { + StoreSDNode *ST = cast<StoreSDNode>(StoreNodes[i].MemNode); + SDValue StoredVal = ST->getValue(); + bool IsElementZero = false; + if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(StoredVal)) + IsElementZero = C->isNullValue(); + else if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(StoredVal)) + IsElementZero = C->getConstantFPValue()->isNullValue(); + if (IsElementZero) { + if (NonZero && FirstZeroAfterNonZero == NumConsecutiveStores) + FirstZeroAfterNonZero = i; + } + NonZero |= !IsElementZero; + + // Find a legal type for the constant store. + unsigned SizeInBits = (i + 1) * ElementSizeBytes * 8; + EVT StoreTy = EVT::getIntegerVT(Context, SizeInBits); + bool IsFast = false; + + // Break early when size is too large to be legal. + if (StoreTy.getSizeInBits() > MaximumLegalStoreInBits) + break; + + if (TLI.isTypeLegal(StoreTy) && + TLI.canMergeStoresTo(FirstStoreAS, StoreTy, DAG) && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstInChain->getMemOperand(), &IsFast) && + IsFast) { + LastIntegerTrunc = false; + LastLegalType = i + 1; + // Or check whether a truncstore is legal. + } else if (TLI.getTypeAction(Context, StoreTy) == + TargetLowering::TypePromoteInteger) { + EVT LegalizedStoredValTy = + TLI.getTypeToTransformTo(Context, StoredVal.getValueType()); + if (TLI.isTruncStoreLegal(LegalizedStoredValTy, StoreTy) && + TLI.canMergeStoresTo(FirstStoreAS, LegalizedStoredValTy, DAG) && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstInChain->getMemOperand(), &IsFast) && + IsFast) { + LastIntegerTrunc = true; + LastLegalType = i + 1; + } + } + + // We only use vectors if the constant is known to be zero or the + // target allows it and the function is not marked with the + // noimplicitfloat attribute. + if ((!NonZero || + TLI.storeOfVectorConstantIsCheap(MemVT, i + 1, FirstStoreAS)) && + AllowVectors) { + // Find a legal type for the vector store. + unsigned Elts = (i + 1) * NumMemElts; + EVT Ty = EVT::getVectorVT(Context, MemVT.getScalarType(), Elts); + if (TLI.isTypeLegal(Ty) && TLI.isTypeLegal(MemVT) && + TLI.canMergeStoresTo(FirstStoreAS, Ty, DAG) && + TLI.allowsMemoryAccess(Context, DL, Ty, + *FirstInChain->getMemOperand(), &IsFast) && + IsFast) + LastLegalVectorType = i + 1; + } + } + + bool UseVector = (LastLegalVectorType > LastLegalType) && AllowVectors; + unsigned NumElem = (UseVector) ? LastLegalVectorType : LastLegalType; + + // Check if we found a legal integer type that creates a meaningful + // merge. + if (NumElem < 2) { + // We know that candidate stores are in order and of correct + // shape. While there is no mergeable sequence from the + // beginning one may start later in the sequence. The only + // reason a merge of size N could have failed where another of + // the same size would not have, is if the alignment has + // improved or we've dropped a non-zero value. Drop as many + // candidates as we can here. + unsigned NumSkip = 1; + while ((NumSkip < NumConsecutiveStores) && + (NumSkip < FirstZeroAfterNonZero) && + (StoreNodes[NumSkip].MemNode->getAlignment() <= FirstStoreAlign)) + NumSkip++; + + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumSkip); + NumConsecutiveStores -= NumSkip; + continue; + } + + // Check that we can merge these candidates without causing a cycle. + if (!checkMergeStoreCandidatesForDependencies(StoreNodes, NumElem, + RootNode)) { + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumElem); + NumConsecutiveStores -= NumElem; + continue; + } + + MadeChange |= mergeStoresOfConstantsOrVecElts( + StoreNodes, MemVT, NumElem, true, UseVector, LastIntegerTrunc); + + // Remove merged stores for next iteration. + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumElem); + NumConsecutiveStores -= NumElem; + } + return MadeChange; +} + +bool DAGCombiner::tryStoreMergeOfExtracts( + SmallVectorImpl<MemOpLink> &StoreNodes, unsigned NumConsecutiveStores, + EVT MemVT, SDNode *RootNode) { + LLVMContext &Context = *DAG.getContext(); + const DataLayout &DL = DAG.getDataLayout(); + unsigned NumMemElts = MemVT.isVector() ? MemVT.getVectorNumElements() : 1; + bool MadeChange = false; + + // Loop on Consecutive Stores on success. + while (NumConsecutiveStores >= 2) { + LSBaseSDNode *FirstInChain = StoreNodes[0].MemNode; + unsigned FirstStoreAS = FirstInChain->getAddressSpace(); + unsigned FirstStoreAlign = FirstInChain->getAlignment(); + unsigned NumStoresToMerge = 1; + for (unsigned i = 0; i < NumConsecutiveStores; ++i) { + // Find a legal type for the vector store. + unsigned Elts = (i + 1) * NumMemElts; + EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT.getScalarType(), Elts); + bool IsFast = false; + + // Break early when size is too large to be legal. + if (Ty.getSizeInBits() > MaximumLegalStoreInBits) + break; + + if (TLI.isTypeLegal(Ty) && TLI.canMergeStoresTo(FirstStoreAS, Ty, DAG) && + TLI.allowsMemoryAccess(Context, DL, Ty, + *FirstInChain->getMemOperand(), &IsFast) && + IsFast) + NumStoresToMerge = i + 1; + } + + // Check if we found a legal integer type creating a meaningful + // merge. + if (NumStoresToMerge < 2) { + // We know that candidate stores are in order and of correct + // shape. While there is no mergeable sequence from the + // beginning one may start later in the sequence. The only + // reason a merge of size N could have failed where another of + // the same size would not have, is if the alignment has + // improved. Drop as many candidates as we can here. + unsigned NumSkip = 1; + while ((NumSkip < NumConsecutiveStores) && + (StoreNodes[NumSkip].MemNode->getAlignment() <= FirstStoreAlign)) + NumSkip++; + + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumSkip); + NumConsecutiveStores -= NumSkip; + continue; + } + + // Check that we can merge these candidates without causing a cycle. + if (!checkMergeStoreCandidatesForDependencies(StoreNodes, NumStoresToMerge, + RootNode)) { + StoreNodes.erase(StoreNodes.begin(), + StoreNodes.begin() + NumStoresToMerge); + NumConsecutiveStores -= NumStoresToMerge; + continue; + } + + MadeChange |= mergeStoresOfConstantsOrVecElts( + StoreNodes, MemVT, NumStoresToMerge, false, true, false); + + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumStoresToMerge); + NumConsecutiveStores -= NumStoresToMerge; + } + return MadeChange; +} + +bool DAGCombiner::tryStoreMergeOfLoads(SmallVectorImpl<MemOpLink> &StoreNodes, + unsigned NumConsecutiveStores, EVT MemVT, + SDNode *RootNode, bool AllowVectors, + bool IsNonTemporalStore, + bool IsNonTemporalLoad) { + LLVMContext &Context = *DAG.getContext(); + const DataLayout &DL = DAG.getDataLayout(); + int64_t ElementSizeBytes = MemVT.getStoreSize(); + unsigned NumMemElts = MemVT.isVector() ? MemVT.getVectorNumElements() : 1; + bool MadeChange = false; + + int64_t StartAddress = StoreNodes[0].OffsetFromBase; + + // Look for load nodes which are used by the stored values. + SmallVector<MemOpLink, 8> LoadNodes; + + // Find acceptable loads. Loads need to have the same chain (token factor), + // must not be zext, volatile, indexed, and they must be consecutive. + BaseIndexOffset LdBasePtr; + + for (unsigned i = 0; i < NumConsecutiveStores; ++i) { + StoreSDNode *St = cast<StoreSDNode>(StoreNodes[i].MemNode); + SDValue Val = peekThroughBitcasts(St->getValue()); + LoadSDNode *Ld = cast<LoadSDNode>(Val); + + BaseIndexOffset LdPtr = BaseIndexOffset::match(Ld, DAG); + // If this is not the first ptr that we check. + int64_t LdOffset = 0; + if (LdBasePtr.getBase().getNode()) { + // The base ptr must be the same. + if (!LdBasePtr.equalBaseIndex(LdPtr, DAG, LdOffset)) + break; + } else { + // Check that all other base pointers are the same as this one. + LdBasePtr = LdPtr; + } + + // We found a potential memory operand to merge. + LoadNodes.push_back(MemOpLink(Ld, LdOffset)); + } + + while (NumConsecutiveStores >= 2 && LoadNodes.size() >= 2) { + Align RequiredAlignment; + bool NeedRotate = false; + if (LoadNodes.size() == 2) { + // If we have load/store pair instructions and we only have two values, + // don't bother merging. + if (TLI.hasPairedLoad(MemVT, RequiredAlignment) && + StoreNodes[0].MemNode->getAlign() >= RequiredAlignment) { + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + 2); + LoadNodes.erase(LoadNodes.begin(), LoadNodes.begin() + 2); + break; + } + // If the loads are reversed, see if we can rotate the halves into place. + int64_t Offset0 = LoadNodes[0].OffsetFromBase; + int64_t Offset1 = LoadNodes[1].OffsetFromBase; + EVT PairVT = EVT::getIntegerVT(Context, ElementSizeBytes * 8 * 2); + if (Offset0 - Offset1 == ElementSizeBytes && + (hasOperation(ISD::ROTL, PairVT) || + hasOperation(ISD::ROTR, PairVT))) { + std::swap(LoadNodes[0], LoadNodes[1]); + NeedRotate = true; + } + } + LSBaseSDNode *FirstInChain = StoreNodes[0].MemNode; + unsigned FirstStoreAS = FirstInChain->getAddressSpace(); + Align FirstStoreAlign = FirstInChain->getAlign(); + LoadSDNode *FirstLoad = cast<LoadSDNode>(LoadNodes[0].MemNode); + + // Scan the memory operations on the chain and find the first + // non-consecutive load memory address. These variables hold the index in + // the store node array. + + unsigned LastConsecutiveLoad = 1; + + // This variable refers to the size and not index in the array. + unsigned LastLegalVectorType = 1; + unsigned LastLegalIntegerType = 1; + bool isDereferenceable = true; + bool DoIntegerTruncate = false; + StartAddress = LoadNodes[0].OffsetFromBase; + SDValue LoadChain = FirstLoad->getChain(); + for (unsigned i = 1; i < LoadNodes.size(); ++i) { + // All loads must share the same chain. + if (LoadNodes[i].MemNode->getChain() != LoadChain) + break; + + int64_t CurrAddress = LoadNodes[i].OffsetFromBase; + if (CurrAddress - StartAddress != (ElementSizeBytes * i)) + break; + LastConsecutiveLoad = i; + + if (isDereferenceable && !LoadNodes[i].MemNode->isDereferenceable()) + isDereferenceable = false; + + // Find a legal type for the vector store. + unsigned Elts = (i + 1) * NumMemElts; + EVT StoreTy = EVT::getVectorVT(Context, MemVT.getScalarType(), Elts); + + // Break early when size is too large to be legal. + if (StoreTy.getSizeInBits() > MaximumLegalStoreInBits) + break; + + bool IsFastSt = false; + bool IsFastLd = false; + if (TLI.isTypeLegal(StoreTy) && + TLI.canMergeStoresTo(FirstStoreAS, StoreTy, DAG) && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstInChain->getMemOperand(), &IsFastSt) && + IsFastSt && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstLoad->getMemOperand(), &IsFastLd) && + IsFastLd) { + LastLegalVectorType = i + 1; + } + + // Find a legal type for the integer store. + unsigned SizeInBits = (i + 1) * ElementSizeBytes * 8; + StoreTy = EVT::getIntegerVT(Context, SizeInBits); + if (TLI.isTypeLegal(StoreTy) && + TLI.canMergeStoresTo(FirstStoreAS, StoreTy, DAG) && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstInChain->getMemOperand(), &IsFastSt) && + IsFastSt && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstLoad->getMemOperand(), &IsFastLd) && + IsFastLd) { + LastLegalIntegerType = i + 1; + DoIntegerTruncate = false; + // Or check whether a truncstore and extload is legal. + } else if (TLI.getTypeAction(Context, StoreTy) == + TargetLowering::TypePromoteInteger) { + EVT LegalizedStoredValTy = TLI.getTypeToTransformTo(Context, StoreTy); + if (TLI.isTruncStoreLegal(LegalizedStoredValTy, StoreTy) && + TLI.canMergeStoresTo(FirstStoreAS, LegalizedStoredValTy, DAG) && + TLI.isLoadExtLegal(ISD::ZEXTLOAD, LegalizedStoredValTy, StoreTy) && + TLI.isLoadExtLegal(ISD::SEXTLOAD, LegalizedStoredValTy, StoreTy) && + TLI.isLoadExtLegal(ISD::EXTLOAD, LegalizedStoredValTy, StoreTy) && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstInChain->getMemOperand(), &IsFastSt) && + IsFastSt && + TLI.allowsMemoryAccess(Context, DL, StoreTy, + *FirstLoad->getMemOperand(), &IsFastLd) && + IsFastLd) { + LastLegalIntegerType = i + 1; + DoIntegerTruncate = true; + } + } + } + + // Only use vector types if the vector type is larger than the integer + // type. If they are the same, use integers. + bool UseVectorTy = + LastLegalVectorType > LastLegalIntegerType && AllowVectors; + unsigned LastLegalType = + std::max(LastLegalVectorType, LastLegalIntegerType); + + // We add +1 here because the LastXXX variables refer to location while + // the NumElem refers to array/index size. + unsigned NumElem = std::min(NumConsecutiveStores, LastConsecutiveLoad + 1); + NumElem = std::min(LastLegalType, NumElem); + Align FirstLoadAlign = FirstLoad->getAlign(); + + if (NumElem < 2) { + // We know that candidate stores are in order and of correct + // shape. While there is no mergeable sequence from the + // beginning one may start later in the sequence. The only + // reason a merge of size N could have failed where another of + // the same size would not have is if the alignment or either + // the load or store has improved. Drop as many candidates as we + // can here. + unsigned NumSkip = 1; + while ((NumSkip < LoadNodes.size()) && + (LoadNodes[NumSkip].MemNode->getAlign() <= FirstLoadAlign) && + (StoreNodes[NumSkip].MemNode->getAlign() <= FirstStoreAlign)) + NumSkip++; + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumSkip); + LoadNodes.erase(LoadNodes.begin(), LoadNodes.begin() + NumSkip); + NumConsecutiveStores -= NumSkip; + continue; + } + + // Check that we can merge these candidates without causing a cycle. + if (!checkMergeStoreCandidatesForDependencies(StoreNodes, NumElem, + RootNode)) { + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumElem); + LoadNodes.erase(LoadNodes.begin(), LoadNodes.begin() + NumElem); + NumConsecutiveStores -= NumElem; + continue; + } + + // Find if it is better to use vectors or integers to load and store + // to memory. + EVT JointMemOpVT; + if (UseVectorTy) { + // Find a legal type for the vector store. + unsigned Elts = NumElem * NumMemElts; + JointMemOpVT = EVT::getVectorVT(Context, MemVT.getScalarType(), Elts); + } else { + unsigned SizeInBits = NumElem * ElementSizeBytes * 8; + JointMemOpVT = EVT::getIntegerVT(Context, SizeInBits); + } + + SDLoc LoadDL(LoadNodes[0].MemNode); + SDLoc StoreDL(StoreNodes[0].MemNode); + + // The merged loads are required to have the same incoming chain, so + // using the first's chain is acceptable. + + SDValue NewStoreChain = getMergeStoreChains(StoreNodes, NumElem); + AddToWorklist(NewStoreChain.getNode()); + + MachineMemOperand::Flags LdMMOFlags = + isDereferenceable ? MachineMemOperand::MODereferenceable + : MachineMemOperand::MONone; + if (IsNonTemporalLoad) + LdMMOFlags |= MachineMemOperand::MONonTemporal; + + MachineMemOperand::Flags StMMOFlags = IsNonTemporalStore + ? MachineMemOperand::MONonTemporal + : MachineMemOperand::MONone; + + SDValue NewLoad, NewStore; + if (UseVectorTy || !DoIntegerTruncate) { + NewLoad = DAG.getLoad( + JointMemOpVT, LoadDL, FirstLoad->getChain(), FirstLoad->getBasePtr(), + FirstLoad->getPointerInfo(), FirstLoadAlign, LdMMOFlags); + SDValue StoreOp = NewLoad; + if (NeedRotate) { + unsigned LoadWidth = ElementSizeBytes * 8 * 2; + assert(JointMemOpVT == EVT::getIntegerVT(Context, LoadWidth) && + "Unexpected type for rotate-able load pair"); + SDValue RotAmt = + DAG.getShiftAmountConstant(LoadWidth / 2, JointMemOpVT, LoadDL); + // Target can convert to the identical ROTR if it does not have ROTL. + StoreOp = DAG.getNode(ISD::ROTL, LoadDL, JointMemOpVT, NewLoad, RotAmt); + } + NewStore = DAG.getStore( + NewStoreChain, StoreDL, StoreOp, FirstInChain->getBasePtr(), + FirstInChain->getPointerInfo(), FirstStoreAlign, StMMOFlags); + } else { // This must be the truncstore/extload case + EVT ExtendedTy = + TLI.getTypeToTransformTo(*DAG.getContext(), JointMemOpVT); + NewLoad = DAG.getExtLoad(ISD::EXTLOAD, LoadDL, ExtendedTy, + FirstLoad->getChain(), FirstLoad->getBasePtr(), + FirstLoad->getPointerInfo(), JointMemOpVT, + FirstLoadAlign, LdMMOFlags); + NewStore = DAG.getTruncStore( + NewStoreChain, StoreDL, NewLoad, FirstInChain->getBasePtr(), + FirstInChain->getPointerInfo(), JointMemOpVT, + FirstInChain->getAlign(), FirstInChain->getMemOperand()->getFlags()); + } + + // Transfer chain users from old loads to the new load. + for (unsigned i = 0; i < NumElem; ++i) { + LoadSDNode *Ld = cast<LoadSDNode>(LoadNodes[i].MemNode); + DAG.ReplaceAllUsesOfValueWith(SDValue(Ld, 1), + SDValue(NewLoad.getNode(), 1)); + } + + // Replace all stores with the new store. Recursively remove corresponding + // values if they are no longer used. + for (unsigned i = 0; i < NumElem; ++i) { + SDValue Val = StoreNodes[i].MemNode->getOperand(1); + CombineTo(StoreNodes[i].MemNode, NewStore); + if (Val.getNode()->use_empty()) + recursivelyDeleteUnusedNodes(Val.getNode()); + } + + MadeChange = true; + StoreNodes.erase(StoreNodes.begin(), StoreNodes.begin() + NumElem); + LoadNodes.erase(LoadNodes.begin(), LoadNodes.begin() + NumElem); + NumConsecutiveStores -= NumElem; + } + return MadeChange; +} + +bool DAGCombiner::mergeConsecutiveStores(StoreSDNode *St) { + if (OptLevel == CodeGenOpt::None || !EnableStoreMerging) + return false; + + // TODO: Extend this function to merge stores of scalable vectors. + // (i.e. two <vscale x 8 x i8> stores can be merged to one <vscale x 16 x i8> + // store since we know <vscale x 16 x i8> is exactly twice as large as + // <vscale x 8 x i8>). Until then, bail out for scalable vectors. + EVT MemVT = St->getMemoryVT(); + if (MemVT.isScalableVector()) + return false; + if (!MemVT.isSimple() || MemVT.getSizeInBits() * 2 > MaximumLegalStoreInBits) + return false; + + // This function cannot currently deal with non-byte-sized memory sizes. + int64_t ElementSizeBytes = MemVT.getStoreSize(); + if (ElementSizeBytes * 8 != (int64_t)MemVT.getSizeInBits()) + return false; + + // Do not bother looking at stored values that are not constants, loads, or + // extracted vector elements. + SDValue StoredVal = peekThroughBitcasts(St->getValue()); + const StoreSource StoreSrc = getStoreSource(StoredVal); + if (StoreSrc == StoreSource::Unknown) + return false; + + SmallVector<MemOpLink, 8> StoreNodes; + SDNode *RootNode; + // Find potential store merge candidates by searching through chain sub-DAG + getStoreMergeCandidates(St, StoreNodes, RootNode); + + // Check if there is anything to merge. + if (StoreNodes.size() < 2) + return false; + + // Sort the memory operands according to their distance from the + // base pointer. + llvm::sort(StoreNodes, [](MemOpLink LHS, MemOpLink RHS) { + return LHS.OffsetFromBase < RHS.OffsetFromBase; + }); + + bool AllowVectors = !DAG.getMachineFunction().getFunction().hasFnAttribute( + Attribute::NoImplicitFloat); + bool IsNonTemporalStore = St->isNonTemporal(); + bool IsNonTemporalLoad = StoreSrc == StoreSource::Load && + cast<LoadSDNode>(StoredVal)->isNonTemporal(); + + // Store Merge attempts to merge the lowest stores. This generally + // works out as if successful, as the remaining stores are checked + // after the first collection of stores is merged. However, in the + // case that a non-mergeable store is found first, e.g., {p[-2], + // p[0], p[1], p[2], p[3]}, we would fail and miss the subsequent + // mergeable cases. To prevent this, we prune such stores from the + // front of StoreNodes here. + bool MadeChange = false; + while (StoreNodes.size() > 1) { + unsigned NumConsecutiveStores = + getConsecutiveStores(StoreNodes, ElementSizeBytes); + // There are no more stores in the list to examine. + if (NumConsecutiveStores == 0) + return MadeChange; + + // We have at least 2 consecutive stores. Try to merge them. + assert(NumConsecutiveStores >= 2 && "Expected at least 2 stores"); + switch (StoreSrc) { + case StoreSource::Constant: + MadeChange |= tryStoreMergeOfConstants(StoreNodes, NumConsecutiveStores, + MemVT, RootNode, AllowVectors); + break; + + case StoreSource::Extract: + MadeChange |= tryStoreMergeOfExtracts(StoreNodes, NumConsecutiveStores, + MemVT, RootNode); + break; + + case StoreSource::Load: + MadeChange |= tryStoreMergeOfLoads(StoreNodes, NumConsecutiveStores, + MemVT, RootNode, AllowVectors, + IsNonTemporalStore, IsNonTemporalLoad); + break; + + default: + llvm_unreachable("Unhandled store source type"); + } + } + return MadeChange; +} + +SDValue DAGCombiner::replaceStoreChain(StoreSDNode *ST, SDValue BetterChain) { + SDLoc SL(ST); + SDValue ReplStore; + + // Replace the chain to avoid dependency. + if (ST->isTruncatingStore()) { + ReplStore = DAG.getTruncStore(BetterChain, SL, ST->getValue(), + ST->getBasePtr(), ST->getMemoryVT(), + ST->getMemOperand()); + } else { + ReplStore = DAG.getStore(BetterChain, SL, ST->getValue(), ST->getBasePtr(), + ST->getMemOperand()); + } + + // Create token to keep both nodes around. + SDValue Token = DAG.getNode(ISD::TokenFactor, SL, + MVT::Other, ST->getChain(), ReplStore); + + // Make sure the new and old chains are cleaned up. + AddToWorklist(Token.getNode()); + + // Don't add users to work list. + return CombineTo(ST, Token, false); +} + +SDValue DAGCombiner::replaceStoreOfFPConstant(StoreSDNode *ST) { + SDValue Value = ST->getValue(); + if (Value.getOpcode() == ISD::TargetConstantFP) + return SDValue(); + + if (!ISD::isNormalStore(ST)) + return SDValue(); + + SDLoc DL(ST); + + SDValue Chain = ST->getChain(); + SDValue Ptr = ST->getBasePtr(); + + const ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(Value); + + // NOTE: If the original store is volatile, this transform must not increase + // the number of stores. For example, on x86-32 an f64 can be stored in one + // processor operation but an i64 (which is not legal) requires two. So the + // transform should not be done in this case. + + SDValue Tmp; + switch (CFP->getSimpleValueType(0).SimpleTy) { + default: + llvm_unreachable("Unknown FP type"); + case MVT::f16: // We don't do this for these yet. + case MVT::f80: + case MVT::f128: + case MVT::ppcf128: + return SDValue(); + case MVT::f32: + if ((isTypeLegal(MVT::i32) && !LegalOperations && ST->isSimple()) || + TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { + ; + Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF(). + bitcastToAPInt().getZExtValue(), SDLoc(CFP), + MVT::i32); + return DAG.getStore(Chain, DL, Tmp, Ptr, ST->getMemOperand()); + } + + return SDValue(); + case MVT::f64: + if ((TLI.isTypeLegal(MVT::i64) && !LegalOperations && + ST->isSimple()) || + TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) { + ; + Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt(). + getZExtValue(), SDLoc(CFP), MVT::i64); + return DAG.getStore(Chain, DL, Tmp, + Ptr, ST->getMemOperand()); + } + + if (ST->isSimple() && + TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) { + // Many FP stores are not made apparent until after legalize, e.g. for + // argument passing. Since this is so common, custom legalize the + // 64-bit integer store into two 32-bit stores. + uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); + SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, SDLoc(CFP), MVT::i32); + SDValue Hi = DAG.getConstant(Val >> 32, SDLoc(CFP), MVT::i32); + if (DAG.getDataLayout().isBigEndian()) + std::swap(Lo, Hi); + + MachineMemOperand::Flags MMOFlags = ST->getMemOperand()->getFlags(); + AAMDNodes AAInfo = ST->getAAInfo(); + + SDValue St0 = DAG.getStore(Chain, DL, Lo, Ptr, ST->getPointerInfo(), + ST->getOriginalAlign(), MMOFlags, AAInfo); + Ptr = DAG.getMemBasePlusOffset(Ptr, TypeSize::Fixed(4), DL); + SDValue St1 = DAG.getStore(Chain, DL, Hi, Ptr, + ST->getPointerInfo().getWithOffset(4), + ST->getOriginalAlign(), MMOFlags, AAInfo); + return DAG.getNode(ISD::TokenFactor, DL, MVT::Other, + St0, St1); + } + + return SDValue(); + } +} + +SDValue DAGCombiner::visitSTORE(SDNode *N) { + StoreSDNode *ST = cast<StoreSDNode>(N); + SDValue Chain = ST->getChain(); + SDValue Value = ST->getValue(); + SDValue Ptr = ST->getBasePtr(); + + // If this is a store of a bit convert, store the input value if the + // resultant store does not need a higher alignment than the original. + if (Value.getOpcode() == ISD::BITCAST && !ST->isTruncatingStore() && + ST->isUnindexed()) { + EVT SVT = Value.getOperand(0).getValueType(); + // If the store is volatile, we only want to change the store type if the + // resulting store is legal. Otherwise we might increase the number of + // memory accesses. We don't care if the original type was legal or not + // as we assume software couldn't rely on the number of accesses of an + // illegal type. + // TODO: May be able to relax for unordered atomics (see D66309) + if (((!LegalOperations && ST->isSimple()) || + TLI.isOperationLegal(ISD::STORE, SVT)) && + TLI.isStoreBitCastBeneficial(Value.getValueType(), SVT, + DAG, *ST->getMemOperand())) { + return DAG.getStore(Chain, SDLoc(N), Value.getOperand(0), Ptr, + ST->getMemOperand()); + } + } + + // Turn 'store undef, Ptr' -> nothing. + if (Value.isUndef() && ST->isUnindexed()) + return Chain; + + // Try to infer better alignment information than the store already has. + if (OptLevel != CodeGenOpt::None && ST->isUnindexed() && !ST->isAtomic()) { + if (MaybeAlign Alignment = DAG.InferPtrAlign(Ptr)) { + if (*Alignment > ST->getAlign() && + isAligned(*Alignment, ST->getSrcValueOffset())) { + SDValue NewStore = + DAG.getTruncStore(Chain, SDLoc(N), Value, Ptr, ST->getPointerInfo(), + ST->getMemoryVT(), *Alignment, + ST->getMemOperand()->getFlags(), ST->getAAInfo()); + // NewStore will always be N as we are only refining the alignment + assert(NewStore.getNode() == N); + (void)NewStore; + } + } + } + + // Try transforming a pair floating point load / store ops to integer + // load / store ops. + if (SDValue NewST = TransformFPLoadStorePair(N)) + return NewST; + + // Try transforming several stores into STORE (BSWAP). + if (SDValue Store = mergeTruncStores(ST)) + return Store; + + if (ST->isUnindexed()) { + // Walk up chain skipping non-aliasing memory nodes, on this store and any + // adjacent stores. + if (findBetterNeighborChains(ST)) { + // replaceStoreChain uses CombineTo, which handled all of the worklist + // manipulation. Return the original node to not do anything else. + return SDValue(ST, 0); + } + Chain = ST->getChain(); + } + + // FIXME: is there such a thing as a truncating indexed store? + if (ST->isTruncatingStore() && ST->isUnindexed() && + Value.getValueType().isInteger() && + (!isa<ConstantSDNode>(Value) || + !cast<ConstantSDNode>(Value)->isOpaque())) { + APInt TruncDemandedBits = + APInt::getLowBitsSet(Value.getScalarValueSizeInBits(), + ST->getMemoryVT().getScalarSizeInBits()); + + // See if we can simplify the input to this truncstore with knowledge that + // only the low bits are being used. For example: + // "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8" + AddToWorklist(Value.getNode()); + if (SDValue Shorter = DAG.GetDemandedBits(Value, TruncDemandedBits)) + return DAG.getTruncStore(Chain, SDLoc(N), Shorter, Ptr, ST->getMemoryVT(), + ST->getMemOperand()); + + // Otherwise, see if we can simplify the operation with + // SimplifyDemandedBits, which only works if the value has a single use. + if (SimplifyDemandedBits(Value, TruncDemandedBits)) { + // Re-visit the store if anything changed and the store hasn't been merged + // with another node (N is deleted) SimplifyDemandedBits will add Value's + // node back to the worklist if necessary, but we also need to re-visit + // the Store node itself. + if (N->getOpcode() != ISD::DELETED_NODE) + AddToWorklist(N); + return SDValue(N, 