[PATCH] D86396: [Attributor] Change AANoUndef not to deduce noundef for dead returned positions

[Shinji Okumura via Phabricator via llvm-commits]

okura added a comment.

When I fix the identification of AANoUndef in `identifyDefaultAbstractAttributes`, I noticed that noundef should not be deduced for dead argument and dead call site argument position too. (I found wrong transformation in e.g. `callbacks.ll`)
Not to deduce for dead positions, we should not indicate optimistic fixpoint in `initialize` because once fixpoint is indicated we cannot change the state. However, it weakens the deduction significantly.
So I want to suggest that we check not only noundef but also liveness in AAUndefinedBehavior.


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  https://reviews.llvm.org/D86396/new/

https://reviews.llvm.org/D86396