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      1 //===---- MemCpyOptimizer.h - memcpy optimization ---------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This pass performs various transformations related to eliminating memcpy
     11 // calls, or transforming sets of stores into memset's.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
     16 #define LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
     17 
     18 #include "llvm/ADT/STLExtras.h"
     19 #include "llvm/Analysis/AliasAnalysis.h"
     20 #include "llvm/Analysis/AssumptionCache.h"
     21 #include "llvm/Analysis/GlobalsModRef.h"
     22 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
     23 #include "llvm/Analysis/TargetLibraryInfo.h"
     24 #include "llvm/IR/Dominators.h"
     25 #include "llvm/IR/Function.h"
     26 #include "llvm/IR/Instructions.h"
     27 #include "llvm/IR/IntrinsicInst.h"
     28 #include "llvm/IR/PassManager.h"
     29 
     30 namespace llvm {
     31 
     32 class MemCpyOptPass : public PassInfoMixin<MemCpyOptPass> {
     33   MemoryDependenceResults *MD = nullptr;
     34   TargetLibraryInfo *TLI = nullptr;
     35   std::function<AliasAnalysis &()> LookupAliasAnalysis;
     36   std::function<AssumptionCache &()> LookupAssumptionCache;
     37   std::function<DominatorTree &()> LookupDomTree;
     38 
     39 public:
     40   MemCpyOptPass() {}
     41   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
     42   // Glue for the old PM.
     43   bool runImpl(Function &F, MemoryDependenceResults *MD_,
     44                TargetLibraryInfo *TLI_,
     45                std::function<AliasAnalysis &()> LookupAliasAnalysis_,
     46                std::function<AssumptionCache &()> LookupAssumptionCache_,
     47                std::function<DominatorTree &()> LookupDomTree_);
     48 
     49 private:
     50   // Helper functions
     51   bool processStore(StoreInst *SI, BasicBlock::iterator &BBI);
     52   bool processMemSet(MemSetInst *SI, BasicBlock::iterator &BBI);
     53   bool processMemCpy(MemCpyInst *M);
     54   bool processMemMove(MemMoveInst *M);
     55   bool performCallSlotOptzn(Instruction *cpy, Value *cpyDst, Value *cpySrc,
     56                             uint64_t cpyLen, unsigned cpyAlign, CallInst *C);
     57   bool processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep);
     58   bool processMemSetMemCpyDependence(MemCpyInst *M, MemSetInst *MDep);
     59   bool performMemCpyToMemSetOptzn(MemCpyInst *M, MemSetInst *MDep);
     60   bool processByValArgument(CallSite CS, unsigned ArgNo);
     61   Instruction *tryMergingIntoMemset(Instruction *I, Value *StartPtr,
     62                                     Value *ByteVal);
     63 
     64   bool iterateOnFunction(Function &F);
     65 };
     66 }
     67 
     68 #endif // LLVM_TRANSFORMS_SCALAR_MEMCPYOPTIMIZER_H
     69