InlineCost.cpp revision b381578fcb5fea988f661dbbee9747b8fd55c5fb
1e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman//===- InlineCost.cpp - Cost analysis for inliner -------------------------===// 2e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// 3e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// The LLVM Compiler Infrastructure 4e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// 5e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// This file is distributed under the University of Illinois Open Source 6e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// License. See LICENSE.TXT for details. 7e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// 8e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman//===----------------------------------------------------------------------===// 9e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// 10e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// This file implements inline cost analysis. 11e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman// 12e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman//===----------------------------------------------------------------------===// 13e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 14f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#define DEBUG_TYPE "inline-cost" 15e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman#include "llvm/Analysis/InlineCost.h" 16f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Analysis/ConstantFolding.h" 17f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Analysis/InstructionSimplify.h" 18e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman#include "llvm/Support/CallSite.h" 19f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Support/Debug.h" 20f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Support/InstVisitor.h" 21f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Support/GetElementPtrTypeIterator.h" 22f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Support/raw_ostream.h" 23e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman#include "llvm/CallingConv.h" 24e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman#include "llvm/IntrinsicInst.h" 25f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/Operator.h" 26f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/GlobalAlias.h" 27b2ab2fa524f3f90376639037bd81924483cca0afAndrew Trick#include "llvm/Target/TargetData.h" 28f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/ADT/STLExtras.h" 29f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/ADT/SetVector.h" 30f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#include "llvm/ADT/SmallVector.h" 31e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman#include "llvm/ADT/SmallPtrSet.h" 324e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 33e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohmanusing namespace llvm; 34e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 35f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthnamespace { 36f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 37f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthclass CallAnalyzer : public InstVisitor<CallAnalyzer, bool> { 38f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth typedef InstVisitor<CallAnalyzer, bool> Base; 39f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth friend class InstVisitor<CallAnalyzer, bool>; 40f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 41f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // TargetData if available, or null. 42f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth const TargetData *const TD; 43f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 44f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // The called function. 45f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Function &F; 46f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 47f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int Threshold; 48f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int Cost; 49f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth const bool AlwaysInline; 50f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 51f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool IsRecursive; 52f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool ExposesReturnsTwice; 53f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool HasDynamicAlloca; 54f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumInstructions, NumVectorInstructions; 55f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int FiftyPercentVectorBonus, TenPercentVectorBonus; 56f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int VectorBonus; 57f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 58f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // While we walk the potentially-inlined instructions, we build up and 59f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // maintain a mapping of simplified values specific to this callsite. The 60f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // idea is to propagate any special information we have about arguments to 61f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // this call through the inlinable section of the function, and account for 62f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // likely simplifications post-inlining. The most important aspect we track 63f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // is CFG altering simplifications -- when we prove a basic block dead, that 64f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // can cause dramatic shifts in the cost of inlining a function. 65f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, Constant *> SimplifiedValues; 66f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 67f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Keep track of the values which map back (through function arguments) to 68f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // allocas on the caller stack which could be simplified through SROA. 69f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, Value *> SROAArgValues; 70f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 71f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // The mapping of caller Alloca values to their accumulated cost savings. If 72f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // we have to disable SROA for one of the allocas, this tells us how much 73f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // cost must be added. 74f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int> SROAArgCosts; 75f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 76f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Keep track of values which map to a pointer base and constant offset. 77f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, std::pair<Value *, APInt> > ConstantOffsetPtrs; 78f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 79f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Custom simplification helper routines. 80f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool isAllocaDerivedArg(Value *V); 81f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool lookupSROAArgAndCost(Value *V, Value *&Arg, 82f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator &CostIt); 83f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void disableSROA(DenseMap<Value *, int>::iterator CostIt); 84f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void disableSROA(Value *V); 85f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void accumulateSROACost(DenseMap<Value *, int>::iterator CostIt, 86f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int InstructionCost); 87f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool handleSROACandidate(bool IsSROAValid, 88f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt, 89f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int InstructionCost); 90f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool isGEPOffsetConstant(GetElementPtrInst &GEP); 91f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset); 92f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V); 93f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 94f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Custom analysis routines. 95f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool analyzeBlock(BasicBlock *BB); 96f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 97f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Disable several entry points to the visitor so we don't accidentally use 98f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // them by declaring but not defining them here. 99f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void visit(Module *); void visit(Module &); 100f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void visit(Function *); void visit(Function &); 101f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void visit(BasicBlock *); void visit(BasicBlock &); 102f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 103f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Provide base case for our instruction visit. 104f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitInstruction(Instruction &I); 105f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 106f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Our visit overrides. 