intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

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diff --git a/contrib/libs/llvm12/include/llvm/Analysis/SparsePropagation.h b/contrib/libs/llvm12/include/llvm/Analysis/SparsePropagation.h
new file mode 100644
index 0000000000..6f35675503
--- /dev/null
+++ b/contrib/libs/llvm12/include/llvm/Analysis/SparsePropagation.h
@@ -0,0 +1,536 @@
+#pragma once
+
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#endif
+
+//===- SparsePropagation.h - Sparse Conditional Property Propagation ------===//
+//
+// 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 file implements an abstract sparse conditional propagation algorithm,
+// modeled after SCCP, but with a customizable lattice function.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_SPARSEPROPAGATION_H
+#define LLVM_ANALYSIS_SPARSEPROPAGATION_H
+
+#include "llvm/IR/Instructions.h"
+#include "llvm/Support/Debug.h"
+#include <set>
+
+#define DEBUG_TYPE "sparseprop"
+
+namespace llvm {
+
+/// A template for translating between LLVM Values and LatticeKeys. Clients must
+/// provide a specialization of LatticeKeyInfo for their LatticeKey type.
+template <class LatticeKey> struct LatticeKeyInfo {
+  // static inline Value *getValueFromLatticeKey(LatticeKey Key);
+  // static inline LatticeKey getLatticeKeyFromValue(Value *V);
+};
+
+template <class LatticeKey, class LatticeVal,
+          class KeyInfo = LatticeKeyInfo<LatticeKey>>
+class SparseSolver;
+
+/// AbstractLatticeFunction - This class is implemented by the dataflow instance
+/// to specify what the lattice values are and how they handle merges etc.  This
+/// gives the client the power to compute lattice values from instructions,
+/// constants, etc.  The current requirement is that lattice values must be
+/// copyable.  At the moment, nothing tries to avoid copying.  Additionally,
+/// lattice keys must be able to be used as keys of a mapping data structure.
+/// Internally, the generic solver currently uses a DenseMap to map lattice keys
+/// to lattice values.  If the lattice key is a non-standard type, a
+/// specialization of DenseMapInfo must be provided.
+template <class LatticeKey, class LatticeVal> class AbstractLatticeFunction {
+private:
+  LatticeVal UndefVal, OverdefinedVal, UntrackedVal;
+
+public:
+  AbstractLatticeFunction(LatticeVal undefVal, LatticeVal overdefinedVal,
+                          LatticeVal untrackedVal) {
+    UndefVal = undefVal;
+    OverdefinedVal = overdefinedVal;
+    UntrackedVal = untrackedVal;
+  }
+
+  virtual ~AbstractLatticeFunction() = default;
+
+  LatticeVal getUndefVal()       const { return UndefVal; }
+  LatticeVal getOverdefinedVal() const { return OverdefinedVal; }
+  LatticeVal getUntrackedVal()   const { return UntrackedVal; }
+
+  /// IsUntrackedValue - If the specified LatticeKey is obviously uninteresting
+  /// to the analysis (i.e., it would always return UntrackedVal), this
+  /// function can return true to avoid pointless work.
+  virtual bool IsUntrackedValue(LatticeKey Key) { return false; }
+
+  /// ComputeLatticeVal - Compute and return a LatticeVal corresponding to the
+  /// given LatticeKey.
+  virtual LatticeVal ComputeLatticeVal(LatticeKey Key) {
+    return getOverdefinedVal();
+  }
+
+  /// IsSpecialCasedPHI - Given a PHI node, determine whether this PHI node is
+  /// one that the we want to handle through ComputeInstructionState.
+  virtual bool IsSpecialCasedPHI(PHINode *PN) { return false; }
+
+  /// MergeValues - Compute and return the merge of the two specified lattice
+  /// values.  Merging should only move one direction down the lattice to
+  /// guarantee convergence (toward overdefined).
+  virtual LatticeVal MergeValues(LatticeVal X, LatticeVal Y) {
+    return getOverdefinedVal(); // always safe, never useful.
+  }
+
+  /// ComputeInstructionState - Compute the LatticeKeys that change as a result
+  /// of executing instruction \p I. Their associated LatticeVals are store in
+  /// \p ChangedValues.
+  virtual void
+  ComputeInstructionState(Instruction &I,
+                          DenseMap<LatticeKey, LatticeVal> &ChangedValues,
+                          SparseSolver<LatticeKey, LatticeVal> &SS) = 0;
+
+  /// PrintLatticeVal - Render the given LatticeVal to the specified stream.
