14b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick//===-- SimplifyIndVar.cpp - Induction variable simplification ------------===// 24b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// 34b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// The LLVM Compiler Infrastructure 44b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// 54b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// This file is distributed under the University of Illinois Open Source 64b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// License. See LICENSE.TXT for details. 74b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// 84b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick//===----------------------------------------------------------------------===// 94b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// 104b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// This file implements induction variable simplification. It does 114b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// not define any actual pass or policy, but provides a single function to 124b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// simplify a loop's induction variables based on ScalarEvolution. 134b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick// 144b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick//===----------------------------------------------------------------------===// 154b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 164b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#define DEBUG_TYPE "indvars" 174b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 184b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Instructions.h" 194b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Analysis/IVUsers.h" 204b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Analysis/LoopInfo.h" 214b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Analysis/LoopPass.h" 224b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Analysis/ScalarEvolutionExpressions.h" 234b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Support/CommandLine.h" 244b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Support/Debug.h" 254b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Support/raw_ostream.h" 264b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Transforms/Utils/SimplifyIndVar.h" 274b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/Target/TargetData.h" 284b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/ADT/SmallVector.h" 294b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick#include "llvm/ADT/Statistic.h" 304b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 314b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickusing namespace llvm; 324b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 334b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew TrickSTATISTIC(NumElimIdentity, "Number of IV identities eliminated"); 344b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew TrickSTATISTIC(NumElimOperand, "Number of IV operands folded into a use"); 354b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew TrickSTATISTIC(NumElimRem , "Number of IV remainder operations eliminated"); 364b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew TrickSTATISTIC(NumElimCmp , "Number of IV comparisons eliminated"); 374b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 384b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Tricknamespace { 394b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// SimplifyIndvar - This is a utility for simplifying induction variables 404b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// based on ScalarEvolution. It is the primary instrument of the 414b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// IndvarSimplify pass, but it may also be directly invoked to cleanup after 424b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// other loop passes that preserve SCEV. 434b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick class SimplifyIndvar { 444b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Loop *L; 454b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick LoopInfo *LI; 464b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ScalarEvolution *SE; 474b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const TargetData *TD; // May be NULL 484b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 494b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallVectorImpl<WeakVH> &DeadInsts; 504b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 514b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool Changed; 524b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 534b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick public: 54bddb7f82103deb226baa6793f41c5961661167e7Andrew Trick SimplifyIndvar(Loop *Loop, ScalarEvolution *SE, LPPassManager *LPM, 554b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallVectorImpl<WeakVH> &Dead, IVUsers *IVU = NULL) : 564b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick L(Loop), 574b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick LI(LPM->getAnalysisIfAvailable<LoopInfo>()), 58bddb7f82103deb226baa6793f41c5961661167e7Andrew Trick SE(SE), 594b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick TD(LPM->getAnalysisIfAvailable<TargetData>()), 604b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DeadInsts(Dead), 614b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Changed(false) { 62bddb7f82103deb226baa6793f41c5961661167e7Andrew Trick assert(LI && "IV simplification requires LoopInfo"); 634b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 644b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 654b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool hasChanged() const { return Changed; } 664b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 674b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// Iteratively perform simplification on a worklist of users of the 684b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// specified induction variable. This is the top-level driver that applies 694b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick /// all simplicitions to users of an IV. 704b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick void simplifyUsers(PHINode *CurrIV, IVVisitor *V = NULL); 714b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 72ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick Value *foldIVUser(Instruction *UseInst, Instruction *IVOperand); 734b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 744b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool eliminateIVUser(Instruction *UseInst, Instruction *IVOperand); 754b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick void eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand); 764b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick void eliminateIVRemainder(BinaryOperator *Rem, Value *IVOperand, 774b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool IsSigned); 784b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick }; 794b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 804b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 814b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// foldIVUser - Fold an IV operand into its use. This removes increments of an 824b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// aligned IV when used by a instruction that ignores the low bits. 83ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick/// 8424f48ece526d81e7a3138f4cff57171b7de9e02fAndrew Trick/// IVOperand is guaranteed SCEVable, but UseInst may not be. 8524f48ece526d81e7a3138f4cff57171b7de9e02fAndrew Trick/// 86ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick/// Return the operand of IVOperand for this induction variable if IVOperand can 877cb3dcb927a8f8a872cdf309f78cd80e197d2f14Andrew Trick/// be folded (in case more folding opportunities have been exposed). 88ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick/// Otherwise return null. 89ea23daa4461de489abbfd54a9641091862945f3eAndrew TrickValue *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand) { 904b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Value *IVSrc = 0; 914b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick unsigned OperIdx = 0; 924b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *FoldedExpr = 0; 934b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick switch (UseInst->getOpcode()) { 944b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick default: 95ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return 0; 964b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick case Instruction::UDiv: 974b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick case Instruction::LShr: 984b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // We're only interested in the case where we know something about 994b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // the numerator and have a constant denominator. 1004b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (IVOperand != UseInst->getOperand(OperIdx) || 1014b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick !isa<ConstantInt>(UseInst->getOperand(1))) 102ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return 0; 1034b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1044b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Attempt to fold a binary operator with constant operand. 1054b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // e.g. ((I + 1) >> 2) => I >> 2 1064f3052403ca5ea9542a118c2e54ff9c82038f41cAndrew Trick if (!isa<BinaryOperator>(IVOperand) 1074f3052403ca5ea9542a118c2e54ff9c82038f41cAndrew Trick || !isa<ConstantInt>(IVOperand->getOperand(1))) 108ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return 0; 1094b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1104b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick IVSrc = IVOperand->getOperand(0); 1114b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // IVSrc must be the (SCEVable) IV, since the other operand is const. 1124b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick assert(SE->isSCEVable(IVSrc->getType()) && "Expect SCEVable IV operand"); 1134b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1144b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ConstantInt *D = cast<ConstantInt>(UseInst->getOperand(1)); 1154b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (UseInst->getOpcode() == Instruction::LShr) { 1164b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Get a constant for the divisor. See createSCEV. 1174b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick uint32_t BitWidth = cast<IntegerType>(UseInst->getType())->getBitWidth(); 1184b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (D->getValue().uge(BitWidth)) 119ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return 0; 1204b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1214b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick D = ConstantInt::get(UseInst->getContext(), 1224b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick APInt(BitWidth, 1).shl(D->getZExtValue())); 1234b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 1244b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick FoldedExpr = SE->getUDivExpr(SE->getSCEV(IVSrc), SE->getSCEV(D)); 1254b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 1264b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // We have something that might fold it's operand. Compare SCEVs. 1274b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (!SE->isSCEVable(UseInst->getType())) 128ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return 0; 1294b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1304b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Bypass the operand if SCEV can prove it has no effect. 1314b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (SE->getSCEV(UseInst) != FoldedExpr) 132ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return 0; 1334b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1344b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DEBUG(dbgs() << "INDVARS: Eliminated IV operand: " << *IVOperand 1354b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick << " -> " << *UseInst << '\n'); 1364b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1374b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick UseInst->setOperand(OperIdx, IVSrc); 1384b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick assert(SE->getSCEV(UseInst) == FoldedExpr && "bad SCEV with folded oper"); 1394b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1404b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ++NumElimOperand; 1414b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Changed = true; 1424b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (IVOperand->use_empty()) 1434b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DeadInsts.push_back(IVOperand); 144ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick return IVSrc; 1454b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 1464b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1474b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// eliminateIVComparison - SimplifyIVUsers helper for eliminating useless 1484b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// comparisons against an induction variable. 1494b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickvoid SimplifyIndvar::eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand) { 1504b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick unsigned IVOperIdx = 0; 1514b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ICmpInst::Predicate Pred = ICmp->getPredicate(); 1524b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (IVOperand != ICmp->getOperand(0)) { 1534b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Swapped 1544b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick assert(IVOperand == ICmp->getOperand(1) && "Can't find IVOperand"); 1554b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick IVOperIdx = 1; 1564b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Pred = ICmpInst::getSwappedPredicate(Pred); 1574b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 1584b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1594b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Get the SCEVs for the ICmp operands. 