107f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitAlloca(AllocaInst &I); 108f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitPHI(PHINode &I); 109f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitGetElementPtr(GetElementPtrInst &I); 110f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitBitCast(BitCastInst &I); 111f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitPtrToInt(PtrToIntInst &I); 112f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitIntToPtr(IntToPtrInst &I); 113f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitCastInst(CastInst &I); 114f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitUnaryInstruction(UnaryInstruction &I); 115f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitICmp(ICmpInst &I); 116f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitSub(BinaryOperator &I); 117f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitBinaryOperator(BinaryOperator &I); 118f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitLoad(LoadInst &I); 119f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitStore(StoreInst &I); 120f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool visitCallSite(CallSite CS); 121f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 122f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthpublic: 123f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth CallAnalyzer(const TargetData *TD, Function &Callee, int Threshold) 124f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth : TD(TD), F(Callee), Threshold(Threshold), Cost(0), 125f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth AlwaysInline(F.hasFnAttr(Attribute::AlwaysInline)), 126f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth IsRecursive(false), ExposesReturnsTwice(false), HasDynamicAlloca(false), 127f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumInstructions(0), NumVectorInstructions(0), 128f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth FiftyPercentVectorBonus(0), TenPercentVectorBonus(0), VectorBonus(0), 129f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumConstantArgs(0), NumConstantOffsetPtrArgs(0), NumAllocaArgs(0), 130f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumConstantPtrCmps(0), NumConstantPtrDiffs(0), 131f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumInstructionsSimplified(0), SROACostSavings(0), SROACostSavingsLost(0) { 132f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 1333d1d895c866b76ac4d862301f36e2b95d803f0abChandler Carruth 134f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool analyzeCall(CallSite CS); 135082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson 136f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int getThreshold() { return Threshold; } 137f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int getCost() { return Cost; } 138082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson 139f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Keep a bunch of stats about the cost savings found so we can print them 140f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // out when debugging. 141f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumConstantArgs; 142f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumConstantOffsetPtrArgs; 143f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumAllocaArgs; 144f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumConstantPtrCmps; 145f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumConstantPtrDiffs; 146f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned NumInstructionsSimplified; 147f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned SROACostSavings; 148f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned SROACostSavingsLost; 149082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson 150f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth void dump(); 151f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth}; 152082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson 153f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} // namespace 154e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 155f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Test whether the given value is an Alloca-derived function argument. 156f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::isAllocaDerivedArg(Value *V) { 157f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return SROAArgValues.count(V); 158f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 159e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 160f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Lookup the SROA-candidate argument and cost iterator which V maps to. 161f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// Returns false if V does not map to a SROA-candidate. 162f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::lookupSROAArgAndCost( 163f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *V, Value *&Arg, DenseMap<Value *, int>::iterator &CostIt) { 164f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (SROAArgValues.empty() || SROAArgCosts.empty()) 165f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 166e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 167f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, Value *>::iterator ArgIt = SROAArgValues.find(V); 168f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (ArgIt == SROAArgValues.end()) 169f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 170e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 171f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Arg = ArgIt->second; 172f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth CostIt = SROAArgCosts.find(Arg); 173f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return CostIt != SROAArgCosts.end(); 174e8187e02949571e8a610644762b843ef2891f011Chandler Carruth} 175e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 176f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Disable SROA for the candidate marked by this cost iterator. 177e8187e02949571e8a610644762b843ef2891f011Chandler Carruth/// 178f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// This markes the candidate as no longer viable for SROA, and adds the cost 179f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// savings associated with it back into the inline cost measurement. 180f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthvoid CallAnalyzer::disableSROA(DenseMap<Value *, int>::iterator CostIt) { 181f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If we're no longer able to perform SROA we need to undo its cost savings 182f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // and prevent subsequent analysis. 183f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += CostIt->second; 184f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROACostSavings -= CostIt->second; 185f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROACostSavingsLost += CostIt->second; 186f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgCosts.erase(CostIt); 187f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 188f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 189f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief If 'V' maps to a SROA candidate, disable SROA for it. 190f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthvoid CallAnalyzer::disableSROA(Value *V) { 191f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 192f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 193f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(V, SROAArg, CostIt)) 194f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 195f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 196f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 197f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Accumulate the given cost for a particular SROA candidate. 198f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthvoid CallAnalyzer::accumulateSROACost(DenseMap<Value *, int>::iterator CostIt, 199f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int InstructionCost) { 200f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth CostIt->second += InstructionCost; 201f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROACostSavings += InstructionCost; 202f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 203f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 204f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Helper for the common pattern of handling a SROA candidate. 205f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// Either accumulates the cost savings if the SROA remains valid, or disables 206f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// SROA for the candidate. 207f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::handleSROACandidate(bool IsSROAValid, 208f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt, 209f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int InstructionCost) { 210f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (IsSROAValid) { 211f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth accumulateSROACost(CostIt, InstructionCost); 212e8187e02949571e8a610644762b843ef2891f011Chandler Carruth return true; 213e8187e02949571e8a610644762b843ef2891f011Chandler Carruth } 214e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 215f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 216f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 217f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 218f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 219f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Check whether a GEP's indices are all constant. 220f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// 221f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// Respects any simplified values known during the analysis of this callsite. 222f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::isGEPOffsetConstant(GetElementPtrInst &GEP) { 223f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I) 224f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!isa<Constant>(*I) && !SimplifiedValues.lookup(*I)) 225e8187e02949571e8a610644762b843ef2891f011Chandler Carruth return false; 226e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 227f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 228f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 229f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 230f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Accumulate a constant GEP offset into an APInt if possible. 231f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// 232f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// Returns false if unable to compute the offset for any reason. Respects any 233f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// simplified values known during the analysis of this callsite. 234f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) { 235f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!TD) 236f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 237f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 238f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned IntPtrWidth = TD->getPointerSizeInBits(); 239f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth assert(IntPtrWidth == Offset.getBitWidth()); 240f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 241f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP); 242f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth GTI != GTE; ++GTI) { 243f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand()); 244f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!OpC) 245f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *SimpleOp = SimplifiedValues.lookup(GTI.getOperand())) 246f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth OpC = dyn_cast<ConstantInt>(SimpleOp); 247f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!OpC) 248e8187e02949571e8a610644762b843ef2891f011Chandler Carruth return false; 249f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (OpC->isZero()) continue; 250e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 251f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Handle a struct index, which adds its field offset to the pointer. 