intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 784 insertions, 0 deletions

diff --git a/contrib/libs/llvm12/include/llvm/Analysis/LoopAccessAnalysis.h b/contrib/libs/llvm12/include/llvm/Analysis/LoopAccessAnalysis.h
new file mode 100644
index 0000000000..e1460d75cf
--- /dev/null
+++ b/contrib/libs/llvm12/include/llvm/Analysis/LoopAccessAnalysis.h
@@ -0,0 +1,784 @@
+#pragma once
+
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#endif
+
+//===- llvm/Analysis/LoopAccessAnalysis.h -----------------------*- C++ -*-===//
+//
+// 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 defines the interface for the loop memory dependence framework that
+// was originally developed for the Loop Vectorizer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_LOOPACCESSANALYSIS_H
+#define LLVM_ANALYSIS_LOOPACCESSANALYSIS_H
+
+#include "llvm/ADT/EquivalenceClasses.h"
+#include "llvm/Analysis/LoopAnalysisManager.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/Pass.h"
+
+namespace llvm {
+
+class AAResults;
+class DataLayout;
+class Loop;
+class LoopAccessInfo;
+class OptimizationRemarkEmitter;
+class raw_ostream;
+class SCEV;
+class SCEVUnionPredicate;
+class Value;
+
+/// Collection of parameters shared beetween the Loop Vectorizer and the
+/// Loop Access Analysis.
+struct VectorizerParams {
+  /// Maximum SIMD width.
+  static const unsigned MaxVectorWidth;
+
+  /// VF as overridden by the user.
+  static unsigned VectorizationFactor;
+  /// Interleave factor as overridden by the user.
+  static unsigned VectorizationInterleave;
+  /// True if force-vector-interleave was specified by the user.
+  static bool isInterleaveForced();
+
+  /// \When performing memory disambiguation checks at runtime do not
+  /// make more than this number of comparisons.
+  static unsigned RuntimeMemoryCheckThreshold;
+};
+
+/// Checks memory dependences among accesses to the same underlying
+/// object to determine whether there vectorization is legal or not (and at
+/// which vectorization factor).
+///
+/// Note: This class will compute a conservative dependence for access to
+/// different underlying pointers. Clients, such as the loop vectorizer, will
+/// sometimes deal these potential dependencies by emitting runtime checks.
+///
+/// We use the ScalarEvolution framework to symbolically evalutate access
+/// functions pairs. Since we currently don't restructure the loop we can rely
+/// on the program order of memory accesses to determine their safety.
+/// At the moment we will only deem accesses as safe for:
+///  * A negative constant distance assuming program order.
+///
+///      Safe: tmp = a[i + 1];     OR     a[i + 1] = x;
+///            a[i] = tmp;                y = a[i];
+///
+///   The latter case is safe because later checks guarantuee that there can't
+///   be a cycle through a phi node (that is, we check that "x" and "y" is not
+///   the same variable: a header phi can only be an induction or a reduction, a
+///   reduction can't have a memory sink, an induction can't have a memory
+///   source). This is important and must not be violated (or we have to
+///   resort to checking for cycles through memory).
+///
+///  * A positive constant distance assuming program order that is bigger
+///    than the biggest memory access.
+///
+///     tmp = a[i]        OR              b[i] = x
+///     a[i+2] = tmp                      y = b[i+2];
+///
+///     Safe distance: 2 x sizeof(a[0]), and 2 x sizeof(b[0]), respectively.
+///
+///  * Zero distances and all accesses have the same size.
+///
+class MemoryDepChecker {
+public:
+  typedef PointerIntPair<Value *, 1, bool> MemAccessInfo;
+  typedef SmallVector<MemAccessInfo, 8> MemAccessInfoList;
+  /// Set of potential dependent memory accesses.
+  typedef EquivalenceClasses<MemAccessInfo> DepCandidates;
+
+  /// Type to keep track of the status of the dependence check. The order of
+  /// the elements is important and has to be from most permissive to least
+  /// permissive.
+  enum class VectorizationSafetyStatus {
+    // Can vectorize safely without RT checks. All dependences are known to be
+    // safe.
