[PATCH] D72733: [InstCombine] allow more narrowing of casted select

Tue Jan 14 14:55:26 PST 2020

spatel added a comment.

In D72733#1820606 <https://reviews.llvm.org/D72733#1820606>, @lebedev.ri wrote:

> I'm not sure what kind of fallout this will cause.
>  For example, won't this affect 'saturating math' peephole?
>  Won't this affect clamp (min-max) pattern?

As with PRPR44545, it's hard to see the fallout in advance, but keep in mind this patch is only restoring part of the behavior before D47163 <https://reviews.llvm.org/D47163>. 
If we are detecting min/max patterns with ValueTracking's matchSelectPattern(), that can optionally include casts, so we should be able to peek through. If you have a pattern in mind that would be affected, let me know.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D72733/new/

https://reviews.llvm.org/D72733