Update aosp/master LLVM for rebase to r230699.

Change-Id: I2b5be30509658cb8266be782de0ab24f9099f9b9

1 files changed, 290 insertions, 0 deletions

diff --git a/include/llvm/Analysis/LoopAccessAnalysis.h b/include/llvm/Analysis/LoopAccessAnalysis.h
new file mode 100644
index 0000000..323af98
--- /dev/null
+++ b/include/llvm/Analysis/LoopAccessAnalysis.h
@@ -0,0 +1,290 @@
+//===- llvm/Analysis/LoopAccessAnalysis.h -----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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/ADT/Optional.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AliasSetTracker.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+
+class Value;
+class DataLayout;
+class AliasAnalysis;
+class ScalarEvolution;
+class Loop;
+class SCEV;
+
+/// Optimization analysis message produced during vectorization. Messages inform
+/// the user why vectorization did not occur.
+class LoopAccessReport {
+  std::string Message;
+  const Instruction *Instr;
+
+protected:
+  LoopAccessReport(const Twine &Message, const Instruction *I)
+      : Message(Message.str()), Instr(I) {}
+
+public:
+  LoopAccessReport(const Instruction *I = nullptr) : Instr(I) {}
+
+  template <typename A> LoopAccessReport &operator<<(const A &Value) {
+    raw_string_ostream Out(Message);
+    Out << Value;
+    return *this;
+  }
+
+  const Instruction *getInstr() const { return Instr; }
+
+  std::string &str() { return Message; }
+  const std::string &str() const { return Message; }
+  operator Twine() { return Message; }
+
+  /// \brief Emit an analysis note for \p PassName with the debug location from
+  /// the instruction in \p Message if available.  Otherwise use the location of
+  /// \p TheLoop.
+  static void emitAnalysis(const LoopAccessReport &Message,
+                           const Function *TheFunction,
+                           const Loop *TheLoop,
+                           const char *PassName);
+};
+
+/// \brief Collection of parameters shared beetween the Loop Vectorizer and the
+/// Loop Access Analysis.
+struct VectorizerParams {
+  /// \brief Maximum SIMD width.
+  static const unsigned MaxVectorWidth;
+
+  /// \brief VF as overridden by the user.
+  static unsigned VectorizationFactor;
+  /// \brief Interleave factor as overridden by the user.
+  static unsigned VectorizationInterleave;
+  /// \brief True if force-vector-interleave was specified by the user.
+  static bool isInterleaveForced();
+
+  /// \\brief When performing memory disambiguation checks at runtime do not
+  /// make more than this number of comparisons.
+  static unsigned RuntimeMemoryCheckThreshold;
+};
+
+/// \brief 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.
+class LoopAccessInfo {
+public:
+  /// This struct holds information about the memory runtime legality check that
+  /// a group of pointers do not overlap.
+  struct RuntimePointerCheck {
+    RuntimePointerCheck() : Need(false) {}
+
+    /// Reset the state of the pointer runtime information.
+    void reset() {
+      Need = false;
+      Pointers.clear();
+      Starts.clear();
+      Ends.clear();
+      IsWritePtr.clear();
+      DependencySetId.clear();
+      AliasSetId.clear();
+    }
+
+    /// Insert a pointer and calculate the start and end SCEVs.
+    void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr, bool WritePtr,
+                unsigned DepSetId, unsigned ASId,
+                const ValueToValueMap &Strides);
+
+    /// \brief No run-time memory checking is necessary.
+    bool empty() const { return Pointers.empty(); }
+
+    /// \brief 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;
+
+    /// \brief Print the list run-time memory checks necessary.
+    void print(raw_ostream &OS, unsigned Depth = 0) const;
+
+    /// This flag indicates if we need to add the runtime check.
+    bool Need;
+    /// Holds the pointers that we need to check.
+    SmallVector<TrackingVH<Value>, 2> Pointers;
+    /// Holds the pointer value at the beginning of the loop.
+    SmallVector<const SCEV*, 2> Starts;
+    /// Holds the pointer value at the end of the loop.
+    SmallVector<const SCEV*, 2> Ends;
+    /// Holds the information if this pointer is used for writing to memory.
+    SmallVector<bool, 2> IsWritePtr;
+    /// Holds the id of the set of pointers that could be dependent because of a
+    /// shared underlying object.
+    SmallVector<unsigned, 2> DependencySetId;
