[PATCH] D89219: [ValueTracking] Use assume's noundef operand bundle

[Tyker via Phabricator via llvm-commits]

Tyker added a comment.

you probably want to add noundef to isUsefullToPreserve such that it gets preserved automatically when knowledge retention is turned on.



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Comment at: llvm/lib/Analysis/ValueTracking.cpp:4843
+}
+
 static bool isGuaranteedNotToBeUndefOrPoison(const Value *V,
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jdoerfert wrote:
> I thought we had a helper for this, I think it is `hasAttributeInAssume` in `llvm/include/llvm/Analysis/AssumeBundleQueries.h`. If that is not enough we should extend it for sure. This kind of query is common and easy to get wrong. For example, this doesn't handle multiple `noundef` bundles.
there is getKnowledgeValidInContext which should be enough for what is being done here. it also has a fallback when there is no AssumptionCache.
also getOperandBundle is not valid since there maybe more than one noundef bundle in this assume.


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  https://reviews.llvm.org/D89219/new/

https://reviews.llvm.org/D89219