[PATCH] D59006: [x86] improve the default expansion of uaddsat/usubsat

Thu Mar 21 10:23:35 PDT 2019

nikic added a comment.

In D59006#1438184 <https://reviews.llvm.org/D59006#1438184>, @lebedev.ri wrote:

> This LG, but i'm not sure i understand how this is related to D59066 <https://reviews.llvm.org/D59066>?
>  Here, we are clearly end up with no `select` in ASM.
>  But in D59066 <https://reviews.llvm.org/D59066> we expand to this pattern.
>  So there is something else that is able to do the transform that we do manually in D59066 <https://reviews.llvm.org/D59066>?
>  Should D59066 <https://reviews.llvm.org/D59066> be doing something else to simply trigger the existing transform?

This case should be caught by D59174 <https://reviews.llvm.org/D59174> after the select has been expanded into bitwise logic. D59066 <https://reviews.llvm.org/D59066> forces bitwise logic even if the select would not usually be expanded.

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  https://reviews.llvm.org/D59006/new/

https://reviews.llvm.org/D59006