0); + } + } + + // If this is a load followed by a store to the same location, then the store + // is dead/noop. + // TODO: Can relax for unordered atomics (see D66309) + if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) { + if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() && + ST->isUnindexed() && ST->isSimple() && + // There can't be any side effects between the load and store, such as + // a call or store. + Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) { + // The store is dead, remove it. + return Chain; + } + } + + // TODO: Can relax for unordered atomics (see D66309) + if (StoreSDNode *ST1 = dyn_cast<StoreSDNode>(Chain)) { + if (ST->isUnindexed() && ST->isSimple() && + ST1->isUnindexed() && ST1->isSimple()) { + if (ST1->getBasePtr() == Ptr && ST1->getValue() == Value && + ST->getMemoryVT() == ST1->getMemoryVT()) { + // If this is a store followed by a store with the same value to the + // same location, then the store is dead/noop. + return Chain; + } + + if (OptLevel != CodeGenOpt::None && ST1->hasOneUse() && + !ST1->getBasePtr().isUndef() && + // BaseIndexOffset and the code below requires knowing the size + // of a vector, so bail out if MemoryVT is scalable. + !ST->getMemoryVT().isScalableVector() && + !ST1->getMemoryVT().isScalableVector()) { + const BaseIndexOffset STBase = BaseIndexOffset::match(ST, DAG); + const BaseIndexOffset ChainBase = BaseIndexOffset::match(ST1, DAG); + unsigned STBitSize = ST->getMemoryVT().getFixedSizeInBits(); + unsigned ChainBitSize = ST1->getMemoryVT().getFixedSizeInBits(); + // If this is a store who's preceding store to a subset of the current + // location and no one other node is chained to that store we can + // effectively drop the store. Do not remove stores to undef as they may + // be used as data sinks. + if (STBase.contains(DAG, STBitSize, ChainBase, ChainBitSize)) { + CombineTo(ST1, ST1->getChain()); + return SDValue(); + } + } + } + } + + // If this is an FP_ROUND or TRUNC followed by a store, fold this into a + // truncating store. We can do this even if this is already a truncstore. + if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE) + && Value.getNode()->hasOneUse() && ST->isUnindexed() && + TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(), + ST->getMemoryVT())) { + return DAG.getTruncStore(Chain, SDLoc(N), Value.getOperand(0), + Ptr, ST->getMemoryVT(), ST->getMemOperand()); + } + + // Always perform this optimization before types are legal. If the target + // prefers, also try this after legalization to catch stores that were created + // by intrinsics or other nodes. + if (!LegalTypes || (TLI.mergeStoresAfterLegalization(ST->getMemoryVT()))) { + while (true) { + // There can be multiple store sequences on the same chain. + // Keep trying to merge store sequences until we are unable to do so + // or until we merge the last store on the chain. + bool Changed = mergeConsecutiveStores(ST); + if (!Changed) break; + // Return N as merge only uses CombineTo and no worklist clean + // up is necessary. + if (N->getOpcode() == ISD::DELETED_NODE || !isa<StoreSDNode>(N)) + return SDValue(N, 0); + } + } + + // Try transforming N to an indexed store. + if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) + return SDValue(N, 0); + + // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' + // + // Make sure to do this only after attempting to merge stores in order to + // avoid changing the types of some subset of stores due to visit order, + // preventing their merging. + if (isa<ConstantFPSDNode>(ST->getValue())) { + if (SDValue NewSt = replaceStoreOfFPConstant(ST)) + return NewSt; + } + + if (SDValue NewSt = splitMergedValStore(ST)) + return NewSt; + + return ReduceLoadOpStoreWidth(N); +} + +SDValue DAGCombiner::visitLIFETIME_END(SDNode *N) { + const auto *LifetimeEnd = cast<LifetimeSDNode>(N); + if (!LifetimeEnd->hasOffset()) + return SDValue(); + + const BaseIndexOffset LifetimeEndBase(N->getOperand(1), SDValue(), + LifetimeEnd->getOffset(), false); + + // We walk up the chains to find stores. + SmallVector<SDValue, 8> Chains = {N->getOperand(0)}; + while (!Chains.empty()) { + SDValue Chain = Chains.pop_back_val(); + if (!Chain.hasOneUse()) + continue; + switch (Chain.getOpcode()) { + case ISD::TokenFactor: + for (unsigned Nops = Chain.getNumOperands(); Nops;) + Chains.push_back(Chain.getOperand(--Nops)); + break; + case ISD::LIFETIME_START: + case ISD::LIFETIME_END: + // We can forward past any lifetime start/end that can be proven not to + // alias the node. + if (!isAlias(Chain.getNode(), N)) + Chains.push_back(Chain.getOperand(0)); + break; + case ISD::STORE: { + StoreSDNode *ST = dyn_cast<StoreSDNode>(Chain); + // TODO: Can relax for unordered atomics (see D66309) + if (!ST->isSimple() || ST->isIndexed()) + continue; + const TypeSize StoreSize = ST->getMemoryVT().getStoreSize(); + // The bounds of a scalable store are not known until runtime, so this + // store cannot be elided. + if (StoreSize.isScalable()) + continue; + const BaseIndexOffset StoreBase = BaseIndexOffset::match(ST, DAG); + // If we store purely within object bounds just before its lifetime ends, + // we can remove the store. + if (LifetimeEndBase.contains(DAG, LifetimeEnd->getSize() * 8, StoreBase, + StoreSize.getFixedSize() * 8)) { + LLVM_DEBUG(dbgs() << "\nRemoving store:"; StoreBase.dump(); + dbgs() << "\nwithin LIFETIME_END of : "; + LifetimeEndBase.dump(); dbgs() << "\n"); + CombineTo(ST, ST->getChain()); + return SDValue(N, 0); + } + } + } + } + return SDValue(); +} + +/// For the instruction sequence of store below, F and I values +/// are bundled together as an i64 value before being stored into memory. +/// Sometimes it is more efficent to generate separate stores for F and I, +/// which can remove the bitwise instructions or sink them to colder places. +/// +/// (store (or (zext (bitcast F to i32) to i64), +/// (shl (zext I to i64), 32)), addr) --> +/// (store F, addr) and (store I, addr+4) +/// +/// Similarly, splitting for other merged store can also be beneficial, like: +/// For pair of {i32, i32}, i64 store --> two i32 stores. +/// For pair of {i32, i16}, i64 store --> two i32 stores. +/// For pair of {i16, i16}, i32 store --> two i16 stores. +/// For pair of {i16, i8}, i32 store --> two i16 stores. +/// For pair of {i8, i8}, i16 store --> two i8 stores. +/// +/// We allow each target to determine specifically which kind of splitting is +/// supported. +/// +/// The store patterns are commonly seen from the simple code snippet below +/// if only std::make_pair(...) is sroa transformed before inlined into hoo. +/// void goo(const std::pair<int, float> &); +/// hoo() { +/// ... +/// goo(std::make_pair(tmp, ftmp)); +/// ... +/// } +/// +SDValue DAGCombiner::splitMergedValStore(StoreSDNode *ST) { + if (OptLevel == CodeGenOpt::None) + return SDValue(); + + // Can't change the number of memory accesses for a volatile store or break + // atomicity for an atomic one. + if (!ST->isSimple()) + return SDValue(); + + SDValue Val = ST->getValue(); + SDLoc DL(ST); + + // Match OR operand. + if (!Val.getValueType().isScalarInteger() || Val.getOpcode() != ISD::OR) + return SDValue(); + + // Match SHL operand and get Lower and Higher parts of Val. + SDValue Op1 = Val.getOperand(0); + SDValue Op2 = Val.getOperand(1); + SDValue Lo, Hi; + if (Op1.getOpcode() != ISD::SHL) { + std::swap(Op1, Op2); + if (Op1.getOpcode() != ISD::SHL) + return SDValue(); + } + Lo = Op2; + Hi = Op1.getOperand(0); + if (!Op1.hasOneUse()) + return SDValue(); + + // Match shift amount to HalfValBitSize. + unsigned HalfValBitSize = Val.getValueSizeInBits() / 2; + ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(Op1.getOperand(1)); + if (!ShAmt || ShAmt->getAPIntValue() != HalfValBitSize) + return SDValue(); + + // Lo and Hi are zero-extended from int with size less equal than 32 + // to i64. + if (Lo.getOpcode() != ISD::ZERO_EXTEND || !Lo.hasOneUse() || + !Lo.getOperand(0).getValueType().isScalarInteger() || + Lo.getOperand(0).getValueSizeInBits() > HalfValBitSize || + Hi.getOpcode() != ISD::ZERO_EXTEND || !Hi.hasOneUse() || + !Hi.getOperand(0).getValueType().isScalarInteger() || + Hi.getOperand(0).getValueSizeInBits() > HalfValBitSize) + return SDValue(); + + // Use the EVT of low and high parts before bitcast as the input + // of target query. + EVT LowTy = (Lo.getOperand(0).getOpcode() == ISD::BITCAST) + ? Lo.getOperand(0).getValueType() + : Lo.getValueType(); + EVT HighTy = (Hi.getOperand(0).getOpcode() == ISD::BITCAST) + ? Hi.getOperand(0).getValueType() + : Hi.getValueType(); + if (!TLI.isMultiStoresCheaperThanBitsMerge(LowTy, HighTy)) + return SDValue(); + + // Start to split store. + MachineMemOperand::Flags MMOFlags = ST->getMemOperand()->getFlags(); + AAMDNodes AAInfo = ST->getAAInfo(); + + // Change the sizes of Lo and Hi's value types to HalfValBitSize. + EVT VT = EVT::getIntegerVT(*DAG.getContext(), HalfValBitSize); + Lo = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Lo.getOperand(0)); + Hi = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Hi.getOperand(0)); + + SDValue Chain = ST->getChain(); + SDValue Ptr = ST->getBasePtr(); + // Lower value store. + SDValue St0 = DAG.getStore(Chain, DL, Lo, Ptr, ST->getPointerInfo(), + ST->getOriginalAlign(), MMOFlags, AAInfo); + Ptr = DAG.getMemBasePlusOffset(Ptr, TypeSize::Fixed(HalfValBitSize / 8), DL); + // Higher value store. + SDValue St1 = DAG.getStore( + St0, DL, Hi, Ptr, ST->getPointerInfo().getWithOffset(HalfValBitSize / 8), + ST->getOriginalAlign(), MMOFlags, AAInfo); + return St1; +} + +/// Convert a disguised subvector insertion into a shuffle: +SDValue DAGCombiner::combineInsertEltToShuffle(SDNode *N, unsigned InsIndex) { + assert(N->getOpcode() == ISD::INSERT_VECTOR_ELT && + "Expected extract_vector_elt"); + SDValue InsertVal = N->getOperand(1); + SDValue Vec = N->getOperand(0); + + // (insert_vector_elt (vector_shuffle X, Y), (extract_vector_elt X, N), + // InsIndex) + // --> (vector_shuffle X, Y) and variations where shuffle operands may be + // CONCAT_VECTORS. + if (Vec.getOpcode() == ISD::VECTOR_SHUFFLE && Vec.hasOneUse() && + InsertVal.getOpcode() == ISD::EXTRACT_VECTOR_ELT && + isa<ConstantSDNode>(InsertVal.getOperand(1))) { + ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(Vec.getNode()); + ArrayRef<int> Mask = SVN->getMask(); + + SDValue X = Vec.getOperand(0); + SDValue Y = Vec.getOperand(1); + + // Vec's operand 0 is using indices from 0 to N-1 and + // operand 1 from N to 2N - 1, where N is the number of + // elements in the vectors. + SDValue InsertVal0 = InsertVal.getOperand(0); + int ElementOffset = -1; + + // We explore the inputs of the shuffle in order to see if we find the + // source of the extract_vector_elt. If so, we can use it to modify the + // shuffle rather than perform an insert_vector_elt. + SmallVector<std::pair<int, SDValue>, 8> ArgWorkList; + ArgWorkList.emplace_back(Mask.size(), Y); + ArgWorkList.emplace_back(0, X); + + while (!ArgWorkList.empty()) { + int ArgOffset; + SDValue ArgVal; + std::tie(ArgOffset, ArgVal) = ArgWorkList.pop_back_val(); + + if (ArgVal == InsertVal0) { + ElementOffset = ArgOffset; + break; + } + + // Peek through concat_vector. + if (ArgVal.getOpcode() == ISD::CONCAT_VECTORS) { + int CurrentArgOffset = + ArgOffset + ArgVal.getValueType().getVectorNumElements(); + int Step = ArgVal.getOperand(0).getValueType().getVectorNumElements(); + for (SDValue Op : reverse(ArgVal->ops())) { + CurrentArgOffset -= Step; + ArgWorkList.emplace_back(CurrentArgOffset, Op); + } + + // Make sure we went through all the elements and did not screw up index + // computation. + assert(CurrentArgOffset == ArgOffset); + } + } + + if (ElementOffset != -1) { + SmallVector<int, 16> NewMask(Mask.begin(), Mask.end()); + + auto *ExtrIndex = cast<ConstantSDNode>(InsertVal.getOperand(1)); + NewMask[InsIndex] = ElementOffset + ExtrIndex->getZExtValue(); + assert(NewMask[InsIndex] < + (int)(2 * Vec.getValueType().getVectorNumElements()) && + NewMask[InsIndex] >= 0 && "NewMask[InsIndex] is out of bound"); + + SDValue LegalShuffle = + TLI.buildLegalVectorShuffle(Vec.getValueType(), SDLoc(N), X, + Y, NewMask, DAG); + if (LegalShuffle) + return LegalShuffle; + } + } + + // insert_vector_elt V, (bitcast X from vector type), IdxC --> + // bitcast(shuffle (bitcast V), (extended X), Mask) + // Note: We do not use an insert_subvector node because that requires a + // legal subvector type. + if (InsertVal.getOpcode() != ISD::BITCAST || !InsertVal.hasOneUse() || + !InsertVal.getOperand(0).getValueType().isVector()) + return SDValue(); + + SDValue SubVec = InsertVal.getOperand(0); + SDValue DestVec = N->getOperand(0); + EVT SubVecVT = SubVec.getValueType(); + EVT VT = DestVec.getValueType(); + unsigned NumSrcElts = SubVecVT.getVectorNumElements(); + // If the source only has a single vector element, the cost of creating adding + // it to a vector is likely to exceed the cost of a insert_vector_elt. + if (NumSrcElts == 1) + return SDValue(); + unsigned ExtendRatio = VT.getSizeInBits() / SubVecVT.getSizeInBits(); + unsigned NumMaskVals = ExtendRatio * NumSrcElts; + + // Step 1: Create a shuffle mask that implements this insert operation. The + // vector that we are inserting into will be operand 0 of the shuffle, so + // those elements are just 'i'. The inserted subvector is in the first + // positions of operand 1 of the shuffle. Example: + // insert v4i32 V, (v2i16 X), 2 --> shuffle v8i16 V', X', {0,1,2,3,8,9,6,7} + SmallVector<int, 16> Mask(NumMaskVals); + for (unsigned i = 0; i != NumMaskVals; ++i) { + if (i / NumSrcElts == InsIndex) + Mask[i] = (i % NumSrcElts) + NumMaskVals; + else + Mask[i] = i; + } + + // Bail out if the target can not handle the shuffle we want to create. + EVT SubVecEltVT = SubVecVT.getVectorElementType(); + EVT ShufVT = EVT::getVectorVT(*DAG.getContext(), SubVecEltVT, NumMaskVals); + if (!TLI.isShuffleMaskLegal(Mask, ShufVT)) + return SDValue(); + + // Step 2: Create a wide vector from the inserted source vector by appending + // undefined elements. This is the same size as our destination vector. + SDLoc DL(N); + SmallVector<SDValue, 8> ConcatOps(ExtendRatio, DAG.getUNDEF(SubVecVT)); + ConcatOps[0] = SubVec; + SDValue PaddedSubV = DAG.getNode(ISD::CONCAT_VECTORS, DL, ShufVT, ConcatOps); + + // Step 3: Shuffle in the padded subvector. + SDValue DestVecBC = DAG.getBitcast(ShufVT, DestVec); + SDValue Shuf = DAG.getVectorShuffle(ShufVT, DL, DestVecBC, PaddedSubV, Mask); + AddToWorklist(PaddedSubV.getNode()); + AddToWorklist(DestVecBC.getNode()); + AddToWorklist(Shuf.getNode()); + return DAG.getBitcast(VT, Shuf); +} + +SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { + SDValue InVec = N->getOperand(0); + SDValue InVal = N->getOperand(1); + SDValue EltNo = N->getOperand(2); + SDLoc DL(N); + + EVT VT = InVec.getValueType(); + auto *IndexC = dyn_cast<ConstantSDNode>(EltNo); + + // Insert into out-of-bounds element is undefined. + if (IndexC && VT.isFixedLengthVector() && + IndexC->getZExtValue() >= VT.getVectorNumElements()) + return DAG.getUNDEF(VT); + + // Remove redundant insertions: + // (insert_vector_elt x (extract_vector_elt x idx) idx) -> x + if (InVal.getOpcode() == ISD::EXTRACT_VECTOR_ELT && + InVec == InVal.getOperand(0) && EltNo == InVal.getOperand(1)) + return InVec; + + if (!IndexC) { + // If this is variable insert to undef vector, it might be better to splat: + // inselt undef, InVal, EltNo --> build_vector < InVal, InVal, ... > + if (InVec.isUndef() && TLI.shouldSplatInsEltVarIndex(VT)) { + if (VT.isScalableVector()) + return DAG.getSplatVector(VT, DL, InVal); + else { + SmallVector<SDValue, 8> Ops(VT.getVectorNumElements(), InVal); + return DAG.getBuildVector(VT, DL, Ops); + } + } + return SDValue(); + } + + if (VT.isScalableVector()) + return SDValue(); + + unsigned NumElts = VT.getVectorNumElements(); + + // We must know which element is being inserted for folds below here. + unsigned Elt = IndexC->getZExtValue(); + if (SDValue Shuf = combineInsertEltToShuffle(N, Elt)) + return Shuf; + + // Canonicalize insert_vector_elt dag nodes. + // Example: + // (insert_vector_elt (insert_vector_elt A, Idx0), Idx1) + // -> (insert_vector_elt (insert_vector_elt A, Idx1), Idx0) + // + // Do this only if the child insert_vector node has one use; also + // do this only if indices are both constants and Idx1 < Idx0. + if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT && InVec.hasOneUse() + && isa<ConstantSDNode>(InVec.getOperand(2))) { + unsigned OtherElt = InVec.getConstantOperandVal(2); + if (Elt < OtherElt) { + // Swap nodes. + SDValue NewOp = DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, VT, + InVec.getOperand(0), InVal, EltNo); + AddToWorklist(NewOp.getNode()); + return DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(InVec.getNode()), + VT, NewOp, InVec.getOperand(1), InVec.getOperand(2)); + } + } + + // If we can't generate a legal BUILD_VECTOR, exit + if (LegalOperations && !TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) + return SDValue(); + + // Check that the operand is a BUILD_VECTOR (or UNDEF, which can essentially + // be converted to a BUILD_VECTOR). Fill in the Ops vector with the + // vector elements. + SmallVector<SDValue, 8> Ops; + // Do not combine these two vectors if the output vector will not replace + // the input vector. + if (InVec.getOpcode() == ISD::BUILD_VECTOR && InVec.hasOneUse()) { + Ops.append(InVec.getNode()->op_begin(), + InVec.getNode()->op_end()); + } else if (InVec.isUndef()) { + Ops.append(NumElts, DAG.getUNDEF(InVal.getValueType())); + } else { + return SDValue(); + } + assert(Ops.size() == NumElts && "Unexpected vector size"); + + // Insert the element + if (Elt < Ops.size()) { + // All the operands of BUILD_VECTOR must have the same type; + // we enforce that here. + EVT OpVT = Ops[0].getValueType(); + Ops[Elt] = OpVT.isInteger() ? DAG.getAnyExtOrTrunc(InVal, DL, OpVT) : InVal; + } + + // Return the new vector + return DAG.getBuildVector(VT, DL, Ops); +} + +SDValue DAGCombiner::scalarizeExtractedVectorLoad(SDNode *EVE, EVT InVecVT, + SDValue EltNo, + LoadSDNode *OriginalLoad) { + assert(OriginalLoad->isSimple()); + + EVT ResultVT = EVE->getValueType(0); + EVT VecEltVT = InVecVT.getVectorElementType(); + + // If the vector element type is not a multiple of a byte then we are unable + // to correctly compute an address to load only the extracted element as a + // scalar. + if (!VecEltVT.isByteSized()) + return SDValue(); + + Align Alignment = OriginalLoad->getAlign(); + Align NewAlign = DAG.getDataLayout().getABITypeAlign( + VecEltVT.getTypeForEVT(*DAG.getContext())); + + if (NewAlign > Alignment || + !TLI.isOperationLegalOrCustom(ISD::LOAD, VecEltVT)) + return SDValue(); + + ISD::LoadExtType ExtTy = ResultVT.bitsGT(VecEltVT) ? + ISD::NON_EXTLOAD : ISD::EXTLOAD; + if (!TLI.shouldReduceLoadWidth(OriginalLoad, ExtTy, VecEltVT)) + return SDValue(); + + Alignment = NewAlign; + + SDValue NewPtr = OriginalLoad->getBasePtr(); + SDValue Offset; + EVT PtrType = NewPtr.getValueType(); + MachinePointerInfo MPI; + SDLoc DL(EVE); + if (auto *ConstEltNo = dyn_cast<ConstantSDNode>(EltNo)) { + int Elt = ConstEltNo->getZExtValue(); + unsigned PtrOff = VecEltVT.getSizeInBits() * Elt / 8; + Offset = DAG.getConstant(PtrOff, DL, PtrType); + MPI = OriginalLoad->getPointerInfo().getWithOffset(PtrOff); + } else { + Offset = DAG.getZExtOrTrunc(EltNo, DL, PtrType); + Offset = DAG.getNode( + ISD::MUL, DL, PtrType, Offset, + DAG.getConstant(VecEltVT.getStoreSize(), DL, PtrType)); + // Discard the pointer info except the address space because the memory + // operand can't represent this new access since the offset is variable. + MPI = MachinePointerInfo(OriginalLoad->getPointerInfo().getAddrSpace()); + } + NewPtr = DAG.getMemBasePlusOffset(NewPtr, Offset, DL); + + // The replacement we need to do here is a little tricky: we need to + // replace an extractelement of a load with a load. + // Use ReplaceAllUsesOfValuesWith to do the replacement. + // Note that this replacement assumes that the extractvalue is the only + // use of the load; that's okay because we don't want to perform this + // transformation in other cases anyway. + SDValue Load; + SDValue Chain; + if (ResultVT.bitsGT(VecEltVT)) { + // If the result type of vextract is wider than the load, then issue an + // extending load instead. + ISD::LoadExtType ExtType = TLI.isLoadExtLegal(ISD::ZEXTLOAD, ResultVT, + VecEltVT) + ? ISD::ZEXTLOAD + : ISD::EXTLOAD; + Load = DAG.getExtLoad(ExtType, SDLoc(EVE), ResultVT, + OriginalLoad->getChain(), NewPtr, MPI, VecEltVT, + Alignment, OriginalLoad->getMemOperand()->getFlags(), + OriginalLoad->getAAInfo()); + Chain = Load.getValue(1); + } else { + Load = DAG.getLoad( + VecEltVT, SDLoc(EVE), OriginalLoad->getChain(), NewPtr, MPI, Alignment, + OriginalLoad->getMemOperand()->getFlags(), OriginalLoad->getAAInfo()); + Chain = Load.getValue(1); + if (ResultVT.bitsLT(VecEltVT)) + Load = DAG.getNode(ISD::TRUNCATE, SDLoc(EVE), ResultVT, Load); + else + Load = DAG.getBitcast(ResultVT, Load); + } + WorklistRemover DeadNodes(*this); + SDValue From[] = { SDValue(EVE, 0), SDValue(OriginalLoad, 1) }; + SDValue To[] = { Load, Chain }; + DAG.ReplaceAllUsesOfValuesWith(From, To, 2); + // Make sure to revisit this node to clean it up; it will usually be dead. + AddToWorklist(EVE); + // Since we're explicitly calling ReplaceAllUses, add the new node to the + // worklist explicitly as well. + AddToWorklistWithUsers(Load.getNode()); + ++OpsNarrowed; + return SDValue(EVE, 0); +} + +/// Transform a vector binary operation into a scalar binary operation by moving +/// the math/logic after an extract element of a vector. +static SDValue scalarizeExtractedBinop(SDNode *ExtElt, SelectionDAG &DAG, + bool LegalOperations) { + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + SDValue Vec = ExtElt->getOperand(0); + SDValue Index = ExtElt->getOperand(1); + auto *IndexC = dyn_cast<ConstantSDNode>(Index); + if (!IndexC || !TLI.isBinOp(Vec.getOpcode()) || !Vec.hasOneUse() || + Vec.getNode()->getNumValues() != 1) + return SDValue(); + + // Targets may want to avoid this to prevent an expensive register transfer. + if (!TLI.shouldScalarizeBinop(Vec)) + return SDValue(); + + // Extracting an element of a vector constant is constant-folded, so this + // transform is just replacing a vector op with a scalar op while moving the + // extract. + SDValue Op0 = Vec.getOperand(0); + SDValue Op1 = Vec.getOperand(1); + if (isAnyConstantBuildVector(Op0, true) || + isAnyConstantBuildVector(Op1, true)) { + // extractelt (binop X, C), IndexC --> binop (extractelt X, IndexC), C' + // extractelt (binop C, X), IndexC --> binop C', (extractelt X, IndexC) + SDLoc DL(ExtElt); + EVT VT = ExtElt->getValueType(0); + SDValue Ext0 = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, Op0, Index); + SDValue Ext1 = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, Op1, Index); + return DAG.getNode(Vec.getOpcode(), DL, VT, Ext0, Ext1); + } + + return SDValue(); +} + +SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) { + SDValue VecOp = N->getOperand(0); + SDValue Index = N->getOperand(1); + EVT ScalarVT = N->getValueType(0); + EVT VecVT = VecOp.getValueType(); + if (VecOp.isUndef()) + return DAG.getUNDEF(ScalarVT); + + // extract_vector_elt (insert_vector_elt vec, val, idx), idx) -> val + // + // This only really matters if the index is non-constant since other combines + // on the constant elements already work. + SDLoc DL(N); + if (VecOp.getOpcode() == ISD::INSERT_VECTOR_ELT && + Index == VecOp.getOperand(2)) { + SDValue Elt = VecOp.getOperand(1); + return VecVT.isInteger() ? DAG.getAnyExtOrTrunc(Elt, DL, ScalarVT) : Elt; + } + + // (vextract (scalar_to_vector val, 0) -> val + if (VecOp.getOpcode() == ISD::SCALAR_TO_VECTOR) { + // Only 0'th element of SCALAR_TO_VECTOR is defined. + if (DAG.isKnownNeverZero(Index)) + return DAG.getUNDEF(ScalarVT); + + // Check if the result type doesn't match the inserted element type. A + // SCALAR_TO_VECTOR may truncate the inserted element and the + // EXTRACT_VECTOR_ELT may widen the extracted vector. + SDValue InOp = VecOp.getOperand(0); + if (InOp.getValueType() != ScalarVT) { + assert(InOp.getValueType().isInteger() && ScalarVT.isInteger()); + return DAG.getSExtOrTrunc(InOp, DL, ScalarVT); + } + return InOp; + } + + // extract_vector_elt of out-of-bounds element -> UNDEF + auto *IndexC = dyn_cast<ConstantSDNode>(Index); + if (IndexC && VecVT.isFixedLengthVector() && + IndexC->getAPIntValue().uge(VecVT.getVectorNumElements())) + return DAG.getUNDEF(ScalarVT); + + // extract_vector_elt (build_vector x, y), 1 -> y + if (((IndexC && VecOp.getOpcode() == ISD::BUILD_VECTOR) || + VecOp.getOpcode() == ISD::SPLAT_VECTOR) && + TLI.isTypeLegal(VecVT) && + (VecOp.hasOneUse() || TLI.aggressivelyPreferBuildVectorSources(VecVT))) { + assert((VecOp.getOpcode() != ISD::BUILD_VECTOR || + VecVT.isFixedLengthVector()) && + "BUILD_VECTOR used for scalable vectors"); + unsigned IndexVal = + VecOp.getOpcode() == ISD::BUILD_VECTOR ? IndexC->getZExtValue() : 0; + SDValue Elt = VecOp.getOperand(IndexVal); + EVT InEltVT = Elt.getValueType(); + + // Sometimes build_vector's scalar input types do not match result type. + if (ScalarVT == InEltVT) + return Elt; + + // TODO: It may be useful to truncate if free if the build_vector implicitly + // converts. + } + + if (VecVT.isScalableVector()) + return SDValue(); + + // All the code from this point onwards assumes fixed width vectors, but it's + // possible that some of the combinations could be made to work for scalable + // vectors too. + unsigned NumElts = VecVT.getVectorNumElements(); + unsigned VecEltBitWidth = VecVT.getScalarSizeInBits(); + + // TODO: These transforms should not require the 'hasOneUse' restriction, but + // there are regressions on multiple targets without it. We can end up with a + // mess of scalar and vector code if we reduce only part of the DAG to scalar. + if (IndexC && VecOp.getOpcode() == ISD::BITCAST && VecVT.isInteger() && + VecOp.hasOneUse()) { + // The vector index of the LSBs of the source depend on the endian-ness. + bool IsLE = DAG.getDataLayout().isLittleEndian(); + unsigned ExtractIndex = IndexC->getZExtValue(); + // extract_elt (v2i32 (bitcast i64:x)), BCTruncElt -> i32 (trunc i64:x) + unsigned BCTruncElt = IsLE ? 0 : NumElts - 1; + SDValue BCSrc = VecOp.getOperand(0); + if (ExtractIndex == BCTruncElt && BCSrc.getValueType().isScalarInteger()) + return DAG.getNode(ISD::TRUNCATE, DL, ScalarVT, BCSrc); + + if (LegalTypes && BCSrc.getValueType().isInteger() && + BCSrc.getOpcode() == ISD::SCALAR_TO_VECTOR) { + // ext_elt (bitcast (scalar_to_vec i64 X to v2i64) to v4i32), TruncElt --> + // trunc i64 X to i32 + SDValue X = BCSrc.getOperand(0); + assert(X.getValueType().isScalarInteger() && ScalarVT.isScalarInteger() && + "Extract element and scalar to vector can't change element type " + "from FP to integer."); + unsigned XBitWidth = X.getValueSizeInBits(); + BCTruncElt = IsLE ? 