+    Safe,
+    // Can possibly vectorize with RT checks to overcome unknown dependencies.
+    PossiblySafeWithRtChecks,
+    // Cannot vectorize due to known unsafe dependencies.
+    Unsafe,
+  };
+
+  /// Dependece between memory access instructions.
+  struct Dependence {
+    /// The type of the dependence.
+    enum DepType {
+      // No dependence.
+      NoDep,
+      // We couldn't determine the direction or the distance.
+      Unknown,
+      // Lexically forward.
+      //
+      // FIXME: If we only have loop-independent forward dependences (e.g. a
+      // read and write of A[i]), LAA will locally deem the dependence "safe"
+      // without querying the MemoryDepChecker.  Therefore we can miss
+      // enumerating loop-independent forward dependences in
+      // getDependences.  Note that as soon as there are different
+      // indices used to access the same array, the MemoryDepChecker *is*
+      // queried and the dependence list is complete.
+      Forward,
+      // Forward, but if vectorized, is likely to prevent store-to-load
+      // forwarding.
+      ForwardButPreventsForwarding,
+      // Lexically backward.
+      Backward,
+      // Backward, but the distance allows a vectorization factor of
+      // MaxSafeDepDistBytes.
+      BackwardVectorizable,
+      // Same, but may prevent store-to-load forwarding.
+      BackwardVectorizableButPreventsForwarding
+    };
+
+    /// String version of the types.
+    static const char *DepName[];
+
+    /// Index of the source of the dependence in the InstMap vector.
+    unsigned Source;
+    /// Index of the destination of the dependence in the InstMap vector.
+    unsigned Destination;
+    /// The type of the dependence.
+    DepType Type;
+
+    Dependence(unsigned Source, unsigned Destination, DepType Type)
+        : Source(Source), Destination(Destination), Type(Type) {}
+
+    /// Return the source instruction of the dependence.
+    Instruction *getSource(const LoopAccessInfo &LAI) const;
+    /// Return the destination instruction of the dependence.
+    Instruction *getDestination(const LoopAccessInfo &LAI) const;
+
+    /// Dependence types that don't prevent vectorization.
+    static VectorizationSafetyStatus isSafeForVectorization(DepType Type);
+
+    /// Lexically forward dependence.
+    bool isForward() const;
+    /// Lexically backward dependence.
+    bool isBackward() const;
+
+    /// May be a lexically backward dependence type (includes Unknown).
+    bool isPossiblyBackward() const;
+
+    /// Print the dependence.  \p Instr is used to map the instruction
+    /// indices to instructions.
+    void print(raw_ostream &OS, unsigned Depth,
+               const SmallVectorImpl<Instruction *> &Instrs) const;
+  };
+
+  MemoryDepChecker(PredicatedScalarEvolution &PSE, const Loop *L)
+      : PSE(PSE), InnermostLoop(L), AccessIdx(0), MaxSafeDepDistBytes(0),
+        MaxSafeVectorWidthInBits(-1U),
+        FoundNonConstantDistanceDependence(false),
+        Status(VectorizationSafetyStatus::Safe), RecordDependences(true) {}
+
+  /// Register the location (instructions are given increasing numbers)
+  /// of a write access.
+  void addAccess(StoreInst *SI) {
+    Value *Ptr = SI->getPointerOperand();
+    Accesses[MemAccessInfo(Ptr, true)].push_back(AccessIdx);
+    InstMap.push_back(SI);
+    ++AccessIdx;
+  }
+
+  /// Register the location (instructions are given increasing numbers)
+  /// of a write access.
+  void addAccess(LoadInst *LI) {
+    Value *Ptr = LI->getPointerOperand();
+    Accesses[MemAccessInfo(Ptr, false)].push_back(AccessIdx);
+    InstMap.push_back(LI);
+    ++AccessIdx;
+  }
+
+  /// Check whether the dependencies between the accesses are safe.
+  ///
+  /// Only checks sets with elements in \p CheckDeps.
+  bool areDepsSafe(DepCandidates &AccessSets, MemAccessInfoList &CheckDeps,
+                   const ValueToValueMap &Strides);
+
+  /// No memory dependence was encountered that would inhibit
+  /// vectorization.