1604b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *S = SE->getSCEV(ICmp->getOperand(IVOperIdx)); 1614b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *X = SE->getSCEV(ICmp->getOperand(1 - IVOperIdx)); 1624b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1634b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Simplify unnecessary loops away. 1644b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const Loop *ICmpLoop = LI->getLoopFor(ICmp->getParent()); 1654b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick S = SE->getSCEVAtScope(S, ICmpLoop); 1664b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick X = SE->getSCEVAtScope(X, ICmpLoop); 1674b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1684b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // If the condition is always true or always false, replace it with 1694b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // a constant value. 1704b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (SE->isKnownPredicate(Pred, S, X)) 1714b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ICmp->replaceAllUsesWith(ConstantInt::getTrue(ICmp->getContext())); 1724b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick else if (SE->isKnownPredicate(ICmpInst::getInversePredicate(Pred), S, X)) 1734b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ICmp->replaceAllUsesWith(ConstantInt::getFalse(ICmp->getContext())); 1744b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick else 1754b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return; 1764b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1774b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DEBUG(dbgs() << "INDVARS: Eliminated comparison: " << *ICmp << '\n'); 1784b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ++NumElimCmp; 1794b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Changed = true; 1804b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DeadInsts.push_back(ICmp); 1814b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 1824b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1834b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// eliminateIVRemainder - SimplifyIVUsers helper for eliminating useless 1844b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// remainder operations operating on an induction variable. 1854b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickvoid SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem, 1864b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Value *IVOperand, 1874b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool IsSigned) { 1884b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // We're only interested in the case where we know something about 1894b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // the numerator. 1904b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (IVOperand != Rem->getOperand(0)) 1914b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return; 1924b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1934b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Get the SCEVs for the ICmp operands. 1944b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *S = SE->getSCEV(Rem->getOperand(0)); 1954b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *X = SE->getSCEV(Rem->getOperand(1)); 1964b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 1974b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Simplify unnecessary loops away. 1984b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const Loop *ICmpLoop = LI->getLoopFor(Rem->getParent()); 1994b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick S = SE->getSCEVAtScope(S, ICmpLoop); 2004b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick X = SE->getSCEVAtScope(X, ICmpLoop); 2014b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2024b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // i % n --> i if i is in [0,n). 2034b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if ((!IsSigned || SE->isKnownNonNegative(S)) && 2044b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SE->isKnownPredicate(IsSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT, 2054b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick S, X)) 2064b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Rem->replaceAllUsesWith(Rem->getOperand(0)); 2074b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick else { 2084b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // (i+1) % n --> (i+1)==n?0:(i+1) if i is in [0,n). 2094b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *LessOne = 2104b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SE->getMinusSCEV(S, SE->getConstant(S->getType(), 1)); 2114b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (IsSigned && !SE->isKnownNonNegative(LessOne)) 2124b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return; 2134b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2144b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (!SE->isKnownPredicate(IsSigned ? 2154b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT, 2164b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick LessOne, X)) 2174b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return; 2184b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2194b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ICmpInst *ICmp = new ICmpInst(Rem, ICmpInst::ICMP_EQ, 220a9390a4d5f5d568059a80970d22194b165d097a7Benjamin Kramer Rem->getOperand(0), Rem->getOperand(1)); 2214b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SelectInst *Sel = 2224b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SelectInst::Create(ICmp, 2234b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ConstantInt::get(Rem->getType(), 0), 2244b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Rem->getOperand(0), "tmp", Rem); 2254b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Rem->replaceAllUsesWith(Sel); 2264b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 2274b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2284b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DEBUG(dbgs() << "INDVARS: Simplified rem: " << *Rem << '\n'); 2294b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ++NumElimRem; 2304b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Changed = true; 2314b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DeadInsts.push_back(Rem); 2324b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 2334b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2344b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// eliminateIVUser - Eliminate an operation that consumes a simple IV and has 2354b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// no observable side-effect given the range of IV values. 