[PATCH] D71974: [Attributor][WIP] Connect AAIsDead with AAUndefinedBehavior

[Stefanos Baziotis via Phabricator via llvm-commits]

baziotis updated this revision to Diff 235596.
baziotis added a comment.

- Query AAUB in `identifyAliveSuccessors()` for `BranchInst`.

This is essentially a proposed PoC on how to use AAUB in `AAIsDeadFunction::updateImpl()`. The `TODO` there says  "look for (assumed) UB to backwards propagate "deadness"".
In my understanding that seems kind of unorthodox since the whole process is moving forwards (with an "artificial" recursion so it's not easy to "go back" since we never actually return back). Because of that, I thought it may be better instead of that to just "not go forwards" on successors (and BBs) that have UB (not going forwards into them means they're not put in `AssumedLiveBlocks`, effectively keeping them dead).

- Passed the attributor in `isAssumedDead()` etc. (that resulted in changes all over the place, I hope that's ok).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71974/new/

https://reviews.llvm.org/D71974

Files:
  llvm/include/llvm/Transforms/IPO/Attributor.h
  llvm/lib/Transforms/IPO/Attributor.cpp

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