+  bool isSafeForVectorization() const {
+    return Status == VectorizationSafetyStatus::Safe;
+  }
+
+  /// Return true if the number of elements that are safe to operate on
+  /// simultaneously is not bounded.
+  bool isSafeForAnyVectorWidth() const {
+    return MaxSafeVectorWidthInBits == UINT_MAX;
+  }
+
+  /// The maximum number of bytes of a vector register we can vectorize
+  /// the accesses safely with.
+  uint64_t getMaxSafeDepDistBytes() { return MaxSafeDepDistBytes; }
+
+  /// Return the number of elements that are safe to operate on
+  /// simultaneously, multiplied by the size of the element in bits.
+  uint64_t getMaxSafeVectorWidthInBits() const {
+    return MaxSafeVectorWidthInBits;
+  }
+
+  /// In same cases when the dependency check fails we can still
+  /// vectorize the loop with a dynamic array access check.
+  bool shouldRetryWithRuntimeCheck() const {
+    return FoundNonConstantDistanceDependence &&
+           Status == VectorizationSafetyStatus::PossiblySafeWithRtChecks;
+  }
+
+  /// Returns the memory dependences.  If null is returned we exceeded
+  /// the MaxDependences threshold and this information is not
+  /// available.
+  const SmallVectorImpl<Dependence> *getDependences() const {
+    return RecordDependences ? &Dependences : nullptr;
+  }
+
+  void clearDependences() { Dependences.clear(); }
+
+  /// The vector of memory access instructions.  The indices are used as
+  /// instruction identifiers in the Dependence class.
+  const SmallVectorImpl<Instruction *> &getMemoryInstructions() const {
+    return InstMap;
+  }
+
+  /// Generate a mapping between the memory instructions and their
+  /// indices according to program order.
+  DenseMap<Instruction *, unsigned> generateInstructionOrderMap() const {
+    DenseMap<Instruction *, unsigned> OrderMap;
+
+    for (unsigned I = 0; I < InstMap.size(); ++I)
+      OrderMap[InstMap[I]] = I;
+
+    return OrderMap;
+  }
+
+  /// Find the set of instructions that read or write via \p Ptr.
+  SmallVector<Instruction *, 4> getInstructionsForAccess(Value *Ptr,
+                                                         bool isWrite) const;
+
+private:
+  /// A wrapper around ScalarEvolution, used to add runtime SCEV checks, and
+  /// applies dynamic knowledge to simplify SCEV expressions and convert them
+  /// to a more usable form. We need this in case assumptions about SCEV
+  /// expressions need to be made in order to avoid unknown dependences. For
+  /// example we might assume a unit stride for a pointer in order to prove
+  /// that a memory access is strided and doesn't wrap.
+  PredicatedScalarEvolution &PSE;
+  const Loop *InnermostLoop;
+
+  /// Maps access locations (ptr, read/write) to program order.
+  DenseMap<MemAccessInfo, std::vector<unsigned> > Accesses;
+
+  /// Memory access instructions in program order.
+  SmallVector<Instruction *, 16> InstMap;
+
+  /// The program order index to be used for the next instruction.
+  unsigned AccessIdx;
+
+  // We can access this many bytes in parallel safely.
+  uint64_t MaxSafeDepDistBytes;
+
+  /// Number of elements (from consecutive iterations) that are safe to
+  /// operate on simultaneously, multiplied by the size of the element in bits.
+  /// The size of the element is taken from the memory access that is most
+  /// restrictive.
+  uint64_t MaxSafeVectorWidthInBits;
+
+  /// If we see a non-constant dependence distance we can still try to
+  /// vectorize this loop with runtime checks.
+  bool FoundNonConstantDistanceDependence;
+
+  /// Result of the dependence checks, indicating whether the checked
+  /// dependences are safe for vectorization, require RT checks or are known to
+  /// be unsafe.
+  VectorizationSafetyStatus Status;
+
+  //// True if Dependences reflects the dependences in the
+  //// loop.  If false we exceeded MaxDependences and
+  //// Dependences is invalid.
