[PATCH] D71799: [Attributor] AAUndefinedBehavior: Check for branches on undef value.

Fri Dec 27 07:35:46 PST 2019

uenoku added a comment.

> Well, if we go by the book, which would be the LLVM IR ref manual, and optimize aggressively for UB, undef can be considered to have any bit pattern.
>  And we can choose it to have the null bit pattern, which is UB for both volatile and non-volatile.

Ok, thanks.

> As another note (and related to the diff update message), I realize that it's difficult for both of us to try and correct 16 test cases that currently fail in this revision.
>  I think it's better to remove the AAValueSimplify in the memory accessing instructions. That will make the failing test-cases only 3. I could then try to fix them
>  and it should be easier for you to review as well.

Please split the patch.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71799/new/

https://reviews.llvm.org/D71799