577 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			577 lines
		
	
	
		
			24 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===- InstCombineInternal.h - InstCombine pass internals -------*- C++ -*-===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| /// \file
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| ///
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| /// This file provides internal interfaces used to implement the InstCombine.
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| ///
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| //===----------------------------------------------------------------------===//
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| 
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| #ifndef LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
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| #define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
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| 
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| #include "llvm/Analysis/AliasAnalysis.h"
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| #include "llvm/Analysis/AssumptionCache.h"
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| #include "llvm/Analysis/LoopInfo.h"
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| #include "llvm/Analysis/TargetFolder.h"
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| #include "llvm/Analysis/ValueTracking.h"
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| #include "llvm/IR/Dominators.h"
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| #include "llvm/IR/IRBuilder.h"
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| #include "llvm/IR/InstVisitor.h"
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| #include "llvm/IR/IntrinsicInst.h"
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| #include "llvm/IR/Operator.h"
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| #include "llvm/IR/PatternMatch.h"
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| #include "llvm/Pass.h"
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| #include "llvm/Transforms/InstCombine/InstCombineWorklist.h"
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| 
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| #define DEBUG_TYPE "instcombine"
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| 
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| namespace llvm {
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| class CallSite;
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| class DataLayout;
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| class DominatorTree;
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| class TargetLibraryInfo;
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| class DbgDeclareInst;
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| class MemIntrinsic;
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| class MemSetInst;
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| 
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| /// \brief Assign a complexity or rank value to LLVM Values.
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| ///
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| /// This routine maps IR values to various complexity ranks:
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| ///   0 -> undef
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| ///   1 -> Constants
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| ///   2 -> Other non-instructions
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| ///   3 -> Arguments
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| ///   3 -> Unary operations
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| ///   4 -> Other instructions
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| static inline unsigned getComplexity(Value *V) {
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|   if (isa<Instruction>(V)) {
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|     if (BinaryOperator::isNeg(V) || BinaryOperator::isFNeg(V) ||
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|         BinaryOperator::isNot(V))
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|       return 3;
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|     return 4;
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|   }
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|   if (isa<Argument>(V))
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|     return 3;
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|   return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
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| }
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| 
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| /// \brief Add one to a Constant
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| static inline Constant *AddOne(Constant *C) {
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|   return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1));
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| }
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| /// \brief Subtract one from a Constant
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| static inline Constant *SubOne(Constant *C) {
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|   return ConstantExpr::getSub(C, ConstantInt::get(C->getType(), 1));
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| }
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| 
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| /// \brief Return true if the specified value is free to invert (apply ~ to).
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| /// This happens in cases where the ~ can be eliminated.  If WillInvertAllUses
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| /// is true, work under the assumption that the caller intends to remove all
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| /// uses of V and only keep uses of ~V.
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| ///
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| static inline bool IsFreeToInvert(Value *V, bool WillInvertAllUses) {
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|   // ~(~(X)) -> X.
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|   if (BinaryOperator::isNot(V))
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|     return true;
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| 
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|   // Constants can be considered to be not'ed values.
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|   if (isa<ConstantInt>(V))
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|     return true;
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| 
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|   // Compares can be inverted if all of their uses are being modified to use the
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|   // ~V.
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|   if (isa<CmpInst>(V))
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|     return WillInvertAllUses;
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| 
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|   // If `V` is of the form `A + Constant` then `-1 - V` can be folded into `(-1
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|   // - Constant) - A` if we are willing to invert all of the uses.
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|   if (BinaryOperator *BO = dyn_cast<BinaryOperator>(V))
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|     if (BO->getOpcode() == Instruction::Add ||
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|         BO->getOpcode() == Instruction::Sub)
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|       if (isa<Constant>(BO->getOperand(0)) || isa<Constant>(BO->getOperand(1)))
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|         return WillInvertAllUses;
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| 
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|   return false;
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| }
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| 
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| 
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| /// \brief Specific patterns of overflow check idioms that we match.
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| enum OverflowCheckFlavor {
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|   OCF_UNSIGNED_ADD,
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|   OCF_SIGNED_ADD,
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|   OCF_UNSIGNED_SUB,
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|   OCF_SIGNED_SUB,
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|   OCF_UNSIGNED_MUL,
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|   OCF_SIGNED_MUL,
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| 
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|   OCF_INVALID
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| };
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| 
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| /// \brief Returns the OverflowCheckFlavor corresponding to a overflow_with_op
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| /// intrinsic.