0 : XBitWidth / VecEltBitWidth - 1; + + // An extract element return value type can be wider than its vector + // operand element type. In that case, the high bits are undefined, so + // it's possible that we may need to extend rather than truncate. + if (ExtractIndex == BCTruncElt && XBitWidth > VecEltBitWidth) { + assert(XBitWidth % VecEltBitWidth == 0 && + "Scalar bitwidth must be a multiple of vector element bitwidth"); + return DAG.getAnyExtOrTrunc(X, DL, ScalarVT); + } + } + } + + if (SDValue BO = scalarizeExtractedBinop(N, DAG, LegalOperations)) + return BO; + + // Transform: (EXTRACT_VECTOR_ELT( VECTOR_SHUFFLE )) -> EXTRACT_VECTOR_ELT. + // We only perform this optimization before the op legalization phase because + // we may introduce new vector instructions which are not backed by TD + // patterns. For example on AVX, extracting elements from a wide vector + // without using extract_subvector. However, if we can find an underlying + // scalar value, then we can always use that. + if (IndexC && VecOp.getOpcode() == ISD::VECTOR_SHUFFLE) { + auto *Shuf = cast<ShuffleVectorSDNode>(VecOp); + // Find the new index to extract from. + int OrigElt = Shuf->getMaskElt(IndexC->getZExtValue()); + + // Extracting an undef index is undef. + if (OrigElt == -1) + return DAG.getUNDEF(ScalarVT); + + // Select the right vector half to extract from. + SDValue SVInVec; + if (OrigElt < (int)NumElts) { + SVInVec = VecOp.getOperand(0); + } else { + SVInVec = VecOp.getOperand(1); + OrigElt -= NumElts; + } + + if (SVInVec.getOpcode() == ISD::BUILD_VECTOR) { + SDValue InOp = SVInVec.getOperand(OrigElt); + if (InOp.getValueType() != ScalarVT) { + assert(InOp.getValueType().isInteger() && ScalarVT.isInteger()); + InOp = DAG.getSExtOrTrunc(InOp, DL, ScalarVT); + } + + return InOp; + } + + // FIXME: We should handle recursing on other vector shuffles and + // scalar_to_vector here as well. + + if (!LegalOperations || + // FIXME: Should really be just isOperationLegalOrCustom. + TLI.isOperationLegal(ISD::EXTRACT_VECTOR_ELT, VecVT) || + TLI.isOperationExpand(ISD::VECTOR_SHUFFLE, VecVT)) { + return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, ScalarVT, SVInVec, + DAG.getVectorIdxConstant(OrigElt, DL)); + } + } + + // If only EXTRACT_VECTOR_ELT nodes use the source vector we can + // simplify it based on the (valid) extraction indices. + if (llvm::all_of(VecOp->uses(), [&](SDNode *Use) { + return Use->getOpcode() == ISD::EXTRACT_VECTOR_ELT && + Use->getOperand(0) == VecOp && + isa<ConstantSDNode>(Use->getOperand(1)); + })) { + APInt DemandedElts = APInt::getNullValue(NumElts); + for (SDNode *Use : VecOp->uses()) { + auto *CstElt = cast<ConstantSDNode>(Use->getOperand(1)); + if (CstElt->getAPIntValue().ult(NumElts)) + DemandedElts.setBit(CstElt->getZExtValue()); + } + if (SimplifyDemandedVectorElts(VecOp, DemandedElts, true)) { + // We simplified the vector operand of this extract element. If this + // extract is not dead, visit it again so it is folded properly. + if (N->getOpcode() != ISD::DELETED_NODE) + AddToWorklist(N); + return SDValue(N, 0); + } + APInt DemandedBits = APInt::getAllOnesValue(VecEltBitWidth); + if (SimplifyDemandedBits(VecOp, DemandedBits, DemandedElts, true)) { + // We simplified the vector operand of this extract element. If this + // extract is not dead, visit it again so it is folded properly. + if (N->getOpcode() != ISD::DELETED_NODE) + AddToWorklist(N); + return SDValue(N, 0); + } + } + + // Everything under here is trying to match an extract of a loaded value. + // If the result of load has to be truncated, then it's not necessarily + // profitable. + bool BCNumEltsChanged = false; + EVT ExtVT = VecVT.getVectorElementType(); + EVT LVT = ExtVT; + if (ScalarVT.bitsLT(LVT) && !TLI.isTruncateFree(LVT, ScalarVT)) + return SDValue(); + + if (VecOp.getOpcode() == ISD::BITCAST) { + // Don't duplicate a load with other uses. + if (!VecOp.hasOneUse()) + return SDValue(); + + EVT BCVT = VecOp.getOperand(0).getValueType(); + if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType())) + return SDValue(); + if (NumElts != BCVT.getVectorNumElements()) + BCNumEltsChanged = true; + VecOp = VecOp.getOperand(0); + ExtVT = BCVT.getVectorElementType(); + } + + // extract (vector load $addr), i --> load $addr + i * size + if (!LegalOperations && !IndexC && VecOp.hasOneUse() && + ISD::isNormalLoad(VecOp.getNode()) && + !Index->hasPredecessor(VecOp.getNode())) { + auto *VecLoad = dyn_cast<LoadSDNode>(VecOp); + if (VecLoad && VecLoad->isSimple()) + return scalarizeExtractedVectorLoad(N, VecVT, Index, VecLoad); + } + + // Perform only after legalization to ensure build_vector / vector_shuffle + // optimizations have already been done. + if (!LegalOperations || !IndexC) + return SDValue(); + + // (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size) + // (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size) + // (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr) + int Elt = IndexC->getZExtValue(); + LoadSDNode *LN0 = nullptr; + if (ISD::isNormalLoad(VecOp.getNode())) { + LN0 = cast<LoadSDNode>(VecOp); + } else if (VecOp.getOpcode() == ISD::SCALAR_TO_VECTOR && + VecOp.getOperand(0).getValueType() == ExtVT && + ISD::isNormalLoad(VecOp.getOperand(0).getNode())) { + // Don't duplicate a load with other uses. + if (!VecOp.hasOneUse()) + return SDValue(); + + LN0 = cast<LoadSDNode>(VecOp.getOperand(0)); + } + if (auto *Shuf = dyn_cast<ShuffleVectorSDNode>(VecOp)) { + // (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1) + // => + // (load $addr+1*size) + + // Don't duplicate a load with other uses. + if (!VecOp.hasOneUse()) + return SDValue(); + + // If the bit convert changed the number of elements, it is unsafe + // to examine the mask. + if (BCNumEltsChanged) + return SDValue(); + + // Select the input vector, guarding against out of range extract vector. + int Idx = (Elt > (int)NumElts) ? -1 : Shuf->getMaskElt(Elt); + VecOp = (Idx < (int)NumElts) ? VecOp.getOperand(0) : VecOp.getOperand(1); + + if (VecOp.getOpcode() == ISD::BITCAST) { + // Don't duplicate a load with other uses. + if (!VecOp.hasOneUse()) + return SDValue(); + + VecOp = VecOp.getOperand(0); + } + if (ISD::isNormalLoad(VecOp.getNode())) { + LN0 = cast<LoadSDNode>(VecOp); + Elt = (Idx < (int)NumElts) ? Idx : Idx - (int)NumElts; + Index = DAG.getConstant(Elt, DL, Index.getValueType()); + } + } else if (VecOp.getOpcode() == ISD::CONCAT_VECTORS && !BCNumEltsChanged && + VecVT.getVectorElementType() == ScalarVT && + (!LegalTypes || + TLI.isTypeLegal( + VecOp.getOperand(0).getValueType().getVectorElementType()))) { + // extract_vector_elt (concat_vectors v2i16:a, v2i16:b), 0 + // -> extract_vector_elt a, 0 + // extract_vector_elt (concat_vectors v2i16:a, v2i16:b), 1 + // -> extract_vector_elt a, 1 + // extract_vector_elt (concat_vectors v2i16:a, v2i16:b), 2 + // -> extract_vector_elt b, 0 + // extract_vector_elt (concat_vectors v2i16:a, v2i16:b), 3 + // -> extract_vector_elt b, 1 + SDLoc SL(N); + EVT ConcatVT = VecOp.getOperand(0).getValueType(); + unsigned ConcatNumElts = ConcatVT.getVectorNumElements(); + SDValue NewIdx = DAG.getConstant(Elt % ConcatNumElts, SL, + Index.getValueType()); + + SDValue ConcatOp = VecOp.getOperand(Elt / ConcatNumElts); + SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, + ConcatVT.getVectorElementType(), + ConcatOp, NewIdx); + return DAG.getNode(ISD::BITCAST, SL, ScalarVT, Elt); + } + + // Make sure we found a non-volatile load and the extractelement is + // the only use. + if (!LN0 || !LN0->hasNUsesOfValue(1,0) || !LN0->isSimple()) + return SDValue(); + + // If Idx was -1 above, Elt is going to be -1, so just return undef. + if (Elt == -1) + return DAG.getUNDEF(LVT); + + return scalarizeExtractedVectorLoad(N, VecVT, Index, LN0); +} + +// Simplify (build_vec (ext )) to (bitcast (build_vec )) +SDValue DAGCombiner::reduceBuildVecExtToExtBuildVec(SDNode *N) { + // We perform this optimization post type-legalization because + // the type-legalizer often scalarizes integer-promoted vectors. + // Performing this optimization before may create bit-casts which + // will be type-legalized to complex code sequences. + // We perform this optimization only before the operation legalizer because we + // may introduce illegal operations. + if (Level != AfterLegalizeVectorOps && Level != AfterLegalizeTypes) + return SDValue(); + + unsigned NumInScalars = N->getNumOperands(); + SDLoc DL(N); + EVT VT = N->getValueType(0); + + // Check to see if this is a BUILD_VECTOR of a bunch of values + // which come from any_extend or zero_extend nodes. If so, we can create + // a new BUILD_VECTOR using bit-casts which may enable other BUILD_VECTOR + // optimizations. We do not handle sign-extend because we can't fill the sign + // using shuffles. + EVT SourceType = MVT::Other; + bool AllAnyExt = true; + + for (unsigned i = 0; i != NumInScalars; ++i) { + SDValue In = N->getOperand(i); + // Ignore undef inputs. + if (In.isUndef()) continue; + + bool AnyExt = In.getOpcode() == ISD::ANY_EXTEND; + bool ZeroExt = In.getOpcode() == ISD::ZERO_EXTEND; + + // Abort if the element is not an extension. + if (!ZeroExt && !AnyExt) { + SourceType = MVT::Other; + break; + } + + // The input is a ZeroExt or AnyExt. Check the original type. + EVT InTy = In.getOperand(0).getValueType(); + + // Check that all of the widened source types are the same. + if (SourceType == MVT::Other) + // First time. + SourceType = InTy; + else if (InTy != SourceType) { + // Multiple income types. Abort. + SourceType = MVT::Other; + break; + } + + // Check if all of the extends are ANY_EXTENDs. + AllAnyExt &= AnyExt; + } + + // In order to have valid types, all of the inputs must be extended from the + // same source type and all of the inputs must be any or zero extend. + // Scalar sizes must be a power of two. + EVT OutScalarTy = VT.getScalarType(); + bool ValidTypes = SourceType != MVT::Other && + isPowerOf2_32(OutScalarTy.getSizeInBits()) && + isPowerOf2_32(SourceType.getSizeInBits()); + + // Create a new simpler BUILD_VECTOR sequence which other optimizations can + // turn into a single shuffle instruction. + if (!ValidTypes) + return SDValue(); + + // If we already have a splat buildvector, then don't fold it if it means + // introducing zeros. + if (!AllAnyExt && DAG.isSplatValue(SDValue(N, 0), /*AllowUndefs*/ true)) + return SDValue(); + + bool isLE = DAG.getDataLayout().isLittleEndian(); + unsigned ElemRatio = OutScalarTy.getSizeInBits()/SourceType.getSizeInBits(); + assert(ElemRatio > 1 && "Invalid element size ratio"); + SDValue Filler = AllAnyExt ? DAG.getUNDEF(SourceType): + DAG.getConstant(0, DL, SourceType); + + unsigned NewBVElems = ElemRatio * VT.getVectorNumElements(); + SmallVector<SDValue, 8> Ops(NewBVElems, Filler); + + // Populate the new build_vector + for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { + SDValue Cast = N->getOperand(i); + assert((Cast.getOpcode() == ISD::ANY_EXTEND || + Cast.getOpcode() == ISD::ZERO_EXTEND || + Cast.isUndef()) && "Invalid cast opcode"); + SDValue In; + if (Cast.isUndef()) + In = DAG.getUNDEF(SourceType); + else + In = Cast->getOperand(0); + unsigned Index = isLE ? (i * ElemRatio) : + (i * ElemRatio + (ElemRatio - 1)); + + assert(Index < Ops.size() && "Invalid index"); + Ops[Index] = In; + } + + // The type of the new BUILD_VECTOR node. + EVT VecVT = EVT::getVectorVT(*DAG.getContext(), SourceType, NewBVElems); + assert(VecVT.getSizeInBits() == VT.getSizeInBits() && + "Invalid vector size"); + // Check if the new vector type is legal. + if (!isTypeLegal(VecVT) || + (!TLI.isOperationLegal(ISD::BUILD_VECTOR, VecVT) && + TLI.isOperationLegal(ISD::BUILD_VECTOR, VT))) + return SDValue(); + + // Make the new BUILD_VECTOR. + SDValue BV = DAG.getBuildVector(VecVT, DL, Ops); + + // The new BUILD_VECTOR node has the potential to be further optimized. + AddToWorklist(BV.getNode()); + // Bitcast to the desired type. + return DAG.getBitcast(VT, BV); +} + +// Simplify (build_vec (trunc $1) +// (trunc (srl $1 half-width)) +// (trunc (srl $1 (2 * half-width))) …) +// to (bitcast $1) +SDValue DAGCombiner::reduceBuildVecTruncToBitCast(SDNode *N) { + assert(N->getOpcode() == ISD::BUILD_VECTOR && "Expected build vector"); + + // Only for little endian + if (!DAG.getDataLayout().isLittleEndian()) + return SDValue(); + + SDLoc DL(N); + EVT VT = N->getValueType(0); + EVT OutScalarTy = VT.getScalarType(); + uint64_t ScalarTypeBitsize = OutScalarTy.getSizeInBits(); + + // Only for power of two types to be sure that bitcast works well + if (!isPowerOf2_64(ScalarTypeBitsize)) + return SDValue(); + + unsigned NumInScalars = N->getNumOperands(); + + // Look through bitcasts + auto PeekThroughBitcast = [](SDValue Op) { + if (Op.getOpcode() == ISD::BITCAST) + return Op.getOperand(0); + return Op; + }; + + // The source value where all the parts are extracted. + SDValue Src; + for (unsigned i = 0; i != NumInScalars; ++i) { + SDValue In = PeekThroughBitcast(N->getOperand(i)); + // Ignore undef inputs. + if (In.isUndef()) continue; + + if (In.getOpcode() != ISD::TRUNCATE) + return SDValue(); + + In = PeekThroughBitcast(In.getOperand(0)); + + if (In.getOpcode() != ISD::SRL) { + // For now only build_vec without shuffling, handle shifts here in the + // future. + if (i != 0) + return SDValue(); + + Src = In; + } else { + // In is SRL + SDValue part = PeekThroughBitcast(In.getOperand(0)); + + if (!Src) { + Src = part; + } else if (Src != part) { + // Vector parts do not stem from the same variable + return SDValue(); + } + + SDValue ShiftAmtVal = In.getOperand(1); + if (!isa<ConstantSDNode>(ShiftAmtVal)) + return SDValue(); + + uint64_t ShiftAmt = In.getNode()->getConstantOperandVal(1); + + // The extracted value is not extracted at the right position + if (ShiftAmt != i * ScalarTypeBitsize) + return SDValue(); + } + } + + // Only cast if the size is the same + if (Src.getValueType().getSizeInBits() != VT.getSizeInBits()) + return SDValue(); + + return DAG.getBitcast(VT, Src); +} + +SDValue DAGCombiner::createBuildVecShuffle(const SDLoc &DL, SDNode *N, + ArrayRef<int> VectorMask, + SDValue VecIn1, SDValue VecIn2, + unsigned LeftIdx, bool DidSplitVec) { + SDValue ZeroIdx = DAG.getVectorIdxConstant(0, DL); + + EVT VT = N->getValueType(0); + EVT InVT1 = VecIn1.getValueType(); + EVT InVT2 = VecIn2.getNode() ? VecIn2.getValueType() : InVT1; + + unsigned NumElems = VT.getVectorNumElements(); + unsigned ShuffleNumElems = NumElems; + + // If we artificially split a vector in two already, then the offsets in the + // operands will all be based off of VecIn1, even those in VecIn2. + unsigned Vec2Offset = DidSplitVec ? 0 : InVT1.getVectorNumElements(); + + uint64_t VTSize = VT.getFixedSizeInBits(); + uint64_t InVT1Size = InVT1.getFixedSizeInBits(); + uint64_t InVT2Size = InVT2.getFixedSizeInBits(); + + // We can't generate a shuffle node with mismatched input and output types. + // Try to make the types match the type of the output. + if (InVT1 != VT || InVT2 != VT) { + if ((VTSize % InVT1Size == 0) && InVT1 == InVT2) { + // If the output vector length is a multiple of both input lengths, + // we can concatenate them and pad the rest with undefs. + unsigned NumConcats = VTSize / InVT1Size; + assert(NumConcats >= 2 && "Concat needs at least two inputs!"); + SmallVector<SDValue, 2> ConcatOps(NumConcats, DAG.getUNDEF(InVT1)); + ConcatOps[0] = VecIn1; + ConcatOps[1] = VecIn2 ? VecIn2 : DAG.getUNDEF(InVT1); + VecIn1 = DAG.getNode(ISD::CONCAT_VECTORS, DL, VT, ConcatOps); + VecIn2 = SDValue(); + } else if (InVT1Size == VTSize * 2) { + if (!TLI.isExtractSubvectorCheap(VT, InVT1, NumElems)) + return SDValue(); + + if (!VecIn2.getNode()) { + // If we only have one input vector, and it's twice the size of the + // output, split it in two. + VecIn2 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, VT, VecIn1, + DAG.getVectorIdxConstant(NumElems, DL)); + VecIn1 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, VT, VecIn1, ZeroIdx); + // Since we now have shorter input vectors, adjust the offset of the + // second vector's start. + Vec2Offset = NumElems; + } else if (InVT2Size <= InVT1Size) { + // VecIn1 is wider than the output, and we have another, possibly + // smaller input. Pad the smaller input with undefs, shuffle at the + // input vector width, and extract the output. + // The shuffle type is different than VT, so check legality again. + if (LegalOperations && + !TLI.isOperationLegal(ISD::VECTOR_SHUFFLE, InVT1)) + return SDValue(); + + // Legalizing INSERT_SUBVECTOR is tricky - you basically have to + // lower it back into a BUILD_VECTOR. So if the inserted type is + // illegal, don't even try. + if (InVT1 != InVT2) { + if (!TLI.isTypeLegal(InVT2)) + return SDValue(); + VecIn2 = DAG.getNode(ISD::INSERT_SUBVECTOR, DL, InVT1, + DAG.getUNDEF(InVT1), VecIn2, ZeroIdx); + } + ShuffleNumElems = NumElems * 2; + } else { + // Both VecIn1 and VecIn2 are wider than the output, and VecIn2 is wider + // than VecIn1. We can't handle this for now - this case will disappear + // when we start sorting the vectors by type. + return SDValue(); + } + } else if (InVT2Size * 2 == VTSize && InVT1Size == VTSize) { + SmallVector<SDValue, 2> ConcatOps(2, DAG.getUNDEF(InVT2)); + ConcatOps[0] = VecIn2; + VecIn2 = DAG.getNode(ISD::CONCAT_VECTORS, DL, VT, ConcatOps); + } else { + // TODO: Support cases where the length mismatch isn't exactly by a + // factor of 2. + // TODO: Move this check upwards, so that if we have bad type + // mismatches, we don't create any DAG nodes. + return SDValue(); + } + } + + // Initialize mask to undef. + SmallVector<int, 8> Mask(ShuffleNumElems, -1); + + // Only need to run up to the number of elements actually used, not the + // total number of elements in the shuffle - if we are shuffling a wider + // vector, the high lanes should be set to undef. + for (unsigned i = 0; i != NumElems; ++i) { + if (VectorMask[i] <= 0) + continue; + + unsigned ExtIndex = N->getOperand(i).getConstantOperandVal(1); + if (VectorMask[i] == (int)LeftIdx) { + Mask[i] = ExtIndex; + } else if (VectorMask[i] == (int)LeftIdx + 1) { + Mask[i] = Vec2Offset + ExtIndex; + } + } + + // The type the input vectors may have changed above. + InVT1 = VecIn1.getValueType(); + + // If we already have a VecIn2, it should have the same type as VecIn1. + // If we don't, get an undef/zero vector of the appropriate type. + VecIn2 = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(InVT1); + assert(InVT1 == VecIn2.getValueType() && "Unexpected second input type."); + + SDValue Shuffle = DAG.getVectorShuffle(InVT1, DL, VecIn1, VecIn2, Mask); + if (ShuffleNumElems > NumElems) + Shuffle = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, VT, Shuffle, ZeroIdx); + + return Shuffle; +} + +static SDValue reduceBuildVecToShuffleWithZero(SDNode *BV, SelectionDAG &DAG) { + assert(BV->getOpcode() == ISD::BUILD_VECTOR && "Expected build vector"); + + // First, determine where the build vector is not undef. + // TODO: We could extend this to handle zero elements as well as undefs. + int NumBVOps = BV->getNumOperands(); + int ZextElt = -1; + for (int i = 0; i != NumBVOps; ++i) { + SDValue Op = BV->getOperand(i); + if (Op.isUndef()) + continue; + if (ZextElt == -1) + ZextElt = i; + else + return SDValue(); + } + // Bail out if there's no non-undef element. + if (ZextElt == -1) + return SDValue(); + + // The build vector contains some number of undef elements and exactly + // one other element. That other element must be a zero-extended scalar + // extracted from a vector at a constant index to turn this into a shuffle. + // Also, require that the build vector does not implicitly truncate/extend + // its elements. + // TODO: This could be enhanced to allow ANY_EXTEND as well as ZERO_EXTEND. + EVT VT = BV->getValueType(0); + SDValue Zext = BV->getOperand(ZextElt); + if (Zext.getOpcode() != ISD::ZERO_EXTEND || !Zext.hasOneUse() || + Zext.getOperand(0).getOpcode() != ISD::EXTRACT_VECTOR_ELT || + !isa<ConstantSDNode>(Zext.getOperand(0).getOperand(1)) || + Zext.getValueSizeInBits() != VT.getScalarSizeInBits()) + return SDValue(); + + // The zero-extend must be a multiple of the source size, and we must be + // building a vector of the same size as the source of the extract element. + SDValue Extract = Zext.getOperand(0); + unsigned DestSize = Zext.getValueSizeInBits(); + unsigned SrcSize = Extract.getValueSizeInBits(); + if (DestSize % SrcSize != 0 || + Extract.getOperand(0).getValueSizeInBits() != VT.getSizeInBits()) + return SDValue(); + + // Create a shuffle mask that will combine the extracted element with zeros + // and undefs. + int ZextRatio = DestSize / SrcSize; + int NumMaskElts = NumBVOps * ZextRatio; + SmallVector<int, 32> ShufMask(NumMaskElts, -1); + for (int i = 0; i != NumMaskElts; ++i) { + if (i / ZextRatio == ZextElt) { + // The low bits of the (potentially translated) extracted element map to + // the source vector. The high bits map to zero. We will use a zero vector + // as the 2nd source operand of the shuffle, so use the 1st element of + // that vector (mask value is number-of-elements) for the high bits. + if (i % ZextRatio == 0) + ShufMask[i] = Extract.getConstantOperandVal(1); + else + ShufMask[i] = NumMaskElts; + } + + // Undef elements of the build vector remain undef because we initialize + // the shuffle mask with -1. + } + + // buildvec undef, ..., (zext (extractelt V, IndexC)), undef... --> + // bitcast (shuffle V, ZeroVec, VectorMask) + SDLoc DL(BV); + EVT VecVT = Extract.getOperand(0).getValueType(); + SDValue ZeroVec = DAG.getConstant(0, DL, VecVT); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + SDValue Shuf = TLI.buildLegalVectorShuffle(VecVT, DL, Extract.getOperand(0), + ZeroVec, ShufMask, DAG); + if (!Shuf) + return SDValue(); + return DAG.getBitcast(VT, Shuf); +} + +// Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT +// operations. If the types of the vectors we're extracting from allow it, +// turn this into a vector_shuffle node. +SDValue DAGCombiner::reduceBuildVecToShuffle(SDNode *N) { + SDLoc DL(N); + EVT VT = N->getValueType(0); + + // Only type-legal BUILD_VECTOR nodes are converted to shuffle nodes. + if (!isTypeLegal(VT)) + return SDValue(); + + if (SDValue V = reduceBuildVecToShuffleWithZero(N, DAG)) + return V; + + // May only combine to shuffle after legalize if shuffle is legal. + if (LegalOperations && !TLI.isOperationLegal(ISD::VECTOR_SHUFFLE, VT)) + return SDValue(); + + bool UsesZeroVector = false; + unsigned NumElems = N->getNumOperands(); + + // Record, for each element of the newly built vector, which input vector + // that element comes from. -1 stands for undef, 0 for the zero vector, + // and positive values for the input vectors. + // VectorMask maps each element to its vector number, and VecIn maps vector + // numbers to their initial SDValues. + + SmallVector<int, 8> VectorMask(NumElems, -1); + SmallVector<SDValue, 8> VecIn; + VecIn.push_back(SDValue()); + + for (unsigned i = 0; i != NumElems; ++i) { + SDValue Op = N->getOperand(i); + + if (Op.isUndef()) + continue; + + // See if we can use a blend with a zero vector. + // TODO: Should we generalize this to a blend with an arbitrary constant + // vector? + if (isNullConstant(Op) || isNullFPConstant(Op)) { + UsesZeroVector = true; + VectorMask[i] = 0; + continue; + } + + // Not an undef or zero. If the input is something other than an + // EXTRACT_VECTOR_ELT with an in-range constant index, bail out. + if (Op.getOpcode() != ISD::EXTRACT_VECTOR_ELT || + !isa<ConstantSDNode>(Op.getOperand(1))) + return SDValue(); + SDValue ExtractedFromVec = Op.getOperand(0); + + if (ExtractedFromVec.getValueType().isScalableVector()) + return SDValue(); + + const APInt &ExtractIdx = Op.getConstantOperandAPInt(1); + if (ExtractIdx.uge(ExtractedFromVec.getValueType().getVectorNumElements())) + return SDValue(); + + // All inputs must have the same element type as the output. + if (VT.getVectorElementType() != + ExtractedFromVec.getValueType().getVectorElementType()) + return SDValue(); + + // Have we seen this input vector before? + // The vectors are expected to be tiny (usually 1 or 2 elements), so using + // a map back from SDValues to numbers isn't worth it. + unsigned Idx = std::distance(VecIn.begin(), find(VecIn, ExtractedFromVec)); + if (Idx == VecIn.size()) + VecIn.push_back(ExtractedFromVec); + + VectorMask[i] = Idx; + } + + // If we didn't find at least one input vector, bail out. + if (VecIn.size() < 2) + return SDValue(); + + // If all the Operands of BUILD_VECTOR extract from same + // vector, then split the vector efficiently based on the maximum + // vector access index and adjust the VectorMask and + // VecIn accordingly. + bool DidSplitVec = false; + if (VecIn.size() == 2) { + unsigned MaxIndex = 0; + unsigned NearestPow2 = 0; + SDValue Vec = VecIn.back(); + EVT InVT = Vec.getValueType(); + SmallVector<unsigned, 8> IndexVec(NumElems, 0); + + for (unsigned i = 0; i < NumElems; i++) { + if (VectorMask[i] <= 0) + continue; + unsigned Index = N->getOperand(i).getConstantOperandVal(1); + IndexVec[i] = Index; + MaxIndex = std::max(MaxIndex, Index); + } + + NearestPow2 = PowerOf2Ceil(MaxIndex); + if (InVT.isSimple() && NearestPow2 > 2 && MaxIndex < NearestPow2 && + NumElems * 2 < NearestPow2) { + unsigned SplitSize = NearestPow2 / 2; + EVT SplitVT = EVT::getVectorVT(*DAG.getContext(), + InVT.getVectorElementType(), SplitSize); + if (TLI.isTypeLegal(SplitVT)) { + SDValue VecIn2 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, SplitVT, Vec, + DAG.getVectorIdxConstant(SplitSize, DL)); + SDValue VecIn1 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, SplitVT, Vec, + DAG.getVectorIdxConstant(0, DL)); + VecIn.pop_back(); + VecIn.push_back(VecIn1); + VecIn.push_back(VecIn2); + DidSplitVec = true; + + for (unsigned i = 0; i < NumElems; i++) { + if (VectorMask[i] <= 0) + continue; + VectorMask[i] = (IndexVec[i] < SplitSize) ? 