+  virtual void PrintLatticeVal(LatticeVal LV, raw_ostream &OS);
+
+  /// PrintLatticeKey - Render the given LatticeKey to the specified stream.
+  virtual void PrintLatticeKey(LatticeKey Key, raw_ostream &OS);
+
+  /// GetValueFromLatticeVal - If the given LatticeVal is representable as an
+  /// LLVM value, return it; otherwise, return nullptr. If a type is given, the
+  /// returned value must have the same type. This function is used by the
+  /// generic solver in attempting to resolve branch and switch conditions.
+  virtual Value *GetValueFromLatticeVal(LatticeVal LV, Type *Ty = nullptr) {
+    return nullptr;
+  }
+};
+
+/// SparseSolver - This class is a general purpose solver for Sparse Conditional
+/// Propagation with a programmable lattice function.
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+class SparseSolver {
+
+  /// LatticeFunc - This is the object that knows the lattice and how to
+  /// compute transfer functions.
+  AbstractLatticeFunction<LatticeKey, LatticeVal> *LatticeFunc;
+
+  /// ValueState - Holds the LatticeVals associated with LatticeKeys.
+  DenseMap<LatticeKey, LatticeVal> ValueState;
+
+  /// BBExecutable - Holds the basic blocks that are executable.
+  SmallPtrSet<BasicBlock *, 16> BBExecutable;
+
+  /// ValueWorkList - Holds values that should be processed.
+  SmallVector<Value *, 64> ValueWorkList;
+
+  /// BBWorkList - Holds basic blocks that should be processed.
+  SmallVector<BasicBlock *, 64> BBWorkList;
+
+  using Edge = std::pair<BasicBlock *, BasicBlock *>;
+
+  /// KnownFeasibleEdges - Entries in this set are edges which have already had
+  /// PHI nodes retriggered.
+  std::set<Edge> KnownFeasibleEdges;
+
+public:
+  explicit SparseSolver(
+      AbstractLatticeFunction<LatticeKey, LatticeVal> *Lattice)
+      : LatticeFunc(Lattice) {}
+  SparseSolver(const SparseSolver &) = delete;
+  SparseSolver &operator=(const SparseSolver &) = delete;
+
+  /// Solve - Solve for constants and executable blocks.
+  void Solve();
+
+  void Print(raw_ostream &OS) const;
+
+  /// getExistingValueState - Return the LatticeVal object corresponding to the
+  /// given value from the ValueState map. If the value is not in the map,
+  /// UntrackedVal is returned, unlike the getValueState method.
+  LatticeVal getExistingValueState(LatticeKey Key) const {
+    auto I = ValueState.find(Key);
+    return I != ValueState.end() ? I->second : LatticeFunc->getUntrackedVal();
+  }
+
+  /// getValueState - Return the LatticeVal object corresponding to the given
+  /// value from the ValueState map. If the value is not in the map, its state
+  /// is initialized.
+  LatticeVal getValueState(LatticeKey Key);
+
+  /// isEdgeFeasible - Return true if the control flow edge from the 'From'
+  /// basic block to the 'To' basic block is currently feasible.  If
+  /// AggressiveUndef is true, then this treats values with unknown lattice
+  /// values as undefined.  This is generally only useful when solving the
+  /// lattice, not when querying it.
+  bool isEdgeFeasible(BasicBlock *From, BasicBlock *To,
+                      bool AggressiveUndef = false);
+
+  /// isBlockExecutable - Return true if there are any known feasible
+  /// edges into the basic block.  This is generally only useful when
+  /// querying the lattice.
+  bool isBlockExecutable(BasicBlock *BB) const {
+    return BBExecutable.count(BB);
+  }
+
+  /// MarkBlockExecutable - This method can be used by clients to mark all of
+  /// the blocks that are known to be intrinsically live in the processed unit.
+  void MarkBlockExecutable(BasicBlock *BB);
+
+private:
+  /// UpdateState - When the state of some LatticeKey is potentially updated to
+  /// the given LatticeVal, this function notices and adds the LLVM value
+  /// corresponding the key to the work list, if needed.
+  void UpdateState(LatticeKey Key, LatticeVal LV);
+
+  /// markEdgeExecutable - Mark a basic block as executable, adding it to the BB
+  /// work list if it is not already executable.
