1f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner//===- InstCombinePHI.cpp -------------------------------------------------===// 2f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// 3f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// The LLVM Compiler Infrastructure 4f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// 5f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// This file is distributed under the University of Illinois Open Source 6f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// License. See LICENSE.TXT for details. 7f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// 8f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner//===----------------------------------------------------------------------===// 9f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// 10f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// This file implements the visitPHINode function. 11f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// 12f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner//===----------------------------------------------------------------------===// 13f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 14ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#include "InstCombineInternal.h" 15d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/STLExtras.h" 16d04a8d4b33ff316ca4cf961e06c9e312eff8e64fChandler Carruth#include "llvm/ADT/SmallPtrSet.h" 17cd6636c737a82949ad13db2d0d918af6424fb78bDuncan Sands#include "llvm/Analysis/InstructionSimplify.h" 18de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar#include "llvm/Analysis/ValueTracking.h" 19de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar#include "llvm/IR/PatternMatch.h" 20f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar#include "llvm/Transforms/Utils/Local.h" 21f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnerusing namespace llvm; 22de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainarusing namespace llvm::PatternMatch; 23f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 24dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines#define DEBUG_TYPE "instcombine" 25dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines 26f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// If we have something like phi [add (a,b), add(a,c)] and if a/b/c and the 27f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// adds all have a single use, turn this into a phi and a single binop. 28f54e72962991005a3c0cc7dce0c550a14af90792Chris LattnerInstruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) { 29f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Instruction *FirstInst = cast<Instruction>(PN.getIncomingValue(0)); 30f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner assert(isa<BinaryOperator>(FirstInst) || isa<CmpInst>(FirstInst)); 31f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned Opc = FirstInst->getOpcode(); 32f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *LHSVal = FirstInst->getOperand(0); 33f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *RHSVal = FirstInst->getOperand(1); 3403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 35db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner Type *LHSType = LHSVal->getType(); 36db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner Type *RHSType = RHSVal->getType(); 3703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 38f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan to see if all operands are the same opcode, and all have one use. 39f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) { 40f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Instruction *I = dyn_cast<Instruction>(PN.getIncomingValue(i)); 41f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!I || I->getOpcode() != Opc || !I->hasOneUse() || 42f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Verify type of the LHS matches so we don't fold cmp's of different 43c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner // types. 44f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner I->getOperand(0)->getType() != LHSType || 45f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner I->getOperand(1)->getType() != RHSType) 46dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 47f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 48f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If they are CmpInst instructions, check their predicates 49c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner if (CmpInst *CI = dyn_cast<CmpInst>(I)) 50c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner if (CI->getPredicate() != cast<CmpInst>(FirstInst)->getPredicate()) 51dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 5203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 53f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Keep track of which operand needs a phi node. 54dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (I->getOperand(0) != LHSVal) LHSVal = nullptr; 55dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (I->getOperand(1) != RHSVal) RHSVal = nullptr; 56f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 57f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 58f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If both LHS and RHS would need a PHI, don't do this transformation, 59f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // because it would increase the number of PHIs entering the block, 60f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // which leads to higher register pressure. This is especially 61f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // bad when the PHIs are in the header of a loop. 62f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!LHSVal && !RHSVal) 63dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 6403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 65f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Otherwise, this is safe to transform! 6603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 67f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *InLHS = FirstInst->getOperand(0); 68f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *InRHS = FirstInst->getOperand(1); 69dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines PHINode *NewLHS = nullptr, *NewRHS = nullptr; 70dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (!LHSVal) { 713ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad NewLHS = PHINode::Create(LHSType, PN.getNumIncomingValues(), 72f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner FirstInst->getOperand(0)->getName() + ".pn"); 73f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewLHS->addIncoming(InLHS, PN.getIncomingBlock(0)); 74f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner InsertNewInstBefore(NewLHS, PN); 75f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LHSVal = NewLHS; 76f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 7703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 78dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (!RHSVal) { 793ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad NewRHS = PHINode::Create(RHSType, PN.getNumIncomingValues(), 80f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner FirstInst->getOperand(1)->getName() + ".pn"); 81f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewRHS->addIncoming(InRHS, PN.getIncomingBlock(0)); 82f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner InsertNewInstBefore(NewRHS, PN); 83f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner RHSVal = NewRHS; 84f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 8503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 86f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Add all operands to the new PHIs. 87f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (NewLHS || NewRHS) { 88f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { 89f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Instruction *InInst = cast<Instruction>(PN.getIncomingValue(i)); 90f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (NewLHS) { 91f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *NewInLHS = InInst->getOperand(0); 92f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewLHS->addIncoming(NewInLHS, PN.getIncomingBlock(i)); 93f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 94f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (NewRHS) { 95f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *NewInRHS = InInst->getOperand(1); 96f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewRHS->addIncoming(NewInRHS, PN.getIncomingBlock(i)); 97f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 98f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 99f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 10003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 101a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman if (CmpInst *CIOp = dyn_cast<CmpInst>(FirstInst)) { 102a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman CmpInst *NewCI = CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(), 103a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman LHSVal, RHSVal); 104a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman NewCI->setDebugLoc(FirstInst->getDebugLoc()); 105a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman return NewCI; 106a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman } 107a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman 108c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner BinaryOperator *BinOp = cast<BinaryOperator>(FirstInst); 109c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner BinaryOperator *NewBinOp = 110c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner BinaryOperator::Create(BinOp->getOpcode(), LHSVal, RHSVal); 111de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar 112de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar NewBinOp->copyIRFlags(PN.getIncomingValue(0)); 113de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar 114de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) 115de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar NewBinOp->andIRFlags(PN.getIncomingValue(i)); 116de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar 117a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman NewBinOp->setDebugLoc(FirstInst->getDebugLoc()); 118c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner return NewBinOp; 119f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 120f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 121f54e72962991005a3c0cc7dce0c550a14af90792Chris LattnerInstruction *InstCombiner::FoldPHIArgGEPIntoPHI(PHINode &PN) { 122f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner GetElementPtrInst *FirstInst =cast<GetElementPtrInst>(PN.getIncomingValue(0)); 12303fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 12403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach SmallVector<Value*, 16> FixedOperands(FirstInst->op_begin(), 125f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner FirstInst->op_end()); 126f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // This is true if all GEP bases are allocas and if all indices into them are 127f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // constants. 