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| static inline OverflowCheckFlavor
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| IntrinsicIDToOverflowCheckFlavor(unsigned ID) {
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|   switch (ID) {
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|   default:
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|     return OCF_INVALID;
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|   case Intrinsic::uadd_with_overflow:
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|     return OCF_UNSIGNED_ADD;
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|   case Intrinsic::sadd_with_overflow:
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|     return OCF_SIGNED_ADD;
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|   case Intrinsic::usub_with_overflow:
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|     return OCF_UNSIGNED_SUB;
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|   case Intrinsic::ssub_with_overflow:
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|     return OCF_SIGNED_SUB;
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|   case Intrinsic::umul_with_overflow:
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|     return OCF_UNSIGNED_MUL;
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|   case Intrinsic::smul_with_overflow:
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|     return OCF_SIGNED_MUL;
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|   }
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| }
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| 
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| /// \brief An IRBuilder inserter that adds new instructions to the instcombine
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| /// worklist.
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| class LLVM_LIBRARY_VISIBILITY InstCombineIRInserter
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|     : public IRBuilderDefaultInserter<true> {
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|   InstCombineWorklist &Worklist;
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|   AssumptionCache *AC;
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| 
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| public:
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|   InstCombineIRInserter(InstCombineWorklist &WL, AssumptionCache *AC)
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|       : Worklist(WL), AC(AC) {}
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| 
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|   void InsertHelper(Instruction *I, const Twine &Name, BasicBlock *BB,
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|                     BasicBlock::iterator InsertPt) const {
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|     IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
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|     Worklist.Add(I);
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| 
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|     using namespace llvm::PatternMatch;
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|     if (match(I, m_Intrinsic<Intrinsic::assume>()))
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|       AC->registerAssumption(cast<CallInst>(I));
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|   }
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| };
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| 
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| /// \brief The core instruction combiner logic.
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| ///
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| /// This class provides both the logic to recursively visit instructions and
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| /// combine them, as well as the pass infrastructure for running this as part
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| /// of the LLVM pass pipeline.
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| class LLVM_LIBRARY_VISIBILITY InstCombiner
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|     : public InstVisitor<InstCombiner, Instruction *> {
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|   // FIXME: These members shouldn't be public.
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| public:
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|   /// \brief A worklist of the instructions that need to be simplified.
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|   InstCombineWorklist &Worklist;
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| 
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|   /// \brief An IRBuilder that automatically inserts new instructions into the
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|   /// worklist.
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|   typedef IRBuilder<true, TargetFolder, InstCombineIRInserter> BuilderTy;
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|   BuilderTy *Builder;
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| 
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| private:
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|   // Mode in which we are running the combiner.
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|   const bool MinimizeSize;
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| 
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|   AliasAnalysis *AA;
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| 
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|   // Required analyses.
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|   // FIXME: These can never be null and should be references.
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|   AssumptionCache *AC;
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|   TargetLibraryInfo *TLI;
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|   DominatorTree *DT;
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|   const DataLayout &DL;
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| 
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|   // Optional analyses. When non-null, these can both be used to do better
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|   // combining and will be updated to reflect any changes.
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|   LoopInfo *LI;
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| 
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|   bool MadeIRChange;
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| 
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| public:
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|   InstCombiner(InstCombineWorklist &Worklist, BuilderTy *Builder,
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|                bool MinimizeSize, AliasAnalysis *AA,
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|                AssumptionCache *AC, TargetLibraryInfo *TLI,
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|                DominatorTree *DT, const DataLayout &DL, LoopInfo *LI)
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|       : Worklist(Worklist), Builder(Builder), MinimizeSize(MinimizeSize),
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|         AA(AA), AC(AC), TLI(TLI), DT(DT), DL(DL), LI(LI), MadeIRChange(false) {}
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| 
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|   /// \brief Run the combiner over the entire worklist until it is empty.
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|   ///
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|   /// \returns true if the IR is changed.