252f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (StructType *STy = dyn_cast<StructType>(*GTI)) { 253f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned ElementIdx = OpC->getZExtValue(); 254f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth const StructLayout *SL = TD->getStructLayout(STy); 255f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx)); 256f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth continue; 257f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 258f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 259f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth APInt TypeSize(IntPtrWidth, TD->getTypeAllocSize(GTI.getIndexedType())); 260f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize; 261e8187e02949571e8a610644762b843ef2891f011Chandler Carruth } 262f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 263f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 264f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 265f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitAlloca(AllocaInst &I) { 266f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // FIXME: Check whether inlining will turn a dynamic alloca into a static 267f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // alloca, and handle that case. 268e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 269f5f256cffd7535d31dc24e7c9166f2084fe66e47Chandler Carruth // We will happily inline static alloca instructions or dynamic alloca 270f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // instructions in always-inline situations. 271f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (AlwaysInline || I.isStaticAlloca()) 272f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return Base::visitAlloca(I); 273f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 274f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // FIXME: This is overly conservative. Dynamic allocas are inefficient for 275f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // a variety of reasons, and so we would like to not inline them into 276f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // functions which don't currently have a dynamic alloca. This simply 277f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // disables inlining altogether in the presence of a dynamic alloca. 278f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth HasDynamicAlloca = true; 279f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 280f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 281f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 282f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitPHI(PHINode &I) { 283f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // FIXME: We should potentially be tracking values through phi nodes, 284f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // especially when they collapse to a single value due to deleted CFG edges 285f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // during inlining. 286f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 287f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // FIXME: We need to propagate SROA *disabling* through phi nodes, even 288f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // though we don't want to propagate it's bonuses. The idea is to disable 289f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // SROA if it *might* be used in an inappropriate manner. 290f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 291f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Phi nodes are always zero-cost. 292f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 293f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 294f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 295f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitGetElementPtr(GetElementPtrInst &I) { 296f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 297f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 298f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool SROACandidate = lookupSROAArgAndCost(I.getPointerOperand(), 299f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArg, CostIt); 300f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 301f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Try to fold GEPs of constant-offset call site argument pointers. This 302f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // requires target data and inbounds GEPs. 303f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (TD && I.isInBounds()) { 304f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Check if we have a base + offset for the pointer. 305f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *Ptr = I.getPointerOperand(); 306f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Ptr); 307f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BaseAndOffset.first) { 308f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Check if the offset of this GEP is constant, and if so accumulate it 309f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // into Offset. 310f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!accumulateGEPOffset(cast<GEPOperator>(I), BaseAndOffset.second)) { 311f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Non-constant GEPs aren't folded, and disable SROA. 312f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (SROACandidate) 313f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 314e8187e02949571e8a610644762b843ef2891f011Chandler Carruth return false; 315f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 316f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 317f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Add the result as a new mapping to Base + Offset. 318f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantOffsetPtrs[&I] = BaseAndOffset; 319f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 320f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Also handle SROA candidates here, we already know that the GEP is 321f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // all-constant indexed. 322f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (SROACandidate) 323f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgValues[&I] = SROAArg; 324f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 325f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 326e8187e02949571e8a610644762b843ef2891f011Chandler Carruth } 327f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 328f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 329f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isGEPOffsetConstant(I)) { 330f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (SROACandidate) 331f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgValues[&I] = SROAArg; 332f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 333f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Constant GEPs are modeled as free. 334e8187e02949571e8a610644762b843ef2891f011Chandler Carruth return true; 335e8187e02949571e8a610644762b843ef2891f011Chandler Carruth } 336e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 337f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Variable GEPs will require math and will disable SROA. 338f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (SROACandidate) 339f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 340f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 341f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 342f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 343f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitBitCast(BitCastInst &I) { 344f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Propagate constants through bitcasts. 345f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) 346f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getBitCast(COp, I.getType())) { 347f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 348e8187e02949571e8a610644762b843ef2891f011Chandler Carruth return true; 349e8187e02949571e8a610644762b843ef2891f011Chandler Carruth } 350f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 351f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Track base/offsets through casts 352f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth std::pair<Value *, APInt> BaseAndOffset 353f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth = ConstantOffsetPtrs.lookup(I.getOperand(0)); 354f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Casts don't change the offset, just wrap it up. 355f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BaseAndOffset.first) 356f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantOffsetPtrs[&I] = BaseAndOffset; 357f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 358f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Also look for SROA candidates here. 359f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 360f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 361f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) 362f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgValues[&I] = SROAArg; 363f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 364f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Bitcasts are always zero cost. 365f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 366f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 367f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 368f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitPtrToInt(PtrToIntInst &I) { 369f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Propagate constants through ptrtoint. 370f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) 371f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getPtrToInt(COp, I.getType())) { 372f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 373f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 374f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 375f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 376f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Track base/offset pairs when converted to a plain integer provided the 377f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // integer is large enough to represent the pointer. 378f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned IntegerSize = I.getType()->getScalarSizeInBits(); 379f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (TD && IntegerSize >= TD->getPointerSizeInBits()) { 380f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth std::pair<Value *, APInt> BaseAndOffset 381f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth = ConstantOffsetPtrs.lookup(I.getOperand(0)); 382f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BaseAndOffset.first) 383f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantOffsetPtrs[&I] = BaseAndOffset; 384e8187e02949571e8a610644762b843ef2891f011Chandler Carruth } 385e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 386f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // This is really weird. Technically, ptrtoint will disable SROA. However, 387f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // unless that ptrtoint is *used* somewhere in the live basic blocks after 388f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // inlining, it will be nuked, and SROA should proceed. All of the uses which 389f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // would block SROA would also block SROA if applied directly to a pointer, 390f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // and so we can just add the integer in here. The only places where SROA is 391f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // preserved either cannot fire on an integer, or won't in-and-of themselves 392f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // disable SROA (ext) w/o some later use that we would see and disable. 