128f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner bool AllBasePointersAreAllocas = true; 129f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 130f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // We don't want to replace this phi if the replacement would require 131f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // more than one phi, which leads to higher register pressure. This is 132f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // especially bad when the PHIs are in the header of a loop. 133f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner bool NeededPhi = false; 13403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 1354bd8217af3cf38f9fcce378fbc687162e28a7cf8Chris Lattner bool AllInBounds = true; 13603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 137f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan to see if all operands are the same opcode, and all have one use. 138f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) { 139f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner GetElementPtrInst *GEP= dyn_cast<GetElementPtrInst>(PN.getIncomingValue(i)); 140f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!GEP || !GEP->hasOneUse() || GEP->getType() != FirstInst->getType() || 141f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner GEP->getNumOperands() != FirstInst->getNumOperands()) 142dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 143f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 1444bd8217af3cf38f9fcce378fbc687162e28a7cf8Chris Lattner AllInBounds &= GEP->isInBounds(); 14503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 146f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Keep track of whether or not all GEPs are of alloca pointers. 147f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (AllBasePointersAreAllocas && 148f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner (!isa<AllocaInst>(GEP->getOperand(0)) || 149f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner !GEP->hasAllConstantIndices())) 150f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner AllBasePointersAreAllocas = false; 15103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 152f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Compare the operand lists. 153f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned op = 0, e = FirstInst->getNumOperands(); op != e; ++op) { 154f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (FirstInst->getOperand(op) == GEP->getOperand(op)) 155f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 15603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 157f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Don't merge two GEPs when two operands differ (introducing phi nodes) 158f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // if one of the PHIs has a constant for the index. The index may be 159f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // substantially cheaper to compute for the constants, so making it a 160f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // variable index could pessimize the path. This also handles the case 161f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // for struct indices, which must always be constant. 162f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isa<ConstantInt>(FirstInst->getOperand(op)) || 163f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner isa<ConstantInt>(GEP->getOperand(op))) 164dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 16503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 166f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (FirstInst->getOperand(op)->getType() !=GEP->getOperand(op)->getType()) 167dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 168f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 169f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If we already needed a PHI for an earlier operand, and another operand 170f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // also requires a PHI, we'd be introducing more PHIs than we're 171f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // eliminating, which increases register pressure on entry to the PHI's 172f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // block. 173f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (NeededPhi) 174dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 175f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 176dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines FixedOperands[op] = nullptr; // Needs a PHI. 177f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NeededPhi = true; 178f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 179f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 18003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 181f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If all of the base pointers of the PHI'd GEPs are from allocas, don't 182f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // bother doing this transformation. At best, this will just save a bit of 183f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // offset calculation, but all the predecessors will have to materialize the 184f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // stack address into a register anyway. We'd actually rather *clone* the 185f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // load up into the predecessors so that we have a load of a gep of an alloca, 186f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // which can usually all be folded into the load. 187f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (AllBasePointersAreAllocas) 188dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 18903fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 190f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Otherwise, this is safe to transform. Insert PHI nodes for each operand 191f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // that is variable. 192f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner SmallVector<PHINode*, 16> OperandPhis(FixedOperands.size()); 19303fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 194f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner bool HasAnyPHIs = false; 195f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 0, e = FixedOperands.size(); i != e; ++i) { 196f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (FixedOperands[i]) continue; // operand doesn't need a phi. 197f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *FirstOp = FirstInst->getOperand(i); 1983ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad PHINode *NewPN = PHINode::Create(FirstOp->getType(), e, 199f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner FirstOp->getName()+".pn"); 200f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner InsertNewInstBefore(NewPN, PN); 20103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 202f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewPN->addIncoming(FirstOp, PN.getIncomingBlock(0)); 203f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner OperandPhis[i] = NewPN; 204f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner FixedOperands[i] = NewPN; 205f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner HasAnyPHIs = true; 206f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 207f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 20803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 209f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Add all operands to the new PHIs. 210f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (HasAnyPHIs) { 211f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { 212f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner GetElementPtrInst *InGEP =cast<GetElementPtrInst>(PN.getIncomingValue(i)); 213f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner BasicBlock *InBB = PN.getIncomingBlock(i); 21403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 215f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned op = 0, e = OperandPhis.size(); op != e; ++op) 216f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHINode *OpPhi = OperandPhis[op]) 217f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner OpPhi->addIncoming(InGEP->getOperand(op), InBB); 218f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 219f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 22003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 221f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *Base = FixedOperands[0]; 22203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach GetElementPtrInst *NewGEP = 2234c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar GetElementPtrInst::Create(FirstInst->getSourceElementType(), Base, 2244c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar makeArrayRef(FixedOperands).slice(1)); 2251521e91fc442b5c27d56118b45248e3d5707f7e2Chris Lattner if (AllInBounds) NewGEP->setIsInBounds(); 226a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman NewGEP->setDebugLoc(FirstInst->getDebugLoc()); 2274bd8217af3cf38f9fcce378fbc687162e28a7cf8Chris Lattner return NewGEP; 228f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 229f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 230f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 231f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// Return true if we know that it is safe to sink the load out of the block 232f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// that defines it. This means that it must be obvious the value of the load is 233f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// not changed from the point of the load to the end of the block it is in. 234f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// 2357a2bdde0a0eebcd2125055e0eacaca040f0b766cChris Lattner/// Finally, it is safe, but not profitable, to sink a load targeting a 236f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// non-address-taken alloca. Doing so will cause us to not promote the alloca 237f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// to a register. 238f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnerstatic bool isSafeAndProfitableToSinkLoad(LoadInst *L) { 239f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar BasicBlock::iterator BBI = L->getIterator(), E = L->getParent()->end(); 24003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 241f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (++BBI; BBI != E; ++BBI) 242f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (BBI->mayWriteToMemory()) 243f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 24403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 245f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Check for non-address taken alloca. If not address-taken already, it isn't 246f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // profitable to do this xform. 247f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (AllocaInst *AI = dyn_cast<AllocaInst>(L->getOperand(0))) { 248f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner bool isAddressTaken = false; 24936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines for (User *U : AI->users()) { 25040119ceeecafdd6d47bd7bb7f520262858b931dfGabor Greif if (isa<LoadInst>(U)) continue; 25140119ceeecafdd6d47bd7bb7f520262858b931dfGabor Greif if (StoreInst *SI = dyn_cast<StoreInst>(U)) { 252f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If storing TO the alloca, then the address isn't taken. 