[PATCH] D83360: [InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X

[Nuno Lopes via Phabricator via cfe-commits]

nlopes added a subscriber: tgt.
nlopes added a comment.

In D83360#2142457 <https://reviews.llvm.org/D83360#2142457>, @efriedma wrote:

> > that's fine but I still don't understand why the counterexample to my version says %x2 in @src can be undef
>
> If I'm understanding correctly, this reduces to something like the following:
>
> define i32 @src() {
>
>   %x2 = freeze i32 undef
>   ret i32 %x2
>
> }
>
> define i32 @tgt() {
>
>   ret i32 undef
>
> }
>
> This seems a little suspect, yes.


This is a known bug: https://github.com/AliveToolkit/alive2/issues/3
gotta fix this soon.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D83360/new/

https://reviews.llvm.org/D83360