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|   bool run();
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| 
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|   AssumptionCache *getAssumptionCache() const { return AC; }
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| 
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|   const DataLayout &getDataLayout() const { return DL; }
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| 
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|   DominatorTree *getDominatorTree() const { return DT; }
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| 
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|   LoopInfo *getLoopInfo() const { return LI; }
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| 
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|   TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
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| 
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|   // Visitation implementation - Implement instruction combining for different
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|   // instruction types.  The semantics are as follows:
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|   // Return Value:
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|   //    null        - No change was made
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|   //     I          - Change was made, I is still valid, I may be dead though
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|   //   otherwise    - Change was made, replace I with returned instruction
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|   //
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|   Instruction *visitAdd(BinaryOperator &I);
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|   Instruction *visitFAdd(BinaryOperator &I);
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|   Value *OptimizePointerDifference(Value *LHS, Value *RHS, Type *Ty);
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|   Instruction *visitSub(BinaryOperator &I);
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|   Instruction *visitFSub(BinaryOperator &I);
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|   Instruction *visitMul(BinaryOperator &I);
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|   Value *foldFMulConst(Instruction *FMulOrDiv, Constant *C,
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|                        Instruction *InsertBefore);
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|   Instruction *visitFMul(BinaryOperator &I);
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|   Instruction *visitURem(BinaryOperator &I);
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|   Instruction *visitSRem(BinaryOperator &I);
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|   Instruction *visitFRem(BinaryOperator &I);
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|   bool SimplifyDivRemOfSelect(BinaryOperator &I);
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|   Instruction *commonRemTransforms(BinaryOperator &I);
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|   Instruction *commonIRemTransforms(BinaryOperator &I);
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|   Instruction *commonDivTransforms(BinaryOperator &I);
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|   Instruction *commonIDivTransforms(BinaryOperator &I);
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|   Instruction *visitUDiv(BinaryOperator &I);
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|   Instruction *visitSDiv(BinaryOperator &I);
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|   Instruction *visitFDiv(BinaryOperator &I);
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|   Value *simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1, bool Inverted);
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|   Value *FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS);
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|   Value *FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
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|   Instruction *visitAnd(BinaryOperator &I);
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|   Value *FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction *CxtI);
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|   Value *FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS);
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|   Instruction *FoldOrWithConstants(BinaryOperator &I, Value *Op, Value *A,
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|                                    Value *B, Value *C);
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|   Instruction *FoldXorWithConstants(BinaryOperator &I, Value *Op, Value *A,
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|                                     Value *B, Value *C);
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|   Instruction *visitOr(BinaryOperator &I);
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|   Instruction *visitXor(BinaryOperator &I);
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|   Instruction *visitShl(BinaryOperator &I);
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|   Instruction *visitAShr(BinaryOperator &I);
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|   Instruction *visitLShr(BinaryOperator &I);
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|   Instruction *commonShiftTransforms(BinaryOperator &I);
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|   Instruction *FoldFCmp_IntToFP_Cst(FCmpInst &I, Instruction *LHSI,
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|                                     Constant *RHSC);
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|   Instruction *FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP,
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|                                             GlobalVariable *GV, CmpInst &ICI,
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|                                             ConstantInt *AndCst = nullptr);
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|   Instruction *visitFCmpInst(FCmpInst &I);
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|   Instruction *visitICmpInst(ICmpInst &I);
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|   Instruction *visitICmpInstWithCastAndCast(ICmpInst &ICI);
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|   Instruction *visitICmpInstWithInstAndIntCst(ICmpInst &ICI, Instruction *LHS,
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|                                               ConstantInt *RHS);
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|   Instruction *FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI,
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|                               ConstantInt *DivRHS);
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|   Instruction *FoldICmpShrCst(ICmpInst &ICI, BinaryOperator *DivI,
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|                               ConstantInt *DivRHS);
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|   Instruction *FoldICmpCstShrCst(ICmpInst &I, Value *Op, Value *A,
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|                                  ConstantInt *CI1, ConstantInt *CI2);
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|   Instruction *FoldICmpCstShlCst(ICmpInst &I, Value *Op, Value *A,
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|                                  ConstantInt *CI1, ConstantInt *CI2);