+  void markEdgeExecutable(BasicBlock *Source, BasicBlock *Dest);
+
+  /// getFeasibleSuccessors - Return a vector of booleans to indicate which
+  /// successors are reachable from a given terminator instruction.
+  void getFeasibleSuccessors(Instruction &TI, SmallVectorImpl<bool> &Succs,
+                             bool AggressiveUndef);
+
+  void visitInst(Instruction &I);
+  void visitPHINode(PHINode &I);
+  void visitTerminator(Instruction &TI);
+};
+
+//===----------------------------------------------------------------------===//
+//                  AbstractLatticeFunction Implementation
+//===----------------------------------------------------------------------===//
+
+template <class LatticeKey, class LatticeVal>
+void AbstractLatticeFunction<LatticeKey, LatticeVal>::PrintLatticeVal(
+    LatticeVal V, raw_ostream &OS) {
+  if (V == UndefVal)
+    OS << "undefined";
+  else if (V == OverdefinedVal)
+    OS << "overdefined";
+  else if (V == UntrackedVal)
+    OS << "untracked";
+  else
+    OS << "unknown lattice value";
+}
+
+template <class LatticeKey, class LatticeVal>
+void AbstractLatticeFunction<LatticeKey, LatticeVal>::PrintLatticeKey(
+    LatticeKey Key, raw_ostream &OS) {
+  OS << "unknown lattice key";
+}
+
+//===----------------------------------------------------------------------===//
+//                          SparseSolver Implementation
+//===----------------------------------------------------------------------===//
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+LatticeVal
+SparseSolver<LatticeKey, LatticeVal, KeyInfo>::getValueState(LatticeKey Key) {
+  auto I = ValueState.find(Key);
+  if (I != ValueState.end())
+    return I->second; // Common case, in the map
+
+  if (LatticeFunc->IsUntrackedValue(Key))
+    return LatticeFunc->getUntrackedVal();
+  LatticeVal LV = LatticeFunc->ComputeLatticeVal(Key);
+
+  // If this value is untracked, don't add it to the map.
+  if (LV == LatticeFunc->getUntrackedVal())
+    return LV;
+  return ValueState[Key] = std::move(LV);
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::UpdateState(LatticeKey Key,
+                                                                LatticeVal LV) {
+  auto I = ValueState.find(Key);
+  if (I != ValueState.end() && I->second == LV)
+    return; // No change.
+
+  // Update the state of the given LatticeKey and add its corresponding LLVM
+  // value to the work list.
+  ValueState[Key] = std::move(LV);
+  if (Value *V = KeyInfo::getValueFromLatticeKey(Key))
+    ValueWorkList.push_back(V);
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::MarkBlockExecutable(
+    BasicBlock *BB) {
+  if (!BBExecutable.insert(BB).second)
+    return;
+  LLVM_DEBUG(dbgs() << "Marking Block Executable: " << BB->getName() << "\n");
+  BBWorkList.push_back(BB); // Add the block to the work list!
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::markEdgeExecutable(
+    BasicBlock *Source, BasicBlock *Dest) {
+  if (!KnownFeasibleEdges.insert(Edge(Source, Dest)).second)
+    return; // This edge is already known to be executable!
+
+  LLVM_DEBUG(dbgs() << "Marking Edge Executable: " << Source->getName()
+                    << " -> " << Dest->getName() << "\n");
+
+  if (BBExecutable.count(Dest)) {
+    // The destination is already executable, but we just made an edge
+    // feasible that wasn't before.  Revisit the PHI nodes in the block
+    // because they have potentially new operands.
+    for (BasicBlock::iterator I = Dest->begin(); isa<PHINode>(I); ++I)
+      visitPHINode(*cast<PHINode>(I));
+  } else {
+    MarkBlockExecutable(Dest);
+  }
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::getFeasibleSuccessors(
+    Instruction &TI, SmallVectorImpl<bool> &Succs, bool AggressiveUndef) {
+  Succs.resize(TI.getNumSuccessors());
+  if (TI.getNumSuccessors() == 0)
+    return;
+
+  if (BranchInst *BI = dyn_cast<BranchInst>(&TI)) {
+    if (BI->isUnconditional()) {
+      Succs[0] = true;
+      return;
+    }
+
+    LatticeVal BCValue;
+    if (AggressiveUndef)
+      BCValue =
+          getValueState(KeyInfo::getLatticeKeyFromValue(BI->getCondition()));
+    else
+      BCValue = getExistingValueState(
+          KeyInfo::getLatticeKeyFromValue(BI->getCondition()));
+
+    if (BCValue == LatticeFunc->getOverdefinedVal() ||
+        BCValue == LatticeFunc->getUntrackedVal()) {
+      // Overdefined condition variables can branch either way.
