[PATCH] D36890: [X86] Emit testl instead of testb for select condition where possible

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D36890#848823, @aivchenk wrote:

> yeah, now I also think that I covered only a narrow case for the issue: we need more general approach.
>
> My 2 cents on your points:
>
> 1. If the result of AssertZext is truncated with no other uses, can we just delete that AssertZext?


I don't think we want to do that. IIUC, the point of the AssertZext is to preserve 'zeroext' info on values that would otherwise be lost during legalization/lowering. If we delete the AssertZext, we'll probably produce worse code?

> Could you please share the x86 test changes after your patch?

Sure - let me clean up the draft patch and post it for review.


https://reviews.llvm.org/D36890