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|   Instruction *FoldICmpAddOpCst(Instruction &ICI, Value *X, ConstantInt *CI,
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|                                 ICmpInst::Predicate Pred);
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|   Instruction *FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
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|                            ICmpInst::Predicate Cond, Instruction &I);
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|   Instruction *FoldAllocaCmp(ICmpInst &ICI, AllocaInst *Alloca, Value *Other);
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|   Instruction *FoldShiftByConstant(Value *Op0, Constant *Op1,
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|                                    BinaryOperator &I);
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|   Instruction *commonCastTransforms(CastInst &CI);
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|   Instruction *commonPointerCastTransforms(CastInst &CI);
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|   Instruction *visitTrunc(TruncInst &CI);
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|   Instruction *visitZExt(ZExtInst &CI);
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|   Instruction *visitSExt(SExtInst &CI);
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|   Instruction *visitFPTrunc(FPTruncInst &CI);
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|   Instruction *visitFPExt(CastInst &CI);
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|   Instruction *visitFPToUI(FPToUIInst &FI);
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|   Instruction *visitFPToSI(FPToSIInst &FI);
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|   Instruction *visitUIToFP(CastInst &CI);
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|   Instruction *visitSIToFP(CastInst &CI);
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|   Instruction *visitPtrToInt(PtrToIntInst &CI);
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|   Instruction *visitIntToPtr(IntToPtrInst &CI);
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|   Instruction *visitBitCast(BitCastInst &CI);
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|   Instruction *visitAddrSpaceCast(AddrSpaceCastInst &CI);
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|   Instruction *FoldSelectOpOp(SelectInst &SI, Instruction *TI, Instruction *FI);
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|   Instruction *FoldSelectIntoOp(SelectInst &SI, Value *, Value *);
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|   Instruction *FoldSPFofSPF(Instruction *Inner, SelectPatternFlavor SPF1,
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|                             Value *A, Value *B, Instruction &Outer,
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|                             SelectPatternFlavor SPF2, Value *C);
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|   Instruction *FoldItoFPtoI(Instruction &FI);
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|   Instruction *visitSelectInst(SelectInst &SI);
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|   Instruction *visitSelectInstWithICmp(SelectInst &SI, ICmpInst *ICI);
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|   Instruction *visitCallInst(CallInst &CI);
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|   Instruction *visitInvokeInst(InvokeInst &II);
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| 
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|   Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
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|   Instruction *visitPHINode(PHINode &PN);
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|   Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
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|   Instruction *visitAllocaInst(AllocaInst &AI);
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|   Instruction *visitAllocSite(Instruction &FI);
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|   Instruction *visitFree(CallInst &FI);
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|   Instruction *visitLoadInst(LoadInst &LI);
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|   Instruction *visitStoreInst(StoreInst &SI);
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|   Instruction *visitBranchInst(BranchInst &BI);
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|   Instruction *visitSwitchInst(SwitchInst &SI);
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|   Instruction *visitReturnInst(ReturnInst &RI);
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|   Instruction *visitInsertValueInst(InsertValueInst &IV);
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|   Instruction *visitInsertElementInst(InsertElementInst &IE);
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|   Instruction *visitExtractElementInst(ExtractElementInst &EI);
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|   Instruction *visitShuffleVectorInst(ShuffleVectorInst &SVI);
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|   Instruction *visitExtractValueInst(ExtractValueInst &EV);
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|   Instruction *visitLandingPadInst(LandingPadInst &LI);
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| 
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|   // visitInstruction - Specify what to return for unhandled instructions...
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|   Instruction *visitInstruction(Instruction &I) { return nullptr; }
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| 
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|   // True when DB dominates all uses of DI execpt UI.
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|   // UI must be in the same block as DI.
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|   // The routine checks that the DI parent and DB are different.
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|   bool dominatesAllUses(const Instruction *DI, const Instruction *UI,
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|                         const BasicBlock *DB) const;
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| 
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|   // Replace select with select operand SIOpd in SI-ICmp sequence when possible
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|   bool replacedSelectWithOperand(SelectInst *SI, const ICmpInst *Icmp,
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|                                  const unsigned SIOpd);
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| 
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| private:
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|   bool ShouldChangeType(unsigned FromBitWidth, unsigned ToBitWidth) const;
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|   bool ShouldChangeType(Type *From, Type *To) const;
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|   Value *dyn_castNegVal(Value *V) const;
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|   Value *dyn_castFNegVal(Value *V, bool NoSignedZero = false) const;
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|   Type *FindElementAtOffset(PointerType *PtrTy, int64_t Offset,
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|                             SmallVectorImpl<Value *> &NewIndices);
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|   Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);
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| 
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|   /// \brief Classify whether a cast is worth optimizing.
