[PATCH] D76973: [LangRef] Clarify the semantics of branch on undef

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune added a comment.

Yes, introducing branches is unsound if its condition can be undef or poison. LoopUnswitch was reverted due to performance issue sadly, but I'm reapplying similar changes that less affect the quality of generated code.
For example, https://reviews.llvm.org/D76179 , which freezes condition when transforming select to br , in CodeGenPrepare.
It will be great if such transformations are tracked & fixed.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D76973/new/

https://reviews.llvm.org/D76973