1 : 2; + } + } + } + } + + // TODO: We want to sort the vectors by descending length, so that adjacent + // pairs have similar length, and the longer vector is always first in the + // pair. + + // TODO: Should this fire if some of the input vectors has illegal type (like + // it does now), or should we let legalization run its course first? + + // Shuffle phase: + // Take pairs of vectors, and shuffle them so that the result has elements + // from these vectors in the correct places. + // For example, given: + // t10: i32 = extract_vector_elt t1, Constant:i64<0> + // t11: i32 = extract_vector_elt t2, Constant:i64<0> + // t12: i32 = extract_vector_elt t3, Constant:i64<0> + // t13: i32 = extract_vector_elt t1, Constant:i64<1> + // t14: v4i32 = BUILD_VECTOR t10, t11, t12, t13 + // We will generate: + // t20: v4i32 = vector_shuffle<0,4,u,1> t1, t2 + // t21: v4i32 = vector_shuffle<u,u,0,u> t3, undef + SmallVector<SDValue, 4> Shuffles; + for (unsigned In = 0, Len = (VecIn.size() / 2); In < Len; ++In) { + unsigned LeftIdx = 2 * In + 1; + SDValue VecLeft = VecIn[LeftIdx]; + SDValue VecRight = + (LeftIdx + 1) < VecIn.size() ? VecIn[LeftIdx + 1] : SDValue(); + + if (SDValue Shuffle = createBuildVecShuffle(DL, N, VectorMask, VecLeft, + VecRight, LeftIdx, DidSplitVec)) + Shuffles.push_back(Shuffle); + else + return SDValue(); + } + + // If we need the zero vector as an "ingredient" in the blend tree, add it + // to the list of shuffles. + if (UsesZeroVector) + Shuffles.push_back(VT.isInteger() ? DAG.getConstant(0, DL, VT) + : DAG.getConstantFP(0.0, DL, VT)); + + // If we only have one shuffle, we're done. + if (Shuffles.size() == 1) + return Shuffles[0]; + + // Update the vector mask to point to the post-shuffle vectors. + for (int &Vec : VectorMask) + if (Vec == 0) + Vec = Shuffles.size() - 1; + else + Vec = (Vec - 1) / 2; + + // More than one shuffle. Generate a binary tree of blends, e.g. if from + // the previous step we got the set of shuffles t10, t11, t12, t13, we will + // generate: + // t10: v8i32 = vector_shuffle<0,8,u,u,u,u,u,u> t1, t2 + // t11: v8i32 = vector_shuffle<u,u,0,8,u,u,u,u> t3, t4 + // t12: v8i32 = vector_shuffle<u,u,u,u,0,8,u,u> t5, t6 + // t13: v8i32 = vector_shuffle<u,u,u,u,u,u,0,8> t7, t8 + // t20: v8i32 = vector_shuffle<0,1,10,11,u,u,u,u> t10, t11 + // t21: v8i32 = vector_shuffle<u,u,u,u,4,5,14,15> t12, t13 + // t30: v8i32 = vector_shuffle<0,1,2,3,12,13,14,15> t20, t21 + + // Make sure the initial size of the shuffle list is even. + if (Shuffles.size() % 2) + Shuffles.push_back(DAG.getUNDEF(VT)); + + for (unsigned CurSize = Shuffles.size(); CurSize > 1; CurSize /= 2) { + if (CurSize % 2) { + Shuffles[CurSize] = DAG.getUNDEF(VT); + CurSize++; + } + for (unsigned In = 0, Len = CurSize / 2; In < Len; ++In) { + int Left = 2 * In; + int Right = 2 * In + 1; + SmallVector<int, 8> Mask(NumElems, -1); + for (unsigned i = 0; i != NumElems; ++i) { + if (VectorMask[i] == Left) { + Mask[i] = i; + VectorMask[i] = In; + } else if (VectorMask[i] == Right) { + Mask[i] = i + NumElems; + VectorMask[i] = In; + } + } + + Shuffles[In] = + DAG.getVectorShuffle(VT, DL, Shuffles[Left], Shuffles[Right], Mask); + } + } + return Shuffles[0]; +} + +// Try to turn a build vector of zero extends of extract vector elts into a +// a vector zero extend and possibly an extract subvector. +// TODO: Support sign extend? +// TODO: Allow undef elements? +SDValue DAGCombiner::convertBuildVecZextToZext(SDNode *N) { + if (LegalOperations) + return SDValue(); + + EVT VT = N->getValueType(0); + + bool FoundZeroExtend = false; + SDValue Op0 = N->getOperand(0); + auto checkElem = [&](SDValue Op) -> int64_t { + unsigned Opc = Op.getOpcode(); + FoundZeroExtend |= (Opc == ISD::ZERO_EXTEND); + if ((Opc == ISD::ZERO_EXTEND || Opc == ISD::ANY_EXTEND) && + Op.getOperand(0).getOpcode() == ISD::EXTRACT_VECTOR_ELT && + Op0.getOperand(0).getOperand(0) == Op.getOperand(0).getOperand(0)) + if (auto *C = dyn_cast<ConstantSDNode>(Op.getOperand(0).getOperand(1))) + return C->getZExtValue(); + return -1; + }; + + // Make sure the first element matches + // (zext (extract_vector_elt X, C)) + int64_t Offset = checkElem(Op0); + if (Offset < 0) + return SDValue(); + + unsigned NumElems = N->getNumOperands(); + SDValue In = Op0.getOperand(0).getOperand(0); + EVT InSVT = In.getValueType().getScalarType(); + EVT InVT = EVT::getVectorVT(*DAG.getContext(), InSVT, NumElems); + + // Don't create an illegal input type after type legalization. + if (LegalTypes && !TLI.isTypeLegal(InVT)) + return SDValue(); + + // Ensure all the elements come from the same vector and are adjacent. + for (unsigned i = 1; i != NumElems; ++i) { + if ((Offset + i) != checkElem(N->getOperand(i))) + return SDValue(); + } + + SDLoc DL(N); + In = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, InVT, In, + Op0.getOperand(0).getOperand(1)); + return DAG.getNode(FoundZeroExtend ? ISD::ZERO_EXTEND : ISD::ANY_EXTEND, DL, + VT, In); +} + +SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) { + EVT VT = N->getValueType(0); + + // A vector built entirely of undefs is undef. + if (ISD::allOperandsUndef(N)) + return DAG.getUNDEF(VT); + + // If this is a splat of a bitcast from another vector, change to a + // concat_vector. + // For example: + // (build_vector (i64 (bitcast (v2i32 X))), (i64 (bitcast (v2i32 X)))) -> + // (v2i64 (bitcast (concat_vectors (v2i32 X), (v2i32 X)))) + // + // If X is a build_vector itself, the concat can become a larger build_vector. + // TODO: Maybe this is useful for non-splat too? + if (!LegalOperations) { + if (SDValue Splat = cast<BuildVectorSDNode>(N)->getSplatValue()) { + Splat = peekThroughBitcasts(Splat); + EVT SrcVT = Splat.getValueType(); + if (SrcVT.isVector()) { + unsigned NumElts = N->getNumOperands() * SrcVT.getVectorNumElements(); + EVT NewVT = EVT::getVectorVT(*DAG.getContext(), + SrcVT.getVectorElementType(), NumElts); + if (!LegalTypes || TLI.isTypeLegal(NewVT)) { + SmallVector<SDValue, 8> Ops(N->getNumOperands(), Splat); + SDValue Concat = DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), + NewVT, Ops); + return DAG.getBitcast(VT, Concat); + } + } + } + } + + // A splat of a single element is a SPLAT_VECTOR if supported on the target. + if (TLI.getOperationAction(ISD::SPLAT_VECTOR, VT) != TargetLowering::Expand) + if (SDValue V = cast<BuildVectorSDNode>(N)->getSplatValue()) { + assert(!V.isUndef() && "Splat of undef should have been handled earlier"); + return DAG.getNode(ISD::SPLAT_VECTOR, SDLoc(N), VT, V); + } + + // Check if we can express BUILD VECTOR via subvector extract. + if (!LegalTypes && (N->getNumOperands() > 1)) { + SDValue Op0 = N->getOperand(0); + auto checkElem = [&](SDValue Op) -> uint64_t { + if ((Op.getOpcode() == ISD::EXTRACT_VECTOR_ELT) && + (Op0.getOperand(0) == Op.getOperand(0))) + if (auto CNode = dyn_cast<ConstantSDNode>(Op.getOperand(1))) + return CNode->getZExtValue(); + return -1; + }; + + int Offset = checkElem(Op0); + for (unsigned i = 0; i < N->getNumOperands(); ++i) { + if (Offset + i != checkElem(N->getOperand(i))) { + Offset = -1; + break; + } + } + + if ((Offset == 0) && + (Op0.getOperand(0).getValueType() == N->getValueType(0))) + return Op0.getOperand(0); + if ((Offset != -1) && + ((Offset % N->getValueType(0).getVectorNumElements()) == + 0)) // IDX must be multiple of output size. + return DAG.getNode(ISD::EXTRACT_SUBVECTOR, SDLoc(N), N->getValueType(0), + Op0.getOperand(0), Op0.getOperand(1)); + } + + if (SDValue V = convertBuildVecZextToZext(N)) + return V; + + if (SDValue V = reduceBuildVecExtToExtBuildVec(N)) + return V; + + if (SDValue V = reduceBuildVecTruncToBitCast(N)) + return V; + + if (SDValue V = reduceBuildVecToShuffle(N)) + return V; + + return SDValue(); +} + +static SDValue combineConcatVectorOfScalars(SDNode *N, SelectionDAG &DAG) { + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + EVT OpVT = N->getOperand(0).getValueType(); + + // If the operands are legal vectors, leave them alone. + if (TLI.isTypeLegal(OpVT)) + return SDValue(); + + SDLoc DL(N); + EVT VT = N->getValueType(0); + SmallVector<SDValue, 8> Ops; + + EVT SVT = EVT::getIntegerVT(*DAG.getContext(), OpVT.getSizeInBits()); + SDValue ScalarUndef = DAG.getNode(ISD::UNDEF, DL, SVT); + + // Keep track of what we encounter. + bool AnyInteger = false; + bool AnyFP = false; + for (const SDValue &Op : N->ops()) { + if (ISD::BITCAST == Op.getOpcode() && + !Op.getOperand(0).getValueType().isVector()) + Ops.push_back(Op.getOperand(0)); + else if (ISD::UNDEF == Op.getOpcode()) + Ops.push_back(ScalarUndef); + else + return SDValue(); + + // Note whether we encounter an integer or floating point scalar. + // If it's neither, bail out, it could be something weird like x86mmx. + EVT LastOpVT = Ops.back().getValueType(); + if (LastOpVT.isFloatingPoint()) + AnyFP = true; + else if (LastOpVT.isInteger()) + AnyInteger = true; + else + return SDValue(); + } + + // If any of the operands is a floating point scalar bitcast to a vector, + // use floating point types throughout, and bitcast everything. + // Replace UNDEFs by another scalar UNDEF node, of the final desired type. + if (AnyFP) { + SVT = EVT::getFloatingPointVT(OpVT.getSizeInBits()); + ScalarUndef = DAG.getNode(ISD::UNDEF, DL, SVT); + if (AnyInteger) { + for (SDValue &Op : Ops) { + if (Op.getValueType() == SVT) + continue; + if (Op.isUndef()) + Op = ScalarUndef; + else + Op = DAG.getBitcast(SVT, Op); + } + } + } + + EVT VecVT = EVT::getVectorVT(*DAG.getContext(), SVT, + VT.getSizeInBits() / SVT.getSizeInBits()); + return DAG.getBitcast(VT, DAG.getBuildVector(VecVT, DL, Ops)); +} + +// Check to see if this is a CONCAT_VECTORS of a bunch of EXTRACT_SUBVECTOR +// operations. If so, and if the EXTRACT_SUBVECTOR vector inputs come from at +// most two distinct vectors the same size as the result, attempt to turn this +// into a legal shuffle. +static SDValue combineConcatVectorOfExtracts(SDNode *N, SelectionDAG &DAG) { + EVT VT = N->getValueType(0); + EVT OpVT = N->getOperand(0).getValueType(); + + // We currently can't generate an appropriate shuffle for a scalable vector. + if (VT.isScalableVector()) + return SDValue(); + + int NumElts = VT.getVectorNumElements(); + int NumOpElts = OpVT.getVectorNumElements(); + + SDValue SV0 = DAG.getUNDEF(VT), SV1 = DAG.getUNDEF(VT); + SmallVector<int, 8> Mask; + + for (SDValue Op : N->ops()) { + Op = peekThroughBitcasts(Op); + + // UNDEF nodes convert to UNDEF shuffle mask values. + if (Op.isUndef()) { + Mask.append((unsigned)NumOpElts, -1); + continue; + } + + if (Op.getOpcode() != ISD::EXTRACT_SUBVECTOR) + return SDValue(); + + // What vector are we extracting the subvector from and at what index? + SDValue ExtVec = Op.getOperand(0); + int ExtIdx = Op.getConstantOperandVal(1); + + // We want the EVT of the original extraction to correctly scale the + // extraction index. + EVT ExtVT = ExtVec.getValueType(); + ExtVec = peekThroughBitcasts(ExtVec); + + // UNDEF nodes convert to UNDEF shuffle mask values. + if (ExtVec.isUndef()) { + Mask.append((unsigned)NumOpElts, -1); + continue; + } + + // Ensure that we are extracting a subvector from a vector the same + // size as the result. + if (ExtVT.getSizeInBits() != VT.getSizeInBits()) + return SDValue(); + + // Scale the subvector index to account for any bitcast. + int NumExtElts = ExtVT.getVectorNumElements(); + if (0 == (NumExtElts % NumElts)) + ExtIdx /= (NumExtElts / NumElts); + else if (0 == (NumElts % NumExtElts)) + ExtIdx *= (NumElts / NumExtElts); + else + return SDValue(); + + // At most we can reference 2 inputs in the final shuffle. + if (SV0.isUndef() || SV0 == ExtVec) { + SV0 = ExtVec; + for (int i = 0; i != NumOpElts; ++i) + Mask.push_back(i + ExtIdx); + } else if (SV1.isUndef() || SV1 == ExtVec) { + SV1 = ExtVec; + for (int i = 0; i != NumOpElts; ++i) + Mask.push_back(i + ExtIdx + NumElts); + } else { + return SDValue(); + } + } + + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + return TLI.buildLegalVectorShuffle(VT, SDLoc(N), DAG.getBitcast(VT, SV0), + DAG.getBitcast(VT, SV1), Mask, DAG); +} + +static SDValue combineConcatVectorOfCasts(SDNode *N, SelectionDAG &DAG) { + unsigned CastOpcode = N->getOperand(0).getOpcode(); + switch (CastOpcode) { + case ISD::SINT_TO_FP: + case ISD::UINT_TO_FP: + case ISD::FP_TO_SINT: + case ISD::FP_TO_UINT: + // TODO: Allow more opcodes? + // case ISD::BITCAST: + // case ISD::TRUNCATE: + // case ISD::ZERO_EXTEND: + // case ISD::SIGN_EXTEND: + // case ISD::FP_EXTEND: + break; + default: + return SDValue(); + } + + EVT SrcVT = N->getOperand(0).getOperand(0).getValueType(); + if (!SrcVT.isVector()) + return SDValue(); + + // All operands of the concat must be the same kind of cast from the same + // source type. + SmallVector<SDValue, 4> SrcOps; + for (SDValue Op : N->ops()) { + if (Op.getOpcode() != CastOpcode || !Op.hasOneUse() || + Op.getOperand(0).getValueType() != SrcVT) + return SDValue(); + SrcOps.push_back(Op.getOperand(0)); + } + + // The wider cast must be supported by the target. This is unusual because + // the operation support type parameter depends on the opcode. In addition, + // check the other type in the cast to make sure this is really legal. + EVT VT = N->getValueType(0); + EVT SrcEltVT = SrcVT.getVectorElementType(); + ElementCount NumElts = SrcVT.getVectorElementCount() * N->getNumOperands(); + EVT ConcatSrcVT = EVT::getVectorVT(*DAG.getContext(), SrcEltVT, NumElts); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + switch (CastOpcode) { + case ISD::SINT_TO_FP: + case ISD::UINT_TO_FP: + if (!TLI.isOperationLegalOrCustom(CastOpcode, ConcatSrcVT) || + !TLI.isTypeLegal(VT)) + return SDValue(); + break; + case ISD::FP_TO_SINT: + case ISD::FP_TO_UINT: + if (!TLI.isOperationLegalOrCustom(CastOpcode, VT) || + !TLI.isTypeLegal(ConcatSrcVT)) + return SDValue(); + break; + default: + llvm_unreachable("Unexpected cast opcode"); + } + + // concat (cast X), (cast Y)... -> cast (concat X, Y...) + SDLoc DL(N); + SDValue NewConcat = DAG.getNode(ISD::CONCAT_VECTORS, DL, ConcatSrcVT, SrcOps); + return DAG.getNode(CastOpcode, DL, VT, NewConcat); +} + +SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) { + // If we only have one input vector, we don't need to do any concatenation. + if (N->getNumOperands() == 1) + return N->getOperand(0); + + // Check if all of the operands are undefs. + EVT VT = N->getValueType(0); + if (ISD::allOperandsUndef(N)) + return DAG.getUNDEF(VT); + + // Optimize concat_vectors where all but the first of the vectors are undef. + if (all_of(drop_begin(N->ops()), + [](const SDValue &Op) { return Op.isUndef(); })) { + SDValue In = N->getOperand(0); + assert(In.getValueType().isVector() && "Must concat vectors"); + + // If the input is a concat_vectors, just make a larger concat by padding + // with smaller undefs. + if (In.getOpcode() == ISD::CONCAT_VECTORS && In.hasOneUse()) { + unsigned NumOps = N->getNumOperands() * In.getNumOperands(); + SmallVector<SDValue, 4> Ops(In->op_begin(), In->op_end()); + Ops.resize(NumOps, DAG.getUNDEF(Ops[0].getValueType())); + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, Ops); + } + + SDValue Scalar = peekThroughOneUseBitcasts(In); + + // concat_vectors(scalar_to_vector(scalar), undef) -> + // scalar_to_vector(scalar) + if (!LegalOperations && Scalar.getOpcode() == ISD::SCALAR_TO_VECTOR && + Scalar.hasOneUse()) { + EVT SVT = Scalar.getValueType().getVectorElementType(); + if (SVT == Scalar.getOperand(0).getValueType()) + Scalar = Scalar.getOperand(0); + } + + // concat_vectors(scalar, undef) -> scalar_to_vector(scalar) + if (!Scalar.getValueType().isVector()) { + // If the bitcast type isn't legal, it might be a trunc of a legal type; + // look through the trunc so we can still do the transform: + // concat_vectors(trunc(scalar), undef) -> scalar_to_vector(scalar) + if (Scalar->getOpcode() == ISD::TRUNCATE && + !TLI.isTypeLegal(Scalar.getValueType()) && + TLI.isTypeLegal(Scalar->getOperand(0).getValueType())) + Scalar = Scalar->getOperand(0); + + EVT SclTy = Scalar.getValueType(); + + if (!SclTy.isFloatingPoint() && !SclTy.isInteger()) + return SDValue(); + + // Bail out if the vector size is not a multiple of the scalar size. + if (VT.getSizeInBits() % SclTy.getSizeInBits()) + return SDValue(); + + unsigned VNTNumElms = VT.getSizeInBits() / SclTy.getSizeInBits(); + if (VNTNumElms < 2) + return SDValue(); + + EVT NVT = EVT::getVectorVT(*DAG.getContext(), SclTy, VNTNumElms); + if (!TLI.isTypeLegal(NVT) || !TLI.isTypeLegal(Scalar.getValueType())) + return SDValue(); + + SDValue Res = DAG.getNode(ISD::SCALAR_TO_VECTOR, SDLoc(N), NVT, Scalar); + return DAG.getBitcast(VT, Res); + } + } + + // Fold any combination of BUILD_VECTOR or UNDEF nodes into one BUILD_VECTOR. + // We have already tested above for an UNDEF only concatenation. + // fold (concat_vectors (BUILD_VECTOR A, B, ...), (BUILD_VECTOR C, D, ...)) + // -> (BUILD_VECTOR A, B, ..., C, D, ...) + auto IsBuildVectorOrUndef = [](const SDValue &Op) { + return ISD::UNDEF == Op.getOpcode() || ISD::BUILD_VECTOR == Op.getOpcode(); + }; + if (llvm::all_of(N->ops(), IsBuildVectorOrUndef)) { + SmallVector<SDValue, 8> Opnds; + EVT SVT = VT.getScalarType(); + + EVT MinVT = SVT; + if (!SVT.isFloatingPoint()) { + // If BUILD_VECTOR are from built from integer, they may have different + // operand types. Get the smallest type and truncate all operands to it. + bool FoundMinVT = false; + for (const SDValue &Op : N->ops()) + if (ISD::BUILD_VECTOR == Op.getOpcode()) { + EVT OpSVT = Op.getOperand(0).getValueType(); + MinVT = (!FoundMinVT || OpSVT.bitsLE(MinVT)) ? OpSVT : MinVT; + FoundMinVT = true; + } + assert(FoundMinVT && "Concat vector type mismatch"); + } + + for (const SDValue &Op : N->ops()) { + EVT OpVT = Op.getValueType(); + unsigned NumElts = OpVT.getVectorNumElements(); + + if (ISD::UNDEF == Op.getOpcode()) + Opnds.append(NumElts, DAG.getUNDEF(MinVT)); + + if (ISD::BUILD_VECTOR == Op.getOpcode()) { + if (SVT.isFloatingPoint()) { + assert(SVT == OpVT.getScalarType() && "Concat vector type mismatch"); + Opnds.append(Op->op_begin(), Op->op_begin() + NumElts); + } else { + for (unsigned i = 0; i != NumElts; ++i) + Opnds.push_back( + DAG.getNode(ISD::TRUNCATE, SDLoc(N), MinVT, Op.getOperand(i))); + } + } + } + + assert(VT.getVectorNumElements() == Opnds.size() && + "Concat vector type mismatch"); + return DAG.getBuildVector(VT, SDLoc(N), Opnds); + } + + // Fold CONCAT_VECTORS of only bitcast scalars (or undef) to BUILD_VECTOR. + if (SDValue V = combineConcatVectorOfScalars(N, DAG)) + return V; + + // Fold CONCAT_VECTORS of EXTRACT_SUBVECTOR (or undef) to VECTOR_SHUFFLE. + if (Level < AfterLegalizeVectorOps && TLI.isTypeLegal(VT)) + if (SDValue V = combineConcatVectorOfExtracts(N, DAG)) + return V; + + if (SDValue V = combineConcatVectorOfCasts(N, DAG)) + return V; + + // Type legalization of vectors and DAG canonicalization of SHUFFLE_VECTOR + // nodes often generate nop CONCAT_VECTOR nodes. Scan the CONCAT_VECTOR + // operands and look for a CONCAT operations that place the incoming vectors + // at the exact same location. + // + // For scalable vectors, EXTRACT_SUBVECTOR indexes are implicitly scaled. + SDValue SingleSource = SDValue(); + unsigned PartNumElem = + N->getOperand(0).getValueType().getVectorMinNumElements(); + + for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { + SDValue Op = N->getOperand(i); + + if (Op.isUndef()) + continue; + + // Check if this is the identity extract: + if (Op.getOpcode() != ISD::EXTRACT_SUBVECTOR) + return SDValue(); + + // Find the single incoming vector for the extract_subvector. + if (SingleSource.getNode()) { + if (Op.getOperand(0) != SingleSource) + return SDValue(); + } else { + SingleSource = Op.getOperand(0); + + // Check the source type is the same as the type of the result. + // If not, this concat may extend the vector, so we can not + // optimize it away. + if (SingleSource.getValueType() != N->getValueType(0)) + return SDValue(); + } + + // Check that we are reading from the identity index. + unsigned IdentityIndex = i * PartNumElem; + if (Op.getConstantOperandAPInt(1) != IdentityIndex) + return SDValue(); + } + + if (SingleSource.getNode()) + return SingleSource; + + return SDValue(); +} + +// Helper that peeks through INSERT_SUBVECTOR/CONCAT_VECTORS to find +// if the subvector can be sourced for free. +static SDValue getSubVectorSrc(SDValue V, SDValue Index, EVT SubVT) { + if (V.getOpcode() == ISD::INSERT_SUBVECTOR && + V.getOperand(1).getValueType() == SubVT && V.getOperand(2) == Index) { + return V.getOperand(1); + } + auto *IndexC = dyn_cast<ConstantSDNode>(Index); + if (IndexC && V.getOpcode() == ISD::CONCAT_VECTORS && + V.getOperand(0).getValueType() == SubVT && + (IndexC->getZExtValue() % SubVT.getVectorMinNumElements()) == 0) { + uint64_t SubIdx = IndexC->getZExtValue() / SubVT.getVectorMinNumElements(); + return V.getOperand(SubIdx); + } + return SDValue(); +} + +static SDValue narrowInsertExtractVectorBinOp(SDNode *Extract, + SelectionDAG &DAG, + bool LegalOperations) { + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + SDValue BinOp = Extract->getOperand(0); + unsigned BinOpcode = BinOp.getOpcode(); + if (!TLI.isBinOp(BinOpcode) || BinOp.getNode()->getNumValues() != 1) + return SDValue(); + + EVT VecVT = BinOp.getValueType(); + SDValue Bop0 = BinOp.getOperand(0), Bop1 = BinOp.getOperand(1); + if (VecVT != Bop0.getValueType() || VecVT != Bop1.getValueType()) + return SDValue(); + + SDValue Index = Extract->getOperand(1); + EVT SubVT = Extract->getValueType(0); + if (!TLI.isOperationLegalOrCustom(BinOpcode, SubVT, LegalOperations)) + return SDValue(); + + SDValue Sub0 = getSubVectorSrc(Bop0, Index, SubVT); + SDValue Sub1 = getSubVectorSrc(Bop1, Index, SubVT); + + // TODO: We could handle the case where only 1 operand is being inserted by + // creating an extract of the other operand, but that requires checking + // number of uses and/or costs. + if (!Sub0 || !Sub1) + return SDValue(); + + // We are inserting both operands of the wide binop only to extract back + // to the narrow vector size. Eliminate all of the insert/extract: + // ext (binop (ins ?, X, Index), (ins ?, Y, Index)), Index --> binop X, Y + return DAG.getNode(BinOpcode, SDLoc(Extract), SubVT, Sub0, Sub1, + BinOp->getFlags()); +} + +/// If we are extracting a subvector produced by a wide binary operator try +/// to use a narrow binary operator and/or avoid concatenation and extraction. +static SDValue narrowExtractedVectorBinOp(SDNode *Extract, SelectionDAG &DAG, + bool LegalOperations) { + // TODO: Refactor with the caller (visitEXTRACT_SUBVECTOR), so we can share + // some of these bailouts with other transforms. + + if (SDValue V = narrowInsertExtractVectorBinOp(Extract, DAG, LegalOperations)) + return V; + + // The extract index must be a constant, so we can map it to a concat operand. + auto *ExtractIndexC = dyn_cast<ConstantSDNode>(Extract->getOperand(1)); + if (!ExtractIndexC) + return SDValue(); + + // We are looking for an optionally bitcasted wide vector binary operator + // feeding an extract subvector. + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + SDValue BinOp = peekThroughBitcasts(Extract->getOperand(0)); + unsigned BOpcode = BinOp.getOpcode(); + if (!TLI.isBinOp(BOpcode) || BinOp.getNode()->getNumValues() != 1) + return SDValue(); + + // Exclude the fake form of fneg (fsub -0.0, x) because that is likely to be + // reduced to the unary fneg when it is visited, and we probably want to deal + // with fneg in a target-specific way. + if (BOpcode == ISD::FSUB) { + auto *C = isConstOrConstSplatFP(BinOp.getOperand(0), /*AllowUndefs*/ true); + if (C && C->getValueAPF().isNegZero()) + return SDValue(); + } + + // The binop must be a vector type, so we can extract some fraction of it. + EVT WideBVT = BinOp.getValueType(); + // The optimisations below currently assume we are dealing with fixed length + // vectors. It is possible to add support for scalable vectors, but at the + // moment we've done no analysis to prove whether they are profitable or not. + if (!WideBVT.isFixedLengthVector()) + return SDValue(); + + EVT VT = Extract->getValueType(0); + unsigned ExtractIndex = ExtractIndexC->getZExtValue(); + assert(ExtractIndex % VT.getVectorNumElements() == 0 && + "Extract index is not a multiple of the vector length."); + + // Bail out if this is not a proper multiple width extraction. + unsigned WideWidth = WideBVT.getSizeInBits(); + unsigned NarrowWidth = VT.getSizeInBits(); + if (WideWidth % NarrowWidth != 0) + return SDValue(); + + // Bail out if we are extracting a fraction of a single operation. This can + // occur because we potentially looked through a bitcast of the binop. + unsigned NarrowingRatio = WideWidth / NarrowWidth; + unsigned WideNumElts = WideBVT.getVectorNumElements(); + if (WideNumElts % NarrowingRatio != 0) + return SDValue(); + + // Bail out if the target does not support a narrower version of the binop. + EVT NarrowBVT = EVT::getVectorVT(*DAG.getContext(), WideBVT.getScalarType(), + WideNumElts / NarrowingRatio); + if (!TLI.isOperationLegalOrCustomOrPromote(BOpcode, NarrowBVT)) + return SDValue(); + + // If extraction is cheap, we don't need to look at the binop operands + // for concat ops. The narrow binop alone makes this transform profitable. + // We can't just reuse the original extract index operand because we may have + // bitcasted. + unsigned ConcatOpNum = ExtractIndex / VT.getVectorNumElements(); + unsigned ExtBOIdx = ConcatOpNum * NarrowBVT.getVectorNumElements(); + if (TLI.isExtractSubvectorCheap(NarrowBVT, WideBVT, ExtBOIdx) && + BinOp.hasOneUse() && Extract->getOperand(0)->hasOneUse()) { + // extract (binop B0, B1), N --> binop (extract B0, N), (extract B1, N) + SDLoc DL(Extract); + SDValue NewExtIndex = DAG.getVectorIdxConstant(ExtBOIdx, DL); + SDValue X = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NarrowBVT, + BinOp.getOperand(0), NewExtIndex); + SDValue Y = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NarrowBVT, + BinOp.getOperand(1), NewExtIndex); + SDValue NarrowBinOp = DAG.getNode(BOpcode, DL, NarrowBVT, X, Y, + BinOp.getNode()->getFlags()); + return DAG.getBitcast(VT, NarrowBinOp); + } + + // Only handle the case where we are doubling and then halving. A larger ratio + // may require more than two narrow binops to replace the wide binop. + if (NarrowingRatio != 2) + return SDValue(); + + // TODO: The motivating case for this transform is an x86 AVX1 target. That + // target has temptingly almost legal versions of bitwise logic ops in 256-bit + // flavors, but no other 256-bit integer support. This could be extended to + // handle any binop, but that may require fixing/adding other folds to avoid + // codegen regressions. + if (BOpcode != ISD::AND && BOpcode != ISD::OR && BOpcode != ISD::XOR) + return SDValue(); + + // We need at least one concatenation operation of a binop operand to make + // this transform worthwhile. The concat must double the input vector sizes. + auto GetSubVector = [ConcatOpNum](SDValue V) -> SDValue { + if (V.getOpcode() == ISD::CONCAT_VECTORS && V.getNumOperands() == 2) + return V.getOperand(ConcatOpNum); + return SDValue(); + }; + SDValue SubVecL = GetSubVector(peekThroughBitcasts(BinOp.getOperand(0))); + SDValue SubVecR = GetSubVector(peekThroughBitcasts(BinOp.getOperand(1))); + + if (SubVecL || SubVecR) { + // If a binop operand was not the result of a concat, we must extract a + // half-sized operand for our new narrow binop: + // extract (binop (concat X1, X2), (concat Y1, Y2)), N --> binop XN, YN + // extract (binop (concat X1, X2), Y), N --> binop XN, (extract Y, IndexC) + // extract (binop X, (concat Y1, Y2)), N --> binop (extract X, IndexC), YN + SDLoc DL(Extract); + SDValue IndexC = DAG.getVectorIdxConstant(ExtBOIdx, DL); + SDValue X = SubVecL ? DAG.getBitcast(NarrowBVT, SubVecL) + : DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NarrowBVT, + BinOp.getOperand(0), IndexC); + + SDValue Y = SubVecR ? DAG.getBitcast(NarrowBVT, SubVecR) + : DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NarrowBVT, + BinOp.getOperand(1), IndexC); + + SDValue NarrowBinOp = DAG.getNode(BOpcode, DL, NarrowBVT, X, Y); + return DAG.getBitcast(VT, NarrowBinOp); + } + + return SDValue(); +} + +/// If we are extracting a subvector from a wide vector load, convert to a +/// narrow load to eliminate the extraction: +/// (extract_subvector (load wide vector)) --> (load narrow vector) +static SDValue narrowExtractedVectorLoad(SDNode *Extract, SelectionDAG &DAG) { + // TODO: Add support for big-endian. The offset calculation must be adjusted. + if (DAG.getDataLayout().isBigEndian()) + return SDValue(); + + auto *Ld = dyn_cast<LoadSDNode>(Extract->getOperand(0)); + auto *ExtIdx = dyn_cast<ConstantSDNode>(Extract->getOperand(1)); + if (!Ld || Ld->getExtensionType() || !Ld->isSimple() || + !ExtIdx) + return SDValue(); + + // Allow targets to opt-out. + EVT VT = Extract->getValueType(0); + + // We can only create byte sized loads. + if (!VT.isByteSized()) + return SDValue(); + + unsigned Index = ExtIdx->getZExtValue(); + unsigned NumElts = VT.getVectorMinNumElements(); + + // The definition