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|   ///
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|   /// Returns true if the cast from "V to Ty" actually results in any code
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|   /// being generated and is interesting to optimize out. If the cast can be
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|   /// eliminated by some other simple transformation, we prefer to do the
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|   /// simplification first.
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|   bool ShouldOptimizeCast(Instruction::CastOps opcode, const Value *V,
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|                           Type *Ty);
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| 
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|   /// \brief Try to optimize a sequence of instructions checking if an operation
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|   /// on LHS and RHS overflows.
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|   ///
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|   /// If this overflow check is done via one of the overflow check intrinsics,
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|   /// then CtxI has to be the call instruction calling that intrinsic.  If this
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|   /// overflow check is done by arithmetic followed by a compare, then CtxI has
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|   /// to be the arithmetic instruction.
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|   ///
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|   /// If a simplification is possible, stores the simplified result of the
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|   /// operation in OperationResult and result of the overflow check in
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|   /// OverflowResult, and return true.  If no simplification is possible,
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|   /// returns false.
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|   bool OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS, Value *RHS,
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|                              Instruction &CtxI, Value *&OperationResult,
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|                              Constant *&OverflowResult);
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| 
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|   Instruction *visitCallSite(CallSite CS);
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|   Instruction *tryOptimizeCall(CallInst *CI);
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|   bool transformConstExprCastCall(CallSite CS);
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|   Instruction *transformCallThroughTrampoline(CallSite CS,
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|                                               IntrinsicInst *Tramp);
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|   Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
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|                                  bool DoXform = true);
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|   Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);
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|   bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS, Instruction &CxtI);
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|   bool WillNotOverflowSignedSub(Value *LHS, Value *RHS, Instruction &CxtI);
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|   bool WillNotOverflowUnsignedSub(Value *LHS, Value *RHS, Instruction &CxtI);
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|   bool WillNotOverflowSignedMul(Value *LHS, Value *RHS, Instruction &CxtI);
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|   Value *EmitGEPOffset(User *GEP);
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|   Instruction *scalarizePHI(ExtractElementInst &EI, PHINode *PN);
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|   Value *EvaluateInDifferentElementOrder(Value *V, ArrayRef<int> Mask);
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| 
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| public:
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|   /// \brief Inserts an instruction \p New before instruction \p Old
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|   ///
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|   /// Also adds the new instruction to the worklist and returns \p New so that
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|   /// it is suitable for use as the return from the visitation patterns.
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|   Instruction *InsertNewInstBefore(Instruction *New, Instruction &Old) {
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|     assert(New && !New->getParent() &&
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|            "New instruction already inserted into a basic block!");
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|     BasicBlock *BB = Old.getParent();
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|     BB->getInstList().insert(Old.getIterator(), New); // Insert inst
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|     Worklist.Add(New);
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|     return New;
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|   }
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| 
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|   /// \brief Same as InsertNewInstBefore, but also sets the debug loc.
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|   Instruction *InsertNewInstWith(Instruction *New, Instruction &Old) {
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|     New->setDebugLoc(Old.getDebugLoc());
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|     return InsertNewInstBefore(New, Old);
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|   }
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| 
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|   /// \brief A combiner-aware RAUW-like routine.
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|   ///
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|   /// This method is to be used when an instruction is found to be dead,
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|   /// replacable with another preexisting expression. Here we add all uses of
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|   /// I to the worklist, replace all uses of I with the new value, then return
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|   /// I, so that the inst combiner will know that I was modified.
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|   Instruction *ReplaceInstUsesWith(Instruction &I, Value *V) {
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|     // If there are no uses to replace, then we return nullptr to indicate that
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|     // no changes were made to the program.
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|     if (I.use_empty()) return nullptr;
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| 
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|     Worklist.AddUsersToWorkList(I); // Add all modified instrs to worklist.
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| 
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|     // If we are replacing the instruction with itself, this must be in a
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|     // segment of unreachable code, so just clobber the instruction.
