[PATCH] D134982: [X86] Add support for "light" AVX

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

In D134982#3999687 <https://reviews.llvm.org/D134982#3999687>, @TokarIP wrote:

> In D134982#3999680 <https://reviews.llvm.org/D134982#3999680>, @lebedev.ri wrote:
>
>> I think `LightAVX` is a misnomer. If we want to
>> always utilize full potential of vector load-store unit,
>> then the Tuning should say as much.
>
> I'll probably expand this to other "light" AVX instructions (like vpcmpeq for memcmp intrinsic) in the future.
> Also we don't want the full width, 512-bit load/stores still cause some frequency drop on skylake.

Do we have a definitive list of what intel considers "light" 256-bit instructions?



================
Comment at: llvm/test/CodeGen/X86/memcpy-light-avx.ll:1
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=haswell -mattr=prefer-128-bit | FileCheck %s
+
----------------
Test with generic settings as well (e.g. -mattr=avx2,+prefer-128-bit,+allow-light-avx)


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https://reviews.llvm.org/D134982