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
}
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);
}