[PATCH] D77868: [InstSimplify] fold select of bools using bitwise logic

Fri Apr 10 08:27:33 PDT 2020

spatel added a comment.

In D77868#1974358 <https://reviews.llvm.org/D77868#1974358>, @lebedev.ri wrote:

> > This fixes regressions that would be visible if we remove known poison-unsafe transforms in instcombine mentioned here:
> >  https://reviews.llvm.org/D72396#1810460
>
> I think the problem is being misunderstood:
>
>   %frozen_x = freeze i1 %x

Ah, yes I know we could introduce freeze (or predicate with isGuaranteedNotToBeUndefOrPoison()?), but I thought we're not ready to introduce that as part of canonicalization because it would cause too much perf fallout currently.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77868/new/

https://reviews.llvm.org/D77868