of EXTRACT_SUBVECTOR states that the index must be a + // multiple of the minimum number of elements in the result type. + assert(Index % NumElts == 0 && "The extract subvector index is not a " + "multiple of the result's element count"); + + // It's fine to use TypeSize here as we know the offset will not be negative. + TypeSize Offset = VT.getStoreSize() * (Index / NumElts); + + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + if (!TLI.shouldReduceLoadWidth(Ld, Ld->getExtensionType(), VT)) + return SDValue(); + + // The narrow load will be offset from the base address of the old load if + // we are extracting from something besides index 0 (little-endian). + SDLoc DL(Extract); + + // TODO: Use "BaseIndexOffset" to make this more effective. + SDValue NewAddr = DAG.getMemBasePlusOffset(Ld->getBasePtr(), Offset, DL); + + uint64_t StoreSize = MemoryLocation::getSizeOrUnknown(VT.getStoreSize()); + MachineFunction &MF = DAG.getMachineFunction(); + MachineMemOperand *MMO; + if (Offset.isScalable()) { + MachinePointerInfo MPI = + MachinePointerInfo(Ld->getPointerInfo().getAddrSpace()); + MMO = MF.getMachineMemOperand(Ld->getMemOperand(), MPI, StoreSize); + } else + MMO = MF.getMachineMemOperand(Ld->getMemOperand(), Offset.getFixedSize(), + StoreSize); + + SDValue NewLd = DAG.getLoad(VT, DL, Ld->getChain(), NewAddr, MMO); + DAG.makeEquivalentMemoryOrdering(Ld, NewLd); + return NewLd; +} + +SDValue DAGCombiner::visitEXTRACT_SUBVECTOR(SDNode *N) { + EVT NVT = N->getValueType(0); + SDValue V = N->getOperand(0); + uint64_t ExtIdx = N->getConstantOperandVal(1); + + // Extract from UNDEF is UNDEF. + if (V.isUndef()) + return DAG.getUNDEF(NVT); + + if (TLI.isOperationLegalOrCustomOrPromote(ISD::LOAD, NVT)) + if (SDValue NarrowLoad = narrowExtractedVectorLoad(N, DAG)) + return NarrowLoad; + + // Combine an extract of an extract into a single extract_subvector. + // ext (ext X, C), 0 --> ext X, C + if (ExtIdx == 0 && V.getOpcode() == ISD::EXTRACT_SUBVECTOR && V.hasOneUse()) { + if (TLI.isExtractSubvectorCheap(NVT, V.getOperand(0).getValueType(), + V.getConstantOperandVal(1)) && + TLI.isOperationLegalOrCustom(ISD::EXTRACT_SUBVECTOR, NVT)) { + return DAG.getNode(ISD::EXTRACT_SUBVECTOR, SDLoc(N), NVT, V.getOperand(0), + V.getOperand(1)); + } + } + + // Try to move vector bitcast after extract_subv by scaling extraction index: + // extract_subv (bitcast X), Index --> bitcast (extract_subv X, Index') + if (V.getOpcode() == ISD::BITCAST && + V.getOperand(0).getValueType().isVector()) { + SDValue SrcOp = V.getOperand(0); + EVT SrcVT = SrcOp.getValueType(); + unsigned SrcNumElts = SrcVT.getVectorMinNumElements(); + unsigned DestNumElts = V.getValueType().getVectorMinNumElements(); + if ((SrcNumElts % DestNumElts) == 0) { + unsigned SrcDestRatio = SrcNumElts / DestNumElts; + ElementCount NewExtEC = NVT.getVectorElementCount() * SrcDestRatio; + EVT NewExtVT = EVT::getVectorVT(*DAG.getContext(), SrcVT.getScalarType(), + NewExtEC); + if (TLI.isOperationLegalOrCustom(ISD::EXTRACT_SUBVECTOR, NewExtVT)) { + SDLoc DL(N); + SDValue NewIndex = DAG.getVectorIdxConstant(ExtIdx * SrcDestRatio, DL); + SDValue NewExtract = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NewExtVT, + V.getOperand(0), NewIndex); + return DAG.getBitcast(NVT, NewExtract); + } + } + if ((DestNumElts % SrcNumElts) == 0) { + unsigned DestSrcRatio = DestNumElts / SrcNumElts; + if (NVT.getVectorElementCount().isKnownMultipleOf(DestSrcRatio)) { + ElementCount NewExtEC = + NVT.getVectorElementCount().divideCoefficientBy(DestSrcRatio); + EVT ScalarVT = SrcVT.getScalarType(); + if ((ExtIdx % DestSrcRatio) == 0) { + SDLoc DL(N); + unsigned IndexValScaled = ExtIdx / DestSrcRatio; + EVT NewExtVT = + EVT::getVectorVT(*DAG.getContext(), ScalarVT, NewExtEC); + if (TLI.isOperationLegalOrCustom(ISD::EXTRACT_SUBVECTOR, NewExtVT)) { + SDValue NewIndex = DAG.getVectorIdxConstant(IndexValScaled, DL); + SDValue NewExtract = + DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NewExtVT, + V.getOperand(0), NewIndex); + return DAG.getBitcast(NVT, NewExtract); + } + if (NewExtEC.isScalar() && + TLI.isOperationLegalOrCustom(ISD::EXTRACT_VECTOR_ELT, ScalarVT)) { + SDValue NewIndex = DAG.getVectorIdxConstant(IndexValScaled, DL); + SDValue NewExtract = + DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, ScalarVT, + V.getOperand(0), NewIndex); + return DAG.getBitcast(NVT, NewExtract); + } + } + } + } + } + + if (V.getOpcode() == ISD::CONCAT_VECTORS) { + unsigned ExtNumElts = NVT.getVectorMinNumElements(); + EVT ConcatSrcVT = V.getOperand(0).getValueType(); + assert(ConcatSrcVT.getVectorElementType() == NVT.getVectorElementType() && + "Concat and extract subvector do not change element type"); + assert((ExtIdx % ExtNumElts) == 0 && + "Extract index is not a multiple of the input vector length."); + + unsigned ConcatSrcNumElts = ConcatSrcVT.getVectorMinNumElements(); + unsigned ConcatOpIdx = ExtIdx / ConcatSrcNumElts; + + // If the concatenated source types match this extract, it's a direct + // simplification: + // extract_subvec (concat V1, V2, ...), i --> Vi + if (ConcatSrcNumElts == ExtNumElts) + return V.getOperand(ConcatOpIdx); + + // If the concatenated source vectors are a multiple length of this extract, + // then extract a fraction of one of those source vectors directly from a + // concat operand. Example: + // v2i8 extract_subvec (v16i8 concat (v8i8 X), (v8i8 Y), 14 --> + // v2i8 extract_subvec v8i8 Y, 6 + if (NVT.isFixedLengthVector() && ConcatSrcNumElts % ExtNumElts == 0) { + SDLoc DL(N); + unsigned NewExtIdx = ExtIdx - ConcatOpIdx * ConcatSrcNumElts; + assert(NewExtIdx + ExtNumElts <= ConcatSrcNumElts && + "Trying to extract from >1 concat operand?"); + assert(NewExtIdx % ExtNumElts == 0 && + "Extract index is not a multiple of the input vector length."); + SDValue NewIndexC = DAG.getVectorIdxConstant(NewExtIdx, DL); + return DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, NVT, + V.getOperand(ConcatOpIdx), NewIndexC); + } + } + + V = peekThroughBitcasts(V); + + // If the input is a build vector. Try to make a smaller build vector. + if (V.getOpcode() == ISD::BUILD_VECTOR) { + EVT InVT = V.getValueType(); + unsigned ExtractSize = NVT.getSizeInBits(); + unsigned EltSize = InVT.getScalarSizeInBits(); + // Only do this if we won't split any elements. + if (ExtractSize % EltSize == 0) { + unsigned NumElems = ExtractSize / EltSize; + EVT EltVT = InVT.getVectorElementType(); + EVT ExtractVT = + NumElems == 1 ? EltVT + : EVT::getVectorVT(*DAG.getContext(), EltVT, NumElems); + if ((Level < AfterLegalizeDAG || + (NumElems == 1 || + TLI.isOperationLegal(ISD::BUILD_VECTOR, ExtractVT))) && + (!LegalTypes || TLI.isTypeLegal(ExtractVT))) { + unsigned IdxVal = (ExtIdx * NVT.getScalarSizeInBits()) / EltSize; + + if (NumElems == 1) { + SDValue Src = V->getOperand(IdxVal); + if (EltVT != Src.getValueType()) + Src = DAG.getNode(ISD::TRUNCATE, SDLoc(N), InVT, Src); + return DAG.getBitcast(NVT, Src); + } + + // Extract the pieces from the original build_vector. + SDValue BuildVec = DAG.getBuildVector(ExtractVT, SDLoc(N), + V->ops().slice(IdxVal, NumElems)); + return DAG.getBitcast(NVT, BuildVec); + } + } + } + + if (V.getOpcode() == ISD::INSERT_SUBVECTOR) { + // Handle only simple case where vector being inserted and vector + // being extracted are of same size. + EVT SmallVT = V.getOperand(1).getValueType(); + if (!NVT.bitsEq(SmallVT)) + return SDValue(); + + // Combine: + // (extract_subvec (insert_subvec V1, V2, InsIdx), ExtIdx) + // Into: + // indices are equal or bit offsets are equal => V1 + // otherwise => (extract_subvec V1, ExtIdx) + uint64_t InsIdx = V.getConstantOperandVal(2); + if (InsIdx * SmallVT.getScalarSizeInBits() == + ExtIdx * NVT.getScalarSizeInBits()) + return DAG.getBitcast(NVT, V.getOperand(1)); + return DAG.getNode( + ISD::EXTRACT_SUBVECTOR, SDLoc(N), NVT, + DAG.getBitcast(N->getOperand(0).getValueType(), V.getOperand(0)), + N->getOperand(1)); + } + + if (SDValue NarrowBOp = narrowExtractedVectorBinOp(N, DAG, LegalOperations)) + return NarrowBOp; + + if (SimplifyDemandedVectorElts(SDValue(N, 0))) + return SDValue(N, 0); + + return SDValue(); +} + +/// Try to convert a wide shuffle of concatenated vectors into 2 narrow shuffles +/// followed by concatenation. Narrow vector ops may have better performance +/// than wide ops, and this can unlock further narrowing of other vector ops. +/// Targets can invert this transform later if it is not profitable. +static SDValue foldShuffleOfConcatUndefs(ShuffleVectorSDNode *Shuf, + SelectionDAG &DAG) { + SDValue N0 = Shuf->getOperand(0), N1 = Shuf->getOperand(1); + if (N0.getOpcode() != ISD::CONCAT_VECTORS || N0.getNumOperands() != 2 || + N1.getOpcode() != ISD::CONCAT_VECTORS || N1.getNumOperands() != 2 || + !N0.getOperand(1).isUndef() || !N1.getOperand(1).isUndef()) + return SDValue(); + + // Split the wide shuffle mask into halves. Any mask element that is accessing + // operand 1 is offset down to account for narrowing of the vectors. + ArrayRef<int> Mask = Shuf->getMask(); + EVT VT = Shuf->getValueType(0); + unsigned NumElts = VT.getVectorNumElements(); + unsigned HalfNumElts = NumElts / 2; + SmallVector<int, 16> Mask0(HalfNumElts, -1); + SmallVector<int, 16> Mask1(HalfNumElts, -1); + for (unsigned i = 0; i != NumElts; ++i) { + if (Mask[i] == -1) + continue; + int M = Mask[i] < (int)NumElts ? Mask[i] : Mask[i] - (int)HalfNumElts; + if (i < HalfNumElts) + Mask0[i] = M; + else + Mask1[i - HalfNumElts] = M; + } + + // Ask the target if this is a valid transform. + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + EVT HalfVT = EVT::getVectorVT(*DAG.getContext(), VT.getScalarType(), + HalfNumElts); + if (!TLI.isShuffleMaskLegal(Mask0, HalfVT) || + !TLI.isShuffleMaskLegal(Mask1, HalfVT)) + return SDValue(); + + // shuffle (concat X, undef), (concat Y, undef), Mask --> + // concat (shuffle X, Y, Mask0), (shuffle X, Y, Mask1) + SDValue X = N0.getOperand(0), Y = N1.getOperand(0); + SDLoc DL(Shuf); + SDValue Shuf0 = DAG.getVectorShuffle(HalfVT, DL, X, Y, Mask0); + SDValue Shuf1 = DAG.getVectorShuffle(HalfVT, DL, X, Y, Mask1); + return DAG.getNode(ISD::CONCAT_VECTORS, DL, VT, Shuf0, Shuf1); +} + +// Tries to turn a shuffle of two CONCAT_VECTORS into a single concat, +// or turn a shuffle of a single concat into simpler shuffle then concat. +static SDValue partitionShuffleOfConcats(SDNode *N, SelectionDAG &DAG) { + EVT VT = N->getValueType(0); + unsigned NumElts = VT.getVectorNumElements(); + + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N); + ArrayRef<int> Mask = SVN->getMask(); + + SmallVector<SDValue, 4> Ops; + EVT ConcatVT = N0.getOperand(0).getValueType(); + unsigned NumElemsPerConcat = ConcatVT.getVectorNumElements(); + unsigned NumConcats = NumElts / NumElemsPerConcat; + + auto IsUndefMaskElt = [](int i) { return i == -1; }; + + // Special case: shuffle(concat(A,B)) can be more efficiently represented + // as concat(shuffle(A,B),UNDEF) if the shuffle doesn't set any of the high + // half vector elements. + if (NumElemsPerConcat * 2 == NumElts && N1.isUndef() && + llvm::all_of(Mask.slice(NumElemsPerConcat, NumElemsPerConcat), + IsUndefMaskElt)) { + N0 = DAG.getVectorShuffle(ConcatVT, SDLoc(N), N0.getOperand(0), + N0.getOperand(1), + Mask.slice(0, NumElemsPerConcat)); + N1 = DAG.getUNDEF(ConcatVT); + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, N0, N1); + } + + // Look at every vector that's inserted. We're looking for exact + // subvector-sized copies from a concatenated vector + for (unsigned I = 0; I != NumConcats; ++I) { + unsigned Begin = I * NumElemsPerConcat; + ArrayRef<int> SubMask = Mask.slice(Begin, NumElemsPerConcat); + + // Make sure we're dealing with a copy. + if (llvm::all_of(SubMask, IsUndefMaskElt)) { + Ops.push_back(DAG.getUNDEF(ConcatVT)); + continue; + } + + int OpIdx = -1; + for (int i = 0; i != (int)NumElemsPerConcat; ++i) { + if (IsUndefMaskElt(SubMask[i])) + continue; + if ((SubMask[i] % (int)NumElemsPerConcat) != i) + return SDValue(); + int EltOpIdx = SubMask[i] / NumElemsPerConcat; + if (0 <= OpIdx && EltOpIdx != OpIdx) + return SDValue(); + OpIdx = EltOpIdx; + } + assert(0 <= OpIdx && "Unknown concat_vectors op"); + + if (OpIdx < (int)N0.getNumOperands()) + Ops.push_back(N0.getOperand(OpIdx)); + else + Ops.push_back(N1.getOperand(OpIdx - N0.getNumOperands())); + } + + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, Ops); +} + +// Attempt to combine a shuffle of 2 inputs of 'scalar sources' - +// BUILD_VECTOR or SCALAR_TO_VECTOR into a single BUILD_VECTOR. +// +// SHUFFLE(BUILD_VECTOR(), BUILD_VECTOR()) -> BUILD_VECTOR() is always +// a simplification in some sense, but it isn't appropriate in general: some +// BUILD_VECTORs are substantially cheaper than others. The general case +// of a BUILD_VECTOR requires inserting each element individually (or +// performing the equivalent in a temporary stack variable). A BUILD_VECTOR of +// all constants is a single constant pool load. A BUILD_VECTOR where each +// element is identical is a splat. A BUILD_VECTOR where most of the operands +// are undef lowers to a small number of element insertions. +// +// To deal with this, we currently use a bunch of mostly arbitrary heuristics. +// We don't fold shuffles where one side is a non-zero constant, and we don't +// fold shuffles if the resulting (non-splat) BUILD_VECTOR would have duplicate +// non-constant operands. This seems to work out reasonably well in practice. +static SDValue combineShuffleOfScalars(ShuffleVectorSDNode *SVN, + SelectionDAG &DAG, + const TargetLowering &TLI) { + EVT VT = SVN->getValueType(0); + unsigned NumElts = VT.getVectorNumElements(); + SDValue N0 = SVN->getOperand(0); + SDValue N1 = SVN->getOperand(1); + + if (!N0->hasOneUse()) + return SDValue(); + + // If only one of N1,N2 is constant, bail out if it is not ALL_ZEROS as + // discussed above. + if (!N1.isUndef()) { + if (!N1->hasOneUse()) + return SDValue(); + + bool N0AnyConst = isAnyConstantBuildVector(N0); + bool N1AnyConst = isAnyConstantBuildVector(N1); + if (N0AnyConst && !N1AnyConst && !ISD::isBuildVectorAllZeros(N0.getNode())) + return SDValue(); + if (!N0AnyConst && N1AnyConst && !ISD::isBuildVectorAllZeros(N1.getNode())) + return SDValue(); + } + + // If both inputs are splats of the same value then we can safely merge this + // to a single BUILD_VECTOR with undef elements based on the shuffle mask. + bool IsSplat = false; + auto *BV0 = dyn_cast<BuildVectorSDNode>(N0); + auto *BV1 = dyn_cast<BuildVectorSDNode>(N1); + if (BV0 && BV1) + if (SDValue Splat0 = BV0->getSplatValue()) + IsSplat = (Splat0 == BV1->getSplatValue()); + + SmallVector<SDValue, 8> Ops; + SmallSet<SDValue, 16> DuplicateOps; + for (int M : SVN->getMask()) { + SDValue Op = DAG.getUNDEF(VT.getScalarType()); + if (M >= 0) { + int Idx = M < (int)NumElts ? M : M - NumElts; + SDValue &S = (M < (int)NumElts ? N0 : N1); + if (S.getOpcode() == ISD::BUILD_VECTOR) { + Op = S.getOperand(Idx); + } else if (S.getOpcode() == ISD::SCALAR_TO_VECTOR) { + SDValue Op0 = S.getOperand(0); + Op = Idx == 0 ? Op0 : DAG.getUNDEF(Op0.getValueType()); + } else { + // Operand can't be combined - bail out. + return SDValue(); + } + } + + // Don't duplicate a non-constant BUILD_VECTOR operand unless we're + // generating a splat; semantically, this is fine, but it's likely to + // generate low-quality code if the target can't reconstruct an appropriate + // shuffle. + if (!Op.isUndef() && !isa<ConstantSDNode>(Op) && !isa<ConstantFPSDNode>(Op)) + if (!IsSplat && !DuplicateOps.insert(Op).second) + return SDValue(); + + Ops.push_back(Op); + } + + // BUILD_VECTOR requires all inputs to be of the same type, find the + // maximum type and extend them all. + EVT SVT = VT.getScalarType(); + if (SVT.isInteger()) + for (SDValue &Op : Ops) + SVT = (SVT.bitsLT(Op.getValueType()) ? Op.getValueType() : SVT); + if (SVT != VT.getScalarType()) + for (SDValue &Op : Ops) + Op = TLI.isZExtFree(Op.getValueType(), SVT) + ? DAG.getZExtOrTrunc(Op, SDLoc(SVN), SVT) + : DAG.getSExtOrTrunc(Op, SDLoc(SVN), SVT); + return DAG.getBuildVector(VT, SDLoc(SVN), Ops); +} + +// Match shuffles that can be converted to any_vector_extend_in_reg. +// This is often generated during legalization. +// e.g. v4i32 <0,u,1,u> -> (v2i64 any_vector_extend_in_reg(v4i32 src)) +// TODO Add support for ZERO_EXTEND_VECTOR_INREG when we have a test case. +static SDValue combineShuffleToVectorExtend(ShuffleVectorSDNode *SVN, + SelectionDAG &DAG, + const TargetLowering &TLI, + bool LegalOperations) { + EVT VT = SVN->getValueType(0); + bool IsBigEndian = DAG.getDataLayout().isBigEndian(); + + // TODO Add support for big-endian when we have a test case. + if (!VT.isInteger() || IsBigEndian) + return SDValue(); + + unsigned NumElts = VT.getVectorNumElements(); + unsigned EltSizeInBits = VT.getScalarSizeInBits(); + ArrayRef<int> Mask = SVN->getMask(); + SDValue N0 = SVN->getOperand(0); + + // shuffle<0,-1,1,-1> == (v2i64 anyextend_vector_inreg(v4i32)) + auto isAnyExtend = [&Mask, &NumElts](unsigned Scale) { + for (unsigned i = 0; i != NumElts; ++i) { + if (Mask[i] < 0) + continue; + if ((i % Scale) == 0 && Mask[i] == (int)(i / Scale)) + continue; + return false; + } + return true; + }; + + // Attempt to match a '*_extend_vector_inreg' shuffle, we just search for + // power-of-2 extensions as they are the most likely. + for (unsigned Scale = 2; Scale < NumElts; Scale *= 2) { + // Check for non power of 2 vector sizes + if (NumElts % Scale != 0) + continue; + if (!isAnyExtend(Scale)) + continue; + + EVT OutSVT = EVT::getIntegerVT(*DAG.getContext(), EltSizeInBits * Scale); + EVT OutVT = EVT::getVectorVT(*DAG.getContext(), OutSVT, NumElts / Scale); + // Never create an illegal type. Only create unsupported operations if we + // are pre-legalization. + if (TLI.isTypeLegal(OutVT)) + if (!LegalOperations || + TLI.isOperationLegalOrCustom(ISD::ANY_EXTEND_VECTOR_INREG, OutVT)) + return DAG.getBitcast(VT, + DAG.getNode(ISD::ANY_EXTEND_VECTOR_INREG, + SDLoc(SVN), OutVT, N0)); + } + + return SDValue(); +} + +// Detect 'truncate_vector_inreg' style shuffles that pack the lower parts of +// each source element of a large type into the lowest elements of a smaller +// destination type. This is often generated during legalization. +// If the source node itself was a '*_extend_vector_inreg' node then we should +// then be able to remove it. +static SDValue combineTruncationShuffle(ShuffleVectorSDNode *SVN, + SelectionDAG &DAG) { + EVT VT = SVN->getValueType(0); + bool IsBigEndian = DAG.getDataLayout().isBigEndian(); + + // TODO Add support for big-endian when we have a test case. + if (!VT.isInteger() || IsBigEndian) + return SDValue(); + + SDValue N0 = peekThroughBitcasts(SVN->getOperand(0)); + + unsigned Opcode = N0.getOpcode(); + if (Opcode != ISD::ANY_EXTEND_VECTOR_INREG && + Opcode != ISD::SIGN_EXTEND_VECTOR_INREG && + Opcode != ISD::ZERO_EXTEND_VECTOR_INREG) + return SDValue(); + + SDValue N00 = N0.getOperand(0); + ArrayRef<int> Mask = SVN->getMask(); + unsigned NumElts = VT.getVectorNumElements(); + unsigned EltSizeInBits = VT.getScalarSizeInBits(); + unsigned ExtSrcSizeInBits = N00.getScalarValueSizeInBits(); + unsigned ExtDstSizeInBits = N0.getScalarValueSizeInBits(); + + if (ExtDstSizeInBits % ExtSrcSizeInBits != 0) + return SDValue(); + unsigned ExtScale = ExtDstSizeInBits / ExtSrcSizeInBits; + + // (v4i32 truncate_vector_inreg(v2i64)) == shuffle<0,2-1,-1> + // (v8i16 truncate_vector_inreg(v4i32)) == shuffle<0,2,4,6,-1,-1,-1,-1> + // (v8i16 truncate_vector_inreg(v2i64)) == shuffle<0,4,-1,-1,-1,-1,-1,-1> + auto isTruncate = [&Mask, &NumElts](unsigned Scale) { + for (unsigned i = 0; i != NumElts; ++i) { + if (Mask[i] < 0) + continue; + if ((i * Scale) < NumElts && Mask[i] == (int)(i * Scale)) + continue; + return false; + } + return true; + }; + + // At the moment we just handle the case where we've truncated back to the + // same size as before the extension. + // TODO: handle more extension/truncation cases as cases arise. + if (EltSizeInBits != ExtSrcSizeInBits) + return SDValue(); + + // We can remove *extend_vector_inreg only if the truncation happens at + // the same scale as the extension. + if (isTruncate(ExtScale)) + return DAG.getBitcast(VT, N00); + + return SDValue(); +} + +// Combine shuffles of splat-shuffles of the form: +// shuffle (shuffle V, undef, splat-mask), undef, M +// If splat-mask contains undef elements, we need to be careful about +// introducing undef's in the folded mask which are not the result of composing +// the masks of the shuffles. +static SDValue combineShuffleOfSplatVal(ShuffleVectorSDNode *Shuf, + SelectionDAG &DAG) { + if (!Shuf->getOperand(1).isUndef()) + return SDValue(); + auto *Splat = dyn_cast<ShuffleVectorSDNode>(Shuf->getOperand(0)); + if (!Splat || !Splat->isSplat()) + return SDValue(); + + ArrayRef<int> ShufMask = Shuf->getMask(); + ArrayRef<int> SplatMask = Splat->getMask(); + assert(ShufMask.size() == SplatMask.size() && "Mask length mismatch"); + + // Prefer simplifying to the splat-shuffle, if possible. This is legal if + // every undef mask element in the splat-shuffle has a corresponding undef + // element in the user-shuffle's mask or if the composition of mask elements + // would result in undef. + // Examples for (shuffle (shuffle v, undef, SplatMask), undef, UserMask): + // * UserMask=[0,2,u,u], SplatMask=[2,u,2,u] -> [2,2,u,u] + // In this case it is not legal to simplify to the splat-shuffle because we + // may be exposing the users of the shuffle an undef element at index 1 + // which was not there before the combine. + // * UserMask=[0,u,2,u], SplatMask=[2,u,2,u] -> [2,u,2,u] + // In this case the composition of masks yields SplatMask, so it's ok to + // simplify to the splat-shuffle. + // * UserMask=[3,u,2,u], SplatMask=[2,u,2,u] -> [u,u,2,u] + // In this case the composed mask includes all undef elements of SplatMask + // and in addition sets element zero to undef. It is safe to simplify to + // the splat-shuffle. + auto CanSimplifyToExistingSplat = [](ArrayRef<int> UserMask, + ArrayRef<int> SplatMask) { + for (unsigned i = 0, e = UserMask.size(); i != e; ++i) + if (UserMask[i] != -1 && SplatMask[i] == -1 && + SplatMask[UserMask[i]] != -1) + return false; + return true; + }; + if (CanSimplifyToExistingSplat(ShufMask, SplatMask)) + return Shuf->getOperand(0); + + // Create a new shuffle with a mask that is composed of the two shuffles' + // masks. + SmallVector<int, 32> NewMask; + for (int Idx : ShufMask) + NewMask.push_back(Idx == -1 ? -1 : SplatMask[Idx]); + + return DAG.getVectorShuffle(Splat->getValueType(0), SDLoc(Splat), + Splat->getOperand(0), Splat->getOperand(1), + NewMask); +} + +/// Combine shuffle of shuffle of the form: +/// shuf (shuf X, undef, InnerMask), undef, OuterMask --> splat X +static SDValue formSplatFromShuffles(ShuffleVectorSDNode *OuterShuf, + SelectionDAG &DAG) { + if (!OuterShuf->getOperand(1).isUndef()) + return SDValue(); + auto *InnerShuf = dyn_cast<ShuffleVectorSDNode>(OuterShuf->getOperand(0)); + if (!InnerShuf || !InnerShuf->getOperand(1).isUndef()) + return SDValue(); + + ArrayRef<int> OuterMask = OuterShuf->getMask(); + ArrayRef<int> InnerMask = InnerShuf->getMask(); + unsigned NumElts = OuterMask.size(); + assert(NumElts == InnerMask.size() && "Mask length mismatch"); + SmallVector<int, 32> CombinedMask(NumElts, -1); + int SplatIndex = -1; + for (unsigned i = 0; i != NumElts; ++i) { + // Undef lanes remain undef. + int OuterMaskElt = OuterMask[i]; + if (OuterMaskElt == -1) + continue; + + // Peek through the shuffle masks to get the underlying source element. + int InnerMaskElt = InnerMask[OuterMaskElt]; + if (InnerMaskElt == -1) + continue; + + // Initialize the splatted element. + if (SplatIndex == -1) + SplatIndex = InnerMaskElt; + + // Non-matching index - this is not a splat. + if (SplatIndex != InnerMaskElt) + return SDValue(); + + CombinedMask[i] = InnerMaskElt; + } + assert((all_of(CombinedMask, [](int M) { return M == -1; }) || + getSplatIndex(CombinedMask) != -1) && + "Expected a splat mask"); + + // TODO: The transform may be a win even if the mask is not legal. + EVT VT = OuterShuf->getValueType(0); + assert(VT == InnerShuf->getValueType(0) && "Expected matching shuffle types"); + if (!DAG.getTargetLoweringInfo().isShuffleMaskLegal(CombinedMask, VT)) + return SDValue(); + + return DAG.getVectorShuffle(VT, SDLoc(OuterShuf), InnerShuf->getOperand(0), + InnerShuf->getOperand(1), CombinedMask); +} + +/// If the shuffle mask is taking exactly one element from the first vector +/// operand and passing through all other elements from the second vector +/// operand, return the index of the mask element that is choosing an element +/// from the first operand. Otherwise, return -1. +static int getShuffleMaskIndexOfOneElementFromOp0IntoOp1(ArrayRef<int> Mask) { + int MaskSize = Mask.size(); + int EltFromOp0 = -1; + // TODO: This does not match if there are undef elements in the shuffle mask. + // Should we ignore undefs in the shuffle mask instead? The trade-off is + // removing an instruction (a shuffle), but losing the knowledge that some + // vector lanes are not needed. + for (int i = 0; i != MaskSize; ++i) { + if (Mask[i] >= 0 && Mask[i] < MaskSize) { + // We're looking for a shuffle of exactly one element from operand 0. + if (EltFromOp0 != -1) + return -1; + EltFromOp0 = i; + } else if (Mask[i] != i + MaskSize) { + // Nothing from operand 1 can change lanes. + return -1; + } + } + return EltFromOp0; +} + +/// If a shuffle inserts exactly one element from a source vector operand into +/// another vector operand and we can access the specified element as a scalar, +/// then we can eliminate the shuffle. +static SDValue replaceShuffleOfInsert(ShuffleVectorSDNode *Shuf, + SelectionDAG &DAG) { + // First, check if we are taking one element of a vector and shuffling that + // element into another vector. + ArrayRef<int> Mask = Shuf->getMask(); + SmallVector<int, 16> CommutedMask(Mask.begin(), Mask.end()); + SDValue Op0 = Shuf->getOperand(0); + SDValue Op1 = Shuf->getOperand(1); + int ShufOp0Index = getShuffleMaskIndexOfOneElementFromOp0IntoOp1(Mask); + if (ShufOp0Index == -1) { + // Commute mask and check again. + ShuffleVectorSDNode::commuteMask(CommutedMask); + ShufOp0Index = getShuffleMaskIndexOfOneElementFromOp0IntoOp1(CommutedMask); + if (ShufOp0Index == -1) + return SDValue(); + // Commute operands to match the commuted shuffle mask. + std::swap(Op0, Op1); + Mask = CommutedMask; + } + + // The shuffle inserts exactly one element from operand 0 into operand 1. + // Now see if we can access that element as a scalar via a real insert element + // instruction. + // TODO: We can try harder to locate the element as a scalar. Examples: it + // could be an operand of SCALAR_TO_VECTOR, BUILD_VECTOR, or a constant. + assert(Mask[ShufOp0Index] >= 0 && Mask[ShufOp0Index] < (int)Mask.size() && + "Shuffle mask value must be from operand 0"); + if (Op0.getOpcode() != ISD::INSERT_VECTOR_ELT) + return SDValue(); + + auto *InsIndexC = dyn_cast<ConstantSDNode>(Op0.getOperand(2)); + if (!InsIndexC || InsIndexC->getSExtValue() != Mask[ShufOp0Index]) + return SDValue(); + + // There's an existing insertelement with constant insertion index, so we + // don't need to check the legality/profitability of a replacement operation + // that differs at most in the constant