393f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 394f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 395f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) 396f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgValues[&I] = SROAArg; 397f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 398f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // A ptrtoint cast is free so long as the result is large enough to store the 399f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // pointer, and a legal integer type. 400f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return TD && TD->isLegalInteger(IntegerSize) && 401f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth IntegerSize >= TD->getPointerSizeInBits(); 402e8187e02949571e8a610644762b843ef2891f011Chandler Carruth} 403e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 404f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitIntToPtr(IntToPtrInst &I) { 405f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Propagate constants through ptrtoint. 406f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) 407f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getIntToPtr(COp, I.getType())) { 408f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 409f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 410f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 4116977e79526a6342b9408c358bca21c3b0c7e61d5Nick Lewycky 412f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Track base/offset pairs when round-tripped through a pointer without 413f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // modifications provided the integer is not too large. 414f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *Op = I.getOperand(0); 415f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned IntegerSize = Op->getType()->getScalarSizeInBits(); 416f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (TD && IntegerSize <= TD->getPointerSizeInBits()) { 417f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Op); 418f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BaseAndOffset.first) 419f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantOffsetPtrs[&I] = BaseAndOffset; 420f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 421e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 422f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // "Propagate" SROA here in the same manner as we do for ptrtoint above. 423f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 424f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 425f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(Op, SROAArg, CostIt)) 426f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgValues[&I] = SROAArg; 427e8187e02949571e8a610644762b843ef2891f011Chandler Carruth 428f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // An inttoptr cast is free so long as the input is a legal integer type 429f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // which doesn't contain values outside the range of a pointer. 430f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return TD && TD->isLegalInteger(IntegerSize) && 431f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth IntegerSize <= TD->getPointerSizeInBits(); 432f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 433f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 434f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitCastInst(CastInst &I) { 435f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Propagate constants through ptrtoint. 436f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) 437f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) { 438f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 439f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 440082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson } 441082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson 442f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Disable SROA in the face of arbitrary casts we don't whitelist elsewhere. 443f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(I.getOperand(0)); 444f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 445f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // No-op casts don't have any cost. 446f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (I.isLosslessCast()) 447f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 448f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 449f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // trunc to a native type is free (assuming the target has compare and 450f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // shift-right of the same width). 451f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (TD && isa<TruncInst>(I) && 452f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth TD->isLegalInteger(TD->getTypeSizeInBits(I.getType()))) 453f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 454f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 455f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Result of a cmp instruction is often extended (to be used by other 456f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // cmp instructions, logical or return instructions). These are usually 457f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // no-ops on most sane targets. 458f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isa<CmpInst>(I.getOperand(0))) 459f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 460f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 461f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Assume the rest of the casts require work. 462f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 463082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson} 464082bf2a977b6bb91d61ac5155e1906ecc6ba47bfOwen Anderson 465f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitUnaryInstruction(UnaryInstruction &I) { 466f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *Operand = I.getOperand(0); 467f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Constant *Ops[1] = { dyn_cast<Constant>(Operand) }; 468f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Ops[0] || (Ops[0] = SimplifiedValues.lookup(Operand))) 469f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantFoldInstOperands(I.getOpcode(), I.getType(), 470f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Ops, TD)) { 471f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 472f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 473f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 474274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth 475f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Disable any SROA on the argument to arbitrary unary operators. 476f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(Operand); 477f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 478f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 479f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 480f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 481f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitICmp(ICmpInst &I) { 482f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); 483f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // First try to handle simplified comparisons. 484f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!isa<Constant>(LHS)) 485f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) 486f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth LHS = SimpleLHS; 487f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!isa<Constant>(RHS)) 488f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) 489f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth RHS = SimpleRHS; 490f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *CLHS = dyn_cast<Constant>(LHS)) 491f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *CRHS = dyn_cast<Constant>(RHS)) 492f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) { 493f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 494f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 495274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth } 496274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth 497f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Otherwise look for a comparison between constant offset pointers with 498f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // a common base. 499f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *LHSBase, *RHSBase; 500f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth APInt LHSOffset, RHSOffset; 501f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth llvm::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); 502f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (LHSBase) { 503f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth llvm::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); 504f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (RHSBase && LHSBase == RHSBase) { 505f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We have common bases, fold the icmp to a constant based on the 506f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // offsets. 507f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); 508f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); 509f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) { 510f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 511f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ++NumConstantPtrCmps; 512f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 513274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth } 514f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 515f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 516274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth 517f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If the comparison is an equality comparison with null, we can simplify it 518f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // for any alloca-derived argument. 