23624f48ece526d81e7a3138f4cff57171b7de9e02fAndrew Trick/// IVOperand is guaranteed SCEVable, but UseInst may not be. 2374b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickbool SimplifyIndvar::eliminateIVUser(Instruction *UseInst, 2384b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Instruction *IVOperand) { 2394b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (ICmpInst *ICmp = dyn_cast<ICmpInst>(UseInst)) { 2404b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick eliminateIVComparison(ICmp, IVOperand); 2414b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return true; 2424b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 2434b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (BinaryOperator *Rem = dyn_cast<BinaryOperator>(UseInst)) { 2444b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool IsSigned = Rem->getOpcode() == Instruction::SRem; 2454b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (IsSigned || Rem->getOpcode() == Instruction::URem) { 2464b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick eliminateIVRemainder(Rem, IVOperand, IsSigned); 2474b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return true; 2484b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 2494b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 2504b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2514b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Eliminate any operation that SCEV can prove is an identity function. 2524b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (!SE->isSCEVable(UseInst->getType()) || 2534b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick (UseInst->getType() != IVOperand->getType()) || 2544b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick (SE->getSCEV(UseInst) != SE->getSCEV(IVOperand))) 2554b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return false; 2564b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2574b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DEBUG(dbgs() << "INDVARS: Eliminated identity: " << *UseInst << '\n'); 2584b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2594b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick UseInst->replaceAllUsesWith(IVOperand); 2604b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick ++NumElimIdentity; 2614b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Changed = true; 2624b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick DeadInsts.push_back(UseInst); 2634b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return true; 2644b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 2654b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2664b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// pushIVUsers - Add all uses of Def to the current IV's worklist. 2674b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// 2684b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickstatic void pushIVUsers( 2694b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Instruction *Def, 2704b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallPtrSet<Instruction*,16> &Simplified, 2714b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallVectorImpl< std::pair<Instruction*,Instruction*> > &SimpleIVUsers) { 2724b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2734b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick for (Value::use_iterator UI = Def->use_begin(), E = Def->use_end(); 2744b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick UI != E; ++UI) { 2754b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick Instruction *User = cast<Instruction>(*UI); 2764b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2774b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Avoid infinite or exponential worklist processing. 2784b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Also ensure unique worklist users. 2794b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // If Def is a LoopPhi, it may not be in the Simplified set, so check for 2804b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // self edges first. 2814b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (User != Def && Simplified.insert(User)) 2824b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SimpleIVUsers.push_back(std::make_pair(User, Def)); 2834b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 2844b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 2854b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2864b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// isSimpleIVUser - Return true if this instruction generates a simple SCEV 2874b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// expression in terms of that IV. 2884b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// 2897cb3dcb927a8f8a872cdf309f78cd80e197d2f14Andrew Trick/// This is similar to IVUsers' isInteresting() but processes each instruction 2904b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// non-recursively when the operand is already known to be a simpleIVUser. 2914b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// 2924b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickstatic bool isSimpleIVUser(Instruction *I, const Loop *L, ScalarEvolution *SE) { 2934b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (!SE->isSCEVable(I->getType())) 2944b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return false; 2954b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2964b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Get the symbolic expression for this instruction. 2974b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEV *S = SE->getSCEV(I); 2984b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 2994b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Only consider affine recurrences. 3004b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S); 3014b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (AR && AR->getLoop() == L) 3024b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return true; 3034b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3044b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return false; 3054b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 3064b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3074b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// simplifyUsers - Iteratively perform simplification on a worklist of users 3084b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// of the specified induction variable. Each successive simplification may push 3094b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// more users which may themselves be candidates for simplification. 3104b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// 3114b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// This algorithm does not require IVUsers analysis. Instead, it simplifies 3124b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// instructions in-place during analysis. Rather than rewriting induction 3134b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// variables bottom-up from their users, it transforms a chain of IVUsers 3144b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// top-down, updating the IR only when it encouters a clear optimization 3154b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// opportunitiy. 