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|     if (&I == V)
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|       V = UndefValue::get(I.getType());
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| 
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|     DEBUG(dbgs() << "IC: Replacing " << I << "\n"
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|                  << "    with " << *V << '\n');
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| 
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|     I.replaceAllUsesWith(V);
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|     return &I;
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|   }
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| 
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|   /// Creates a result tuple for an overflow intrinsic \p II with a given
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|   /// \p Result and a constant \p Overflow value.
 | |
|   Instruction *CreateOverflowTuple(IntrinsicInst *II, Value *Result,
 | |
|                                    Constant *Overflow) {
 | |
|     Constant *V[] = {UndefValue::get(Result->getType()), Overflow};
 | |
|     StructType *ST = cast<StructType>(II->getType());
 | |
|     Constant *Struct = ConstantStruct::get(ST, V);
 | |
|     return InsertValueInst::Create(Struct, Result, 0);
 | |
|   }
 | |
| 
 | |
|   /// \brief Combiner aware instruction erasure.
 | |
|   ///
 | |
|   /// When dealing with an instruction that has side effects or produces a void
 | |
|   /// value, we can't rely on DCE to delete the instruction. Instead, visit
 | |
|   /// methods should return the value returned by this function.
 | |
|   Instruction *EraseInstFromFunction(Instruction &I) {
 | |
|     DEBUG(dbgs() << "IC: ERASE " << I << '\n');
 | |
| 
 | |
|     assert(I.use_empty() && "Cannot erase instruction that is used!");
 | |
|     // Make sure that we reprocess all operands now that we reduced their
 | |
|     // use counts.
 | |
|     if (I.getNumOperands() < 8) {
 | |
|       for (User::op_iterator i = I.op_begin(), e = I.op_end(); i != e; ++i)
 | |
|         if (Instruction *Op = dyn_cast<Instruction>(*i))
 | |
|           Worklist.Add(Op);
 | |
|     }
 | |
|     Worklist.Remove(&I);
 | |
|     I.eraseFromParent();
 | |
|     MadeIRChange = true;
 | |
|     return nullptr; // Don't do anything with FI
 | |
|   }
 | |
| 
 | |
|   void computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne,
 | |
|                         unsigned Depth, Instruction *CxtI) const {
 | |
|     return llvm::computeKnownBits(V, KnownZero, KnownOne, DL, Depth, AC, CxtI,
 | |
|                                   DT);
 | |
|   }
 | |
| 
 | |
|   bool MaskedValueIsZero(Value *V, const APInt &Mask, unsigned Depth = 0,
 | |
|                          Instruction *CxtI = nullptr) const {
 | |
|     return llvm::MaskedValueIsZero(V, Mask, DL, Depth, AC, CxtI, DT);
 | |
|   }
 | |
|   unsigned ComputeNumSignBits(Value *Op, unsigned Depth = 0,
 | |
|                               Instruction *CxtI = nullptr) const {
 | |
|     return llvm::ComputeNumSignBits(Op, DL, Depth, AC, CxtI, DT);
 | |
|   }
 | |
|   void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,
 | |
|                       unsigned Depth = 0, Instruction *CxtI = nullptr) const {
 | |
|     return llvm::ComputeSignBit(V, KnownZero, KnownOne, DL, Depth, AC, CxtI,
 | |
|                                 DT);
 | |
|   }
 | |
|   OverflowResult computeOverflowForUnsignedMul(Value *LHS, Value *RHS,
 | |
|                                                const Instruction *CxtI) {
 | |
|     return llvm::computeOverflowForUnsignedMul(LHS, RHS, DL, AC, CxtI, DT);
 | |
|   }
 | |
|   OverflowResult computeOverflowForUnsignedAdd(Value *LHS, Value *RHS,
 | |
|                                                const Instruction *CxtI) {
 | |
|     return llvm::computeOverflowForUnsignedAdd(LHS, RHS, DL, AC, CxtI, DT);
 | |
|   }
 | |
| 
 | |
| private:
 | |
|   /// \brief Performs a few simplifications for operators which are associative
 | |
|   /// or commutative.
 | |
|   bool SimplifyAssociativeOrCommutative(BinaryOperator &I);
 | |
| 
 | |
|   /// \brief Tries to simplify binary operations which some other binary
 | |
|   /// operation distributes over.
 | |
|   ///
 | |
|   /// It does this by either by factorizing out common terms (eg "(A*B)+(A*C)"
 | |
|   /// -> "A*(B+C)") or expanding out if this results in simplifications (eg: "A
 | |
|   /// & (B | C) -> (A&B) | (A&C)" if this is a win).  Returns the simplified
 | |
|   /// value, or null if it didn't simplify.