253f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (SI->getOperand(1) == AI) continue; 254f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 255f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner isAddressTaken = true; 256f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner break; 257f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 25803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 259f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!isAddressTaken && AI->isStaticAlloca()) 260f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 261f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 26203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 263f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If this load is a load from a GEP with a constant offset from an alloca, 264f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // then we don't want to sink it. In its present form, it will be 265f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // load [constant stack offset]. Sinking it will cause us to have to 266f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // materialize the stack addresses in each predecessor in a register only to 267f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // do a shared load from register in the successor. 268f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(L->getOperand(0))) 269f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (AllocaInst *AI = dyn_cast<AllocaInst>(GEP->getOperand(0))) 270f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (AI->isStaticAlloca() && GEP->hasAllConstantIndices()) 271f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 27203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 273f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return true; 274f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 275f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 276f54e72962991005a3c0cc7dce0c550a14af90792Chris LattnerInstruction *InstCombiner::FoldPHIArgLoadIntoPHI(PHINode &PN) { 277f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LoadInst *FirstLI = cast<LoadInst>(PN.getIncomingValue(0)); 278cc4a0435b7ee34af2c64a6f7ee63642f56096d1bEli Friedman 279cc4a0435b7ee34af2c64a6f7ee63642f56096d1bEli Friedman // FIXME: This is overconservative; this transform is allowed in some cases 280cc4a0435b7ee34af2c64a6f7ee63642f56096d1bEli Friedman // for atomic operations. 281cc4a0435b7ee34af2c64a6f7ee63642f56096d1bEli Friedman if (FirstLI->isAtomic()) 282dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 283cc4a0435b7ee34af2c64a6f7ee63642f56096d1bEli Friedman 284f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // When processing loads, we need to propagate two bits of information to the 285f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // sunk load: whether it is volatile, and what its alignment is. We currently 286f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // don't sink loads when some have their alignment specified and some don't. 287f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // visitLoadInst will propagate an alignment onto the load when TD is around, 288f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // and if TD isn't around, we can't handle the mixed case. 289f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner bool isVolatile = FirstLI->isVolatile(); 290f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned LoadAlignment = FirstLI->getAlignment(); 2914c5fb1a311a7a5e3ceb802f5b26329d30f2713b1Chris Lattner unsigned LoadAddrSpace = FirstLI->getPointerAddressSpace(); 29203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 293f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // We can't sink the load if the loaded value could be modified between the 294f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // load and the PHI. 295f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (FirstLI->getParent() != PN.getIncomingBlock(0) || 296f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner !isSafeAndProfitableToSinkLoad(FirstLI)) 297dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 29803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 299f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If the PHI is of volatile loads and the load block has multiple 300f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // successors, sinking it would remove a load of the volatile value from 301f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the path through the other successor. 30203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach if (isVolatile && 303f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner FirstLI->getParent()->getTerminator()->getNumSuccessors() != 1) 304dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 30503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 306f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Check to see if all arguments are the same operation. 307f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { 308f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LoadInst *LI = dyn_cast<LoadInst>(PN.getIncomingValue(i)); 309f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!LI || !LI->hasOneUse()) 310dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 31103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 31203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach // We can't sink the load if the loaded value could be modified between 313f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the load and the PHI. 314f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (LI->isVolatile() != isVolatile || 315f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LI->getParent() != PN.getIncomingBlock(i) || 3164c5fb1a311a7a5e3ceb802f5b26329d30f2713b1Chris Lattner LI->getPointerAddressSpace() != LoadAddrSpace || 317f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner !isSafeAndProfitableToSinkLoad(LI)) 318dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 31903fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 320f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If some of the loads have an alignment specified but not all of them, 321f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // we can't do the transformation. 322f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if ((LoadAlignment != 0) != (LI->getAlignment() != 0)) 323dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 32403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 325f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LoadAlignment = std::min(LoadAlignment, LI->getAlignment()); 32603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 327f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If the PHI is of volatile loads and the load block has multiple 328f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // successors, sinking it would remove a load of the volatile value from 329f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the path through the other successor. 330f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isVolatile && 331f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LI->getParent()->getTerminator()->getNumSuccessors() != 1) 332dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 333f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 33403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 335f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Okay, they are all the same operation. Create a new PHI node of the 336f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // correct type, and PHI together all of the LHS's of the instructions. 337f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *NewPN = PHINode::Create(FirstLI->getOperand(0)->getType(), 3383ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad PN.getNumIncomingValues(), 339f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.getName()+".in"); 34003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 341f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *InVal = FirstLI->getOperand(0); 342f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewPN->addIncoming(InVal, PN.getIncomingBlock(0)); 343f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LoadInst *NewLI = new LoadInst(NewPN, "", isVolatile, LoadAlignment); 344f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 345f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar unsigned KnownIDs[] = { 346f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_tbaa, 347f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_range, 348f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_invariant_load, 349f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_alias_scope, 350f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_noalias, 351f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_nonnull, 352f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_align, 353f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_dereferenceable, 354f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LLVMContext::MD_dereferenceable_or_null, 355f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar }; 35603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 357f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar for (unsigned ID : KnownIDs) 358f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NewLI->setMetadata(ID, FirstLI->getMetadata(ID)); 359f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 360f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // Add all operands to the new PHI and combine TBAA metadata. 361f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { 362f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar LoadInst *LI = cast<LoadInst>(PN.getIncomingValue(i)); 363f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar combineMetadata(NewLI, LI, KnownIDs); 364f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar Value *NewInVal = LI->getOperand(0); 365f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (NewInVal != InVal) 366dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines InVal = nullptr; 367f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i)); 368f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 36903fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 370f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (InVal) { 371f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // The new PHI unions all of the same values together. This is really 372f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // common, so we handle it intelligently here for compile-time speed. 373f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NewLI->setOperand(0, InVal); 374f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner delete NewPN; 375f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } else { 376f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner InsertNewInstBefore(NewPN, PN); 377f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 37803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 379f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If this was a volatile load that we are merging, make sure to loop through 380f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // and mark all the input loads as non-volatile. If we don't do this, we will 381f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // insert a new volatile load and the old ones will not be deletable. 