519f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (I.isEquality() && isa<ConstantPointerNull>(I.getOperand(1))) 520f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isAllocaDerivedArg(I.getOperand(0))) { 521f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We can actually predict the result of comparisons between an 522f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // alloca-derived value and null. Note that this fires regardless of 523f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // SROA firing. 524f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE; 525f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(I.getType()) 526f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth : ConstantInt::getFalse(I.getType()); 527f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 528f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 529274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth 530f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Finally check for SROA candidates in comparisons. 531f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 532f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 533f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { 534f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isa<ConstantPointerNull>(I.getOperand(1))) { 535f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth accumulateSROACost(CostIt, InlineConstants::InstrCost); 536f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 537274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth } 538274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth 539f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 540274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth } 541e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 542f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 54342c7d23c6d56e0743169d94025264eaf17eb799dKenneth Uildriks} 54474fa7327d690e6ceda6ce77e4e5b8ef75cb12538Kenneth Uildriks 545f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitSub(BinaryOperator &I) { 546f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Try to handle a special case: we can fold computing the difference of two 547f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // constant-related pointers. 548f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); 549f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *LHSBase, *RHSBase; 550f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth APInt LHSOffset, RHSOffset; 551f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth llvm::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); 552f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (LHSBase) { 553f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth llvm::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); 554f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (RHSBase && LHSBase == RHSBase) { 555f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We have common bases, fold the subtract to a constant based on the 556f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // offsets. 557f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); 558f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); 559f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = ConstantExpr::getSub(CLHS, CRHS)) { 560f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 561f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ++NumConstantPtrDiffs; 562f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 563f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 564f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 565f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 5665c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 567f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Otherwise, fall back to the generic logic for simplifying and handling 568f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // instructions. 569f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return Base::visitSub(I); 570f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 571f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 572f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) { 573f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); 574f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!isa<Constant>(LHS)) 575f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) 576f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth LHS = SimpleLHS; 577f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!isa<Constant>(RHS)) 578f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) 579f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth RHS = SimpleRHS; 580f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, TD); 581f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = dyn_cast_or_null<Constant>(SimpleV)) { 582f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[&I] = C; 583f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 584f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 5855c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 586f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Disable any SROA on arguments to arbitrary, unsimplified binary operators. 587f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(LHS); 588f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(RHS); 5895c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 590f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 5914e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher} 5924e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 593f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitLoad(LoadInst &I) { 594f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 595f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 596f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { 597f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (I.isSimple()) { 598f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth accumulateSROACost(CostIt, InlineConstants::InstrCost); 599f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 6008e2da0ce9d70606e10889d17f481842586132d88Eric Christopher } 6018e2da0ce9d70606e10889d17f481842586132d88Eric Christopher 602f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 603f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 6048e2da0ce9d70606e10889d17f481842586132d88Eric Christopher 605f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 606f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 607f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 608f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitStore(StoreInst &I) { 609f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *SROAArg; 610f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DenseMap<Value *, int>::iterator CostIt; 611f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { 612f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (I.isSimple()) { 613f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth accumulateSROACost(CostIt, InlineConstants::InstrCost); 614f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 6158e2da0ce9d70606e10889d17f481842586132d88Eric Christopher } 616f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 617f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(CostIt); 6188e2da0ce9d70606e10889d17f481842586132d88Eric Christopher } 6195c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 620f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 6214e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher} 6224e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 623f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitCallSite(CallSite CS) { 624f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (CS.isCall() && cast<CallInst>(CS.getInstruction())->canReturnTwice() && 625f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth !F.hasFnAttr(Attribute::ReturnsTwice)) { 626f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // This aborts the entire analysis. 627f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ExposesReturnsTwice = true; 628f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 6294e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher } 6305c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 631f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CS.getInstruction())) { 632f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth switch (II->getIntrinsicID()) { 633f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth default: 634f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return Base::visitCallSite(CS); 635274d377ea68195989c3238fe96ce2ca812a12fafChandler Carruth 636f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::dbg_declare: 637f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::dbg_value: 638f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::invariant_start: 639f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::invariant_end: 640f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::lifetime_start: 641f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::lifetime_end: 642f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::memset: 643f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::memcpy: 644f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::memmove: 645f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::objectsize: 646f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::ptr_annotation: 647f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth case Intrinsic::var_annotation: 648f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // SROA can usually chew through these intrinsics and they have no cost 649f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // so don't pay the price of analyzing them in detail. 