[PATCH] D27684: [X86][SSE] Fix domains for VZEXT_LOAD type instructions

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

In https://reviews.llvm.org/D27684#620266, @mkuper wrote:

> Is there actually a domain crossing penalty for these cases?
>  (Adding Dave & Zia as authoritative sources of truth :-) )


The penalties are minor (and non-existent on some latest architectures), but definitely present on pre-AVX targets. It does allow us to be consistent along an instruction chain which isn't a bad thing. By allowing domain switching we also encourage float domain instructions which often have shorter encodings.


Repository:
  rL LLVM

https://reviews.llvm.org/D27684