+  bool RecordDependences;
+
+  /// Memory dependences collected during the analysis.  Only valid if
+  /// RecordDependences is true.
+  SmallVector<Dependence, 8> Dependences;
+
+  /// Check whether there is a plausible dependence between the two
+  /// accesses.
+  ///
+  /// Access \p A must happen before \p B in program order. The two indices
+  /// identify the index into the program order map.
+  ///
+  /// This function checks  whether there is a plausible dependence (or the
+  /// absence of such can't be proved) between the two accesses. If there is a
+  /// plausible dependence but the dependence distance is bigger than one
+  /// element access it records this distance in \p MaxSafeDepDistBytes (if this
+  /// distance is smaller than any other distance encountered so far).
+  /// Otherwise, this function returns true signaling a possible dependence.
+  Dependence::DepType isDependent(const MemAccessInfo &A, unsigned AIdx,
+                                  const MemAccessInfo &B, unsigned BIdx,
+                                  const ValueToValueMap &Strides);
+
+  /// Check whether the data dependence could prevent store-load
+  /// forwarding.
+  ///
+  /// \return false if we shouldn't vectorize at all or avoid larger
+  /// vectorization factors by limiting MaxSafeDepDistBytes.
+  bool couldPreventStoreLoadForward(uint64_t Distance, uint64_t TypeByteSize);
+
+  /// Updates the current safety status with \p S. We can go from Safe to
+  /// either PossiblySafeWithRtChecks or Unsafe and from
+  /// PossiblySafeWithRtChecks to Unsafe.
+  void mergeInStatus(VectorizationSafetyStatus S);
+};
+
+class RuntimePointerChecking;
+/// A grouping of pointers. A single memcheck is required between
+/// two groups.
+struct RuntimeCheckingPtrGroup {
+  /// Create a new pointer checking group containing a single
+  /// pointer, with index \p Index in RtCheck.
+  RuntimeCheckingPtrGroup(unsigned Index, RuntimePointerChecking &RtCheck);
+
+  /// Tries to add the pointer recorded in RtCheck at index
+  /// \p Index to this pointer checking group. We can only add a pointer
+  /// to a checking group if we will still be able to get
+  /// the upper and lower bounds of the check. Returns true in case
+  /// of success, false otherwise.
+  bool addPointer(unsigned Index);
+
+  /// Constitutes the context of this pointer checking group. For each
+  /// pointer that is a member of this group we will retain the index
+  /// at which it appears in RtCheck.
+  RuntimePointerChecking &RtCheck;
+  /// The SCEV expression which represents the upper bound of all the
+  /// pointers in this group.
+  const SCEV *High;
+  /// The SCEV expression which represents the lower bound of all the
+  /// pointers in this group.
+  const SCEV *Low;
+  /// Indices of all the pointers that constitute this grouping.
+  SmallVector<unsigned, 2> Members;
+};
+
+/// A memcheck which made up of a pair of grouped pointers.
+typedef std::pair<const RuntimeCheckingPtrGroup *,
+                  const RuntimeCheckingPtrGroup *>
+    RuntimePointerCheck;
+
+/// Holds information about the memory runtime legality checks to verify
+/// that a group of pointers do not overlap.
+class RuntimePointerChecking {
+  friend struct RuntimeCheckingPtrGroup;
+
+public:
+  struct PointerInfo {
+    /// Holds the pointer value that we need to check.
+    TrackingVH<Value> PointerValue;
+    /// Holds the smallest byte address accessed by the pointer throughout all
+    /// iterations of the loop.
+    const SCEV *Start;
+    /// Holds the largest byte address accessed by the pointer throughout all
+    /// iterations of the loop, plus 1.
+    const SCEV *End;
+    /// Holds the information if this pointer is used for writing to memory.
+    bool IsWritePtr;
+    /// Holds the id of the set of pointers that could be dependent because of a
+    /// shared underlying object.
+    unsigned DependencySetId;
+    /// Holds the id of the disjoint alias set to which this pointer belongs.
+    unsigned AliasSetId;
+    /// SCEV for the access.