+      Succs[0] = Succs[1] = true;
+      return;
+    }
+
+    // If undefined, neither is feasible yet.
+    if (BCValue == LatticeFunc->getUndefVal())
+      return;
+
+    Constant *C =
+        dyn_cast_or_null<Constant>(LatticeFunc->GetValueFromLatticeVal(
+            std::move(BCValue), BI->getCondition()->getType()));
+    if (!C || !isa<ConstantInt>(C)) {
+      // Non-constant values can go either way.
+      Succs[0] = Succs[1] = true;
+      return;
+    }
+
+    // Constant condition variables mean the branch can only go a single way
+    Succs[C->isNullValue()] = true;
+    return;
+  }
+
+  if (TI.isExceptionalTerminator() ||
+      TI.isIndirectTerminator()) {
+    Succs.assign(Succs.size(), true);
+    return;
+  }
+
+  SwitchInst &SI = cast<SwitchInst>(TI);
+  LatticeVal SCValue;
+  if (AggressiveUndef)
+    SCValue = getValueState(KeyInfo::getLatticeKeyFromValue(SI.getCondition()));
+  else
+    SCValue = getExistingValueState(
+        KeyInfo::getLatticeKeyFromValue(SI.getCondition()));
+
+  if (SCValue == LatticeFunc->getOverdefinedVal() ||
+      SCValue == LatticeFunc->getUntrackedVal()) {
+    // All destinations are executable!
+    Succs.assign(TI.getNumSuccessors(), true);
+    return;
+  }
+
+  // If undefined, neither is feasible yet.
+  if (SCValue == LatticeFunc->getUndefVal())
+    return;
+
+  Constant *C = dyn_cast_or_null<Constant>(LatticeFunc->GetValueFromLatticeVal(
+      std::move(SCValue), SI.getCondition()->getType()));
+  if (!C || !isa<ConstantInt>(C)) {
+    // All destinations are executable!
+    Succs.assign(TI.getNumSuccessors(), true);
+    return;
+  }
+  SwitchInst::CaseHandle Case = *SI.findCaseValue(cast<ConstantInt>(C));
+  Succs[Case.getSuccessorIndex()] = true;
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+bool SparseSolver<LatticeKey, LatticeVal, KeyInfo>::isEdgeFeasible(
+    BasicBlock *From, BasicBlock *To, bool AggressiveUndef) {
+  SmallVector<bool, 16> SuccFeasible;
+  Instruction *TI = From->getTerminator();
+  getFeasibleSuccessors(*TI, SuccFeasible, AggressiveUndef);
+
+  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
+    if (TI->getSuccessor(i) == To && SuccFeasible[i])
+      return true;
+
+  return false;
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::visitTerminator(
+    Instruction &TI) {
+  SmallVector<bool, 16> SuccFeasible;
+  getFeasibleSuccessors(TI, SuccFeasible, true);
+
+  BasicBlock *BB = TI.getParent();
+
+  // Mark all feasible successors executable...
+  for (unsigned i = 0, e = SuccFeasible.size(); i != e; ++i)
+    if (SuccFeasible[i])
+      markEdgeExecutable(BB, TI.getSuccessor(i));
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::visitPHINode(PHINode &PN) {
+  // The lattice function may store more information on a PHINode than could be
+  // computed from its incoming values.  For example, SSI form stores its sigma
+  // functions as PHINodes with a single incoming value.
+  if (LatticeFunc->IsSpecialCasedPHI(&PN)) {
+    DenseMap<LatticeKey, LatticeVal> ChangedValues;
+    LatticeFunc->ComputeInstructionState(PN, ChangedValues, *this);
+    for (auto &ChangedValue : ChangedValues)
+      if (ChangedValue.second != LatticeFunc->getUntrackedVal())
+        UpdateState(std::move(ChangedValue.first),
+                    std::move(ChangedValue.second));
+    return;
+  }
+
+  LatticeKey Key = KeyInfo::getLatticeKeyFromValue(&PN);
+  LatticeVal PNIV = getValueState(Key);
+  LatticeVal Overdefined = LatticeFunc->getOverdefinedVal();
+
+  // If this value is already overdefined (common) just return.