+    /// Holds the id of the disjoint alias set to which this pointer belongs.
+    SmallVector<unsigned, 2> AliasSetId;
+  };
+
+  LoopAccessInfo(Loop *L, ScalarEvolution *SE, const DataLayout *DL,
+                 const TargetLibraryInfo *TLI, AliasAnalysis *AA,
+                 DominatorTree *DT, const ValueToValueMap &Strides);
+
+  /// Return true we can analyze the memory accesses in the loop and there are
+  /// no memory dependence cycles.
+  bool canVectorizeMemory() const { return CanVecMem; }
+
+  const RuntimePointerCheck *getRuntimePointerCheck() const {
+    return &PtrRtCheck;
+  }
+
+  /// 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;
+
+  unsigned getMaxSafeDepDistBytes() const { return MaxSafeDepDistBytes; }
+  unsigned getNumStores() const { return NumStores; }
+  unsigned getNumLoads() const { return NumLoads;}
+
+  /// \brief Add code that checks at runtime if the accessed arrays overlap.
+  ///
+  /// Returns a pair of instructions where the first element is the first
+  /// instruction generated in possibly a sequence of instructions and the
+  /// second value is the final comparator value or NULL if no check is needed.
+  std::pair<Instruction *, Instruction *>
+    addRuntimeCheck(Instruction *Loc) const;
+
+  /// \brief The diagnostics report generated for the analysis.  E.g. why we
+  /// couldn't analyze the loop.
+  const Optional<LoopAccessReport> &getReport() const { return Report; }
+
+  /// \brief Print the information about the memory accesses in the loop.
+  void print(raw_ostream &OS, unsigned Depth = 0) const;
+
+  /// \brief Used to ensure that if the analysis was run with speculating the
+  /// value of symbolic strides, the client queries it with the same assumption.
+  /// Only used in DEBUG build but we don't want NDEBUG-dependent ABI.
+  unsigned NumSymbolicStrides;
+
+private:
+  /// \brief Analyze the loop.  Substitute symbolic strides using Strides.
+  void analyzeLoop(const ValueToValueMap &Strides);
+
+  /// \brief Check if the structure of the loop allows it to be analyzed by this
+  /// pass.
+  bool canAnalyzeLoop();
+
+  void emitAnalysis(LoopAccessReport &Message);
+
+  /// We need to check that all of the pointers in this list are disjoint
+  /// at runtime.
+  RuntimePointerCheck PtrRtCheck;
+  Loop *TheLoop;
+  ScalarEvolution *SE;
+  const DataLayout *DL;
+  const TargetLibraryInfo *TLI;
+  AliasAnalysis *AA;
+  DominatorTree *DT;
+
+  unsigned NumLoads;
+  unsigned NumStores;
+
+  unsigned MaxSafeDepDistBytes;
+
+  /// \brief Cache the result of analyzeLoop.
+  bool CanVecMem;
+
+  /// \brief The diagnostics report generated for the analysis.  E.g. why we
+  /// couldn't analyze the loop.
+  Optional<LoopAccessReport> Report;
+};
+
+Value *stripIntegerCast(Value *V);
+
+///\brief Return the SCEV corresponding to a pointer with the symbolic stride
+///replaced with constant one.
+///
+/// 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(ScalarEvolution *SE,
+                                      const ValueToValueMap &PtrToStride,
+                                      Value *Ptr, Value *OrigPtr = nullptr);
+
+/// \brief 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 LoopAccessAnalysis : public FunctionPass {
+public:
+  static char ID;
+
+  LoopAccessAnalysis() : FunctionPass(ID) {
+    initializeLoopAccessAnalysisPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+  /// \brief Query the result of the loop access information for the loop \p L.
+  ///
+  /// If the client speculates (and then issues run-time checks) for the values
+  /// of symbolic strides, \p Strides provides the mapping (see
+  /// replaceSymbolicStrideSCEV).  If there is no cached result available run
+  /// the analysis.
+  const LoopAccessInfo &getInfo(Loop *L, const ValueToValueMap &Strides);
+
+  void releaseMemory() override {
+    // Invalidate the cache when the pass is freed.
+    LoopAccessInfoMap.clear();
+  }
+
+  /// \brief Print the result of the analysis when invoked with -analyze.
+  void print(raw_ostream &OS, const Module *M = nullptr) const override;
+
+private:
+  /// \brief The cache.
+  DenseMap<Loop *, std::unique_ptr<LoopAccessInfo>> LoopAccessInfoMap;
+
+  // The used analysis passes.
+  ScalarEvolution *SE;
+  const DataLayout *DL;
+  const TargetLibraryInfo *TLI;
+  AliasAnalysis *AA;
+  DominatorTree *DT;
+};
+} // End llvm namespace
+
+#endif