diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/LoopIdiomRecognize.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp index 8b022bab83..57a502b1d2 100644 --- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp +++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp @@ -159,6 +159,12 @@ bool LoopIdiomRecognize::runOnLoop(Loop *L, LPPassManager &LPM) { const SCEV *BECount = SE->getBackedgeTakenCount(L); if (isa<SCEVCouldNotCompute>(BECount)) return false; + // If this loop executes exactly one time, then it should be peeled, not + // optimized by this pass. + if (const SCEVConstant *BECst = dyn_cast<SCEVConstant>(BECount)) + if (BECst->getValue()->getValue() == 0) + return false; + // We require target data for now. TD = getAnalysisIfAvailable<TargetData>(); if (TD == 0) return false; |