650f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 651f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 652f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 6534e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 654f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Function *F = CS.getCalledFunction()) { 655f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (F == CS.getInstruction()->getParent()->getParent()) { 656f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // This flag will fully abort the analysis, so don't bother with anything 657f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // else. 658f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth IsRecursive = true; 659f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 660f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 6614e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 662f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!callIsSmall(F)) { 663f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We account for the average 1 instruction per call argument setup 664f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // here. 665f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += CS.arg_size() * InlineConstants::InstrCost; 6664e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 667f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Everything other than inline ASM will also have a significant cost 668f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // merely from making the call. 669f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!isa<InlineAsm>(CS.getCalledValue())) 670f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += InlineConstants::CallPenalty; 671f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 6725c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 673f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return Base::visitCallSite(CS); 674f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 675f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 676f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Otherwise we're in a very special case -- an indirect function call. See 677f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // if we can be particularly clever about this. 678f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *Callee = CS.getCalledValue(); 679f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 680f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // First, pay the price of the argument setup. We account for the average 681f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // 1 instruction per call argument setup here. 682f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += CS.arg_size() * InlineConstants::InstrCost; 683f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 684f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Next, check if this happens to be an indirect function call to a known 685f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // function in this inline context. If not, we've done all we can. 686f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Function *F = dyn_cast_or_null<Function>(SimplifiedValues.lookup(Callee)); 687f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!F) 688f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return Base::visitCallSite(CS); 689f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 690f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If we have a constant that we are calling as a function, we can peer 691f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // through it and see the function target. This happens not infrequently 692f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // during devirtualization and so we want to give it a hefty bonus for 693f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // inlining, but cap that bonus in the event that inlining wouldn't pan 694f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // out. Pretend to inline the function, with a custom threshold. 695f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth CallAnalyzer CA(TD, *F, InlineConstants::IndirectCallThreshold); 696f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (CA.analyzeCall(CS)) { 697f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We were able to inline the indirect call! Subtract the cost from the 698f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // bonus we want to apply, but don't go below zero. 699f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost -= std::max(0, InlineConstants::IndirectCallThreshold - CA.getCost()); 700f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 701f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 702f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return Base::visitCallSite(CS); 7034e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher} 7044e8af6db184118638c21f713ad98e3292c6891c9Eric Christopher 705f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::visitInstruction(Instruction &I) { 706f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We found something we don't understand or can't handle. Mark any SROA-able 707f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // values in the operand list as no longer viable. 708f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (User::op_iterator OI = I.op_begin(), OE = I.op_end(); OI != OE; ++OI) 709f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth disableSROA(*OI); 710f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 711f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 7128e2da0ce9d70606e10889d17f481842586132d88Eric Christopher} 71374fa7327d690e6ceda6ce77e4e5b8ef75cb12538Kenneth Uildriks 714f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 715f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Analyze a basic block for its contribution to the inline cost. 716f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// 717f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// This method walks the analyzer over every instruction in the given basic 718f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// block and accounts for their cost during inlining at this callsite. It 719f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// aborts early if the threshold has been exceeded or an impossible to inline 720f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// construct has been detected. It returns false if inlining is no longer 721f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// viable, and true if inlining remains viable. 722f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::analyzeBlock(BasicBlock *BB) { 723f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (BasicBlock::iterator I = BB->begin(), E = llvm::prior(BB->end()); 724f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth I != E; ++I) { 725f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ++NumInstructions; 726f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isa<ExtractElementInst>(I) || I->getType()->isVectorTy()) 727f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ++NumVectorInstructions; 728f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 729f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If the instruction simplified to a constant, there is no cost to this 730f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // instruction. Visit the instructions using our InstVisitor to account for 731f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // all of the per-instruction logic. The visit tree returns true if we 732f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // consumed the instruction in any way, and false if the instruction's base 733f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // cost should count against inlining. 734f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Base::visit(I)) 735f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ++NumInstructionsSimplified; 736f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth else 737f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += InlineConstants::InstrCost; 738f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 739f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If the visit this instruction detected an uninlinable pattern, abort. 740f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (IsRecursive || ExposesReturnsTwice || HasDynamicAlloca) 741f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 742f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 743f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (NumVectorInstructions > NumInstructions/2) 744f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth VectorBonus = FiftyPercentVectorBonus; 745f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth else if (NumVectorInstructions > NumInstructions/10) 746f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth VectorBonus = TenPercentVectorBonus; 747f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth else 748f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth VectorBonus = 0; 749f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 750f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Check if we've past the threshold so we don't spin in huge basic 751f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // blocks that will never inline. 752f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!AlwaysInline && Cost > (Threshold + VectorBonus)) 753f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 754f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 755f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 756f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 757752e2590585227f6f10e80978f587915d9adb2adDavid Chisnall} 758752e2590585227f6f10e80978f587915d9adb2adDavid Chisnall 759f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Compute the base pointer and cumulative constant offsets for V. 760f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// 761f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// This strips all constant offsets off of V, leaving it the base pointer, and 762f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// accumulates the total constant offset applied in the returned constant. It 763f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// returns 0 if V is not a pointer, and returns the constant '0' if there are 764f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// no constant offsets applied. 765f2286b0152f0b942e82d8e809186e5cc0d247131Chandler CarruthConstantInt *CallAnalyzer::stripAndComputeInBoundsConstantOffsets(Value *&V) { 766f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!TD || !V->getType()->isPointerTy()) 767f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return 0; 768f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 769f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth unsigned IntPtrWidth = TD->getPointerSizeInBits(); 770f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth APInt Offset = APInt::getNullValue(IntPtrWidth); 771f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 772f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Even though we don't look through PHI nodes, we could be called on an 773f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // instruction in an unreachable block, which may be on a cycle. 