382f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isVolatile) 3836948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar for (Value *IncValue : PN.incoming_values()) 3846948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar cast<LoadInst>(IncValue)->setVolatile(false); 38503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 386a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman NewLI->setDebugLoc(FirstLI->getDebugLoc()); 387a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman return NewLI; 388f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 389f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 390f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// TODO: This function could handle other cast types, but then it might 391f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// require special-casing a cast from the 'i1' type. See the comment in 392f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// FoldPHIArgOpIntoPHI() about pessimizing illegal integer types. 393f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga NainarInstruction *InstCombiner::FoldPHIArgZextsIntoPHI(PHINode &Phi) { 394f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // We cannot create a new instruction after the PHI if the terminator is an 395f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // EHPad because there is no valid insertion point. 396f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (TerminatorInst *TI = Phi.getParent()->getTerminator()) 397f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (TI->isEHPad()) 398f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 399f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 400f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // Early exit for the common case of a phi with two operands. These are 401f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // handled elsewhere. See the comment below where we check the count of zexts 402f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // and constants for more details. 403f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar unsigned NumIncomingValues = Phi.getNumIncomingValues(); 404f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (NumIncomingValues < 3) 405f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 406f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 407f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // Find the narrower type specified by the first zext. 408f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar Type *NarrowType = nullptr; 409f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar for (Value *V : Phi.incoming_values()) { 410f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (auto *Zext = dyn_cast<ZExtInst>(V)) { 411f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NarrowType = Zext->getSrcTy(); 412f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar break; 413f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar } 414f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar } 415f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (!NarrowType) 416f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 417f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 418f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // Walk the phi operands checking that we only have zexts or constants that 419f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // we can shrink for free. Store the new operands for the new phi. 420f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar SmallVector<Value *, 4> NewIncoming; 421f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar unsigned NumZexts = 0; 422f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar unsigned NumConsts = 0; 423f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar for (Value *V : Phi.incoming_values()) { 424f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (auto *Zext = dyn_cast<ZExtInst>(V)) { 425f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // All zexts must be identical and have one use. 426f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (Zext->getSrcTy() != NarrowType || !Zext->hasOneUse()) 427f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 428f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NewIncoming.push_back(Zext->getOperand(0)); 429f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NumZexts++; 430f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar } else if (auto *C = dyn_cast<Constant>(V)) { 431f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // Make sure that constants can fit in the new type. 432f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar Constant *Trunc = ConstantExpr::getTrunc(C, NarrowType); 433f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (ConstantExpr::getZExt(Trunc, C->getType()) != C) 434f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 435f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NewIncoming.push_back(Trunc); 436f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NumConsts++; 437f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar } else { 438f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // If it's not a cast or a constant, bail out. 439f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 440f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar } 441f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar } 442f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 443f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // The more common cases of a phi with no constant operands or just one 444f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // variable operand are handled by FoldPHIArgOpIntoPHI() and FoldOpIntoPhi() 445f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // respectively. FoldOpIntoPhi() wants to do the opposite transform that is 446f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // performed here. It tries to replicate a cast in the phi operand's basic 447f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // block to expose other folding opportunities. Thus, InstCombine will 448f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // infinite loop without this check. 449f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (NumConsts == 0 || NumZexts < 2) 450f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 451f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 452f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // All incoming values are zexts or constants that are safe to truncate. 453f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // Create a new phi node of the narrow type, phi together all of the new 454f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // operands, and zext the result back to the original type. 455f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar PHINode *NewPhi = PHINode::Create(NarrowType, NumIncomingValues, 456f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar Phi.getName() + ".shrunk"); 457f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar for (unsigned i = 0; i != NumIncomingValues; ++i) 458f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar NewPhi->addIncoming(NewIncoming[i], Phi.getIncomingBlock(i)); 459f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 460f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar InsertNewInstBefore(NewPhi, Phi); 461f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return CastInst::CreateZExtOrBitCast(NewPhi, Phi.getType()); 462f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar} 463f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 464f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// If all operands to a PHI node are the same "unary" operator and they all are 465f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// only used by the PHI, PHI together their inputs, and do the operation once, 466f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// to the result of the PHI. 467f54e72962991005a3c0cc7dce0c550a14af90792Chris LattnerInstruction *InstCombiner::FoldPHIArgOpIntoPHI(PHINode &PN) { 468f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // We cannot create a new instruction after the PHI if the terminator is an 469f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar // EHPad because there is no valid insertion point. 470f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (TerminatorInst *TI = PN.getParent()->getTerminator()) 471f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (TI->isEHPad()) 472f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return nullptr; 473f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 474f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Instruction *FirstInst = cast<Instruction>(PN.getIncomingValue(0)); 475f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 476f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isa<GetElementPtrInst>(FirstInst)) 477f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return FoldPHIArgGEPIntoPHI(PN); 478f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isa<LoadInst>(FirstInst)) 479f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return FoldPHIArgLoadIntoPHI(PN); 48003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 481f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan the instruction, looking for input operations that can be folded away. 482f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If all input operands to the phi are the same instruction (e.g. a cast from 483f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the same type or "+42") we can pull the operation through the PHI, reducing 484f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // code size and simplifying code. 485dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines Constant *ConstantOp = nullptr; 486dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines Type *CastSrcTy = nullptr; 48703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 488f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isa<CastInst>(FirstInst)) { 489f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner CastSrcTy = FirstInst->getOperand(0)->getType(); 490f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 491f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Be careful about transforming integer PHIs. We don't want to pessimize 492f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the code by turning an i32 into an i1293. 4931df9859c40492511b8aa4321eb76496005d3b75bDuncan Sands if (PN.getType()->isIntegerTy() && CastSrcTy->isIntegerTy()) { 494f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!ShouldChangeType(PN.getType(), CastSrcTy)) 495dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 496f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 497f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } else if (isa<BinaryOperator>(FirstInst) || isa<CmpInst>(FirstInst)) { 49803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach // Can fold binop, compare or shift here if the RHS is a constant, 499f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // otherwise call FoldPHIArgBinOpIntoPHI. 