diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 46 |
1 files changed, 12 insertions, 34 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index 1207dbf8e3..6b52ed7b84 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -97,8 +97,7 @@ namespace { Value *IndVar, BasicBlock *ExitingBlock, BranchInst *BI, - SCEVExpander &Rewriter, - bool SignExtendTripCount); + SCEVExpander &Rewriter); void RewriteLoopExitValues(Loop *L, SCEV *IterationCount); void DeleteTriviallyDeadInstructions(SmallPtrSet<Instruction*, 16> &Insts); @@ -237,8 +236,7 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L, Value *IndVar, BasicBlock *ExitingBlock, BranchInst *BI, - SCEVExpander &Rewriter, - bool SignExtendTripCount) { + SCEVExpander &Rewriter) { // If the exiting block is not the same as the backedge block, we must compare // against the preincremented value, otherwise we prefer to compare against // the post-incremented value. @@ -256,18 +254,11 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L, if ((isa<SCEVConstant>(N) && !N->isZero()) || SE->isLoopGuardedByCond(L, ICmpInst::ICMP_NE, N, Zero)) { // No overflow. Cast the sum. - if (SignExtendTripCount) - IterationCount = SE->getTruncateOrSignExtend(N, IndVar->getType()); - else - IterationCount = SE->getTruncateOrZeroExtend(N, IndVar->getType()); + IterationCount = SE->getTruncateOrZeroExtend(N, IndVar->getType()); } else { // Potential overflow. Cast before doing the add. - if (SignExtendTripCount) - IterationCount = SE->getTruncateOrSignExtend(IterationCount, - IndVar->getType()); - else - IterationCount = SE->getTruncateOrZeroExtend(IterationCount, - IndVar->getType()); + IterationCount = SE->getTruncateOrZeroExtend(IterationCount, + IndVar->getType()); IterationCount = SE->getAddExpr(IterationCount, SE->getIntegerSCEV(1, IndVar->getType())); @@ -279,12 +270,8 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L, CmpIndVar = L->getCanonicalInductionVariableIncrement(); } else { // We have to use the preincremented value... - if (SignExtendTripCount) - IterationCount = SE->getTruncateOrSignExtend(IterationCount, - IndVar->getType()); - else - IterationCount = SE->getTruncateOrZeroExtend(IterationCount, - IndVar->getType()); + IterationCount = SE->getTruncateOrZeroExtend(IterationCount, + IndVar->getType()); CmpIndVar = IndVar; } @@ -482,9 +469,8 @@ static const Type *getEffectiveIndvarType(const PHINode *Phi) { /// whether an induction variable in the same type that starts /// at 0 would undergo signed overflow. /// -/// In addition to setting the NoSignedWrap, NoUnsignedWrap, and -/// SignExtendTripCount variables, return the PHI for this induction -/// variable. +/// In addition to setting the NoSignedWrap, and NoUnsignedWrap, +/// variables, return the PHI for this induction variable. /// /// TODO: This duplicates a fair amount of ScalarEvolution logic. /// Perhaps this can be merged with ScalarEvolution::getIterationCount @@ -494,8 +480,7 @@ static const PHINode *TestOrigIVForWrap(const Loop *L, const BranchInst *BI, const Instruction *OrigCond, bool &NoSignedWrap, - bool &NoUnsignedWrap, - bool &SignExtendTripCount) { + bool &NoUnsignedWrap) { // Verify that the loop is sane and find the exit condition. const ICmpInst *Cmp = dyn_cast<ICmpInst>(OrigCond); if (!Cmp) return 0; @@ -610,10 +595,6 @@ static const PHINode *TestOrigIVForWrap(const Loop *L, // less than some value in the same type. As such, it will never wrap. if (isSigned && !InitialVal->getValue().isMaxSignedValue()) { NoSignedWrap = true; - // If the original induction variable starts at zero or greater, - // the trip count can be considered signed. - if (InitialVal->getValue().isNonNegative()) - SignExtendTripCount = true; } else if (!isSigned && !InitialVal->getValue().isMaxValue()) NoUnsignedWrap = true; return PN; @@ -700,7 +681,6 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) { // using it. We can currently only handle loops with a single exit. bool NoSignedWrap = false; bool NoUnsignedWrap = false; - bool SignExtendTripCount = false; const PHINode *OrigControllingPHI = 0; if (!isa<SCEVCouldNotCompute>(IterationCount) && ExitingBlock) // Can't rewrite non-branch yet. @@ -709,16 +689,14 @@ bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) { // Determine if the OrigIV will ever undergo overflow. OrigControllingPHI = TestOrigIVForWrap(L, BI, OrigCond, - NoSignedWrap, NoUnsignedWrap, - SignExtendTripCount); + NoSignedWrap, NoUnsignedWrap); // We'll be replacing the original condition, so it'll be dead. DeadInsts.insert(OrigCond); } LinearFunctionTestReplace(L, IterationCount, IndVar, - ExitingBlock, BI, Rewriter, - SignExtendTripCount); + ExitingBlock, BI, Rewriter); } // Now that we have a canonical induction variable, we can rewrite any |