+    const SCEV *Expr;
+
+    PointerInfo(Value *PointerValue, const SCEV *Start, const SCEV *End,
+                bool IsWritePtr, unsigned DependencySetId, unsigned AliasSetId,
+                const SCEV *Expr)
+        : PointerValue(PointerValue), Start(Start), End(End),
+          IsWritePtr(IsWritePtr), DependencySetId(DependencySetId),
+          AliasSetId(AliasSetId), Expr(Expr) {}
+  };
+
+  RuntimePointerChecking(ScalarEvolution *SE) : Need(false), SE(SE) {}
+
+  /// Reset the state of the pointer runtime information.
+  void reset() {
+    Need = false;
+    Pointers.clear();
+    Checks.clear();
+  }
+
+  /// Insert a pointer and calculate the start and end SCEVs.
+  /// We need \p PSE in order to compute the SCEV expression of the pointer
+  /// according to the assumptions that we've made during the analysis.
+  /// The method might also version the pointer stride according to \p Strides,
+  /// and add new predicates to \p PSE.
+  void insert(Loop *Lp, Value *Ptr, bool WritePtr, unsigned DepSetId,
+              unsigned ASId, const ValueToValueMap &Strides,
+              PredicatedScalarEvolution &PSE);
+
+  /// No run-time memory checking is necessary.
+  bool empty() const { return Pointers.empty(); }
+
+  /// Generate the checks and store it.  This also performs the grouping
+  /// of pointers to reduce the number of memchecks necessary.
+  void generateChecks(MemoryDepChecker::DepCandidates &DepCands,
+                      bool UseDependencies);
+
+  /// Returns the checks that generateChecks created.
+  const SmallVectorImpl<RuntimePointerCheck> &getChecks() const {
+    return Checks;
+  }
+
+  /// Decide if we need to add a check between two groups of pointers,
+  /// according to needsChecking.
+  bool needsChecking(const RuntimeCheckingPtrGroup &M,
+                     const RuntimeCheckingPtrGroup &N) const;
+
+  /// Returns the number of run-time checks required according to
+  /// needsChecking.
+  unsigned getNumberOfChecks() const { return Checks.size(); }
+
+  /// Print the list run-time memory checks necessary.
+  void print(raw_ostream &OS, unsigned Depth = 0) const;
+
+  /// Print \p Checks.
+  void printChecks(raw_ostream &OS,
+                   const SmallVectorImpl<RuntimePointerCheck> &Checks,
+                   unsigned Depth = 0) const;
+
+  /// This flag indicates if we need to add the runtime check.
+  bool Need;
+
+  /// Information about the pointers that may require checking.
+  SmallVector<PointerInfo, 2> Pointers;
+
+  /// Holds a partitioning of pointers into "check groups".
+  SmallVector<RuntimeCheckingPtrGroup, 2> CheckingGroups;
+
+  /// Check if pointers are in the same partition
+  ///
+  /// \p PtrToPartition contains the partition number for pointers (-1 if the
+  /// pointer belongs to multiple partitions).
+  static bool
+  arePointersInSamePartition(const SmallVectorImpl<int> &PtrToPartition,
+                             unsigned PtrIdx1, unsigned PtrIdx2);
+
+  /// Decide whether we need to issue a run-time check for pointer at
+  /// index \p I and \p J to prove their independence.
+  bool needsChecking(unsigned I, unsigned J) const;
+
+  /// Return PointerInfo for pointer at index \p PtrIdx.
+  const PointerInfo &getPointerInfo(unsigned PtrIdx) const {
+    return Pointers[PtrIdx];
+  }
+
+  ScalarEvolution *getSE() const { return SE; }
+
+private:
+  /// Groups pointers such that a single memcheck is required
+  /// between two different groups. This will clear the CheckingGroups vector
+  /// and re-compute it. We will only group dependecies if \p UseDependencies
+  /// is true, otherwise we will create a separate group for each pointer.
+  void groupChecks(MemoryDepChecker::DepCandidates &DepCands,
+                   bool UseDependencies);
+
+  /// Generate the checks and return them.
+  SmallVector<RuntimePointerCheck, 4> generateChecks() const;
+
+  /// Holds a pointer to the ScalarEvolution analysis.