500f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner ConstantOp = dyn_cast<Constant>(FirstInst->getOperand(1)); 501dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (!ConstantOp) 502f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return FoldPHIArgBinOpIntoPHI(PN); 503f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } else { 504dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; // Cannot fold this operation. 505f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 506f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 507f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Check to see if all arguments are the same operation. 508f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { 509f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Instruction *I = dyn_cast<Instruction>(PN.getIncomingValue(i)); 510dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (!I || !I->hasOneUse() || !I->isSameOperationAs(FirstInst)) 511dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 512f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (CastSrcTy) { 513f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (I->getOperand(0)->getType() != CastSrcTy) 514dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; // Cast operation must match. 515f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } else if (I->getOperand(1) != ConstantOp) { 516dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 517f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 518f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 519f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 520f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Okay, they are all the same operation. Create a new PHI node of the 521f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // correct type, and PHI together all of the LHS's of the instructions. 522f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *NewPN = PHINode::Create(FirstInst->getOperand(0)->getType(), 5233ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad PN.getNumIncomingValues(), 524f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.getName()+".in"); 525f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 526f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *InVal = FirstInst->getOperand(0); 527f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewPN->addIncoming(InVal, PN.getIncomingBlock(0)); 528f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 529f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Add all operands to the new PHI. 530f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) { 531f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *NewInVal = cast<Instruction>(PN.getIncomingValue(i))->getOperand(0); 532f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (NewInVal != InVal) 533dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines InVal = nullptr; 534f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner NewPN->addIncoming(NewInVal, PN.getIncomingBlock(i)); 535f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 536f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 537f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *PhiVal; 538f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (InVal) { 539f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // The new PHI unions all of the same values together. This is really 540f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // common, so we handle it intelligently here for compile-time speed. 541f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PhiVal = InVal; 542f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner delete NewPN; 543f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } else { 544f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner InsertNewInstBefore(NewPN, PN); 545f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PhiVal = NewPN; 546f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 547f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 548f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Insert and return the new operation. 549a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman if (CastInst *FirstCI = dyn_cast<CastInst>(FirstInst)) { 550a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman CastInst *NewCI = CastInst::Create(FirstCI->getOpcode(), PhiVal, 551a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman PN.getType()); 552a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman NewCI->setDebugLoc(FirstInst->getDebugLoc()); 553a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman return NewCI; 554a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman } 55503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 556c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(FirstInst)) { 557c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner BinOp = BinaryOperator::Create(BinOp->getOpcode(), PhiVal, ConstantOp); 558de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar BinOp->copyIRFlags(PN.getIncomingValue(0)); 559de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar 560de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i) 561de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar BinOp->andIRFlags(PN.getIncomingValue(i)); 562de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar 563a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman BinOp->setDebugLoc(FirstInst->getDebugLoc()); 564c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner return BinOp; 565c8cb8ef9c2d5e354db661022d707a19b3533c00eChris Lattner } 56603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 567f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner CmpInst *CIOp = cast<CmpInst>(FirstInst); 568a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman CmpInst *NewCI = CmpInst::Create(CIOp->getOpcode(), CIOp->getPredicate(), 569a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman PhiVal, ConstantOp); 570a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman NewCI->setDebugLoc(FirstInst->getDebugLoc()); 571a311c34d2af7c750f016ef5e4c41bee77a1dfac7Eli Friedman return NewCI; 572f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 573f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 574f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// Return true if this PHI node is only used by a PHI node cycle that is dead. 575f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnerstatic bool DeadPHICycle(PHINode *PN, 57637ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines SmallPtrSetImpl<PHINode*> &PotentiallyDeadPHIs) { 577f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PN->use_empty()) return true; 578f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!PN->hasOneUse()) return false; 579f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 580f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Remember this node, and if we find the cycle, return. 58137ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (!PotentiallyDeadPHIs.insert(PN).second) 582f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return true; 58303fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 584f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Don't scan crazily complex things. 585f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PotentiallyDeadPHIs.size() == 16) 586f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 587f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 58836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (PHINode *PU = dyn_cast<PHINode>(PN->user_back())) 589f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return DeadPHICycle(PU, PotentiallyDeadPHIs); 590f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 591f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 592f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 593f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 594f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// Return true if this phi node is always equal to NonPhiInVal. 595f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// This happens with mutually cyclic phi nodes like: 596f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// z = some value; x = phi (y, z); y = phi (x, z) 59703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbachstatic bool PHIsEqualValue(PHINode *PN, Value *NonPhiInVal, 59837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines SmallPtrSetImpl<PHINode*> &ValueEqualPHIs) { 599f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // See if we already saw this PHI node. 60037ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (!ValueEqualPHIs.insert(PN).second) 601f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return true; 60203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 603f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Don't scan crazily complex things. 604f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (ValueEqualPHIs.size() == 16) 605f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 60603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 607f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan the operands to see if they are either phi nodes or are equal to 608f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the value. 6096948897e478cbd66626159776a8017b3c18579b9Pirama Arumuga Nainar for (Value *Op : PN->incoming_values()) { 610f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHINode *OpPN = dyn_cast<PHINode>(Op)) { 611f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (!PHIsEqualValue(OpPN, NonPhiInVal, ValueEqualPHIs)) 612f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 613f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } else if (Op != NonPhiInVal) 614f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return false; 615f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 61603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 617f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return true; 618f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 619f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 620de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar/// Return an existing non-zero constant if this phi node has one, otherwise 621de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar/// return constant 1. 622de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainarstatic ConstantInt *GetAnyNonZeroConstInt(PHINode &PN) { 623de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar assert(isa<IntegerType>(PN.getType()) && "Expect only intger type phi"); 624de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar for (Value *V : PN.operands()) 625de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar if (auto *ConstVA = dyn_cast<ConstantInt>(V)) 626de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar if (!ConstVA->isZeroValue()) 627de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return ConstVA; 628de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return ConstantInt::get(cast<IntegerType>(PN.getType()), 1); 629de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar} 630f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 631f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnernamespace { 632f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnerstruct PHIUsageRecord { 633f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned PHIId; // The ID # of the PHI (something determinstic to sort on) 634f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned Shift; // The amount shifted. 