[PATCH] D29014: [SelDag][MIR] Add FREEZE

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune added a comment.

BTW, there was a discussion about IMPLICIT_DEF as well, about whether it should return consistent value for every use vs. it can return different values per use (as IR's undef).

Currently IMPLICIT_DEF can yieid different values, and there are a few cases where that happens (such as using IMPLICIT_DEF across function calls).

Making it return consistent value will allow FREEZE to be duplicable, but it would require fixing several transformations that deal with IMPLICIT_DEF.

Before discussion about IMPLICIT_DEF is further made and it is changed to return concrete value, I'd like to suggest leaving FREEZE as semi-duplicable (as suggested by this patch), but not fully duplicable.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D29014/new/

https://reviews.llvm.org/D29014