value. The target should be able to + // lower any of those in a similar way. If not, legalization will expand this + // to a scalar-to-vector plus shuffle. + // + // Note that the shuffle may move the scalar from the position that the insert + // element used. Therefore, our new insert element occurs at the shuffle's + // mask index value, not the insert's index value. + // shuffle (insertelt v1, x, C), v2, mask --> insertelt v2, x, C' + SDValue NewInsIndex = DAG.getVectorIdxConstant(ShufOp0Index, SDLoc(Shuf)); + return DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(Shuf), Op0.getValueType(), + Op1, Op0.getOperand(1), NewInsIndex); +} + +/// If we have a unary shuffle of a shuffle, see if it can be folded away +/// completely. This has the potential to lose undef knowledge because the first +/// shuffle may not have an undef mask element where the second one does. So +/// only call this after doing simplifications based on demanded elements. +static SDValue simplifyShuffleOfShuffle(ShuffleVectorSDNode *Shuf) { + // shuf (shuf0 X, Y, Mask0), undef, Mask + auto *Shuf0 = dyn_cast<ShuffleVectorSDNode>(Shuf->getOperand(0)); + if (!Shuf0 || !Shuf->getOperand(1).isUndef()) + return SDValue(); + + ArrayRef<int> Mask = Shuf->getMask(); + ArrayRef<int> Mask0 = Shuf0->getMask(); + for (int i = 0, e = (int)Mask.size(); i != e; ++i) { + // Ignore undef elements. + if (Mask[i] == -1) + continue; + assert(Mask[i] >= 0 && Mask[i] < e && "Unexpected shuffle mask value"); + + // Is the element of the shuffle operand chosen by this shuffle the same as + // the element chosen by the shuffle operand itself? + if (Mask0[Mask[i]] != Mask0[i]) + return SDValue(); + } + // Every element of this shuffle is identical to the result of the previous + // shuffle, so we can replace this value. + return Shuf->getOperand(0); +} + +SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { + EVT VT = N->getValueType(0); + unsigned NumElts = VT.getVectorNumElements(); + + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + + assert(N0.getValueType() == VT && "Vector shuffle must be normalized in DAG"); + + // Canonicalize shuffle undef, undef -> undef + if (N0.isUndef() && N1.isUndef()) + return DAG.getUNDEF(VT); + + ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N); + + // Canonicalize shuffle v, v -> v, undef + if (N0 == N1) { + SmallVector<int, 8> NewMask; + for (unsigned i = 0; i != NumElts; ++i) { + int Idx = SVN->getMaskElt(i); + if (Idx >= (int)NumElts) Idx -= NumElts; + NewMask.push_back(Idx); + } + return DAG.getVectorShuffle(VT, SDLoc(N), N0, DAG.getUNDEF(VT), NewMask); + } + + // Canonicalize shuffle undef, v -> v, undef. Commute the shuffle mask. + if (N0.isUndef()) + return DAG.getCommutedVectorShuffle(*SVN); + + // Remove references to rhs if it is undef + if (N1.isUndef()) { + bool Changed = false; + SmallVector<int, 8> NewMask; + for (unsigned i = 0; i != NumElts; ++i) { + int Idx = SVN->getMaskElt(i); + if (Idx >= (int)NumElts) { + Idx = -1; + Changed = true; + } + NewMask.push_back(Idx); + } + if (Changed) + return DAG.getVectorShuffle(VT, SDLoc(N), N0, N1, NewMask); + } + + if (SDValue InsElt = replaceShuffleOfInsert(SVN, DAG)) + return InsElt; + + // A shuffle of a single vector that is a splatted value can always be folded. + if (SDValue V = combineShuffleOfSplatVal(SVN, DAG)) + return V; + + if (SDValue V = formSplatFromShuffles(SVN, DAG)) + return V; + + // If it is a splat, check if the argument vector is another splat or a + // build_vector. + if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) { + int SplatIndex = SVN->getSplatIndex(); + if (N0.hasOneUse() && TLI.isExtractVecEltCheap(VT, SplatIndex) && + TLI.isBinOp(N0.getOpcode()) && N0.getNode()->getNumValues() == 1) { + // splat (vector_bo L, R), Index --> + // splat (scalar_bo (extelt L, Index), (extelt R, Index)) + SDValue L = N0.getOperand(0), R = N0.getOperand(1); + SDLoc DL(N); + EVT EltVT = VT.getScalarType(); + SDValue Index = DAG.getVectorIdxConstant(SplatIndex, DL); + SDValue ExtL = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, L, Index); + SDValue ExtR = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, R, Index); + SDValue NewBO = DAG.getNode(N0.getOpcode(), DL, EltVT, ExtL, ExtR, + N0.getNode()->getFlags()); + SDValue Insert = DAG.getNode(ISD::SCALAR_TO_VECTOR, DL, VT, NewBO); + SmallVector<int, 16> ZeroMask(VT.getVectorNumElements(), 0); + return DAG.getVectorShuffle(VT, DL, Insert, DAG.getUNDEF(VT), ZeroMask); + } + + // If this is a bit convert that changes the element type of the vector but + // not the number of vector elements, look through it. Be careful not to + // look though conversions that change things like v4f32 to v2f64. + SDNode *V = N0.getNode(); + if (V->getOpcode() == ISD::BITCAST) { + SDValue ConvInput = V->getOperand(0); + if (ConvInput.getValueType().isVector() && + ConvInput.getValueType().getVectorNumElements() == NumElts) + V = ConvInput.getNode(); + } + + if (V->getOpcode() == ISD::BUILD_VECTOR) { + assert(V->getNumOperands() == NumElts && + "BUILD_VECTOR has wrong number of operands"); + SDValue Base; + bool AllSame = true; + for (unsigned i = 0; i != NumElts; ++i) { + if (!V->getOperand(i).isUndef()) { + Base = V->getOperand(i); + break; + } + } + // Splat of <u, u, u, u>, return <u, u, u, u> + if (!Base.getNode()) + return N0; + for (unsigned i = 0; i != NumElts; ++i) { + if (V->getOperand(i) != Base) { + AllSame = false; + break; + } + } + // Splat of <x, x, x, x>, return <x, x, x, x> + if (AllSame) + return N0; + + // Canonicalize any other splat as a build_vector. + SDValue Splatted = V->getOperand(SplatIndex); + SmallVector<SDValue, 8> Ops(NumElts, Splatted); + SDValue NewBV = DAG.getBuildVector(V->getValueType(0), SDLoc(N), Ops); + + // We may have jumped through bitcasts, so the type of the + // BUILD_VECTOR may not match the type of the shuffle. + if (V->getValueType(0) != VT) + NewBV = DAG.getBitcast(VT, NewBV); + return NewBV; + } + } + + // Simplify source operands based on shuffle mask. + if (SimplifyDemandedVectorElts(SDValue(N, 0))) + return SDValue(N, 0); + + // This is intentionally placed after demanded elements simplification because + // it could eliminate knowledge of undef elements created by this shuffle. + if (SDValue ShufOp = simplifyShuffleOfShuffle(SVN)) + return ShufOp; + + // Match shuffles that can be converted to any_vector_extend_in_reg. + if (SDValue V = combineShuffleToVectorExtend(SVN, DAG, TLI, LegalOperations)) + return V; + + // Combine "truncate_vector_in_reg" style shuffles. + if (SDValue V = combineTruncationShuffle(SVN, DAG)) + return V; + + if (N0.getOpcode() == ISD::CONCAT_VECTORS && + Level < AfterLegalizeVectorOps && + (N1.isUndef() || + (N1.getOpcode() == ISD::CONCAT_VECTORS && + N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()))) { + if (SDValue V = partitionShuffleOfConcats(N, DAG)) + return V; + } + + // A shuffle of a concat of the same narrow vector can be reduced to use + // only low-half elements of a concat with undef: + // shuf (concat X, X), undef, Mask --> shuf (concat X, undef), undef, Mask' + if (N0.getOpcode() == ISD::CONCAT_VECTORS && N1.isUndef() && + N0.getNumOperands() == 2 && + N0.getOperand(0) == N0.getOperand(1)) { + int HalfNumElts = (int)NumElts / 2; + SmallVector<int, 8> NewMask; + for (unsigned i = 0; i != NumElts; ++i) { + int Idx = SVN->getMaskElt(i); + if (Idx >= HalfNumElts) { + assert(Idx < (int)NumElts && "Shuffle mask chooses undef op"); + Idx -= HalfNumElts; + } + NewMask.push_back(Idx); + } + if (TLI.isShuffleMaskLegal(NewMask, VT)) { + SDValue UndefVec = DAG.getUNDEF(N0.getOperand(0).getValueType()); + SDValue NewCat = DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, + N0.getOperand(0), UndefVec); + return DAG.getVectorShuffle(VT, SDLoc(N), NewCat, N1, NewMask); + } + } + + // Attempt to combine a shuffle of 2 inputs of 'scalar sources' - + // BUILD_VECTOR or SCALAR_TO_VECTOR into a single BUILD_VECTOR. + if (Level < AfterLegalizeDAG && TLI.isTypeLegal(VT)) + if (SDValue Res = combineShuffleOfScalars(SVN, DAG, TLI)) + return Res; + + // If this shuffle only has a single input that is a bitcasted shuffle, + // attempt to merge the 2 shuffles and suitably bitcast the inputs/output + // back to their original types. + if (N0.getOpcode() == ISD::BITCAST && N0.hasOneUse() && + N1.isUndef() && Level < AfterLegalizeVectorOps && + TLI.isTypeLegal(VT)) { + + SDValue BC0 = peekThroughOneUseBitcasts(N0); + if (BC0.getOpcode() == ISD::VECTOR_SHUFFLE && BC0.hasOneUse()) { + EVT SVT = VT.getScalarType(); + EVT InnerVT = BC0->getValueType(0); + EVT InnerSVT = InnerVT.getScalarType(); + + // Determine which shuffle works with the smaller scalar type. + EVT ScaleVT = SVT.bitsLT(InnerSVT) ? VT : InnerVT; + EVT ScaleSVT = ScaleVT.getScalarType(); + + if (TLI.isTypeLegal(ScaleVT) && + 0 == (InnerSVT.getSizeInBits() % ScaleSVT.getSizeInBits()) && + 0 == (SVT.getSizeInBits() % ScaleSVT.getSizeInBits())) { + int InnerScale = InnerSVT.getSizeInBits() / ScaleSVT.getSizeInBits(); + int OuterScale = SVT.getSizeInBits() / ScaleSVT.getSizeInBits(); + + // Scale the shuffle masks to the smaller scalar type. + ShuffleVectorSDNode *InnerSVN = cast<ShuffleVectorSDNode>(BC0); + SmallVector<int, 8> InnerMask; + SmallVector<int, 8> OuterMask; + narrowShuffleMaskElts(InnerScale, InnerSVN->getMask(), InnerMask); + narrowShuffleMaskElts(OuterScale, SVN->getMask(), OuterMask); + + // Merge the shuffle masks. + SmallVector<int, 8> NewMask; + for (int M : OuterMask) + NewMask.push_back(M < 0 ? -1 : InnerMask[M]); + + // Test for shuffle mask legality over both commutations. + SDValue SV0 = BC0->getOperand(0); + SDValue SV1 = BC0->getOperand(1); + bool LegalMask = TLI.isShuffleMaskLegal(NewMask, ScaleVT); + if (!LegalMask) { + std::swap(SV0, SV1); + ShuffleVectorSDNode::commuteMask(NewMask); + LegalMask = TLI.isShuffleMaskLegal(NewMask, ScaleVT); + } + + if (LegalMask) { + SV0 = DAG.getBitcast(ScaleVT, SV0); + SV1 = DAG.getBitcast(ScaleVT, SV1); + return DAG.getBitcast( + VT, DAG.getVectorShuffle(ScaleVT, SDLoc(N), SV0, SV1, NewMask)); + } + } + } + } + + if (Level < AfterLegalizeDAG && TLI.isTypeLegal(VT)) { + // Canonicalize shuffles according to rules: + // shuffle(A, shuffle(A, B)) -> shuffle(shuffle(A,B), A) + // shuffle(B, shuffle(A, B)) -> shuffle(shuffle(A,B), B) + // shuffle(B, shuffle(A, Undef)) -> shuffle(shuffle(A, Undef), B) + if (N1.getOpcode() == ISD::VECTOR_SHUFFLE && + N0.getOpcode() != ISD::VECTOR_SHUFFLE) { + // The incoming shuffle must be of the same type as the result of the + // current shuffle. + assert(N1->getOperand(0).getValueType() == VT && + "Shuffle types don't match"); + + SDValue SV0 = N1->getOperand(0); + SDValue SV1 = N1->getOperand(1); + bool HasSameOp0 = N0 == SV0; + bool IsSV1Undef = SV1.isUndef(); + if (HasSameOp0 || IsSV1Undef || N0 == SV1) + // Commute the operands of this shuffle so merging below will trigger. + return DAG.getCommutedVectorShuffle(*SVN); + } + + // Canonicalize splat shuffles to the RHS to improve merging below. + // shuffle(splat(A,u), shuffle(C,D)) -> shuffle'(shuffle(C,D), splat(A,u)) + if (N0.getOpcode() == ISD::VECTOR_SHUFFLE && + N1.getOpcode() == ISD::VECTOR_SHUFFLE && + cast<ShuffleVectorSDNode>(N0)->isSplat() && + !cast<ShuffleVectorSDNode>(N1)->isSplat()) { + return DAG.getCommutedVectorShuffle(*SVN); + } + } + + // Compute the combined shuffle mask for a shuffle with SV0 as the first + // operand, and SV1 as the second operand. + // i.e. Merge SVN(OtherSVN, N1) -> shuffle(SV0, SV1, Mask). + auto MergeInnerShuffle = [NumElts](ShuffleVectorSDNode *SVN, + ShuffleVectorSDNode *OtherSVN, SDValue N1, + SDValue &SV0, SDValue &SV1, + SmallVectorImpl<int> &Mask) -> bool { + // Don't try to fold splats; they're likely to simplify somehow, or they + // might be free. + if (OtherSVN->isSplat()) + return false; + + SV0 = SV1 = SDValue(); + Mask.clear(); + + for (unsigned i = 0; i != NumElts; ++i) { + int Idx = SVN->getMaskElt(i); + if (Idx < 0) { + // Propagate Undef. + Mask.push_back(Idx); + continue; + } + + SDValue CurrentVec; + if (Idx < (int)NumElts) { + // This shuffle index refers to the inner shuffle N0. Lookup the inner + // shuffle mask to identify which vector is actually referenced. + Idx = OtherSVN->getMaskElt(Idx); + if (Idx < 0) { + // Propagate Undef. + Mask.push_back(Idx); + continue; + } + CurrentVec = (Idx < (int)NumElts) ? OtherSVN->getOperand(0) + : OtherSVN->getOperand(1); + } else { + // This shuffle index references an element within N1. + CurrentVec = N1; + } + + // Simple case where 'CurrentVec' is UNDEF. + if (CurrentVec.isUndef()) { + Mask.push_back(-1); + continue; + } + + // Canonicalize the shuffle index. We don't know yet if CurrentVec + // will be the first or second operand of the combined shuffle. + Idx = Idx % NumElts; + if (!SV0.getNode() || SV0 == CurrentVec) { + // Ok. CurrentVec is the left hand side. + // Update the mask accordingly. + SV0 = CurrentVec; + Mask.push_back(Idx); + continue; + } + if (!SV1.getNode() || SV1 == CurrentVec) { + // Ok. CurrentVec is the right hand side. + // Update the mask accordingly. + SV1 = CurrentVec; + Mask.push_back(Idx + NumElts); + continue; + } + + // Last chance - see if the vector is another shuffle and if it + // uses one of the existing candidate shuffle ops. + if (auto *CurrentSVN = dyn_cast<ShuffleVectorSDNode>(CurrentVec)) { + int InnerIdx = CurrentSVN->getMaskElt(Idx); + if (InnerIdx < 0) { + Mask.push_back(-1); + continue; + } + SDValue InnerVec = (InnerIdx < (int)NumElts) + ? CurrentSVN->getOperand(0) + : CurrentSVN->getOperand(1); + if (InnerVec.isUndef()) { + Mask.push_back(-1); + continue; + } + InnerIdx %= NumElts; + if (InnerVec == SV0) { + Mask.push_back(InnerIdx); + continue; + } + if (InnerVec == SV1) { + Mask.push_back(InnerIdx + NumElts); + continue; + } + } + + // Bail out if we cannot convert the shuffle pair into a single shuffle. + return false; + } + return true; + }; + + // Try to fold according to rules: + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(A, B, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(A, C, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(B, C, M2) + // Don't try to fold shuffles with illegal type. + // Only fold if this shuffle is the only user of the other shuffle. + if (N0.getOpcode() == ISD::VECTOR_SHUFFLE && N->isOnlyUserOf(N0.getNode()) && + Level < AfterLegalizeDAG && TLI.isTypeLegal(VT)) { + ShuffleVectorSDNode *OtherSV = cast<ShuffleVectorSDNode>(N0); + + // The incoming shuffle must be of the same type as the result of the + // current shuffle. + assert(OtherSV->getOperand(0).getValueType() == VT && + "Shuffle types don't match"); + + SDValue SV0, SV1; + SmallVector<int, 4> Mask; + if (MergeInnerShuffle(SVN, OtherSV, N1, SV0, SV1, Mask)) { + // Check if all indices in Mask are Undef. In case, propagate Undef. + if (llvm::all_of(Mask, [](int M) { return M < 0; })) + return DAG.getUNDEF(VT); + + if (!SV0.getNode()) + SV0 = DAG.getUNDEF(VT); + if (!SV1.getNode()) + SV1 = DAG.getUNDEF(VT); + + // Avoid introducing shuffles with illegal mask. + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(A, B, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(A, C, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(B, C, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(B, A, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(C, A, M2) + // shuffle(shuffle(A, B, M0), C, M1) -> shuffle(C, B, M2) + return TLI.buildLegalVectorShuffle(VT, SDLoc(N), SV0, SV1, Mask, DAG); + } + } + + if (SDValue V = foldShuffleOfConcatUndefs(SVN, DAG)) + return V; + + return SDValue(); +} + +SDValue DAGCombiner::visitSCALAR_TO_VECTOR(SDNode *N) { + SDValue InVal = N->getOperand(0); + EVT VT = N->getValueType(0); + + // Replace a SCALAR_TO_VECTOR(EXTRACT_VECTOR_ELT(V,C0)) pattern + // with a VECTOR_SHUFFLE and possible truncate. + if (InVal.getOpcode() == ISD::EXTRACT_VECTOR_ELT && + VT.isFixedLengthVector() && + InVal->getOperand(0).getValueType().isFixedLengthVector()) { + SDValue InVec = InVal->getOperand(0); + SDValue EltNo = InVal->getOperand(1); + auto InVecT = InVec.getValueType(); + if (ConstantSDNode *C0 = dyn_cast<ConstantSDNode>(EltNo)) { + SmallVector<int, 8> NewMask(InVecT.getVectorNumElements(), -1); + int Elt = C0->getZExtValue(); + NewMask[0] = Elt; + // If we have an implict truncate do truncate here as long as it's legal. + // if it's not legal, this should + if (VT.getScalarType() != InVal.getValueType() && + InVal.getValueType().isScalarInteger() && + isTypeLegal(VT.getScalarType())) { + SDValue Val = + DAG.getNode(ISD::TRUNCATE, SDLoc(InVal), VT.getScalarType(), InVal); + return DAG.getNode(ISD::SCALAR_TO_VECTOR, SDLoc(N), VT, Val); + } + if (VT.getScalarType() == InVecT.getScalarType() && + VT.getVectorNumElements() <= InVecT.getVectorNumElements()) { + SDValue LegalShuffle = + TLI.buildLegalVectorShuffle(InVecT, SDLoc(N), InVec, + DAG.getUNDEF(InVecT), NewMask, DAG); + if (LegalShuffle) { + // If the initial vector is the correct size this shuffle is a + // valid result. + if (VT == InVecT) + return LegalShuffle; + // If not we must truncate the vector. + if (VT.getVectorNumElements() != InVecT.getVectorNumElements()) { + SDValue ZeroIdx = DAG.getVectorIdxConstant(0, SDLoc(N)); + EVT SubVT = EVT::getVectorVT(*DAG.getContext(), + InVecT.getVectorElementType(), + VT.getVectorNumElements()); + return DAG.getNode(ISD::EXTRACT_SUBVECTOR, SDLoc(N), SubVT, + LegalShuffle, ZeroIdx); + } + } + } + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitINSERT_SUBVECTOR(SDNode *N) { + EVT VT = N->getValueType(0); + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + SDValue N2 = N->getOperand(2); + uint64_t InsIdx = N->getConstantOperandVal(2); + + // If inserting an UNDEF, just return the original vector. + if (N1.isUndef()) + return N0; + + // If this is an insert of an extracted vector into an undef vector, we can + // just use the input to the extract. + if (N0.isUndef() && N1.getOpcode() == ISD::EXTRACT_SUBVECTOR && + N1.getOperand(1) == N2 && N1.getOperand(0).getValueType() == VT) + return N1.getOperand(0); + + // If we are inserting a bitcast value into an undef, with the same + // number of elements, just use the bitcast input of the extract. + // i.e. INSERT_SUBVECTOR UNDEF (BITCAST N1) N2 -> + // BITCAST (INSERT_SUBVECTOR UNDEF N1 N2) + if (N0.isUndef() && N1.getOpcode() == ISD::BITCAST && + N1.getOperand(0).getOpcode() == ISD::EXTRACT_SUBVECTOR && + N1.getOperand(0).getOperand(1) == N2 && + N1.getOperand(0).getOperand(0).getValueType().getVectorElementCount() == + VT.getVectorElementCount() && + N1.getOperand(0).getOperand(0).getValueType().getSizeInBits() == + VT.getSizeInBits()) { + return DAG.getBitcast(VT, N1.getOperand(0).getOperand(0)); + } + + // If both N1 and N2 are bitcast values on which insert_subvector + // would makes sense, pull the bitcast through. + // i.e. INSERT_SUBVECTOR (BITCAST N0) (BITCAST N1) N2 -> + // BITCAST (INSERT_SUBVECTOR N0 N1 N2) + if (N0.getOpcode() == ISD::BITCAST && N1.getOpcode() == ISD::BITCAST) { + SDValue CN0 = N0.getOperand(0); + SDValue CN1 = N1.getOperand(0); + EVT CN0VT = CN0.getValueType(); + EVT CN1VT = CN1.getValueType(); + if (CN0VT.isVector() && CN1VT.isVector() && + CN0VT.getVectorElementType() == CN1VT.getVectorElementType() && + CN0VT.getVectorElementCount() == VT.getVectorElementCount()) { + SDValue NewINSERT = DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), + CN0.getValueType(), CN0, CN1, N2); + return DAG.getBitcast(VT, NewINSERT); + } + } + + // Combine INSERT_SUBVECTORs where we are inserting to the same index. + // INSERT_SUBVECTOR( INSERT_SUBVECTOR( Vec, SubOld, Idx ), SubNew, Idx ) + // --> INSERT_SUBVECTOR( Vec, SubNew, Idx ) + if (N0.getOpcode() == ISD::INSERT_SUBVECTOR && + N0.getOperand(1).getValueType() == N1.getValueType() && + N0.getOperand(2) == N2) + return DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), VT, N0.getOperand(0), + N1, N2); + + // Eliminate an intermediate insert into an undef vector: + // insert_subvector undef, (insert_subvector undef, X, 0), N2 --> + // insert_subvector undef, X, N2 + if (N0.isUndef() && N1.getOpcode() == ISD::INSERT_SUBVECTOR && + N1.getOperand(0).isUndef() && isNullConstant(N1.getOperand(2))) + return DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), VT, N0, + N1.getOperand(1), N2); + + // Push subvector bitcasts to the output, adjusting the index as we go. + // insert_subvector(bitcast(v), bitcast(s), c1) + // -> bitcast(insert_subvector(v, s, c2)) + if ((N0.isUndef() || N0.getOpcode() == ISD::BITCAST) && + N1.getOpcode() == ISD::BITCAST) { + SDValue N0Src = peekThroughBitcasts(N0); + SDValue N1Src = peekThroughBitcasts(N1); + EVT N0SrcSVT = N0Src.getValueType().getScalarType(); + EVT N1SrcSVT = N1Src.getValueType().getScalarType(); + if ((N0.isUndef() || N0SrcSVT == N1SrcSVT) && + N0Src.getValueType().isVector() && N1Src.getValueType().isVector()) { + EVT NewVT; + SDLoc DL(N); + SDValue NewIdx; + LLVMContext &Ctx = *DAG.getContext(); + ElementCount NumElts = VT.getVectorElementCount(); + unsigned EltSizeInBits = VT.getScalarSizeInBits(); + if ((EltSizeInBits % N1SrcSVT.getSizeInBits()) == 0) { + unsigned Scale = EltSizeInBits / N1SrcSVT.getSizeInBits(); + NewVT = EVT::getVectorVT(Ctx, N1SrcSVT, NumElts * Scale); + NewIdx = DAG.getVectorIdxConstant(InsIdx * Scale, DL); + } else if ((N1SrcSVT.getSizeInBits() % EltSizeInBits) == 0) { + unsigned Scale = N1SrcSVT.getSizeInBits() / EltSizeInBits; + if (NumElts.isKnownMultipleOf(Scale) && (InsIdx % Scale) == 0) { + NewVT = EVT::getVectorVT(Ctx, N1SrcSVT, + NumElts.divideCoefficientBy(Scale)); + NewIdx = DAG.getVectorIdxConstant(InsIdx / Scale, DL); + } + } + if (NewIdx && hasOperation(ISD::INSERT_SUBVECTOR, NewVT)) { + SDValue Res = DAG.getBitcast(NewVT, N0Src); + Res = DAG.getNode(ISD::INSERT_SUBVECTOR, DL, NewVT, Res, N1Src, NewIdx); + return DAG.getBitcast(VT, Res); + } + } + } + + // Canonicalize insert_subvector dag nodes. + // Example: + // (insert_subvector (insert_subvector A, Idx0), Idx1) + // -> (insert_subvector (insert_subvector A, Idx1), Idx0) + if (N0.getOpcode() == ISD::INSERT_SUBVECTOR && N0.hasOneUse() && + N1.getValueType() == N0.getOperand(1).getValueType()) { + unsigned OtherIdx = N0.getConstantOperandVal(2); + if (InsIdx < OtherIdx) { + // Swap nodes. + SDValue NewOp = DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N), VT, + N0.getOperand(0), N1, N2); + AddToWorklist(NewOp.getNode()); + return DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(N0.getNode()), + VT, NewOp, N0.getOperand(1), N0.getOperand(2)); + } + } + + // If the input vector is a concatenation, and the insert replaces + // one of the pieces, we can optimize into a single concat_vectors. + if (N0.getOpcode() == ISD::CONCAT_VECTORS && N0.hasOneUse() && + N0.getOperand(0).getValueType() == N1.getValueType() && + N0.getOperand(0).getValueType().isScalableVector() == + N1.getValueType().isScalableVector()) { + unsigned Factor = N1.getValueType().getVectorMinNumElements(); + SmallVector<SDValue, 8> Ops(N0->op_begin(), N0->op_end()); + Ops[InsIdx / Factor] = N1; + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, Ops); + } + + // Simplify source operands based on insertion. + if (SimplifyDemandedVectorElts(SDValue(N, 0))) + return SDValue(N, 0); + + return SDValue(); +} + +SDValue DAGCombiner::visitFP_TO_FP16(SDNode *N) { + SDValue N0 = N->getOperand(0); + + // fold (fp_to_fp16 (fp16_to_fp op)) -> op + if (N0->getOpcode() == ISD::FP16_TO_FP) + return N0->getOperand(0); + + return SDValue(); +} + +SDValue DAGCombiner::visitFP16_TO_FP(SDNode *N) { + SDValue N0 = N->getOperand(0); + + // fold fp16_to_fp(op & 0xffff) -> fp16_to_fp(op) + if (!TLI.shouldKeepZExtForFP16Conv() && N0->getOpcode() == ISD::AND) { + ConstantSDNode *AndConst = getAsNonOpaqueConstant(N0.getOperand(1)); + if (AndConst && AndConst->getAPIntValue() == 0xffff) { + return DAG.getNode(ISD::FP16_TO_FP, SDLoc(N), N->getValueType(0), + N0.getOperand(0)); + } + } + + return SDValue(); +} + +SDValue DAGCombiner::visitVECREDUCE(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N0.getValueType(); + unsigned Opcode = N->getOpcode(); + + // VECREDUCE over 1-element vector is just an extract. + if (VT.getVectorElementCount().isScalar()) { + SDLoc dl(N); + SDValue Res = + DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, VT.getVectorElementType(), N0, + DAG.getVectorIdxConstant(0, dl)); + if (Res.getValueType() != N->getValueType(0)) + Res = DAG.getNode(ISD::ANY_EXTEND, dl, N->getValueType(0), Res); + return Res; + } + + // On an boolean vector an and/or reduction is the same as a umin/umax + // reduction. Convert them if the latter is legal while the former isn't. + if (Opcode == ISD::VECREDUCE_AND || Opcode == ISD::VECREDUCE_OR) { + unsigned NewOpcode = Opcode == ISD::VECREDUCE_AND + ? ISD::VECREDUCE_UMIN : ISD::VECREDUCE_UMAX; + if (!TLI.isOperationLegalOrCustom(Opcode, VT) && + TLI.isOperationLegalOrCustom(NewOpcode, VT) && + DAG.ComputeNumSignBits(N0) == VT.getScalarSizeInBits()) + return DAG.getNode(NewOpcode, SDLoc(N), N->getValueType(0), N0); + } + + return SDValue(); +} + +/// Returns a vector_shuffle if it able to transform an AND to a vector_shuffle +/// with the destination vector and a zero vector. +/// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> +/// vector_shuffle V, Zero, <0, 4, 2, 4> +SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) { + assert(N->getOpcode() == ISD::AND && "Unexpected opcode!"); + + EVT VT = N->getValueType(0); + SDValue LHS = N->getOperand(0); + SDValue RHS = peekThroughBitcasts(N->getOperand(1)); + SDLoc DL(N); + + // Make sure we're not running after operation legalization where it + // may have custom lowered the vector shuffles. + if (LegalOperations) + return SDValue(); + + if (RHS.getOpcode() != ISD::BUILD_VECTOR) + return SDValue(); + + EVT RVT = RHS.getValueType(); + unsigned NumElts = RHS.getNumOperands(); + + // Attempt to create a valid clear mask, splitting the mask into + // sub elements and checking to see if each is + // all zeros or all ones - suitable for shuffle masking. + auto BuildClearMask = [&](int Split) { + int NumSubElts = NumElts * Split; + int NumSubBits = RVT.getScalarSizeInBits() / Split; + + SmallVector<int, 8> Indices; + for (int i = 0; i != NumSubElts; ++i) { + int EltIdx = i / Split; + int SubIdx = i % Split; + SDValue Elt = RHS.getOperand(EltIdx); + // X & undef --> 0 (not undef). So this lane must be converted to choose + // from the zero constant vector (same as if the element had all 0-bits). + if (Elt.isUndef()) { + Indices.push_back(i + NumSubElts); + continue; + } + + APInt Bits; + if (isa<ConstantSDNode>(Elt)) + Bits = cast<ConstantSDNode>(Elt)->getAPIntValue(); + else if (isa<ConstantFPSDNode>(Elt)) + Bits = cast<ConstantFPSDNode>(Elt)->getValueAPF().bitcastToAPInt(); + else + return SDValue(); + + // Extract the sub element from the constant bit mask. + if (DAG.getDataLayout().isBigEndian()) + Bits = Bits.extractBits(NumSubBits, (Split - SubIdx - 1) * NumSubBits); + else + Bits = Bits.extractBits(NumSubBits, SubIdx * NumSubBits); + + if (Bits.isAllOnesValue()) + Indices.push_back(i); + else if (Bits == 0) + Indices.push_back(i + NumSubElts); + else + return SDValue(); + } + + // Let's see if the target supports this vector_shuffle. + EVT ClearSVT = EVT::getIntegerVT(*DAG.getContext(), NumSubBits); + EVT ClearVT = EVT::getVectorVT(*DAG.getContext(), ClearSVT, NumSubElts); + if (!TLI.isVectorClearMaskLegal(Indices, ClearVT)) + return SDValue(); + + SDValue Zero = DAG.getConstant(0, DL, ClearVT); + return DAG.getBitcast(VT, DAG.getVectorShuffle(ClearVT, DL, + DAG.getBitcast(ClearVT, LHS), + Zero, Indices)); + }; + + // Determine maximum split level (byte level masking). + int MaxSplit = 1; + if (RVT.getScalarSizeInBits() % 8 == 0) + MaxSplit = RVT.getScalarSizeInBits() / 8; + + for (int Split = 1; Split <= MaxSplit; ++Split) + if (RVT.getScalarSizeInBits() % Split == 0) + if (SDValue S = BuildClearMask(Split)) + return S; + + return SDValue(); +} + +/// If a vector binop is performed on splat values, it may be profitable to +/// extract, scalarize, and insert/splat. +static SDValue scalarizeBinOpOfSplats(SDNode *N, SelectionDAG &DAG) { + SDValue N0 = N->getOperand(0); + SDValue N1 = N->getOperand(1); + unsigned Opcode = N->getOpcode(); + EVT VT = N->getValueType(0); + EVT EltVT = VT.getVectorElementType(); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); + + // TODO: Remove/replace the extract cost check? If the elements are available + // as scalars, then there may be no extract cost. Should we ask if + // inserting a scalar back into a vector is cheap instead? + int Index0, Index1; + SDValue Src0 = DAG.getSplatSourceVector(N0, Index0); + SDValue Src1 = DAG.getSplatSourceVector(N1, Index1); + if (!Src0 || !Src1 || Index0 != Index1 || + Src0.getValueType().getVectorElementType() != EltVT || + Src1.getValueType().getVectorElementType() != EltVT || + !TLI.isExtractVecEltCheap(VT, Index0) || + !TLI.isOperationLegalOrCustom(Opcode, EltVT)) + return SDValue(); + + SDLoc DL(N); + SDValue IndexC = DAG.getVectorIdxConstant(Index0, DL); + SDValue X = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, Src0, IndexC); + SDValue Y = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, Src1, IndexC); + SDValue ScalarBO = DAG.getNode(Opcode, DL, EltVT, X, Y, N->getFlags()); + + // If all lanes but 1 are undefined, no need to splat the scalar result. + // TODO: Keep track of undefs and use that info in the general case. + if (N0.getOpcode() == ISD::BUILD_VECTOR && N0.getOpcode() == N1.getOpcode() && + count_if(N0->ops(), [](SDValue V) { return !V.isUndef(); }) == 1 && + count_if(N1->ops(), [](SDValue V) { return !V.isUndef(); }) == 1) { + // bo (build_vec ..undef, X, undef...), (build_vec ..undef, Y, undef...) --> + // build_vec ..undef, (bo X, Y), undef... + SmallVector<SDValue, 8> Ops(VT.getVectorNumElements(), DAG.getUNDEF(EltVT)); + Ops[Index0] = ScalarBO; + return DAG.getBuildVector(VT, DL, Ops); + } + + // bo (splat X, Index), (splat Y, Index) --> splat (bo X, Y), Index + SmallVector<SDValue, 8> Ops(VT.getVectorNumElements(), ScalarBO); + return DAG.getBuildVector(VT, DL, Ops); +} + +/// Visit a binary vector operation, like ADD. +SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) { + assert(N->getValueType(0).isVector() && + "SimplifyVBinOp only works on vectors!"); + + SDValue LHS = N->getOperand(0); + SDValue RHS = N->getOperand(1); + SDValue Ops[] = {LHS, RHS}; + EVT VT = N->getValueType(0); + unsigned Opcode = N->getOpcode(); + SDNodeFlags Flags = N->getFlags(); + + // See if we can constant fold the vector operation. + if (SDValue Fold = DAG.FoldConstantVectorArithmetic( + Opcode, SDLoc(LHS), LHS.getValueType(), Ops, N->getFlags())) + return Fold; + + // Move unary shuffles with identical masks after a vector binop: + // VBinOp (shuffle A, Undef, Mask), (shuffle B, Undef, Mask)) + // --> shuffle (VBinOp A, B), Undef, Mask + // This does not require type legality checks because we are creating the + // same types of operations that are in the original sequence. We do have to + // restrict ops like integer div that have immediate UB (eg, div-by-zero) + // though. This code is adapted from the identical transform in instcombine. + if (Opcode != ISD::UDIV && Opcode != ISD::SDIV && + Opcode != ISD::UREM && Opcode != ISD::SREM && + Opcode != ISD::UDIVREM && Opcode != ISD::SDIVREM) { + auto *Shuf0 = dyn_cast<ShuffleVectorSDNode>(LHS); + auto *Shuf1 = dyn_cast<ShuffleVectorSDNode>(RHS); + if (Shuf0 && Shuf1 && Shuf0->getMask().equals(Shuf1->getMask()) && + LHS.getOperand(1).isUndef() && RHS.getOperand(1).isUndef() && + (LHS.hasOneUse() || RHS.hasOneUse() || LHS == RHS)) { + SDLoc DL(N); + SDValue NewBinOp = DAG.getNode(Opcode, DL, VT, LHS.getOperand(0), + RHS.getOperand(0), Flags); + SDValue UndefV = LHS.getOperand(1); + return DAG.getVectorShuffle(VT, DL, NewBinOp, UndefV, Shuf0->getMask()); + } + + // Try to sink a splat shuffle after a binop with a uniform constant. + // This is limited to cases where neither the shuffle nor the constant have + // undefined elements because that could be poison-unsafe or inhibit + // demanded elements analysis. It is further limited to not change a splat + // of an inserted scalar because that may be optimized better by + // load-folding or other target-specific behaviors. + if (isConstOrConstSplat(RHS) && Shuf0 && is_splat(Shuf0->getMask()) && + Shuf0->hasOneUse() && Shuf0->getOperand(1).isUndef() && + Shuf0->getOperand(0).getOpcode() != ISD::INSERT_VECTOR_ELT) { + // binop (splat X), (splat C) --> splat (binop X, C) + SDLoc DL(N); + SDValue X = Shuf0->getOperand(0); + SDValue NewBinOp = DAG.getNode(Opcode, DL, VT, X, RHS, Flags); + return DAG.getVectorShuffle(VT, DL, NewBinOp, DAG.getUNDEF(VT), + Shuf0->getMask()); + } + if (isConstOrConstSplat(LHS) && Shuf1 && is_splat(Shuf1->getMask()) && + Shuf1->hasOneUse() && Shuf1->getOperand(1).isUndef() && + Shuf1->getOperand(0).getOpcode() != ISD::INSERT_VECTOR_ELT) { + // binop (splat C), (splat X) --> splat (binop C, X) + SDLoc DL(N); + SDValue X = Shuf1->getOperand(0); + SDValue NewBinOp = DAG.getNode(Opcode, DL, VT, LHS, X, Flags); + return DAG.getVectorShuffle(VT, DL, NewBinOp, DAG.getUNDEF(VT), + Shuf1->getMask()); + } + } + + // The following pattern is likely to emerge with vector reduction ops. Moving + // the binary operation ahead of insertion may allow using a narrower vector + // instruction that has better performance than the wide version of the op: + // VBinOp (ins undef, X, Z), (ins undef, Y, Z) --> ins VecC, (VBinOp X, Y), Z + if (LHS.getOpcode() == ISD::INSERT_SUBVECTOR && LHS.getOperand(0).isUndef() && + RHS.getOpcode() == ISD::INSERT_SUBVECTOR && RHS.getOperand(0).isUndef() && + LHS.getOperand(2) == RHS.getOperand(2) && + (LHS.hasOneUse() || RHS.hasOneUse())) { + SDValue X = LHS.getOperand(1); + SDValue Y = RHS.getOperand(1); + SDValue Z = LHS.getOperand(2); + EVT NarrowVT = X.getValueType(); + if (NarrowVT == Y.getValueType() && + TLI.isOperationLegalOrCustomOrPromote(Opcode, NarrowVT, + LegalOperations)) { + // (binop undef, undef) may not return undef, so compute that result. + SDLoc DL(N); + SDValue VecC = + DAG.getNode(Opcode, DL, VT, DAG.getUNDEF(VT), DAG.getUNDEF(VT)); + SDValue NarrowBO = DAG.getNode(Opcode, DL, NarrowVT, X, Y); + return DAG.getNode(ISD::INSERT_SUBVECTOR, DL, VT, VecC, NarrowBO, Z); + } + } + + // Make sure all but the first op are undef or constant. + auto ConcatWithConstantOrUndef = [](SDValue Concat) { + return Concat.getOpcode() == ISD::CONCAT_VECTORS && + all_of(drop_begin(Concat->ops()), [](const SDValue &Op) { + return Op.isUndef() || + ISD::isBuildVectorOfConstantSDNodes(Op.getNode()); + }); + }; + + // The following pattern is likely to emerge with vector reduction ops. Moving + // the binary operation ahead of the concat may allow using a narrower vector + // instruction that has better performance than the wide version of the op: + // VBinOp (concat X, undef/constant), (concat Y, undef/constant) --> + // concat (VBinOp X, Y), VecC + if (ConcatWithConstantOrUndef(LHS) && ConcatWithConstantOrUndef(RHS) && + (LHS.hasOneUse() || RHS.hasOneUse())) { + EVT NarrowVT = LHS.getOperand(0).getValueType(); + if (NarrowVT == RHS.getOperand(0).getValueType() && + TLI.isOperationLegalOrCustomOrPromote(Opcode, NarrowVT)) { + SDLoc DL(N); + unsigned NumOperands = LHS.getNumOperands(); + SmallVector<SDValue, 4> ConcatOps; + for (unsigned i = 0; i != NumOperands; ++i) { + // This constant fold for operands 1 and up. + ConcatOps.push_back(DAG.getNode(Opcode, DL, NarrowVT, LHS.getOperand(i), + RHS.getOperand(i))); + } + + return DAG.getNode(ISD::CONCAT_VECTORS, DL, VT, ConcatOps); + } + } + + if (SDValue V = scalarizeBinOpOfSplats(N, DAG)) + return V; + + return SDValue(); +} + +SDValue DAGCombiner::SimplifySelect(const SDLoc &DL, SDValue N0, SDValue N1, + SDValue N2) { + assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); + + SDValue SCC = SimplifySelectCC(DL, N0.getOperand(0), N0.getOperand(1), N1, N2, + cast<CondCodeSDNode>(N0.getOperand(2))->get()); + + // If we got a simplified select_cc node back from SimplifySelectCC, then + // break it down into a new SETCC node, and a new SELECT node, and then return + // the SELECT node, since we were called with a SELECT node. + if (SCC.getNode()) { + // Check to see if we got a select_cc back (to turn into setcc/select). + // Otherwise, just return whatever node we got back, like fabs. + if (SCC.getOpcode() == ISD::SELECT_CC) { + const SDNodeFlags Flags = N0.getNode()->getFlags(); + SDValue SETCC = DAG.getNode(ISD::SETCC, SDLoc(N0), + N0.getValueType(), + SCC.getOperand(0), SCC.getOperand(1), + SCC.getOperand(4), Flags); + AddToWorklist(SETCC.getNode()); + SDValue SelectNode = DAG.getSelect(SDLoc(SCC), SCC.getValueType(), SETCC, + SCC.getOperand(2), SCC.getOperand(3)); + SelectNode->setFlags(Flags); + return SelectNode; + } + + return SCC; + } + return SDValue(); +} + +/// Given a SELECT or a SELECT_CC node, where LHS and RHS are the two values +/// being selected between, see if we can simplify the select. Callers of this +/// should assume that TheSelect is deleted if this returns true. As such, they +/// should return the appropriate thing (e.g. the node) back to the top-level of +/// the DAG combiner loop to avoid it being looked at. +bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS, + SDValue RHS) { + // fold (select (setcc x, [+-]0.0, *lt), NaN, (fsqrt x)) + // The select + setcc is redundant, because fsqrt returns NaN for X < 0. + if (const ConstantFPSDNode *NaN = isConstOrConstSplatFP(LHS)) { + if (NaN->isNaN() && RHS.getOpcode() == ISD::FSQRT) { + // We have: (select (setcc ?, ?, ?), NaN, (fsqrt ?)) + SDValue Sqrt = RHS; + ISD::CondCode CC; + SDValue CmpLHS; + const ConstantFPSDNode *Zero = nullptr; + + if (TheSelect->getOpcode() == ISD::SELECT_CC) { + CC = cast<CondCodeSDNode>(TheSelect->getOperand(4))->get(); + CmpLHS = TheSelect->getOperand(0); + Zero = isConstOrConstSplatFP(TheSelect->getOperand(1)); + } else { + // SELECT or VSELECT + SDValue Cmp = TheSelect->getOperand(0); + if (Cmp.getOpcode() == ISD::SETCC) { + CC = cast<CondCodeSDNode>(Cmp.getOperand(2))->get(); + CmpLHS = Cmp.getOperand(0); + Zero = isConstOrConstSplatFP(Cmp.getOperand(1)); + } + } + if (Zero && Zero->isZero() && + Sqrt.getOperand(0) == CmpLHS && (CC == ISD::SETOLT || + CC == ISD::SETULT || CC == ISD::SETLT)) { + // We have: (select (setcc x, [+-]0.0, *lt), NaN, (fsqrt x)) + CombineTo(TheSelect, Sqrt); + return true; + } + } + } + // Cannot simplify select with vector condition + if (TheSelect->getOperand(0).getValueType().isVector()) return false; + + // If this is a select from two identical things, try to pull the operation + // through the select. + if (LHS.getOpcode() != RHS.getOpcode() || + !LHS.hasOneUse() || !RHS.hasOneUse()) + return false; + + // If this is a load and the token chain is identical, replace the select + // of two loads with a load through a select of the address to load from. + // This triggers in things like "select bool X, 10.0, 123.0" after the FP + // constants have been dropped into the constant pool. + if (LHS.getOpcode() == ISD::LOAD) { + LoadSDNode *LLD = cast<LoadSDNode>(LHS); + LoadSDNode *RLD = cast<LoadSDNode>(RHS); + + // Token chains must be identical. + if (LHS.getOperand(0) != RHS.getOperand(0) || + // Do not let this transformation reduce the number of volatile loads. + // Be conservative for atomics for the moment + // TODO: This does appear to be legal for unordered atomics (see D66309) + !LLD->isSimple() || !RLD->isSimple() || + // FIXME: If either is a pre/post inc/dec load, + // we'd need to split out the address adjustment. + LLD->isIndexed() || RLD->isIndexed() || + // If this is an EXTLOAD, the VT's must match. + LLD->getMemoryVT() != RLD->getMemoryVT() || + // If this is an EXTLOAD, the kind of extension must match. + (LLD->getExtensionType() != RLD->getExtensionType() && + // The only exception is if one of the extensions is anyext. + LLD->getExtensionType() != ISD::EXTLOAD && + RLD->getExtensionType() != ISD::EXTLOAD) || + // FIXME: this discards src value information. This is + // over-conservative. It would be beneficial to be able to remember + // both potential memory locations. Since we are discarding + // src value info, don't do the transformation if the memory + // locations are not in the default address space. + LLD->getPointerInfo().getAddrSpace() != 0 || + RLD->getPointerInfo().getAddrSpace() != 0 || + // We can't produce a CMOV of a TargetFrameIndex since we won't + // generate the address generation required. + LLD->getBasePtr().getOpcode() == ISD::TargetFrameIndex || + RLD->getBasePtr().getOpcode() == ISD::TargetFrameIndex || + !TLI.isOperationLegalOrCustom(TheSelect->getOpcode(), + LLD->getBasePtr().getValueType())) + return false; + + // The loads must not depend on one another. + if (LLD->isPredecessorOf(RLD) || RLD->isPredecessorOf(LLD)) + return false; + + // Check that the select condition doesn't reach either load. If so, + // folding this will induce a cycle into the DAG. If not, this is safe to + // xform, so create a select of the addresses. + + SmallPtrSet<const SDNode *, 32> Visited; + SmallVector<const SDNode *, 16> Worklist; + + // Always fail if LLD and RLD are not independent. TheSelect is a + // predecessor to all Nodes in question so we need not search past it. + + Visited.insert(TheSelect); + Worklist.push_back(LLD); + Worklist.push_back(RLD); + + if (SDNode::hasPredecessorHelper(LLD, Visited, Worklist) || + SDNode::hasPredecessorHelper(RLD, Visited, Worklist)) + return false; + + SDValue Addr; + if (TheSelect->getOpcode() == ISD::SELECT) { + // We cannot do this optimization if any pair of {RLD, LLD} is a + // predecessor to {RLD, LLD, CondNode}. As we've already compared the + // Loads, we only need to check if CondNode is a successor to one of the + // loads. We can further avoid this if there's no use of their chain + // value. + SDNode *CondNode = TheSelect->getOperand(0).getNode(); + Worklist.push_back(CondNode); + + if ((LLD->hasAnyUseOfValue(1) && + SDNode::hasPredecessorHelper(LLD, Visited, Worklist)) || + (RLD->hasAnyUseOfValue(1) && + SDNode::hasPredecessorHelper(RLD, Visited, Worklist))) + return false; + + Addr = DAG.getSelect(SDLoc(TheSelect), + LLD->getBasePtr().getValueType(), + TheSelect->getOperand(0), LLD->getBasePtr(), + RLD->getBasePtr()); + } else { // Otherwise SELECT_CC + // We cannot do this optimization if any pair of {RLD, LLD} is a + // predecessor to {RLD, LLD, CondLHS, CondRHS}. As we've already compared + // the Loads, we only need to check if CondLHS/CondRHS is a successor to + // one of the loads. We can further avoid this if there's no use of their + // chain value. + + SDNode *CondLHS = TheSelect->getOperand(0).getNode(); + SDNode *CondRHS = TheSelect->getOperand(1).getNode(); + Worklist.push_back(CondLHS); + Worklist.push_back(CondRHS); + + if ((LLD->hasAnyUseOfValue(1) && + SDNode::hasPredecessorHelper(LLD, Visited, Worklist)) || + (RLD->hasAnyUseOfValue(1) && + SDNode::hasPredecessorHelper(RLD, Visited, Worklist))) + return false; + + Addr = DAG.getNode(ISD::SELECT_CC, SDLoc(TheSelect), + LLD->getBasePtr().getValueType(), + TheSelect->getOperand(0), + TheSelect->getOperand(1), + LLD->getBasePtr(), RLD->getBasePtr(), + TheSelect->getOperand(4)); + } + + SDValue Load; + // It is safe to replace the two loads if they have different alignments, + // but the new load must be the minimum (most restrictive) alignment of the + // inputs. + Align Alignment = std::min(LLD->getAlign(), RLD->getAlign()); + MachineMemOperand::Flags MMOFlags = LLD->getMemOperand()->getFlags(); + if (!RLD->isInvariant()) + MMOFlags &= ~MachineMemOperand::MOInvariant; + if (!RLD->isDereferenceable()) + MMOFlags &= ~MachineMemOperand::MODereferenceable; + if (LLD->getExtensionType() == ISD::NON_EXTLOAD) { + // FIXME: Discards pointer and AA info. + Load = DAG.getLoad(TheSelect->getValueType(0), SDLoc(TheSelect), + LLD->getChain(), Addr, MachinePointerInfo(), Alignment, + MMOFlags); + } else { + // FIXME: Discards pointer and AA info. + Load = DAG.getExtLoad( + LLD->getExtensionType() == ISD::EXTLOAD ? RLD->getExtensionType() + : LLD->getExtensionType(), + SDLoc(TheSelect), TheSelect->getValueType(0), LLD->getChain(), Addr, + MachinePointerInfo(), LLD->getMemoryVT(), Alignment, MMOFlags); + } + + // Users of the select now use the result of the load. + CombineTo(TheSelect, Load); + + // Users of the old loads now use the new load's chain. We know the + // old-load value is dead now. + CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1)); + CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1)); + return true; + } + + return false; +} + +/// Try to fold an expression of the form (N0 cond N1) ? N2 : N3 to a shift and +/// bitwise 'and'. +SDValue DAGCombiner::foldSelectCCToShiftAnd(const SDLoc &DL, SDValue N0, + SDValue N1, SDValue N2, SDValue N3, + ISD::CondCode CC) { + // If this is a select where the false operand is zero and the compare is a + // check of the sign bit, see if we can perform the "gzip trick": + // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A + // select_cc setgt X, 0, A, 0 -> and (not (sra X, size(X)-1)), A + EVT XType = N0.getValueType(); + EVT AType = N2.getValueType(); + if (!isNullConstant(N3) || !XType.bitsGE(AType)) + return SDValue(); + + // If the comparison is testing for a positive value, we have to invert + // the sign bit mask, so only do that transform if the target has a bitwise + // 'and not' instruction (the invert is free). + if (CC == ISD::SETGT && TLI.hasAndNot(N2)) { + // (X > -1) ? A : 0 + // (X > 0) ? X : 0 <-- This is canonical signed max. + if (!(isAllOnesConstant(N1) || (isNullConstant(N1) && N0 == N2))) + return SDValue(); + } else if (CC == ISD::SETLT) { + // (X < 0) ? A : 0 + // (X < 1) ? X : 0 <-- This is un-canonicalized signed min. + if (!(isNullConstant(N1) || (isOneConstant(N1) && N0 == N2))) + return SDValue(); + } else { + return SDValue(); + } + + // and (sra X, size(X)-1), A -> "and (srl X, C2), A" iff A is a single-bit + // constant. + EVT ShiftAmtTy = getShiftAmountTy(N0.getValueType()); + auto *N2C = dyn_cast<ConstantSDNode>(N2.getNode()); + if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue() - 1)) == 0)) { + unsigned ShCt = XType.getSizeInBits() - N2C->getAPIntValue().logBase2() - 1; + if (!TLI.shouldAvoidTransformToShift(XType, ShCt)) { + SDValue ShiftAmt = DAG.getConstant(ShCt, DL, ShiftAmtTy); + SDValue Shift = DAG.getNode(ISD::SRL, DL, XType, N0, ShiftAmt); + AddToWorklist(Shift.getNode()); + + if (XType.bitsGT(AType)) { + Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); + AddToWorklist(Shift.getNode()); + } + + if (CC == ISD::SETGT) + Shift = DAG.getNOT(DL, Shift, AType); + + return DAG.getNode(ISD::AND, DL, AType, Shift, N2); + } + } + + unsigned ShCt = XType.getSizeInBits() - 1; + if (TLI.shouldAvoidTransformToShift(XType, ShCt)) + return SDValue(); + + SDValue ShiftAmt = DAG.getConstant(ShCt, DL, ShiftAmtTy); + SDValue Shift = DAG.getNode(ISD::SRA, DL, XType, N0, ShiftAmt); + AddToWorklist(Shift.getNode()); + + if (XType.bitsGT(AType)) { + Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift); + AddToWorklist(Shift.getNode()); + } + + if (CC == ISD::SETGT) + Shift = DAG.getNOT(DL, Shift, AType); + + return DAG.getNode(ISD::AND, DL, AType, Shift, N2); +} + +// Transform (fneg/fabs (bitconvert x)) to avoid loading constant pool values. +SDValue DAGCombiner::foldSignChangeInBitcast(SDNode *N) { + SDValue N0 = N->getOperand(0); + EVT VT = N->getValueType(0); + bool IsFabs = N->getOpcode() == ISD::FABS; + bool IsFree = IsFabs ? TLI.isFAbsFree(VT) : TLI.isFNegFree(VT); + + if (IsFree || N0.getOpcode() != ISD::BITCAST || !N0.hasOneUse()) + return SDValue(); + + SDValue Int = N0.getOperand(0); + EVT IntVT = Int.getValueType(); + + // The operand to cast should be integer. + if (!IntVT.isInteger() || IntVT.isVector()) + return SDValue(); + + // (fneg (bitconvert x)) -> (bitconvert (xor x sign)) + // (fabs (bitconvert x)) -> (bitconvert (and x ~sign)) + APInt SignMask; + if (N0.getValueType().isVector()) { + // For vector, create a sign mask (0x80...) or its inverse (for fabs, + // 0x7f...) per element and splat it. + SignMask = APInt::getSignMask(N0.getScalarValueSizeInBits()); + if (IsFabs) + SignMask = ~SignMask; + SignMask = APInt::getSplat(IntVT.getSizeInBits(), SignMask); + } else { + // For scalar, just use the sign mask (0x80... or the inverse, 0x7f...) + SignMask = APInt::getSignMask(IntVT.getSizeInBits()); + if (IsFabs) + SignMask = ~SignMask; + } + SDLoc DL(N0); + Int = DAG.getNode(IsFabs ? ISD::AND : ISD::XOR, DL, IntVT, Int, + DAG.getConstant(SignMask, DL, IntVT)); + AddToWorklist(Int.getNode()); + return DAG.getBitcast(VT, Int); +} + +/// Turn "(a cond b) ? 1.0f : 2.0f" into "load (tmp + ((a cond b) ? 0 : 4)" +/// where "tmp" is a constant pool entry containing an array with 1.0 and 2.0 +/// in it. This may be a win when the constant is not otherwise available +/// because it replaces two constant pool loads with one. +SDValue DAGCombiner::convertSelectOfFPConstantsToLoadOffset( + const SDLoc &DL, SDValue N0, SDValue N1, SDValue N2, SDValue N3, + ISD::CondCode CC) { + if (!TLI.reduceSelectOfFPConstantLoads(N0.getValueType())) + return SDValue(); + + // If we are before legalize types, we want the other legalization to happen + // first (for example, to avoid messing with soft float). + auto *TV = dyn_cast<ConstantFPSDNode>(N2); + auto *FV = dyn_cast<ConstantFPSDNode>(N3); + EVT VT = N2.getValueType(); + if (!TV || !FV || !TLI.isTypeLegal(VT)) + return SDValue(); + + // If a constant can be materialized without loads, this does not make sense. + if (TLI.getOperationAction(ISD::ConstantFP, VT) == TargetLowering::Legal || + TLI.isFPImmLegal(TV->getValueAPF(), TV->getValueType(0), ForCodeSize) || + TLI.isFPImmLegal(FV->getValueAPF(), FV->getValueType(0), ForCodeSize)) + return SDValue(); + + // If both constants have multiple uses, then we won't need to do an extra + // load. The values are likely around in registers for other users. + if (!TV->hasOneUse() && !FV->hasOneUse()) + return SDValue(); + + Constant *Elts[] = { const_cast<ConstantFP*>(FV->getConstantFPValue()), + const_cast<ConstantFP*>(TV->getConstantFPValue()) }; + Type *FPTy = Elts[0]->getType(); + const DataLayout &TD = DAG.getDataLayout(); + + // Create a ConstantArray of the two constants. + Constant *CA = ConstantArray::get(ArrayType::get(FPTy, 2), Elts); + SDValue CPIdx = DAG.getConstantPool(CA, TLI.getPointerTy(DAG.getDataLayout()), + TD.getPrefTypeAlign(FPTy)); + Align Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlign(); + + // Get offsets to the 0 and 1 elements of the array, so we can select between + // them. + SDValue Zero = DAG.getIntPtrConstant(0, DL); + unsigned EltSize = (unsigned)TD.getTypeAllocSize(Elts[0]->getType()); + SDValue One = DAG.getIntPtrConstant(EltSize, SDLoc(FV)); + SDValue Cond = + DAG.getSetCC(DL, getSetCCResultType(N0.getValueType()), N0, N1, CC); + AddToWorklist(Cond.getNode()); + SDValue CstOffset = DAG.getSelect(DL, Zero.getValueType(), Cond, One, Zero); + AddToWorklist(CstOffset.getNode()); + CPIdx = DAG.getNode(ISD::ADD, DL, CPIdx.getValueType(), CPIdx, CstOffset); + AddToWorklist(CPIdx.getNode()); + return DAG.getLoad(TV->getValueType(0), DL, DAG.getEntryNode(), CPIdx, + MachinePointerInfo::getConstantPool( + DAG.getMachineFunction()), Alignment); +} + +/// Simplify an expression of the form (N0 cond N1) ? N2 : N3 +/// where 'cond' is the comparison specified by CC. +SDValue DAGCombiner::SimplifySelectCC(const SDLoc &DL, SDValue N0, SDValue N1, + SDValue N2, SDValue N3, ISD::CondCode CC, + bool NotExtCompare) { + // (x ? y : y) -> y. + if (N2 == N3) return N2; + + EVT CmpOpVT = N0.getValueType(); + EVT CmpResVT = getSetCCResultType(CmpOpVT); + EVT VT = N2.getValueType(); + auto *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); + auto *N2C = dyn_cast<ConstantSDNode>(N2.getNode()); + auto *N3C = dyn_cast<ConstantSDNode>(N3.getNode()); + + // Determine if the condition we're dealing with is constant. + if (SDValue SCC = DAG.FoldSetCC(CmpResVT, N0, N1, CC, DL)) { + AddToWorklist(SCC.getNode()); + if (auto *SCCC = dyn_cast<ConstantSDNode>(SCC)) { + // fold select_cc true, x, y -> x + // fold select_cc false, x, y -> y + return !