[llvm] f494f89 - [LAA] Fix latent missing check bug when mixing scalable and non-scalabe strides
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 20 11:57:07 PDT 2022
Author: Philip Reames
Date: 2022-07-20T11:56:45-07:00
New Revision: f494f89b2a88f9de48781f43e7be2386809c7db5
URL: https://github.com/llvm/llvm-project/commit/f494f89b2a88f9de48781f43e7be2386809c7db5
DIFF: https://github.com/llvm/llvm-project/commit/f494f89b2a88f9de48781f43e7be2386809c7db5.diff
LOG: [LAA] Fix latent missing check bug when mixing scalable and non-scalabe strides
Noticed via inspection; to my knowledge, impossible to hit today. In theory, we could have a fixed stride check be analyzed, then a scalable one. With the old code, the scalable one would be silently dropped, and the runtime guard would go ahead with only the fixed one. This would be a miscompile.
Added:
Modified:
llvm/lib/Analysis/LoopAccessAnalysis.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index f7f0dc4dcb1d..0bc2e761d080 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -293,8 +293,10 @@ void RuntimePointerChecking::tryToCreateDiffCheck(
DC.getInstructionsForAccess(Sink->PointerValue, Sink->IsWritePtr);
Type *SrcTy = getLoadStoreType(SrcInsts[0]);
Type *DstTy = getLoadStoreType(SinkInsts[0]);
- if (isa<ScalableVectorType>(SrcTy) || isa<ScalableVectorType>(DstTy))
+ if (isa<ScalableVectorType>(SrcTy) || isa<ScalableVectorType>(DstTy)) {
+ CanUseDiffCheck = false;
return;
+ }
unsigned AllocSize =
std::max(DL.getTypeAllocSize(SrcTy), DL.getTypeAllocSize(DstTy));
IntegerType *IntTy =
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