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| author | Daniel Berlin <dberlin@dberlin.org> | 2018-01-09 20:12:42 +0000 |
|---|---|---|
| committer | Daniel Berlin <dberlin@dberlin.org> | 2018-01-09 20:12:42 +0000 |
| commit | 56cca7437c1a4c7a8f697e97d9f8b98576b7a97e (patch) | |
| tree | 18f4b0d65f484f624422fe000765c5622e2d37c7 /llvm/lib/Transforms | |
| parent | 55662a8e9ffe0de5dc4af244caa1e1a22659aeb9 (diff) | |
| download | bcm5719-llvm-56cca7437c1a4c7a8f697e97d9f8b98576b7a97e.tar.gz bcm5719-llvm-56cca7437c1a4c7a8f697e97d9f8b98576b7a97e.zip | |
NewGVN: Fix PR/33367, which was causing us to delete non-copy intrinsics accidentally in some rare cases
llvm-svn: 322115
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/NewGVN.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/NewGVN.cpp b/llvm/lib/Transforms/Scalar/NewGVN.cpp index 9ebf2d76935..5e6b58055ec 100644 --- a/llvm/lib/Transforms/Scalar/NewGVN.cpp +++ b/llvm/lib/Transforms/Scalar/NewGVN.cpp @@ -4058,7 +4058,8 @@ bool NewGVN::eliminateInstructions(Function &F) { Value *DominatingLeader = EliminationStack.back(); auto *II = dyn_cast<IntrinsicInst>(DominatingLeader); - if (II && II->getIntrinsicID() == Intrinsic::ssa_copy) + bool isSSACopy = II && II->getIntrinsicID() == Intrinsic::ssa_copy; + if (isSSACopy) DominatingLeader = II->getOperand(0); // Don't replace our existing users with ourselves. @@ -4081,7 +4082,9 @@ bool NewGVN::eliminateInstructions(Function &F) { // It's about to be alive again. if (LeaderUseCount == 0 && isa<Instruction>(DominatingLeader)) ProbablyDead.erase(cast<Instruction>(DominatingLeader)); - if (LeaderUseCount == 0 && II) + // Copy instructions, however, are still dead beacuse we use their + // operand as the leader. + if (LeaderUseCount == 0 && isSSACopy) ProbablyDead.insert(II); ++LeaderUseCount; AnythingReplaced = true; |
