[PATCH] D115462: [SLP]Improve shuffles cost estimation where possible.

Thu Jun 23 12:59:52 PDT 2022

MaskRay added a comment.

In D115462#3605808 <https://reviews.llvm.org/D115462#3605808>, @ABataev wrote:

> In D115462#3603899 <https://reviews.llvm.org/D115462#3603899>, @MaskRay wrote:
>
>> Here is `-mllvm -print-changed -mllvm -print-module-scope` output before SLPVectorizer: https://gist.github.com/MaskRay/23f0db50e136127fda1b4f83db2488da
>
> Double checked the patch and the results. The patch itself does not change the vectorization, just adjusts the cost model estimation. Some of the buildvector sequences are not profitable for re-vectorization after this patch, nothing else. Plus, the code after this patch results in the same code, being applied to the compiler without the patch, i.e. the code transformations are the same, just different vectorization.
> Maybe the debug info is corrupted somehow? Or there are other effects?

I have added IR before/after SLPVectorizer, with and without the two commits, and generated assembly to https://gist.github.com/MaskRay/23f0db50e136127fda1b4f83db2488da
Hope they are useful.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D115462/new/

https://reviews.llvm.org/D115462