774f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SmallPtrSet<Value *, 4> Visited; 775f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Visited.insert(V); 776f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth do { 777f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) { 778f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!GEP->isInBounds() || !accumulateGEPOffset(*GEP, Offset)) 779f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return 0; 780f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth V = GEP->getPointerOperand(); 781f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } else if (Operator::getOpcode(V) == Instruction::BitCast) { 782f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth V = cast<Operator>(V)->getOperand(0); 783f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) { 784f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (GA->mayBeOverridden()) 785f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth break; 786f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth V = GA->getAliasee(); 787f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } else { 788f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth break; 789f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 790f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth assert(V->getType()->isPointerTy() && "Unexpected operand type!"); 791f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } while (Visited.insert(V)); 792e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 793f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Type *IntPtrTy = TD->getIntPtrType(V->getContext()); 794f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return cast<ConstantInt>(ConstantInt::get(IntPtrTy, Offset)); 795f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 796e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 797f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Analyze a call site for potential inlining. 798f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// 799f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// Returns true if inlining this call is viable, and false if it is not 800f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// viable. It computes the cost and adjusts the threshold based on numerous 801f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// factors and heuristics. If this method returns false but the computed cost 802f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// is below the computed threshold, then inlining was forcibly disabled by 803f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// some artifact of the rountine. 804f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthbool CallAnalyzer::analyzeCall(CallSite CS) { 805f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Track whether the post-inlining function would have more than one basic 806f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // block. A single basic block is often intended for inlining. Balloon the 807f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // threshold by 50% until we pass the single-BB phase. 808f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool SingleBB = true; 809f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth int SingleBBBonus = Threshold / 2; 810f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Threshold += SingleBBBonus; 811f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 812f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Unless we are always-inlining, perform some tweaks to the cost and 813f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // threshold based on the direct callsite information. 814f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!AlwaysInline) { 815f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We want to more aggressively inline vector-dense kernels, so up the 816f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // threshold, and we'll lower it if the % of vector instructions gets too 817f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // low. 818f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth assert(NumInstructions == 0); 819f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth assert(NumVectorInstructions == 0); 820f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth FiftyPercentVectorBonus = Threshold; 821f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth TenPercentVectorBonus = Threshold / 2; 822f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 823f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Subtract off one instruction per call argument as those will be free after 824f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // inlining. 825f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost -= CS.arg_size() * InlineConstants::InstrCost; 826f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 827f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If there is only one call of the function, and it has internal linkage, 828f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // the cost of inlining it drops dramatically. 829f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction()) 830f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += InlineConstants::LastCallToStaticBonus; 831f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 832f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If the instruction after the call, or if the normal destination of the 833f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // invoke is an unreachable instruction, the function is noreturn. As such, 834f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // there is little point in inlining this unless there is literally zero cost. 835f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) { 836f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isa<UnreachableInst>(II->getNormalDest()->begin())) 837f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Threshold = 1; 838f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } else if (isa<UnreachableInst>(++BasicBlock::iterator(CS.getInstruction()))) 839f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Threshold = 1; 840f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 841f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If this function uses the coldcc calling convention, prefer not to inline 842f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // it. 843f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (F.getCallingConv() == CallingConv::Cold) 844f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += InlineConstants::ColdccPenalty; 845f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 846f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Check if we're done. This can happen due to bonuses and penalties. 847f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Cost > Threshold) 848f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 849f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 8505c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 851f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (F.empty()) 852f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return true; 853e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 854f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Track whether we've seen a return instruction. The first return 855f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // instruction is free, as at least one will usually disappear in inlining. 856f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool HasReturn = false; 857f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 858f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Populate our simplified values by mapping from function arguments to call 859f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // arguments with known important simplifications. 860f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth CallSite::arg_iterator CAI = CS.arg_begin(); 861f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (Function::arg_iterator FAI = F.arg_begin(), FAE = F.arg_end(); 862f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth FAI != FAE; ++FAI, ++CAI) { 863f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth assert(CAI != CS.arg_end()); 864f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (Constant *C = dyn_cast<Constant>(CAI)) 865f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SimplifiedValues[FAI] = C; 866f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 867f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *PtrArg = *CAI; 868f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (ConstantInt *C = stripAndComputeInBoundsConstantOffsets(PtrArg)) { 869f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth ConstantOffsetPtrs[FAI] = std::make_pair(PtrArg, C->getValue()); 870f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 871f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We can SROA any pointer arguments derived from alloca instructions. 872f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isa<AllocaInst>(PtrArg)) { 873f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgValues[FAI] = PtrArg; 874f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SROAArgCosts[PtrArg] = 0; 875f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 876f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 877f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 878f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumConstantArgs = SimplifiedValues.size(); 879f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumConstantOffsetPtrArgs = ConstantOffsetPtrs.size(); 880f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth NumAllocaArgs = SROAArgValues.size(); 881f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 882f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // The worklist of live basic blocks in the callee *after* inlining. We avoid 883f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // adding basic blocks of the callee which can be proven to be dead for this 884f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // particular call site in order to get more accurate cost estimates. This 885f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // requires a somewhat heavyweight iteration pattern: we need to walk the 886f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // basic blocks in a breadth-first order as we insert live successors. To 887f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // accomplish this, prioritizing for small iterations because we exit after 888f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // crossing our threshold, we use a small-size optimized SetVector. 889f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth typedef SetVector<BasicBlock *, SmallVector<BasicBlock *, 16>, 890f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SmallPtrSet<BasicBlock *, 16> > BBSetVector; 891f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth BBSetVector BBWorklist; 892f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth BBWorklist.insert(&F.getEntryBlock()); 893f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Note that we *must not* cache the size, this loop grows the worklist. 894f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) { 895f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Bail out the moment we cross the threshold. This means we'll under-count 896f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // the cost, but only when undercounting doesn't matter. 897f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!AlwaysInline && Cost > (Threshold + VectorBonus)) 898f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth break; 899f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 900f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth BasicBlock *BB = BBWorklist[Idx]; 901f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BB->empty()) 902f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth continue; 903e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 904f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Handle the terminator cost here where we can track returns and other 905f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // function-wide constructs. 906f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth TerminatorInst *TI = BB->getTerminator(); 907f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 908f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // We never want to inline functions that contain an indirectbr. This is 909f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // incorrect because all the blockaddress's (in static global initializers 910f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // for example) would be referring to the original function, and this indirect 911f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // jump would jump from the inlined copy of the function into the original 912f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // function which is extremely undefined behavior. 913f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // FIXME: This logic isn't really right; we can safely inline functions 914f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // with indirectbr's as long as no other function or global references the 915f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // blockaddress of a block within the current function. And as a QOI issue, 916f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // if someone is using a blockaddress without an indirectbr, and that 917f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // reference somehow ends up in another function or global, we probably 918f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // don't want to inline this function. 919f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (isa<IndirectBrInst>(TI)) 920f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 9215c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 922f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!HasReturn && isa<ReturnInst>(TI)) 923f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth HasReturn = true; 924f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth else 925f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Cost += InlineConstants::InstrCost; 926e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 927f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Analyze the cost of this block. If we blow through the threshold, this 928f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // returns false, and we can bail on out. 929f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!analyzeBlock(BB)) { 930f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (IsRecursive || ExposesReturnsTwice || HasDynamicAlloca) 931f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return false; 932f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth break; 933f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 9345c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 935f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Add in the live successors by first checking whether we have terminator 936f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // that may be simplified based on the values simplified by this call. 937f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BranchInst *BI = dyn_cast<BranchInst>(TI)) { 938f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (BI->isConditional()) { 939f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *Cond = BI->getCondition(); 940f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (ConstantInt *SimpleCond 941f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth = dyn_cast_or_null<ConstantInt>(SimplifiedValues.lookup(Cond))) { 942f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth BBWorklist.insert(BI->getSuccessor(SimpleCond->isZero() ? 1 : 0)); 943f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth continue; 944f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 945f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 946f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) { 947f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Value *Cond = SI->getCondition(); 948f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (ConstantInt *SimpleCond 949f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth = dyn_cast_or_null<ConstantInt>(SimplifiedValues.lookup(Cond))) { 950f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth BBWorklist.insert(SI->findCaseValue(SimpleCond).getCaseSuccessor()); 951f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth continue; 952f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 953f84755b8360d13b1d19df821d9e8692aac7e9b87Chris Lattner } 954e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 955f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If we're unable to select a particular successor, just count all of 956f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // them. 957f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth for (unsigned TIdx = 0, TSize = TI->getNumSuccessors(); TIdx != TSize; ++TIdx) 958f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth BBWorklist.insert(TI->getSuccessor(TIdx)); 959f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth 960f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // If we had any successors at this point, than post-inlining is likely to 961f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // have them as well. Note that we assume any basic blocks which existed 962f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // due to branches or switches which folded above will also fold after 963f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // inlining. 964f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (SingleBB && TI->getNumSuccessors() > 1) { 965f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Take off the bonus we applied to the threshold. 966f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Threshold -= SingleBBBonus; 967f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth SingleBB = false; 968f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth } 969e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman } 970e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 971f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Threshold += VectorBonus; 972e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman 973f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return AlwaysInline || Cost < Threshold; 974f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 9755c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 976f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth/// \brief Dump stats about this call's analysis. 977f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruthvoid CallAnalyzer::dump() { 978f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#define DEBUG_PRINT_STAT(x) llvm::dbgs() << " " #x ": " << x << "\n" 979f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(NumConstantArgs); 980f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(NumConstantOffsetPtrArgs); 981f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(NumAllocaArgs); 982f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(NumConstantPtrCmps); 983f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(NumConstantPtrDiffs); 984f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(NumInstructionsSimplified); 985f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(SROACostSavings); 986f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG_PRINT_STAT(SROACostSavingsLost); 987f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth#undef DEBUG_PRINT_STAT 988e4aeec003f82a5263ffb168e175e6fca8b6f681dDan Gohman} 989f7477470d37ee2ab9075eaee4745fa084d424ab8Jakob Stoklund Olesen 990f2286b0152f0b942e82d8e809186e5cc0d247131Chandler CarruthInlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, int Threshold) { 991b381578fcb5fea988f661dbbee9747b8fd55c5fbDavid Chisnall return getInlineCost(CS, CS.getCalledFunction(), Threshold); 992b381578fcb5fea988f661dbbee9747b8fd55c5fbDavid Chisnall} 993f7477470d37ee2ab9075eaee4745fa084d424ab8Jakob Stoklund Olesen 994b381578fcb5fea988f661dbbee9747b8fd55c5fbDavid ChisnallInlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, Function *Callee, 995b381578fcb5fea988f661dbbee9747b8fd55c5fbDavid Chisnall int Threshold) { 996f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Don't inline functions which can be redefined at link-time to mean 997f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // something else. Don't inline functions marked noinline or call sites 998f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // marked noinline. 999f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!Callee || Callee->mayBeOverridden() || 1000f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth Callee->hasFnAttr(Attribute::NoInline) || CS.isNoInline()) 1001f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return llvm::InlineCost::getNever(); 1002f7477470d37ee2ab9075eaee4745fa084d424ab8Jakob Stoklund Olesen 1003f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG(llvm::dbgs() << " Analyzing call of " << Callee->getName() << "...\n"); 100444b04a5f4ac8a2b9b3208a937f2ba36bcf7aa40fChris Lattner 1005f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth CallAnalyzer CA(TD, *Callee, Threshold); 1006f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth bool ShouldInline = CA.analyzeCall(CS); 10075c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 1008f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth DEBUG(CA.dump()); 100944b04a5f4ac8a2b9b3208a937f2ba36bcf7aa40fChris Lattner 1010f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth // Check if there was a reason to force inlining or no inlining. 1011f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (!ShouldInline && CA.getCost() < CA.getThreshold()) 1012f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return InlineCost::getNever(); 1013f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth if (ShouldInline && CA.getCost() >= CA.getThreshold()) 1014f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return InlineCost::getAlways(); 10155c655413cf9466c29e38204ab3f19b33fffd7996Andrew Trick 1016f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth return llvm::InlineCost::get(CA.getCost(), CA.getThreshold()); 1017f2286b0152f0b942e82d8e809186e5cc0d247131Chandler Carruth} 1018