[PATCH] D104569: [SimplifyCFG] Fix SimplifyBranchOnICmpChain to be undef/poison safe.

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

I have a general policy question here: Do we care about miscompiles that are caused by undef, but not poison? This makes a difference for transforms like these, e.g. no freeze is required if the condition is first in a logical or (or at any position in bitwise or) if we only care about poison.

As we are moving from undef to poison across the board, I'm not sure we should introduce mitigations that would become irrelevant once undef no longer exists. My view here is that miscompiles involving undef are mostly nominal, in that the undef value really should be a poison value and we just haven't switched it one yet.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D104569/new/

https://reviews.llvm.org/D104569