diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/LCSSA.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LCSSA.cpp | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp index 27067668a8d..73b2e4326c4 100644 --- a/llvm/lib/Transforms/Utils/LCSSA.cpp +++ b/llvm/lib/Transforms/Utils/LCSSA.cpp @@ -197,6 +197,17 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist, continue; } + // If we added a single PHI, it must dominate all uses and we can directly + // rename it. + if (AddedPHIs.size() == 1) { + // Tell the VHs that the uses changed. This updates SCEV's caches. + // We might call ValueIsRAUWd multiple times for the same value. + if (UseToRewrite->get()->hasValueHandle()) + ValueHandleBase::ValueIsRAUWd(*UseToRewrite, AddedPHIs[0]); + UseToRewrite->set(AddedPHIs[0]); + continue; + } + // Otherwise, do full PHI insertion. SSAUpdate.RewriteUse(*UseToRewrite); } @@ -210,9 +221,12 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist, BasicBlock *UserBB = DVI->getParent(); if (InstBB == UserBB || L->contains(UserBB)) continue; - // We currently only handle debug values residing in blocks where we have - // inserted a PHI instruction. - if (Value *V = SSAUpdate.FindValueForBlock(UserBB)) + // We currently only handle debug values residing in blocks that were + // traversed while rewriting the uses. If we inserted just a single PHI, + // we will handle all relevant debug values. + Value *V = AddedPHIs.size() == 1 ? AddedPHIs[0] + : SSAUpdate.FindValueForBlock(UserBB); + if (V) DVI->setOperand(0, MetadataAsValue::get(Ctx, ValueAsMetadata::get(V))); } |