+  if (PNIV == Overdefined || PNIV == LatticeFunc->getUntrackedVal())
+    return; // Quick exit
+
+  // Super-extra-high-degree PHI nodes are unlikely to ever be interesting,
+  // and slow us down a lot.  Just mark them overdefined.
+  if (PN.getNumIncomingValues() > 64) {
+    UpdateState(Key, Overdefined);
+    return;
+  }
+
+  // Look at all of the executable operands of the PHI node.  If any of them
+  // are overdefined, the PHI becomes overdefined as well.  Otherwise, ask the
+  // transfer function to give us the merge of the incoming values.
+  for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
+    // If the edge is not yet known to be feasible, it doesn't impact the PHI.
+    if (!isEdgeFeasible(PN.getIncomingBlock(i), PN.getParent(), true))
+      continue;
+
+    // Merge in this value.
+    LatticeVal OpVal =
+        getValueState(KeyInfo::getLatticeKeyFromValue(PN.getIncomingValue(i)));
+    if (OpVal != PNIV)
+      PNIV = LatticeFunc->MergeValues(PNIV, OpVal);
+
+    if (PNIV == Overdefined)
+      break; // Rest of input values don't matter.
+  }
+
+  // Update the PHI with the compute value, which is the merge of the inputs.
+  UpdateState(Key, PNIV);
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::visitInst(Instruction &I) {
+  // PHIs are handled by the propagation logic, they are never passed into the
+  // transfer functions.
+  if (PHINode *PN = dyn_cast<PHINode>(&I))
+    return visitPHINode(*PN);
+
+  // Otherwise, ask the transfer function what the result is.  If this is
+  // something that we care about, remember it.
+  DenseMap<LatticeKey, LatticeVal> ChangedValues;
+  LatticeFunc->ComputeInstructionState(I, ChangedValues, *this);
+  for (auto &ChangedValue : ChangedValues)
+    if (ChangedValue.second != LatticeFunc->getUntrackedVal())
+      UpdateState(ChangedValue.first, ChangedValue.second);
+
+  if (I.isTerminator())
+    visitTerminator(I);
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::Solve() {
+  // Process the work lists until they are empty!
+  while (!BBWorkList.empty() || !ValueWorkList.empty()) {
+    // Process the value work list.
+    while (!ValueWorkList.empty()) {
+      Value *V = ValueWorkList.back();
+      ValueWorkList.pop_back();
+
+      LLVM_DEBUG(dbgs() << "\nPopped off V-WL: " << *V << "\n");
+
+      // "V" got into the work list because it made a transition. See if any
+      // users are both live and in need of updating.
+      for (User *U : V->users())
+        if (Instruction *Inst = dyn_cast<Instruction>(U))
+          if (BBExecutable.count(Inst->getParent())) // Inst is executable?
+            visitInst(*Inst);
+    }
+
+    // Process the basic block work list.
+    while (!BBWorkList.empty()) {
+      BasicBlock *BB = BBWorkList.pop_back_val();
+
+      LLVM_DEBUG(dbgs() << "\nPopped off BBWL: " << *BB);
+
+      // Notify all instructions in this basic block that they are newly
+      // executable.
+      for (Instruction &I : *BB)
+        visitInst(I);
+    }
+  }
+}
+
+template <class LatticeKey, class LatticeVal, class KeyInfo>
+void SparseSolver<LatticeKey, LatticeVal, KeyInfo>::Print(
+    raw_ostream &OS) const {
+  if (ValueState.empty())
+    return;
+
+  LatticeKey Key;
+  LatticeVal LV;
+
+  OS << "ValueState:\n";
+  for (auto &Entry : ValueState) {
+    std::tie(Key, LV) = Entry;
+    if (LV == LatticeFunc->getUntrackedVal())
+      continue;
+    OS << "\t";
+    LatticeFunc->PrintLatticeVal(LV, OS);
+    OS << ": ";
+    LatticeFunc->PrintLatticeKey(Key, OS);
+    OS << "\n";
+  }
+}
+} // end namespace llvm
+
+#undef DEBUG_TYPE
+
+#endif // LLVM_ANALYSIS_SPARSEPROPAGATION_H
+
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif