diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index 4ef5298dc0..429b61b6e5 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -857,6 +857,9 @@ bool JumpThreading::SimplifyPartiallyRedundantLoad(LoadInst *LI) { if (BBIt != LoadBB->begin()) return false; + // If all of the loads and stores that feed the value have the same TBAA tag, + // then we can propagate it onto any newly inserted loads. + MDNode *TBAATag = LI->getMetadata(LLVMContext::MD_tbaa); SmallPtrSet<BasicBlock*, 8> PredsScanned; typedef SmallVector<std::pair<BasicBlock*, Value*>, 8> AvailablePredsTy; @@ -875,11 +878,16 @@ bool JumpThreading::SimplifyPartiallyRedundantLoad(LoadInst *LI) { // Scan the predecessor to see if the value is available in the pred. BBIt = PredBB->end(); - Value *PredAvailable = FindAvailableLoadedValue(LoadedPtr, PredBB, BBIt, 6); + MDNode *ThisTBAATag = 0; + Value *PredAvailable = FindAvailableLoadedValue(LoadedPtr, PredBB, BBIt, 6, + 0, &ThisTBAATag); if (!PredAvailable) { OneUnavailablePred = PredBB; continue; } + + // If tbaa tags disagree or are not present, forget about them. + if (TBAATag != ThisTBAATag) TBAATag = 0; // If so, this load is partially redundant. Remember this info so that we // can create a PHI node. @@ -939,6 +947,9 @@ bool JumpThreading::SimplifyPartiallyRedundantLoad(LoadInst *LI) { LI->getAlignment(), UnavailablePred->getTerminator()); NewVal->setDebugLoc(LI->getDebugLoc()); + if (TBAATag) + NewVal->setMetadata(LLVMContext::MD_tbaa, TBAATag); + AvailablePreds.push_back(std::make_pair(UnavailablePred, NewVal)); } |