+  ScalarEvolution *SE;
+
+  /// Set of run-time checks required to establish independence of
+  /// otherwise may-aliasing pointers in the loop.
+  SmallVector<RuntimePointerCheck, 4> Checks;
+};
+
+/// Drive the analysis of memory accesses in the loop
+///
+/// This class is responsible for analyzing the memory accesses of a loop.  It
+/// collects the accesses and then its main helper the AccessAnalysis class
+/// finds and categorizes the dependences in buildDependenceSets.
+///
+/// For memory dependences that can be analyzed at compile time, it determines
+/// whether the dependence is part of cycle inhibiting vectorization.  This work
+/// is delegated to the MemoryDepChecker class.
+///
+/// For memory dependences that cannot be determined at compile time, it
+/// generates run-time checks to prove independence.  This is done by
+/// AccessAnalysis::canCheckPtrAtRT and the checks are maintained by the
+/// RuntimePointerCheck class.
+///
+/// If pointers can wrap or can't be expressed as affine AddRec expressions by
+/// ScalarEvolution, we will generate run-time checks by emitting a
+/// SCEVUnionPredicate.
+///
+/// Checks for both memory dependences and the SCEV predicates contained in the
+/// PSE must be emitted in order for the results of this analysis to be valid.
+class LoopAccessInfo {
+public:
+  LoopAccessInfo(Loop *L, ScalarEvolution *SE, const TargetLibraryInfo *TLI,
+                 AAResults *AA, DominatorTree *DT, LoopInfo *LI);
+
+  /// Return true we can analyze the memory accesses in the loop and there are
+  /// no memory dependence cycles.
+  bool canVectorizeMemory() const { return CanVecMem; }
+
+  /// Return true if there is a convergent operation in the loop. There may
+  /// still be reported runtime pointer checks that would be required, but it is
+  /// not legal to insert them.
+  bool hasConvergentOp() const { return HasConvergentOp; }
+
+  const RuntimePointerChecking *getRuntimePointerChecking() const {
+    return PtrRtChecking.get();
+  }
+
+  /// Number of memchecks required to prove independence of otherwise
+  /// may-alias pointers.
+  unsigned getNumRuntimePointerChecks() const {
+    return PtrRtChecking->getNumberOfChecks();
+  }
+
+  /// Return true if the block BB needs to be predicated in order for the loop
+  /// to be vectorized.
+  static bool blockNeedsPredication(BasicBlock *BB, Loop *TheLoop,
+                                    DominatorTree *DT);
+
+  /// Returns true if the value V is uniform within the loop.
+  bool isUniform(Value *V) const;
+
+  uint64_t getMaxSafeDepDistBytes() const { return MaxSafeDepDistBytes; }
+  unsigned getNumStores() const { return NumStores; }
+  unsigned getNumLoads() const { return NumLoads;}
+
+  /// The diagnostics report generated for the analysis.  E.g. why we
+  /// couldn't analyze the loop.
+  const OptimizationRemarkAnalysis *getReport() const { return Report.get(); }
+
+  /// the Memory Dependence Checker which can determine the
+  /// loop-independent and loop-carried dependences between memory accesses.
+  const MemoryDepChecker &getDepChecker() const { return *DepChecker; }
+
+  /// Return the list of instructions that use \p Ptr to read or write
+  /// memory.
+  SmallVector<Instruction *, 4> getInstructionsForAccess(Value *Ptr,
+                                                         bool isWrite) const {
+    return DepChecker->getInstructionsForAccess(Ptr, isWrite);
+  }
+
+  /// If an access has a symbolic strides, this maps the pointer value to
+  /// the stride symbol.
+  const ValueToValueMap &getSymbolicStrides() const { return SymbolicStrides; }
+
+  /// Pointer has a symbolic stride.
+  bool hasStride(Value *V) const { return StrideSet.count(V); }
+
+  /// Print the information about the memory accesses in the loop.
+  void print(raw_ostream &OS, unsigned Depth = 0) const;
+
+  /// If the loop has memory dependence involving an invariant address, i.e. two
+  /// stores or a store and a load, then return true, else return false.