3164b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// 3174b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// Once DisableIVRewrite is default, LSR will be the only client of IVUsers. 3184b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// 3194b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trickvoid SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) { 32024f48ece526d81e7a3138f4cff57171b7de9e02fAndrew Trick if (!SE->isSCEVable(CurrIV->getType())) 32124f48ece526d81e7a3138f4cff57171b7de9e02fAndrew Trick return; 32224f48ece526d81e7a3138f4cff57171b7de9e02fAndrew Trick 3234b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Instructions processed by SimplifyIndvar for CurrIV. 3244b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallPtrSet<Instruction*,16> Simplified; 3254b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3264b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Use-def pairs if IV users waiting to be processed for CurrIV. 3274b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallVector<std::pair<Instruction*, Instruction*>, 8> SimpleIVUsers; 3284b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3294b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Push users of the current LoopPhi. In rare cases, pushIVUsers may be 3304b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // called multiple times for the same LoopPhi. This is the proper thing to 3314b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // do for loop header phis that use each other. 3324b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick pushIVUsers(CurrIV, Simplified, SimpleIVUsers); 3334b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3344b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick while (!SimpleIVUsers.empty()) { 3354b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick std::pair<Instruction*, Instruction*> UseOper = 3364b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SimpleIVUsers.pop_back_val(); 3374b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick // Bypass back edges to avoid extra work. 3384b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (UseOper.first == CurrIV) continue; 3394b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 340ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick Instruction *IVOperand = UseOper.second; 341ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick for (unsigned N = 0; IVOperand; ++N) { 342ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick assert(N <= Simplified.size() && "runaway iteration"); 343ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick 344ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick Value *NewOper = foldIVUser(UseOper.first, IVOperand); 345ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick if (!NewOper) 346ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick break; // done folding 347ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick IVOperand = dyn_cast<Instruction>(NewOper); 348ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick } 349ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick if (!IVOperand) 350ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick continue; 3514b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 352ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick if (eliminateIVUser(UseOper.first, IVOperand)) { 353ea23daa4461de489abbfd54a9641091862945f3eAndrew Trick pushIVUsers(IVOperand, Simplified, SimpleIVUsers); 3544b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick continue; 3554b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 3564b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick CastInst *Cast = dyn_cast<CastInst>(UseOper.first); 3574b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (V && Cast) { 3584b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick V->visitCast(Cast); 3594b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick continue; 3604b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 3614b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick if (isSimpleIVUser(UseOper.first, L, SE)) { 3624b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick pushIVUsers(UseOper.first, Simplified, SimpleIVUsers); 3634b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 3644b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 3654b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 3664b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3674b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Tricknamespace llvm { 3684b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3692d24e2a396a1d211baaeedf32148a3b657240170David Blaikievoid IVVisitor::anchor() { } 3702d24e2a396a1d211baaeedf32148a3b657240170David Blaikie 3714b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// simplifyUsersOfIV - Simplify instructions that use this induction variable 3724b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// by using ScalarEvolution to analyze the IV's recurrence. 373bddb7f82103deb226baa6793f41c5961661167e7Andrew Trickbool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, LPPassManager *LPM, 3744b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallVectorImpl<WeakVH> &Dead, IVVisitor *V) 3754b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick{ 3764b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick LoopInfo *LI = &LPM->getAnalysis<LoopInfo>(); 377bddb7f82103deb226baa6793f41c5961661167e7Andrew Trick SimplifyIndvar SIV(LI->getLoopFor(CurrIV->getParent()), SE, LPM, Dead); 3784b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SIV.simplifyUsers(CurrIV, V); 3794b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return SIV.hasChanged(); 3804b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 3814b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3824b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// simplifyLoopIVs - Simplify users of induction variables within this 3834b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick/// loop. This does not actually change or add IVs. 384bddb7f82103deb226baa6793f41c5961661167e7Andrew Trickbool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, LPPassManager *LPM, 3854b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick SmallVectorImpl<WeakVH> &Dead) { 3864b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick bool Changed = false; 3874b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) { 388bddb7f82103deb226baa6793f41c5961661167e7Andrew Trick Changed |= simplifyUsersOfIV(cast<PHINode>(I), SE, LPM, Dead); 3894b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick } 3904b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick return Changed; 3914b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} 3924b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick 3934b4bb71bcdfd8c17cd4acb6116fc9a56c5fecd47Andrew Trick} // namespace llvm 394