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| author | Max Kazantsev <mkazantsev@azul.com> | 2022-08-12 13:27:01 +0700 |
|---|---|---|
| committer | Max Kazantsev <mkazantsev@azul.com> | 2022-08-12 14:23:35 +0700 |
| commit | a3d1fb3b59b473e4f262a05f187de6474b7721e7 (patch) | |
| tree | 8e8995fd72cb135c7a887ec92bbd962b6ed8e489 /llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | |
| parent | 90736babcaeb5222ee5ba50a823b7acffdd5a4dd (diff) | |
| download | llvm-a3d1fb3b59b473e4f262a05f187de6474b7721e7.zip llvm-a3d1fb3b59b473e4f262a05f187de6474b7721e7.tar.gz llvm-a3d1fb3b59b473e4f262a05f187de6474b7721e7.tar.bz2 | |
[SCEV] Prove condition invariance via context
Contextual knowledge may be used to prove invariance of some conditions.
For example, in this case:
```
; %len >= 0
guard(%iv = {start,+,1}<nuw> <s %len)
guard(%iv = {start,+,1}<nuw> <u %len)
```
the 2nd check always fails if `start` is negative and always passes otherwise.
It looks like there are more opportunities of this kind that are still to be
implemented in the future.
Differential Revision: https://reviews.llvm.org/D129753
Reviewed By: apilipenko
Diffstat (limited to 'llvm/lib/Transforms/Utils/SimplifyIndVar.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp index 0a856ee..08c48b0 100644 --- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -213,7 +213,8 @@ bool SimplifyIndvar::makeIVComparisonInvariant(ICmpInst *ICmp, auto *PN = dyn_cast<PHINode>(IVOperand); if (!PN) return false; - auto LIP = SE->getLoopInvariantPredicate(Pred, S, X, L); + + auto LIP = SE->getLoopInvariantPredicate(Pred, S, X, L, ICmp); if (!LIP) return false; ICmpInst::Predicate InvariantPredicate = LIP->Pred; |