+  bool hasDependenceInvolvingLoopInvariantAddress() const {
+    return HasDependenceInvolvingLoopInvariantAddress;
+  }
+
+  /// Used to add runtime SCEV checks. Simplifies SCEV expressions and converts
+  /// them to a more usable form.  All SCEV expressions during the analysis
+  /// should be re-written (and therefore simplified) according to PSE.
+  /// A user of LoopAccessAnalysis will need to emit the runtime checks
+  /// associated with this predicate.
+  const PredicatedScalarEvolution &getPSE() const { return *PSE; }
+
+private:
+  /// Analyze the loop.
+  void analyzeLoop(AAResults *AA, LoopInfo *LI,
+                   const TargetLibraryInfo *TLI, DominatorTree *DT);
+
+  /// Check if the structure of the loop allows it to be analyzed by this
+  /// pass.
+  bool canAnalyzeLoop();
+
+  /// Save the analysis remark.
+  ///
+  /// LAA does not directly emits the remarks.  Instead it stores it which the
+  /// client can retrieve and presents as its own analysis
+  /// (e.g. -Rpass-analysis=loop-vectorize).
+  OptimizationRemarkAnalysis &recordAnalysis(StringRef RemarkName,
+                                             Instruction *Instr = nullptr);
+
+  /// Collect memory access with loop invariant strides.
+  ///
+  /// Looks for accesses like "a[i * StrideA]" where "StrideA" is loop
+  /// invariant.
+  void collectStridedAccess(Value *LoadOrStoreInst);
+
+  std::unique_ptr<PredicatedScalarEvolution> PSE;
+
+  /// We need to check that all of the pointers in this list are disjoint
+  /// at runtime. Using std::unique_ptr to make using move ctor simpler.
+  std::unique_ptr<RuntimePointerChecking> PtrRtChecking;
+
+  /// the Memory Dependence Checker which can determine the
+  /// loop-independent and loop-carried dependences between memory accesses.
+  std::unique_ptr<MemoryDepChecker> DepChecker;
+
+  Loop *TheLoop;
+
+  unsigned NumLoads;
+  unsigned NumStores;
+
+  uint64_t MaxSafeDepDistBytes;
+
+  /// Cache the result of analyzeLoop.
+  bool CanVecMem;
+  bool HasConvergentOp;
+
+  /// Indicator that there are non vectorizable stores to a uniform address.
+  bool HasDependenceInvolvingLoopInvariantAddress;
+
+  /// The diagnostics report generated for the analysis.  E.g. why we
+  /// couldn't analyze the loop.
+  std::unique_ptr<OptimizationRemarkAnalysis> Report;
+
+  /// If an access has a symbolic strides, this maps the pointer value to
+  /// the stride symbol.
+  ValueToValueMap SymbolicStrides;
+
+  /// Set of symbolic strides values.
+  SmallPtrSet<Value *, 8> StrideSet;
+};
+
+Value *stripIntegerCast(Value *V);
+
+/// Return the SCEV corresponding to a pointer with the symbolic stride
+/// replaced with constant one, assuming the SCEV predicate associated with
+/// \p PSE is true.
+///
+/// If necessary this method will version the stride of the pointer according
+/// to \p PtrToStride and therefore add further predicates to \p PSE.
+///
+/// If \p OrigPtr is not null, use it to look up the stride value instead of \p
+/// Ptr.  \p PtrToStride provides the mapping between the pointer value and its
+/// stride as collected by LoopVectorizationLegality::collectStridedAccess.
+const SCEV *replaceSymbolicStrideSCEV(PredicatedScalarEvolution &PSE,
+                                      const ValueToValueMap &PtrToStride,
+                                      Value *Ptr, Value *OrigPtr = nullptr);
+
+/// If the pointer has a constant stride return it in units of its
+/// element size.  Otherwise return zero.
+///
+/// Ensure that it does not wrap in the address space, assuming the predicate
+/// associated with \p PSE is true.
+///
+/// If necessary this method will version the stride of the pointer according
+/// to \p PtrToStride and therefore add further predicates to \p PSE.
