[llvm] 8133778 - [SCEV] Fully invalidate SCEVUnknown on RAUW
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 7 00:39:57 PST 2022
Author: Nikita Popov
Date: 2022-03-07T09:28:28+01:00
New Revision: 8133778d3c8d481891143e21e0c5081a02a9889d
URL: https://github.com/llvm/llvm-project/commit/8133778d3c8d481891143e21e0c5081a02a9889d
DIFF: https://github.com/llvm/llvm-project/commit/8133778d3c8d481891143e21e0c5081a02a9889d.diff
LOG: [SCEV] Fully invalidate SCEVUnknown on RAUW
When a SCEVUnknown gets RAUWd, we currently drop it from the folding
set, but don't forget memoized values. I believe we should be
treating RAUW the same way as deletion here and invalidate all
caches and dependent expressions.
I don't have any specific cases where this causes issues right now,
but it does address the FIXME in https://reviews.llvm.org/D119488.
Differential Revision: https://reviews.llvm.org/D120033
Added:
Modified:
llvm/lib/Analysis/ScalarEvolution.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index e66e9ec52124c..7d2d3381230ba 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -526,12 +526,13 @@ void SCEVUnknown::deleted() {
}
void SCEVUnknown::allUsesReplacedWith(Value *New) {
+ // Clear this SCEVUnknown from various maps.
+ SE->forgetMemoizedResults(this);
+
// Remove this SCEVUnknown from the uniquing map.
SE->UniqueSCEVs.RemoveNode(this);
- // Update this SCEVUnknown to point to the new value. This is needed
- // because there may still be outstanding SCEVs which still point to
- // this SCEVUnknown.
+ // Replace the value pointer in case someone is still using this SCEVUnknown.
setValPtr(New);
}
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