635f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Instruction *Inst; // The trunc instruction. 63603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 637f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHIUsageRecord(unsigned pn, unsigned Sh, Instruction *User) 638f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner : PHIId(pn), Shift(Sh), Inst(User) {} 63903fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 640f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner bool operator<(const PHIUsageRecord &RHS) const { 641f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHIId < RHS.PHIId) return true; 642f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHIId > RHS.PHIId) return false; 643f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (Shift < RHS.Shift) return true; 644f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (Shift > RHS.Shift) return false; 645f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return Inst->getType()->getPrimitiveSizeInBits() < 646f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner RHS.Inst->getType()->getPrimitiveSizeInBits(); 647f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 648f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner}; 64903fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 650f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnerstruct LoweredPHIRecord { 651f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *PN; // The PHI that was lowered. 652f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned Shift; // The amount shifted. 653f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned Width; // The width extracted. 65403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 655db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner LoweredPHIRecord(PHINode *pn, unsigned Sh, Type *Ty) 656f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner : PN(pn), Shift(Sh), Width(Ty->getPrimitiveSizeInBits()) {} 65703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 658f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Ctor form used by DenseMap. 659f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LoweredPHIRecord(PHINode *pn, unsigned Sh) 660f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner : PN(pn), Shift(Sh), Width(0) {} 661f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner}; 662f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 663f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 664f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattnernamespace llvm { 665f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner template<> 666f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner struct DenseMapInfo<LoweredPHIRecord> { 667f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner static inline LoweredPHIRecord getEmptyKey() { 668dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return LoweredPHIRecord(nullptr, 0); 669f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 670f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner static inline LoweredPHIRecord getTombstoneKey() { 671dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return LoweredPHIRecord(nullptr, 1); 672f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 673f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner static unsigned getHashValue(const LoweredPHIRecord &Val) { 674f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return DenseMapInfo<PHINode*>::getHashValue(Val.PN) ^ (Val.Shift>>3) ^ 675f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner (Val.Width>>3); 676f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 677f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner static bool isEqual(const LoweredPHIRecord &LHS, 678f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner const LoweredPHIRecord &RHS) { 679f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return LHS.PN == RHS.PN && LHS.Shift == RHS.Shift && 680f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner LHS.Width == RHS.Width; 681f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 682f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner }; 683f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 684f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 685f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 686f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// This is an integer PHI and we know that it has an illegal type: see if it is 687f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// only used by trunc or trunc(lshr) operations. If so, we split the PHI into 688f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// the various pieces being extracted. This sort of thing is introduced when 689f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar/// SROA promotes an aggregate to large integer values. 690f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// 691f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// TODO: The user of the trunc may be an bitcast to float/double/vector or an 692f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// inttoptr. We should produce new PHIs in the right type. 693f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner/// 694f54e72962991005a3c0cc7dce0c550a14af90792Chris LattnerInstruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) { 695f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // PHIUsers - Keep track of all of the truncated values extracted from a set 696f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // of PHIs, along with their offset. These are the things we want to rewrite. 697f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner SmallVector<PHIUsageRecord, 16> PHIUsers; 69803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 699f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // PHIs are often mutually cyclic, so we keep track of a whole set of PHI 700f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // nodes which are extracted from. PHIsToSlice is a set we use to avoid 701f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // revisiting PHIs, PHIsInspected is a ordered list of PHIs that we need to 702f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // check the uses of (to ensure they are all extracts). 703f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner SmallVector<PHINode*, 8> PHIsToSlice; 704f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner SmallPtrSet<PHINode*, 8> PHIsInspected; 70503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 706f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHIsToSlice.push_back(&FirstPhi); 707f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHIsInspected.insert(&FirstPhi); 70803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 709f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned PHIId = 0; PHIId != PHIsToSlice.size(); ++PHIId) { 710f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *PN = PHIsToSlice[PHIId]; 71103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 712f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan the input list of the PHI. If any input is an invoke, and if the 713f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // input is defined in the predecessor, then we won't be split the critical 714f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // edge which is required to insert a truncate. Because of this, we have to 715f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // bail out. 716f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { 717f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner InvokeInst *II = dyn_cast<InvokeInst>(PN->getIncomingValue(i)); 718dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if (!II) continue; 719f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (II->getParent() != PN->getIncomingBlock(i)) 720f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 72103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 722f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If we have a phi, and if it's directly in the predecessor, then we have 723f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // a critical edge where we need to put the truncate. Since we can't 724f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // split the edge in instcombine, we have to bail out. 725dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 726f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 72703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 72836b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines for (User *U : PN->users()) { 72936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Instruction *UserI = cast<Instruction>(U); 73003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 731f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If the user is a PHI, inspect its uses recursively. 73236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (PHINode *UserPN = dyn_cast<PHINode>(UserI)) { 73337ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines if (PHIsInspected.insert(UserPN).second) 734f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHIsToSlice.push_back(UserPN); 735f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 736f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 73703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 738f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Truncates are always ok. 73936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (isa<TruncInst>(UserI)) { 74036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines PHIUsers.push_back(PHIUsageRecord(PHIId, 0, UserI)); 741f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 742f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 74303fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 744f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Otherwise it must be a lshr which can only be used by one trunc. 74536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines if (UserI->getOpcode() != Instruction::LShr || 74636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines !UserI->hasOneUse() || !isa<TruncInst>(UserI->user_back()) || 74736b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines !isa<ConstantInt>(UserI->getOperand(1))) 748dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 74903fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 75036b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines unsigned Shift = cast<ConstantInt>(UserI->getOperand(1))->getZExtValue(); 75136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines PHIUsers.push_back(PHIUsageRecord(PHIId, Shift, UserI->user_back())); 752f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 753f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 75403fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 755f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If we have no users, they must be all self uses, just nuke the PHI. 756f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHIUsers.empty()) 757de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return replaceInstUsesWith(FirstPhi, UndefValue::get(FirstPhi.getType())); 75803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 759f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If this phi node is transformable, create new PHIs for all the pieces 760f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // extracted out of it. First, sort the users by their offset and size. 761f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner array_pod_sort(PHIUsers.begin(), PHIUsers.end()); 76203fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 763596aa123f46158639c836f1d53b89a9d7898c4b7Matt Arsenault DEBUG(dbgs() << "SLICING UP PHI: " << FirstPhi << '\n'; 764596aa123f46158639c836f1d53b89a9d7898c4b7Matt Arsenault for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i) 765596aa123f46158639c836f1d53b89a9d7898c4b7Matt Arsenault dbgs() << "AND USER PHI #" << i << ": " << *PHIsToSlice[i] << '\n'; 766596aa123f46158639c836f1d53b89a9d7898c4b7Matt Arsenault ); 76703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 768f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // PredValues - This is a temporary used when rewriting PHI nodes. It is 769f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // hoisted out here to avoid construction/destruction thrashing. 