+/// The \p Assume parameter indicates if we are allowed to make additional
+/// run-time assumptions.
+int64_t getPtrStride(PredicatedScalarEvolution &PSE, Value *Ptr, const Loop *Lp,
+                     const ValueToValueMap &StridesMap = ValueToValueMap(),
+                     bool Assume = false, bool ShouldCheckWrap = true);
+
+/// Attempt to sort the pointers in \p VL and return the sorted indices
+/// in \p SortedIndices, if reordering is required.
+///
+/// Returns 'true' if sorting is legal, otherwise returns 'false'.
+///
+/// For example, for a given \p VL of memory accesses in program order, a[i+4],
+/// a[i+0], a[i+1] and a[i+7], this function will sort the \p VL and save the
+/// sorted indices in \p SortedIndices as a[i+0], a[i+1], a[i+4], a[i+7] and
+/// saves the mask for actual memory accesses in program order in
+/// \p SortedIndices as <1,2,0,3>
+bool sortPtrAccesses(ArrayRef<Value *> VL, const DataLayout &DL,
+                     ScalarEvolution &SE,
+                     SmallVectorImpl<unsigned> &SortedIndices);
+
+/// Returns true if the memory operations \p A and \p B are consecutive.
+/// This is a simple API that does not depend on the analysis pass.
+bool isConsecutiveAccess(Value *A, Value *B, const DataLayout &DL,
+                         ScalarEvolution &SE, bool CheckType = true);
+
+/// This analysis provides dependence information for the memory accesses
+/// of a loop.
+///
+/// It runs the analysis for a loop on demand.  This can be initiated by
+/// querying the loop access info via LAA::getInfo.  getInfo return a
+/// LoopAccessInfo object.  See this class for the specifics of what information
+/// is provided.
+class LoopAccessLegacyAnalysis : public FunctionPass {
+public:
+  static char ID;
+
+  LoopAccessLegacyAnalysis();
+
+  bool runOnFunction(Function &F) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+  /// Query the result of the loop access information for the loop \p L.
+  ///
+  /// If there is no cached result available run the analysis.
+  const LoopAccessInfo &getInfo(Loop *L);
+
+  void releaseMemory() override {
+    // Invalidate the cache when the pass is freed.
+    LoopAccessInfoMap.clear();
+  }
+
+  /// Print the result of the analysis when invoked with -analyze.
+  void print(raw_ostream &OS, const Module *M = nullptr) const override;
+
+private:
+  /// The cache.
+  DenseMap<Loop *, std::unique_ptr<LoopAccessInfo>> LoopAccessInfoMap;
+
+  // The used analysis passes.
+  ScalarEvolution *SE = nullptr;
+  const TargetLibraryInfo *TLI = nullptr;
+  AAResults *AA = nullptr;
+  DominatorTree *DT = nullptr;
+  LoopInfo *LI = nullptr;
+};
+
+/// This analysis provides dependence information for the memory
+/// accesses of a loop.
+///
+/// It runs the analysis for a loop on demand.  This can be initiated by
+/// querying the loop access info via AM.getResult<LoopAccessAnalysis>.
+/// getResult return a LoopAccessInfo object.  See this class for the
+/// specifics of what information is provided.
+class LoopAccessAnalysis
+    : public AnalysisInfoMixin<LoopAccessAnalysis> {
+  friend AnalysisInfoMixin<LoopAccessAnalysis>;
+  static AnalysisKey Key;
+
+public:
+  typedef LoopAccessInfo Result;
+
+  Result run(Loop &L, LoopAnalysisManager &AM, LoopStandardAnalysisResults &AR);
+};
+
+inline Instruction *MemoryDepChecker::Dependence::getSource(
+    const LoopAccessInfo &LAI) const {
+  return LAI.getDepChecker().getMemoryInstructions()[Source];
+}
+
+inline Instruction *MemoryDepChecker::Dependence::getDestination(
+    const LoopAccessInfo &LAI) const {
+  return LAI.getDepChecker().getMemoryInstructions()[Destination];
+}
+
+} // End llvm namespace
+
+#endif
+
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif