X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FIVUsers.cpp;h=e5f0a77ab67d57aba5910c31ecaefe85886425bd;hb=865375ca7f68e60c0234916dd6bb365bb674bddb;hp=fbd3e7071275ec61948a494b324ad1ee5a2b6c05;hpb=e521ccb5bd1142b41723de519b15e13ab82914e1;p=oota-llvm.git diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp index fbd3e707127..e5f0a77ab67 100644 --- a/lib/Analysis/IVUsers.cpp +++ b/lib/Analysis/IVUsers.cpp @@ -21,7 +21,8 @@ #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/LoopPass.h" #include "llvm/Analysis/ScalarEvolutionExpressions.h" -#include "llvm/Assembly/AsmAnnotationWriter.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Assembly/Writer.h" #include "llvm/ADT/STLExtras.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" @@ -29,8 +30,13 @@ using namespace llvm; char IVUsers::ID = 0; -static RegisterPass -X("iv-users", "Induction Variable Users", false, true); +INITIALIZE_PASS_BEGIN(IVUsers, "iv-users", + "Induction Variable Users", false, true) +INITIALIZE_PASS_DEPENDENCY(LoopInfo) +INITIALIZE_PASS_DEPENDENCY(DominatorTree) +INITIALIZE_PASS_DEPENDENCY(ScalarEvolution) +INITIALIZE_PASS_END(IVUsers, "iv-users", + "Induction Variable Users", false, true) Pass *llvm::createIVUsersPass() { return new IVUsers(); @@ -39,27 +45,34 @@ Pass *llvm::createIVUsersPass() { /// isInteresting - Test whether the given expression is "interesting" when /// used by the given expression, within the context of analyzing the /// given loop. -static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L) { - // Anything loop-invariant is interesting. - if (!isa(S) && S->isLoopInvariant(L)) - return true; - +static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L, + ScalarEvolution *SE, LoopInfo *LI) { // An addrec is interesting if it's affine or if it has an interesting start. if (const SCEVAddRecExpr *AR = dyn_cast(S)) { - // Keep things simple. Don't touch loop-variant strides. + // Keep things simple. Don't touch loop-variant strides unless they're + // only used outside the loop and we can simplify them. if (AR->getLoop() == L) - return AR->isAffine() || !L->contains(I); - // Otherwise recurse to see if the start value is interesting. - return isInteresting(AR->getStart(), I, L); + return AR->isAffine() || + (!L->contains(I) && + SE->getSCEVAtScope(AR, LI->getLoopFor(I->getParent())) != AR); + // Otherwise recurse to see if the start value is interesting, and that + // the step value is not interesting, since we don't yet know how to + // do effective SCEV expansions for addrecs with interesting steps. + return isInteresting(AR->getStart(), I, L, SE, LI) && + !isInteresting(AR->getStepRecurrence(*SE), I, L, SE, LI); } - // An add is interesting if any of its operands is. + // An add is interesting if exactly one of its operands is interesting. if (const SCEVAddExpr *Add = dyn_cast(S)) { + bool AnyInterestingYet = false; for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end(); OI != OE; ++OI) - if (isInteresting(*OI, I, L)) - return true; - return false; + if (isInteresting(*OI, I, L, SE, LI)) { + if (AnyInterestingYet) + return false; + AnyInterestingYet = true; + } + return AnyInterestingYet; } // Nothing else is interesting here. @@ -74,7 +87,10 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) { return false; // Void and FP expressions cannot be reduced. // LSR is not APInt clean, do not touch integers bigger than 64-bits. - if (SE->getTypeSizeInBits(I->getType()) > 64) + // Also avoid creating IVs of non-native types. For example, we don't want a + // 64-bit IV in 32-bit code just because the loop has one 64-bit cast. + uint64_t Width = SE->getTypeSizeInBits(I->getType()); + if (Width > 64 || (TD && !TD->isLegalInteger(Width))) return false; if (!Processed.insert(I)) @@ -85,7 +101,7 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) { // If we've come to an uninteresting expression, stop the traversal and // call this a user. - if (!isInteresting(ISE, I, L)) + if (!isInteresting(ISE, I, L, SE, LI)) return false; SmallPtrSet UniqueUsers; @@ -113,8 +129,7 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) { << " OF SCEV: " << *ISE << '\n'); AddUserToIVUsers = true; } - } else if (Processed.count(User) || - !AddUsersIfInteresting(User)) { + } else if (Processed.count(User) || !AddUsersIfInteresting(User)) { DEBUG(dbgs() << "FOUND USER: " << *User << '\n' << " OF SCEV: " << *ISE << '\n'); AddUserToIVUsers = true; @@ -122,28 +137,29 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) { if (AddUserToIVUsers) { // Okay, we found a user that we cannot reduce. - IVUses.push_back(new IVStrideUse(this, ISE, User, I)); + IVUses.push_back(new IVStrideUse(this, User, I)); IVStrideUse &NewUse = IVUses.back(); - // Transform the expression into a normalized form. - NewUse.Expr = - TransformForPostIncUse(NormalizeAutodetect, NewUse.Expr, - User, I, - NewUse.PostIncLoops, - *SE, *DT); - DEBUG(dbgs() << " NORMALIZED TO: " << *NewUse.Expr << '\n'); + // Autodetect the post-inc loop set, populating NewUse.PostIncLoops. + // The regular return value here is discarded; instead of recording + // it, we just recompute it when we need it. + ISE = TransformForPostIncUse(NormalizeAutodetect, + ISE, User, I, + NewUse.PostIncLoops, + *SE, *DT); + DEBUG(dbgs() << " NORMALIZED TO: " << *ISE << '\n'); } } return true; } -IVStrideUse &IVUsers::AddUser(const SCEV *Expr, - Instruction *User, Value *Operand) { - IVUses.push_back(new IVStrideUse(this, Expr, User, Operand)); +IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) { + IVUses.push_back(new IVStrideUse(this, User, Operand)); return IVUses.back(); } IVUsers::IVUsers() - : LoopPass(&ID) { + : LoopPass(ID) { + initializeIVUsersPass(*PassRegistry::getPassRegistry()); } void IVUsers::getAnalysisUsage(AnalysisUsage &AU) const { @@ -159,6 +175,7 @@ bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) { LI = &getAnalysis(); DT = &getAnalysis(); SE = &getAnalysis(); + TD = getAnalysisIfAvailable(); // Find all uses of induction variables in this loop, and categorize // them by stride. Start by finding all of the PHI nodes in the header for @@ -169,15 +186,6 @@ bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) { return false; } -/// getReplacementExpr - Return a SCEV expression which computes the -/// value of the OperandValToReplace of the given IVStrideUse. -const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const { - PostIncLoopSet &Loops = const_cast(U.PostIncLoops); - return TransformForPostIncUse(Denormalize, U.getExpr(), - U.getUser(), U.getOperandValToReplace(), - Loops, *SE, *DT); -} - void IVUsers::print(raw_ostream &OS, const Module *M) const { OS << "IV Users for loop "; WriteAsOperand(OS, L->getHeader(), false); @@ -187,15 +195,11 @@ void IVUsers::print(raw_ostream &OS, const Module *M) const { } OS << ":\n"; - // Use a default AssemblyAnnotationWriter to suppress the default info - // comments, which aren't relevant here. - AssemblyAnnotationWriter Annotator; for (ilist::const_iterator UI = IVUses.begin(), E = IVUses.end(); UI != E; ++UI) { OS << " "; WriteAsOperand(OS, UI->getOperandValToReplace(), false); - OS << " = " - << *getReplacementExpr(*UI); + OS << " = " << *getReplacementExpr(*UI); for (PostIncLoopSet::const_iterator I = UI->PostIncLoops.begin(), E = UI->PostIncLoops.end(); I != E; ++I) { @@ -204,7 +208,7 @@ void IVUsers::print(raw_ostream &OS, const Module *M) const { OS << ")"; } OS << " in "; - UI->getUser()->print(OS, &Annotator); + UI->getUser()->print(OS); OS << '\n'; } } @@ -218,6 +222,21 @@ void IVUsers::releaseMemory() { IVUses.clear(); } +/// getReplacementExpr - Return a SCEV expression which computes the +/// value of the OperandValToReplace. +const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &IU) const { + return SE->getSCEV(IU.getOperandValToReplace()); +} + +/// getExpr - Return the expression for the use. +const SCEV *IVUsers::getExpr(const IVStrideUse &IU) const { + return + TransformForPostIncUse(Normalize, getReplacementExpr(IU), + IU.getUser(), IU.getOperandValToReplace(), + const_cast(IU.getPostIncLoops()), + *SE, *DT); +} + static const SCEVAddRecExpr *findAddRecForLoop(const SCEV *S, const Loop *L) { if (const SCEVAddRecExpr *AR = dyn_cast(S)) { if (AR->getLoop() == L) @@ -236,18 +255,13 @@ static const SCEVAddRecExpr *findAddRecForLoop(const SCEV *S, const Loop *L) { return 0; } -const SCEV *IVStrideUse::getStride(const Loop *L) const { - if (const SCEVAddRecExpr *AR = findAddRecForLoop(getExpr(), L)) - return AR->getStepRecurrence(*Parent->SE); +const SCEV *IVUsers::getStride(const IVStrideUse &IU, const Loop *L) const { + if (const SCEVAddRecExpr *AR = findAddRecForLoop(getExpr(IU), L)) + return AR->getStepRecurrence(*SE); return 0; } void IVStrideUse::transformToPostInc(const Loop *L) { - PostIncLoopSet Loops; - Loops.insert(L); - Expr = TransformForPostIncUse(Normalize, Expr, - getUser(), getOperandValToReplace(), - Loops, *Parent->SE, *Parent->DT); PostIncLoops.insert(L); }