770f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner DenseMap<BasicBlock*, Value*> PredValues; 77103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 772f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // ExtractedVals - Each new PHI we introduce is saved here so we don't 773f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // introduce redundant PHIs. 774f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner DenseMap<LoweredPHIRecord, PHINode*> ExtractedVals; 77503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 776f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned UserI = 0, UserE = PHIUsers.size(); UserI != UserE; ++UserI) { 777f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned PHIId = PHIUsers[UserI].PHIId; 778f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *PN = PHIsToSlice[PHIId]; 779f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned Offset = PHIUsers[UserI].Shift; 780db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner Type *Ty = PHIUsers[UserI].Inst->getType(); 78103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 782f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *EltPHI; 78303fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 784f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If we've already lowered a user like this, reuse the previously lowered 785f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // value. 786dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines if ((EltPHI = ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)]) == nullptr) { 78703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 788f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Otherwise, Create the new PHI node for this user. 7893ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad EltPHI = PHINode::Create(Ty, PN->getNumIncomingValues(), 7903ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad PN->getName()+".off"+Twine(Offset), PN); 791f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner assert(EltPHI->getType() != PN->getType() && 792f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner "Truncate didn't shrink phi?"); 79303fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 794f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { 795f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner BasicBlock *Pred = PN->getIncomingBlock(i); 796f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *&PredVal = PredValues[Pred]; 79703fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 798f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If we already have a value for this predecessor, reuse it. 799f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PredVal) { 800f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner EltPHI->addIncoming(PredVal, Pred); 801f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 802f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 803f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 804f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Handle the PHI self-reuse case. 805f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *InVal = PN->getIncomingValue(i); 806f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (InVal == PN) { 807f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PredVal = EltPHI; 808f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner EltPHI->addIncoming(PredVal, Pred); 809f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 810f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 81103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 812f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHINode *InPHI = dyn_cast<PHINode>(PN)) { 813f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If the incoming value was a PHI, and if it was one of the PHIs we 814f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // already rewrote it, just use the lowered value. 815f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (Value *Res = ExtractedVals[LoweredPHIRecord(InPHI, Offset, Ty)]) { 816f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PredVal = Res; 817f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner EltPHI->addIncoming(PredVal, Pred); 818f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner continue; 819f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 820f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 82103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 822f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Otherwise, do an extract in the predecessor. 823f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar Builder->SetInsertPoint(Pred->getTerminator()); 824f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *Res = InVal; 825f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (Offset) 826f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Res = Builder->CreateLShr(Res, ConstantInt::get(InVal->getType(), 827f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Offset), "extract"); 828f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Res = Builder->CreateTrunc(Res, Ty, "extract.t"); 829f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PredVal = Res; 830f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner EltPHI->addIncoming(Res, Pred); 83103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 832f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If the incoming value was a PHI, and if it was one of the PHIs we are 833f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // rewriting, we will ultimately delete the code we inserted. This 834f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // means we need to revisit that PHI to make sure we extract out the 835f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // needed piece. 836f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHINode *OldInVal = dyn_cast<PHINode>(PN->getIncomingValue(i))) 837f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHIsInspected.count(OldInVal)) { 838f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned RefPHIId = std::find(PHIsToSlice.begin(),PHIsToSlice.end(), 839f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner OldInVal)-PHIsToSlice.begin(); 84003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach PHIUsers.push_back(PHIUsageRecord(RefPHIId, Offset, 841f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner cast<Instruction>(Res))); 842f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner ++UserE; 843f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 844f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 845f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PredValues.clear(); 84603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 847596aa123f46158639c836f1d53b89a9d7898c4b7Matt Arsenault DEBUG(dbgs() << " Made element PHI for offset " << Offset << ": " 848f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner << *EltPHI << '\n'); 849f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner ExtractedVals[LoweredPHIRecord(PN, Offset, Ty)] = EltPHI; 850f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 85103fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 852f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Replace the use of this piece with the PHI node. 853de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar replaceInstUsesWith(*PHIUsers[UserI].Inst, EltPHI); 854f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 85503fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 856f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Replace all the remaining uses of the PHI nodes (self uses and the lshrs) 857f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // with undefs. 858f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *Undef = UndefValue::get(FirstPhi.getType()); 859f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 1, e = PHIsToSlice.size(); i != e; ++i) 860de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar replaceInstUsesWith(*PHIsToSlice[i], Undef); 861de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return replaceInstUsesWith(FirstPhi, Undef); 862f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner} 863f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 864f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// PHINode simplification 865f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner// 866f54e72962991005a3c0cc7dce0c550a14af90792Chris LattnerInstruction *InstCombiner::visitPHINode(PHINode &PN) { 867ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines if (Value *V = SimplifyInstruction(&PN, DL, TLI, DT, AC)) 868de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return replaceInstUsesWith(PN, V); 869f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 870f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar if (Instruction *Result = FoldPHIArgZextsIntoPHI(PN)) 871f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar return Result; 872f3ef5332fa3f4d5ec72c178a2b19dac363a19383Pirama Arumuga Nainar 873f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If all PHI operands are the same operation, pull them through the PHI, 874f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // reducing code size. 875f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (isa<Instruction>(PN.getIncomingValue(0)) && 876f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner isa<Instruction>(PN.getIncomingValue(1)) && 877f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner cast<Instruction>(PN.getIncomingValue(0))->getOpcode() == 878f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner cast<Instruction>(PN.getIncomingValue(1))->getOpcode() && 879f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // FIXME: The hasOneUse check will fail for PHIs that use the value more 880f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // than themselves more than once. 881f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.getIncomingValue(0)->hasOneUse()) 882f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (Instruction *Result = FoldPHIArgOpIntoPHI(PN)) 883f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return Result; 884f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 885f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If this is a trivial cycle in the PHI node graph, remove it. Basically, if 886f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // this PHI only has a single use (a PHI), and if that PHI only has one use (a 887f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // PHI)... break the cycle. 888f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PN.hasOneUse()) { 88936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines Instruction *PHIUser = cast<Instruction>(PN.user_back()); 890f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHINode *PU = dyn_cast<PHINode>(PHIUser)) { 891f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner SmallPtrSet<PHINode*, 16> PotentiallyDeadPHIs; 892f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PotentiallyDeadPHIs.insert(&PN); 893f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (DeadPHICycle(PU, PotentiallyDeadPHIs)) 894de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return replaceInstUsesWith(PN, UndefValue::get(PN.getType())); 895f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 89603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 897f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If this phi has a single use, and if that use just computes a value for 898f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the next iteration of a loop, delete the phi. This occurs with unused 899f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // induction variables, e.g. "for (int j = 0; ; ++j);". Detecting this 900f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // common case here is good because the only other things that catch this 901f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // are induction variable analysis (sometimes) and ADCE, which is only run 902f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // late. 903f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHIUser->hasOneUse() && 904f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner (isa<BinaryOperator>(PHIUser) || isa<GetElementPtrInst>(PHIUser)) && 90536b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines PHIUser->user_back() == &PN) { 906de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return replaceInstUsesWith(PN, UndefValue::get(PN.getType())); 907de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar } 908de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // When a PHI is used only to be compared with zero, it is safe to replace 909de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // an incoming value proved as known nonzero with any non-zero constant. 910de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // For example, in the code below, the incoming value %v can be replaced 911de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // with any non-zero constant based on the fact that the PHI is only used to 912de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // be compared with zero and %v is a known non-zero value: 913de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // %v = select %cond, 1, 2 914de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // %p = phi [%v, BB] ... 915de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // icmp eq, %p, 0 916de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar auto *CmpInst = dyn_cast<ICmpInst>(PHIUser); 917de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar // FIXME: To be simple, handle only integer type for now. 918de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar if (CmpInst && isa<IntegerType>(PN.getType()) && CmpInst->isEquality() && 919de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar match(CmpInst->getOperand(1), m_Zero())) { 920de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar ConstantInt *NonZeroConst = nullptr; 921de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) { 922de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar Instruction *CtxI = PN.getIncomingBlock(i)->getTerminator(); 923de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar Value *VA = PN.getIncomingValue(i); 924de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar if (isKnownNonZero(VA, DL, 0, AC, CtxI, DT)) { 925de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar if (!NonZeroConst) 926de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar NonZeroConst = GetAnyNonZeroConstInt(PN); 927de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar PN.setIncomingValue(i, NonZeroConst); 928de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar } 929de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar } 930f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 931f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 932f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 933f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // We sometimes end up with phi cycles that non-obviously end up being the 934f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // same value, for example: 935f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // z = some value; x = phi (y, z); y = phi (x, z) 936f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // where the phi nodes don't necessarily need to be in the same block. Do a 937f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // quick check to see if the PHI node only contains a single non-phi value, if 938f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // so, scan to see if the phi cycle is actually equal to that value. 939f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner { 94086f72a8002ef6049d17ae8b9a536dee18b101fd0Frits van Bommel unsigned InValNo = 0, NumIncomingVals = PN.getNumIncomingValues(); 941f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan for the first non-phi operand. 94286f72a8002ef6049d17ae8b9a536dee18b101fd0Frits van Bommel while (InValNo != NumIncomingVals && 943f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner isa<PHINode>(PN.getIncomingValue(InValNo))) 944f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner ++InValNo; 945f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 94686f72a8002ef6049d17ae8b9a536dee18b101fd0Frits van Bommel if (InValNo != NumIncomingVals) { 9474130278fbee97b9cd1ea4069e9c666bbe89d61f9Jay Foad Value *NonPhiInVal = PN.getIncomingValue(InValNo); 94803fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 949f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // Scan the rest of the operands to see if there are any conflicts, if so 950f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // there is no need to recursively scan other phis. 95186f72a8002ef6049d17ae8b9a536dee18b101fd0Frits van Bommel for (++InValNo; InValNo != NumIncomingVals; ++InValNo) { 952f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *OpVal = PN.getIncomingValue(InValNo); 953f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (OpVal != NonPhiInVal && !isa<PHINode>(OpVal)) 954f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner break; 955f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 95603fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 957f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If we scanned over all operands, then we have one unique value plus 958f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // phi values. Scan PHI nodes to see if they all merge in each other or 959f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the value. 96086f72a8002ef6049d17ae8b9a536dee18b101fd0Frits van Bommel if (InValNo == NumIncomingVals) { 961f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner SmallPtrSet<PHINode*, 16> ValueEqualPHIs; 962f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (PHIsEqualValue(&PN, NonPhiInVal, ValueEqualPHIs)) 963de2d8694e25a814696358e95141f4b1aa4d8847ePirama Arumuga Nainar return replaceInstUsesWith(PN, NonPhiInVal); 964f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 965f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 966f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 967f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 968f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If there are multiple PHIs, sort their operands so that they all list 969f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // the blocks in the same order. This will help identical PHIs be eliminated 970f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // by other passes. Other passes shouldn't depend on this for correctness 971f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // however. 972f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PHINode *FirstPN = cast<PHINode>(PN.getParent()->begin()); 973f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (&PN != FirstPN) 974f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner for (unsigned i = 0, e = FirstPN->getNumIncomingValues(); i != e; ++i) { 975f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner BasicBlock *BBA = PN.getIncomingBlock(i); 976f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner BasicBlock *BBB = FirstPN->getIncomingBlock(i); 977f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (BBA != BBB) { 978f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *VA = PN.getIncomingValue(i); 979f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner unsigned j = PN.getBasicBlockIndex(BBB); 980f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner Value *VB = PN.getIncomingValue(j); 981f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.setIncomingBlock(i, BBB); 982f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.setIncomingValue(i, VB); 983f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.setIncomingBlock(j, BBA); 984f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner PN.setIncomingValue(j, VA); 985f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // NOTE: Instcombine normally would want us to "return &PN" if we 986f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // modified any of the operands of an instruction. However, since we 987f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // aren't adding or removing uses (just rearranging them) we don't do 988f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // this in this case. 989f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 990f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner } 991f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner 992f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // If this is an integer PHI and we know that it has an illegal type, see if 993f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // it is only used by trunc or trunc(lshr) operations. If so, we split the 994f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // PHI into the various pieces being extracted. This sort of thing is 995f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner // introduced when SROA promotes an aggregate to a single large integer type. 9964c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar if (PN.getType()->isIntegerTy() && 9974c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar !DL.isLegalInteger(PN.getType()->getPrimitiveSizeInBits())) 998f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner if (Instruction *Res = SliceUpIllegalIntegerPHI(PN)) 999f54e72962991005a3c0cc7dce0c550a14af90792Chris Lattner return Res; 100003fceff6f69a0261a767aab8e62de8aa9301b86cJim Grosbach 1001dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines return nullptr; 1002eade00209447c07953a609b30666ce5f6d9f9864Benjamin Kramer} 1003