 | |
|   Value *SimplifyUsingDistributiveLaws(BinaryOperator &I);
 | |
| 
 | |
|   /// \brief Attempts to replace V with a simpler value based on the demanded
 | |
|   /// bits.
 | |
|   Value *SimplifyDemandedUseBits(Value *V, APInt DemandedMask, APInt &KnownZero,
 | |
|                                  APInt &KnownOne, unsigned Depth,
 | |
|                                  Instruction *CxtI);
 | |
|   bool SimplifyDemandedBits(Use &U, APInt DemandedMask, APInt &KnownZero,
 | |
|                             APInt &KnownOne, unsigned Depth = 0);
 | |
|   /// Helper routine of SimplifyDemandedUseBits. It tries to simplify demanded
 | |
|   /// bit for "r1 = shr x, c1; r2 = shl r1, c2" instruction sequence.
 | |
|   Value *SimplifyShrShlDemandedBits(Instruction *Lsr, Instruction *Sftl,
 | |
|                                     APInt DemandedMask, APInt &KnownZero,
 | |
|                                     APInt &KnownOne);
 | |
| 
 | |
|   /// \brief Tries to simplify operands to an integer instruction based on its
 | |
|   /// demanded bits.
 | |
|   bool SimplifyDemandedInstructionBits(Instruction &Inst);
 | |
| 
 | |
|   Value *SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
 | |
|                                     APInt &UndefElts, unsigned Depth = 0);
 | |
| 
 | |
|   Value *SimplifyVectorOp(BinaryOperator &Inst);
 | |
|   Value *SimplifyBSwap(BinaryOperator &Inst);
 | |
| 
 | |
|   // FoldOpIntoPhi - Given a binary operator, cast instruction, or select
 | |
|   // which has a PHI node as operand #0, see if we can fold the instruction
 | |
|   // into the PHI (which is only possible if all operands to the PHI are
 | |
|   // constants).
 | |
|   //
 | |
|   Instruction *FoldOpIntoPhi(Instruction &I);
 | |
| 
 | |
|   /// \brief Try to rotate an operation below a PHI node, using PHI nodes for
 | |
|   /// its operands.
 | |
|   Instruction *FoldPHIArgOpIntoPHI(PHINode &PN);
 | |
|   Instruction *FoldPHIArgBinOpIntoPHI(PHINode &PN);
 | |
|   Instruction *FoldPHIArgGEPIntoPHI(PHINode &PN);
 | |
|   Instruction *FoldPHIArgLoadIntoPHI(PHINode &PN);
 | |
|   Instruction *FoldPHIArgZextsIntoPHI(PHINode &PN);
 | |
| 
 | |
|   Instruction *OptAndOp(Instruction *Op, ConstantInt *OpRHS,
 | |
|                         ConstantInt *AndRHS, BinaryOperator &TheAnd);
 | |
| 
 | |
|   Value *FoldLogicalPlusAnd(Value *LHS, Value *RHS, ConstantInt *Mask,
 | |
|                             bool isSub, Instruction &I);
 | |
|   Value *InsertRangeTest(Value *V, Constant *Lo, Constant *Hi, bool isSigned,
 | |
|                          bool Inside);
 | |
|   Instruction *PromoteCastOfAllocation(BitCastInst &CI, AllocaInst &AI);
 | |
|   Instruction *MatchBSwap(BinaryOperator &I);
 | |
|   bool SimplifyStoreAtEndOfBlock(StoreInst &SI);
 | |
|   Instruction *SimplifyMemTransfer(MemIntrinsic *MI);
 | |
|   Instruction *SimplifyMemSet(MemSetInst *MI);
 | |
| 
 | |
|   Value *EvaluateInDifferentType(Value *V, Type *Ty, bool isSigned);
 | |
| 
 | |
|   /// \brief Returns a value X such that Val = X * Scale, or null if none.
 | |
|   ///
 | |
|   /// If the multiplication is known not to overflow then NoSignedWrap is set.
 | |
|   Value *Descale(Value *Val, APInt Scale, bool &NoSignedWrap);
 | |
| };
 | |
| 
 | |
| } // end namespace llvm.
 | |
| 
 | |
| #undef DEBUG_TYPE
 | |
| 
 | |
| #endif
 |