(SCCC->isNullValue()) ? N2 : N3; + } + } + + if (SDValue V = + convertSelectOfFPConstantsToLoadOffset(DL, N0, N1, N2, N3, CC)) + return V; + + if (SDValue V = foldSelectCCToShiftAnd(DL, N0, N1, N2, N3, CC)) + return V; + + // fold (select_cc seteq (and x, y), 0, 0, A) -> (and (shr (shl x)) A) + // where y is has a single bit set. + // A plaintext description would be, we can turn the SELECT_CC into an AND + // when the condition can be materialized as an all-ones register. Any + // single bit-test can be materialized as an all-ones register with + // shift-left and shift-right-arith. + if (CC == ISD::SETEQ && N0->getOpcode() == ISD::AND && + N0->getValueType(0) == VT && isNullConstant(N1) && isNullConstant(N2)) { + SDValue AndLHS = N0->getOperand(0); + auto *ConstAndRHS = dyn_cast<ConstantSDNode>(N0->getOperand(1)); + if (ConstAndRHS && ConstAndRHS->getAPIntValue().countPopulation() == 1) { + // Shift the tested bit over the sign bit. + const APInt &AndMask = ConstAndRHS->getAPIntValue(); + unsigned ShCt = AndMask.getBitWidth() - 1; + if (!TLI.shouldAvoidTransformToShift(VT, ShCt)) { + SDValue ShlAmt = + DAG.getConstant(AndMask.countLeadingZeros(), SDLoc(AndLHS), + getShiftAmountTy(AndLHS.getValueType())); + SDValue Shl = DAG.getNode(ISD::SHL, SDLoc(N0), VT, AndLHS, ShlAmt); + + // Now arithmetic right shift it all the way over, so the result is + // either all-ones, or zero. + SDValue ShrAmt = + DAG.getConstant(ShCt, SDLoc(Shl), + getShiftAmountTy(Shl.getValueType())); + SDValue Shr = DAG.getNode(ISD::SRA, SDLoc(N0), VT, Shl, ShrAmt); + + return DAG.getNode(ISD::AND, DL, VT, Shr, N3); + } + } + } + + // fold select C, 16, 0 -> shl C, 4 + bool Fold = N2C && isNullConstant(N3) && N2C->getAPIntValue().isPowerOf2(); + bool Swap = N3C && isNullConstant(N2) && N3C->getAPIntValue().isPowerOf2(); + + if ((Fold || Swap) && + TLI.getBooleanContents(CmpOpVT) == + TargetLowering::ZeroOrOneBooleanContent && + (!LegalOperations || TLI.isOperationLegal(ISD::SETCC, CmpOpVT))) { + + if (Swap) { + CC = ISD::getSetCCInverse(CC, CmpOpVT); + std::swap(N2C, N3C); + } + + // If the caller doesn't want us to simplify this into a zext of a compare, + // don't do it. + if (NotExtCompare && N2C->isOne()) + return SDValue(); + + SDValue Temp, SCC; + // zext (setcc n0, n1) + if (LegalTypes) { + SCC = DAG.getSetCC(DL, CmpResVT, N0, N1, CC); + if (VT.bitsLT(SCC.getValueType())) + Temp = DAG.getZeroExtendInReg(SCC, SDLoc(N2), VT); + else + Temp = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N2), VT, SCC); + } else { + SCC = DAG.getSetCC(SDLoc(N0), MVT::i1, N0, N1, CC); + Temp = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N2), VT, SCC); + } + + AddToWorklist(SCC.getNode()); + AddToWorklist(Temp.getNode()); + + if (N2C->isOne()) + return Temp; + + unsigned ShCt = N2C->getAPIntValue().logBase2(); + if (TLI.shouldAvoidTransformToShift(VT, ShCt)) + return SDValue(); + + // shl setcc result by log2 n2c + return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp, + DAG.getConstant(ShCt, SDLoc(Temp), + getShiftAmountTy(Temp.getValueType()))); + } + + // select_cc seteq X, 0, sizeof(X), ctlz(X) -> ctlz(X) + // select_cc seteq X, 0, sizeof(X), ctlz_zero_undef(X) -> ctlz(X) + // select_cc seteq X, 0, sizeof(X), cttz(X) -> cttz(X) + // select_cc seteq X, 0, sizeof(X), cttz_zero_undef(X) -> cttz(X) + // select_cc setne X, 0, ctlz(X), sizeof(X) -> ctlz(X) + // select_cc setne X, 0, ctlz_zero_undef(X), sizeof(X) -> ctlz(X) + // select_cc setne X, 0, cttz(X), sizeof(X) -> cttz(X) + // select_cc setne X, 0, cttz_zero_undef(X), sizeof(X) -> cttz(X) + if (N1C && N1C->isNullValue() && (CC == ISD::SETEQ || CC == ISD::SETNE)) { + SDValue ValueOnZero = N2; + SDValue Count = N3; + // If the condition is NE instead of E, swap the operands. + if (CC == ISD::SETNE) + std::swap(ValueOnZero, Count); + // Check if the value on zero is a constant equal to the bits in the type. + if (auto *ValueOnZeroC = dyn_cast<ConstantSDNode>(ValueOnZero)) { + if (ValueOnZeroC->getAPIntValue() == VT.getSizeInBits()) { + // If the other operand is cttz/cttz_zero_undef of N0, and cttz is + // legal, combine to just cttz. + if ((Count.getOpcode() == ISD::CTTZ || + Count.getOpcode() == ISD::CTTZ_ZERO_UNDEF) && + N0 == Count.getOperand(0) && + (!LegalOperations || TLI.isOperationLegal(ISD::CTTZ, VT))) + return DAG.getNode(ISD::CTTZ, DL, VT, N0); + // If the other operand is ctlz/ctlz_zero_undef of N0, and ctlz is + // legal, combine to just ctlz. + if ((Count.getOpcode() == ISD::CTLZ || + Count.getOpcode() == ISD::CTLZ_ZERO_UNDEF) && + N0 == Count.getOperand(0) && + (!LegalOperations || TLI.isOperationLegal(ISD::CTLZ, VT))) + return DAG.getNode(ISD::CTLZ, DL, VT, N0); + } + } + } + + return SDValue(); +} + +/// This is a stub for TargetLowering::SimplifySetCC. +SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0, SDValue N1, + ISD::CondCode Cond, const SDLoc &DL, + bool foldBooleans) { + TargetLowering::DAGCombinerInfo + DagCombineInfo(DAG, Level, false, this); + return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo, DL); +} + +/// Given an ISD::SDIV node expressing a divide by constant, return +/// a DAG expression to select that will generate the same value by multiplying +/// by a magic number. +/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide". +SDValue DAGCombiner::BuildSDIV(SDNode *N) { + // when optimising for minimum size, we don't want to expand a div to a mul + // and a shift. + if (DAG.getMachineFunction().getFunction().hasMinSize()) + return SDValue(); + + SmallVector<SDNode *, 8> Built; + if (SDValue S = TLI.BuildSDIV(N, DAG, LegalOperations, Built)) { + for (SDNode *N : Built) + AddToWorklist(N); + return S; + } + + return SDValue(); +} + +/// Given an ISD::SDIV node expressing a divide by constant power of 2, return a +/// DAG expression that will generate the same value by right shifting. +SDValue DAGCombiner::BuildSDIVPow2(SDNode *N) { + ConstantSDNode *C = isConstOrConstSplat(N->getOperand(1)); + if (!C) + return SDValue(); + + // Avoid division by zero. + if (C->isNullValue()) + return SDValue(); + + SmallVector<SDNode *, 8> Built; + if (SDValue S = TLI.BuildSDIVPow2(N, C->getAPIntValue(), DAG, Built)) { + for (SDNode *N : Built) + AddToWorklist(N); + return S; + } + + return SDValue(); +} + +/// Given an ISD::UDIV node expressing a divide by constant, return a DAG +/// expression that will generate the same value by multiplying by a magic +/// number. +/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide". +SDValue DAGCombiner::BuildUDIV(SDNode *N) { + // when optimising for minimum size, we don't want to expand a div to a mul + // and a shift. + if (DAG.getMachineFunction().getFunction().hasMinSize()) + return SDValue(); + + SmallVector<SDNode *, 8> Built; + if (SDValue S = TLI.BuildUDIV(N, DAG, LegalOperations, Built)) { + for (SDNode *N : Built) + AddToWorklist(N); + return S; + } + + return SDValue(); +} + +/// Determines the LogBase2 value for a non-null input value using the +/// transform: LogBase2(V) = (EltBits - 1) - ctlz(V). +SDValue DAGCombiner::BuildLogBase2(SDValue V, const SDLoc &DL) { + EVT VT = V.getValueType(); + SDValue Ctlz = DAG.getNode(ISD::CTLZ, DL, VT, V); + SDValue Base = DAG.getConstant(VT.getScalarSizeInBits() - 1, DL, VT); + SDValue LogBase2 = DAG.getNode(ISD::SUB, DL, VT, Base, Ctlz); + return LogBase2; +} + +/// Newton iteration for a function: F(X) is X_{i+1} = X_i - F(X_i)/F'(X_i) +/// For the reciprocal, we need to find the zero of the function: +/// F(X) = A X - 1 [which has a zero at X = 1/A] +/// => +/// X_{i+1} = X_i (2 - A X_i) = X_i + X_i (1 - A X_i) [this second form +/// does not require additional intermediate precision] +/// For the last iteration, put numerator N into it to gain more precision: +/// Result = N X_i + X_i (N - N A X_i) +SDValue DAGCombiner::BuildDivEstimate(SDValue N, SDValue Op, + SDNodeFlags Flags) { + if (LegalDAG) + return SDValue(); + + // TODO: Handle half and/or extended types? + EVT VT = Op.getValueType(); + if (VT.getScalarType() != MVT::f32 && VT.getScalarType() != MVT::f64) + return SDValue(); + + // If estimates are explicitly disabled for this function, we're done. + MachineFunction &MF = DAG.getMachineFunction(); + int Enabled = TLI.getRecipEstimateDivEnabled(VT, MF); + if (Enabled == TLI.ReciprocalEstimate::Disabled) + return SDValue(); + + // Estimates may be explicitly enabled for this type with a custom number of + // refinement steps. + int Iterations = TLI.getDivRefinementSteps(VT, MF); + if (SDValue Est = TLI.getRecipEstimate(Op, DAG, Enabled, Iterations)) { + AddToWorklist(Est.getNode()); + + SDLoc DL(Op); + if (Iterations) { + SDValue FPOne = DAG.getConstantFP(1.0, DL, VT); + + // Newton iterations: Est = Est + Est (N - Arg * Est) + // If this is the last iteration, also multiply by the numerator. + for (int i = 0; i < Iterations; ++i) { + SDValue MulEst = Est; + + if (i == Iterations - 1) { + MulEst = DAG.getNode(ISD::FMUL, DL, VT, N, Est, Flags); + AddToWorklist(MulEst.getNode()); + } + + SDValue NewEst = DAG.getNode(ISD::FMUL, DL, VT, Op, MulEst, Flags); + AddToWorklist(NewEst.getNode()); + + NewEst = DAG.getNode(ISD::FSUB, DL, VT, + (i == Iterations - 1 ? N : FPOne), NewEst, Flags); + AddToWorklist(NewEst.getNode()); + + NewEst = DAG.getNode(ISD::FMUL, DL, VT, Est, NewEst, Flags); + AddToWorklist(NewEst.getNode()); + + Est = DAG.getNode(ISD::FADD, DL, VT, MulEst, NewEst, Flags); + AddToWorklist(Est.getNode()); + } + } else { + // If no iterations are available, multiply with N. + Est = DAG.getNode(ISD::FMUL, DL, VT, Est, N, Flags); + AddToWorklist(Est.getNode()); + } + + return Est; + } + + return SDValue(); +} + +/// Newton iteration for a function: F(X) is X_{i+1} = X_i - F(X_i)/F'(X_i) +/// For the reciprocal sqrt, we need to find the zero of the function: +/// F(X) = 1/X^2 - A [which has a zero at X = 1/sqrt(A)] +/// => +/// X_{i+1} = X_i (1.5 - A X_i^2 / 2) +/// As a result, we precompute A/2 prior to the iteration loop. +SDValue DAGCombiner::buildSqrtNROneConst(SDValue Arg, SDValue Est, + unsigned Iterations, + SDNodeFlags Flags, bool Reciprocal) { + EVT VT = Arg.getValueType(); + SDLoc DL(Arg); + SDValue ThreeHalves = DAG.getConstantFP(1.5, DL, VT); + + // We now need 0.5 * Arg which we can write as (1.5 * Arg - Arg) so that + // this entire sequence requires only one FP constant. + SDValue HalfArg = DAG.getNode(ISD::FMUL, DL, VT, ThreeHalves, Arg, Flags); + HalfArg = DAG.getNode(ISD::FSUB, DL, VT, HalfArg, Arg, Flags); + + // Newton iterations: Est = Est * (1.5 - HalfArg * Est * Est) + for (unsigned i = 0; i < Iterations; ++i) { + SDValue NewEst = DAG.getNode(ISD::FMUL, DL, VT, Est, Est, Flags); + NewEst = DAG.getNode(ISD::FMUL, DL, VT, HalfArg, NewEst, Flags); + NewEst = DAG.getNode(ISD::FSUB, DL, VT, ThreeHalves, NewEst, Flags); + Est = DAG.getNode(ISD::FMUL, DL, VT, Est, NewEst, Flags); + } + + // If non-reciprocal square root is requested, multiply the result by Arg. + if (!Reciprocal) + Est = DAG.getNode(ISD::FMUL, DL, VT, Est, Arg, Flags); + + return Est; +} + +/// Newton iteration for a function: F(X) is X_{i+1} = X_i - F(X_i)/F'(X_i) +/// For the reciprocal sqrt, we need to find the zero of the function: +/// F(X) = 1/X^2 - A [which has a zero at X = 1/sqrt(A)] +/// => +/// X_{i+1} = (-0.5 * X_i) * (A * X_i * X_i + (-3.0)) +SDValue DAGCombiner::buildSqrtNRTwoConst(SDValue Arg, SDValue Est, + unsigned Iterations, + SDNodeFlags Flags, bool Reciprocal) { + EVT VT = Arg.getValueType(); + SDLoc DL(Arg); + SDValue MinusThree = DAG.getConstantFP(-3.0, DL, VT); + SDValue MinusHalf = DAG.getConstantFP(-0.5, DL, VT); + + // This routine must enter the loop below to work correctly + // when (Reciprocal == false). + assert(Iterations > 0); + + // Newton iterations for reciprocal square root: + // E = (E * -0.5) * ((A * E) * E + -3.0) + for (unsigned i = 0; i < Iterations; ++i) { + SDValue AE = DAG.getNode(ISD::FMUL, DL, VT, Arg, Est, Flags); + SDValue AEE = DAG.getNode(ISD::FMUL, DL, VT, AE, Est, Flags); + SDValue RHS = DAG.getNode(ISD::FADD, DL, VT, AEE, MinusThree, Flags); + + // When calculating a square root at the last iteration build: + // S = ((A * E) * -0.5) * ((A * E) * E + -3.0) + // (notice a common subexpression) + SDValue LHS; + if (Reciprocal || (i + 1) < Iterations) { + // RSQRT: LHS = (E * -0.5) + LHS = DAG.getNode(ISD::FMUL, DL, VT, Est, MinusHalf, Flags); + } else { + // SQRT: LHS = (A * E) * -0.5 + LHS = DAG.getNode(ISD::FMUL, DL, VT, AE, MinusHalf, Flags); + } + + Est = DAG.getNode(ISD::FMUL, DL, VT, LHS, RHS, Flags); + } + + return Est; +} + +/// Build code to calculate either rsqrt(Op) or sqrt(Op). In the latter case +/// Op*rsqrt(Op) is actually computed, so additional postprocessing is needed if +/// Op can be zero. +SDValue DAGCombiner::buildSqrtEstimateImpl(SDValue Op, SDNodeFlags Flags, + bool Reciprocal) { + if (LegalDAG) + return SDValue(); + + // TODO: Handle half and/or extended types? + EVT VT = Op.getValueType(); + if (VT.getScalarType() != MVT::f32 && VT.getScalarType() != MVT::f64) + return SDValue(); + + // If estimates are explicitly disabled for this function, we're done. + MachineFunction &MF = DAG.getMachineFunction(); + int Enabled = TLI.getRecipEstimateSqrtEnabled(VT, MF); + if (Enabled == TLI.ReciprocalEstimate::Disabled) + return SDValue(); + + // Estimates may be explicitly enabled for this type with a custom number of + // refinement steps. + int Iterations = TLI.getSqrtRefinementSteps(VT, MF); + + bool UseOneConstNR = false; + if (SDValue Est = + TLI.getSqrtEstimate(Op, DAG, Enabled, Iterations, UseOneConstNR, + Reciprocal)) { + AddToWorklist(Est.getNode()); + + if (Iterations) + Est = UseOneConstNR + ? buildSqrtNROneConst(Op, Est, Iterations, Flags, Reciprocal) + : buildSqrtNRTwoConst(Op, Est, Iterations, Flags, Reciprocal); + if (!Reciprocal) { + SDLoc DL(Op); + // Try the target specific test first. + SDValue Test = TLI.getSqrtInputTest(Op, DAG, DAG.getDenormalMode(VT)); + + // The estimate is now completely wrong if the input was exactly 0.0 or + // possibly a denormal. Force the answer to 0.0 or value provided by + // target for those cases. + Est = DAG.getNode( + Test.getValueType().isVector() ? ISD::VSELECT : ISD::SELECT, DL, VT, + Test, TLI.getSqrtResultForDenormInput(Op, DAG), Est); + } + return Est; + } + + return SDValue(); +} + +SDValue DAGCombiner::buildRsqrtEstimate(SDValue Op, SDNodeFlags Flags) { + return buildSqrtEstimateImpl(Op, Flags, true); +} + +SDValue DAGCombiner::buildSqrtEstimate(SDValue Op, SDNodeFlags Flags) { + return buildSqrtEstimateImpl(Op, Flags, false); +} + +/// Return true if there is any possibility that the two addresses overlap. +bool DAGCombiner::isAlias(SDNode *Op0, SDNode *Op1) const { + + struct MemUseCharacteristics { + bool IsVolatile; + bool IsAtomic; + SDValue BasePtr; + int64_t Offset; + Optional<int64_t> NumBytes; + MachineMemOperand *MMO; + }; + + auto getCharacteristics = [](SDNode *N) -> MemUseCharacteristics { + if (const auto *LSN = dyn_cast<LSBaseSDNode>(N)) { + int64_t Offset = 0; + if (auto *C = dyn_cast<ConstantSDNode>(LSN->getOffset())) + Offset = (LSN->getAddressingMode() == ISD::PRE_INC) + ? C->getSExtValue() + : (LSN->getAddressingMode() == ISD::PRE_DEC) + ? -1 * C->getSExtValue() + : 0; + uint64_t Size = + MemoryLocation::getSizeOrUnknown(LSN->getMemoryVT().getStoreSize()); + return {LSN->isVolatile(), LSN->isAtomic(), LSN->getBasePtr(), + Offset /*base offset*/, + Optional<int64_t>(Size), + LSN->getMemOperand()}; + } + if (const auto *LN = cast<LifetimeSDNode>(N)) + return {false /*isVolatile*/, /*isAtomic*/ false, LN->getOperand(1), + (LN->hasOffset()) ? LN->getOffset() : 0, + (LN->hasOffset()) ? Optional<int64_t>(LN->getSize()) + : Optional<int64_t>(), + (MachineMemOperand *)nullptr}; + // Default. + return {false /*isvolatile*/, /*isAtomic*/ false, SDValue(), + (int64_t)0 /*offset*/, + Optional<int64_t>() /*size*/, (MachineMemOperand *)nullptr}; + }; + + MemUseCharacteristics MUC0 = getCharacteristics(Op0), + MUC1 = getCharacteristics(Op1); + + // If they are to the same address, then they must be aliases. + if (MUC0.BasePtr.getNode() && MUC0.BasePtr == MUC1.BasePtr && + MUC0.Offset == MUC1.Offset) + return true; + + // If they are both volatile then they cannot be reordered. + if (MUC0.IsVolatile && MUC1.IsVolatile) + return true; + + // Be conservative about atomics for the moment + // TODO: This is way overconservative for unordered atomics (see D66309) + if (MUC0.IsAtomic && MUC1.IsAtomic) + return true; + + if (MUC0.MMO && MUC1.MMO) { + if ((MUC0.MMO->isInvariant() && MUC1.MMO->isStore()) || + (MUC1.MMO->isInvariant() && MUC0.MMO->isStore())) + return false; + } + + // Try to prove that there is aliasing, or that there is no aliasing. Either + // way, we can return now. If nothing can be proved, proceed with more tests. + bool IsAlias; + if (BaseIndexOffset::computeAliasing(Op0, MUC0.NumBytes, Op1, MUC1.NumBytes, + DAG, IsAlias)) + return IsAlias; + + // The following all rely on MMO0 and MMO1 being valid. Fail conservatively if + // either are not known. + if (!MUC0.MMO || !MUC1.MMO) + return true; + + // If one operation reads from invariant memory, and the other may store, they + // cannot alias. These should really be checking the equivalent of mayWrite, + // but it only matters for memory nodes other than load /store. + if ((MUC0.MMO->isInvariant() && MUC1.MMO->isStore()) || + (MUC1.MMO->isInvariant() && MUC0.MMO->isStore())) + return false; + + // If we know required SrcValue1 and SrcValue2 have relatively large + // alignment compared to the size and offset of the access, we may be able + // to prove they do not alias. This check is conservative for now to catch + // cases created by splitting vector types, it only works when the offsets are + // multiples of the size of the data. + int64_t SrcValOffset0 = MUC0.MMO->getOffset(); + int64_t SrcValOffset1 = MUC1.MMO->getOffset(); + Align OrigAlignment0 = MUC0.MMO->getBaseAlign(); + Align OrigAlignment1 = MUC1.MMO->getBaseAlign(); + auto &Size0 = MUC0.NumBytes; + auto &Size1 = MUC1.NumBytes; + if (OrigAlignment0 == OrigAlignment1 && SrcValOffset0 != SrcValOffset1 && + Size0.hasValue() && Size1.hasValue() && *Size0 == *Size1 && + OrigAlignment0 > *Size0 && SrcValOffset0 % *Size0 == 0 && + SrcValOffset1 % *Size1 == 0) { + int64_t OffAlign0 = SrcValOffset0 % OrigAlignment0.value(); + int64_t OffAlign1 = SrcValOffset1 % OrigAlignment1.value(); + + // There is no overlap between these relatively aligned accesses of + // similar size. Return no alias. + if ((OffAlign0 + *Size0) <= OffAlign1 || (OffAlign1 + *Size1) <= OffAlign0) + return false; + } + + bool UseAA = CombinerGlobalAA.getNumOccurrences() > 0 + ? CombinerGlobalAA + : DAG.getSubtarget().useAA(); +#ifndef NDEBUG + if (CombinerAAOnlyFunc.getNumOccurrences() && + CombinerAAOnlyFunc != DAG.getMachineFunction().getName()) + UseAA = false; +#endif + + if (UseAA && AA && MUC0.MMO->getValue() && MUC1.MMO->getValue() && + Size0.hasValue() && Size1.hasValue()) { + // Use alias analysis information. + int64_t MinOffset = std::min(SrcValOffset0, SrcValOffset1); + int64_t Overlap0 = *Size0 + SrcValOffset0 - MinOffset; + int64_t Overlap1 = *Size1 + SrcValOffset1 - MinOffset; + AliasResult AAResult = AA->alias( + MemoryLocation(MUC0.MMO->getValue(), Overlap0, + UseTBAA ? MUC0.MMO->getAAInfo() : AAMDNodes()), + MemoryLocation(MUC1.MMO->getValue(), Overlap1, + UseTBAA ? MUC1.MMO->getAAInfo() : AAMDNodes())); + if (AAResult == NoAlias) + return false; + } + + // Otherwise we have to assume they alias. + return true; +} + +/// Walk up chain skipping non-aliasing memory nodes, +/// looking for aliasing nodes and adding them to the Aliases vector. +void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain, + SmallVectorImpl<SDValue> &Aliases) { + SmallVector<SDValue, 8> Chains; // List of chains to visit. + SmallPtrSet<SDNode *, 16> Visited; // Visited node set. + + // Get alias information for node. + // TODO: relax aliasing for unordered atomics (see D66309) + const bool IsLoad = isa<LoadSDNode>(N) && cast<LoadSDNode>(N)->isSimple(); + + // Starting off. + Chains.push_back(OriginalChain); + unsigned Depth = 0; + + // Attempt to improve chain by a single step + std::function<bool(SDValue &)> ImproveChain = [&](SDValue &C) -> bool { + switch (C.getOpcode()) { + case ISD::EntryToken: + // No need to mark EntryToken. + C = SDValue(); + return true; + case ISD::LOAD: + case ISD::STORE: { + // Get alias information for C. + // TODO: Relax aliasing for unordered atomics (see D66309) + bool IsOpLoad = isa<LoadSDNode>(C.getNode()) && + cast<LSBaseSDNode>(C.getNode())->isSimple(); + if ((IsLoad && IsOpLoad) || !isAlias(N, C.getNode())) { + // Look further up the chain. + C = C.getOperand(0); + return true; + } + // Alias, so stop here. + return false; + } + + case ISD::CopyFromReg: + // Always forward past past CopyFromReg. + C = C.getOperand(0); + return true; + + case ISD::LIFETIME_START: + case ISD::LIFETIME_END: { + // We can forward past any lifetime start/end that can be proven not to + // alias the memory access. + if (!isAlias(N, C.getNode())) { + // Look further up the chain. + C = C.getOperand(0); + return true; + } + return false; + } + default: + return false; + } + }; + + // Look at each chain and determine if it is an alias. If so, add it to the + // aliases list. If not, then continue up the chain looking for the next + // candidate. + while (!Chains.empty()) { + SDValue Chain = Chains.pop_back_val(); + + // Don't bother if we've seen Chain before. + if (!Visited.insert(Chain.getNode()).second) + continue; + + // For TokenFactor nodes, look at each operand and only continue up the + // chain until we reach the depth limit. + // + // FIXME: The depth check could be made to return the last non-aliasing + // chain we found before we hit a tokenfactor rather than the original + // chain. + if (Depth > TLI.getGatherAllAliasesMaxDepth()) { + Aliases.clear(); + Aliases.push_back(OriginalChain); + return; + } + + if (Chain.getOpcode() == ISD::TokenFactor) { + // We have to check each of the operands of the token factor for "small" + // token factors, so we queue them up. Adding the operands to the queue + // (stack) in reverse order maintains the original order and increases the + // likelihood that getNode will find a matching token factor (CSE.) + if (Chain.getNumOperands() > 16) { + Aliases.push_back(Chain); + continue; + } + for (unsigned n = Chain.getNumOperands(); n;) + Chains.push_back(Chain.getOperand(--n)); + ++Depth; + continue; + } + // Everything else + if (ImproveChain(Chain)) { + // Updated Chain Found, Consider new chain if one exists. + if (Chain.getNode()) + Chains.push_back(Chain); + ++Depth; + continue; + } + // No Improved Chain Possible, treat as Alias. + Aliases.push_back(Chain); + } +} + +/// Walk up chain skipping non-aliasing memory nodes, looking for a better chain +/// (aliasing node.) +SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) { + if (OptLevel == CodeGenOpt::None) + return OldChain; + + // Ops for replacing token factor. + SmallVector<SDValue, 8> Aliases; + + // Accumulate all the aliases to this node. + GatherAllAliases(N, OldChain, Aliases); + + // If no operands then chain to entry token. + if (Aliases.size() == 0) + return DAG.getEntryNode(); + + // If a single operand then chain to it. We don't need to revisit it. + if (Aliases.size() == 1) + return Aliases[0]; + + // Construct a custom tailored token factor. + return DAG.getTokenFactor(SDLoc(N), Aliases); +} + +namespace { +// TODO: Replace with with std::monostate when we move to C++17. +struct UnitT { } Unit; +bool operator==(const UnitT &, const UnitT &) { return true; } +bool operator!=(const UnitT &, const UnitT &) { return false; } +} // namespace + +// This function tries to collect a bunch of potentially interesting +// nodes to improve the chains of, all at once. This might seem +// redundant, as this function gets called when visiting every store +// node, so why not let the work be done on each store as it's visited? +// +// I believe this is mainly important because mergeConsecutiveStores +// is unable to deal with merging stores of different sizes, so unless +// we improve the chains of all the potential candidates up-front +// before running mergeConsecutiveStores, it might only see some of +// the nodes that will eventually be candidates, and then not be able +// to go from a partially-merged state to the desired final +// fully-merged state. + +bool DAGCombiner::parallelizeChainedStores(StoreSDNode *St) { + SmallVector<StoreSDNode *, 8> ChainedStores; + StoreSDNode *STChain = St; + // Intervals records which offsets from BaseIndex have been covered. In + // the common case, every store writes to the immediately previous address + // space and thus merged with the previous interval at insertion time. + + using IMap = + llvm::IntervalMap<int64_t, UnitT, 8, IntervalMapHalfOpenInfo<int64_t>>; + IMap::Allocator A; + IMap Intervals(A); + + // This holds the base pointer, index, and the offset in bytes from the base + // pointer. + const BaseIndexOffset BasePtr = BaseIndexOffset::match(St, DAG); + + // We must have a base and an offset. + if (!BasePtr.getBase().getNode()) + return false; + + // Do not handle stores to undef base pointers. + if (BasePtr.getBase().isUndef()) + return false; + + // BaseIndexOffset assumes that offsets are fixed-size, which + // is not valid for scalable vectors where the offsets are + // scaled by `vscale`, so bail out early. + if (St->getMemoryVT().isScalableVector()) + return false; + + // Add ST's interval. + Intervals.insert(0, (St->getMemoryVT().getSizeInBits() + 7) / 8, Unit); + + while (StoreSDNode *Chain = dyn_cast<StoreSDNode>(STChain->getChain())) { + // If the chain has more than one use, then we can't reorder the mem ops. + if (!SDValue(Chain, 0)->hasOneUse()) + break; + // TODO: Relax for unordered atomics (see D66309) + if (!Chain->isSimple() || Chain->isIndexed()) + break; + + // Find the base pointer and offset for this memory node. + const BaseIndexOffset Ptr = BaseIndexOffset::match(Chain, DAG); + // Check that the base pointer is the same as the original one. + int64_t Offset; + if (!BasePtr.equalBaseIndex(Ptr, DAG, Offset)) + break; + int64_t Length = (Chain->getMemoryVT().getSizeInBits() + 7) / 8; + // Make sure we don't overlap with other intervals by checking the ones to + // the left or right before inserting. + auto I = Intervals.find(Offset); + // If there's a next interval, we should end before it. + if (I != Intervals.end() && I.start() < (Offset + Length)) + break; + // If there's a previous interval, we should start after it. + if (I != Intervals.begin() && (--I).stop() <= Offset) + break; + Intervals.insert(Offset, Offset + Length, Unit); + + ChainedStores.push_back(Chain); + STChain = Chain; + } + + // If we didn't find a chained store, exit. + if (ChainedStores.size() == 0) + return false; + + // Improve all chained stores (St and ChainedStores members) starting from + // where the store chain ended and return single TokenFactor. + SDValue NewChain = STChain->getChain(); + SmallVector<SDValue, 8> TFOps; + for (unsigned I = ChainedStores.size(); I;) { + StoreSDNode *S = ChainedStores[--I]; + SDValue BetterChain = FindBetterChain(S, NewChain); + S = cast<StoreSDNode>(DAG.UpdateNodeOperands( + S, BetterChain, S->getOperand(1), S->getOperand(2), S->getOperand(3))); + TFOps.push_back(SDValue(S, 0)); + ChainedStores[I] = S; + } + + // Improve St's chain. Use a new node to avoid creating a loop from CombineTo. + SDValue BetterChain = FindBetterChain(St, NewChain); + SDValue NewST; + if (St->isTruncatingStore()) + NewST = DAG.getTruncStore(BetterChain, SDLoc(St), St->getValue(), + St->getBasePtr(), St->getMemoryVT(), + St->getMemOperand()); + else + NewST = DAG.getStore(BetterChain, SDLoc(St), St->getValue(), + St->getBasePtr(), St->getMemOperand()); + + TFOps.push_back(NewST); + + // If we improved every element of TFOps, then we've lost the dependence on + // NewChain to successors of St and we need to add it back to TFOps. Do so at + // the beginning to keep relative order consistent with FindBetterChains. + auto hasImprovedChain = [&](SDValue ST) -> bool { + return ST->getOperand(0) != NewChain; + }; + bool AddNewChain = llvm::all_of(TFOps, hasImprovedChain); + if (AddNewChain) + TFOps.insert(TFOps.begin(), NewChain); + + SDValue TF = DAG.getTokenFactor(SDLoc(STChain), TFOps); + CombineTo(St, TF); + + // Add TF and its operands to the worklist. + AddToWorklist(TF.getNode()); + for (const SDValue &Op : TF->ops()) + AddToWorklist(Op.getNode()); + AddToWorklist(STChain); + return true; +} + +bool DAGCombiner::findBetterNeighborChains(StoreSDNode *St) { + if (OptLevel == CodeGenOpt::None) + return false; + + const BaseIndexOffset BasePtr = BaseIndexOffset::match(St, DAG); + + // We must have a base and an offset. + if (!BasePtr.getBase().getNode()) + return false; + + // Do not handle stores to undef base pointers. + if (BasePtr.getBase().isUndef()) + return false; + + // Directly improve a chain of disjoint stores starting at St. + if (parallelizeChainedStores(St)) + return true; + + // Improve St's Chain.. + SDValue BetterChain = FindBetterChain(St, St->getChain()); + if (St->getChain() != BetterChain) { + replaceStoreChain(St, BetterChain); + return true; + } + return false; +} + +/// This is the entry point for the file. +void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis *AA, + CodeGenOpt::Level OptLevel) { + /// This is the main entry point to this class. + DAGCombiner(*this, AA, OptLevel).Run(Level); +} |