[PATCH] D156532: [Pipelines] Perform hoisting prior to GVN

Tue Aug 8 07:32:47 PDT 2023

dmgreen added a comment.

Sorry I had to revert this as it caused some large regressions. I'm not sure if I have the greatest reason though. The most important is probably x264 from Spec, which I'm seeing a 9-10% regressions depending on the specific configuration. There are also some downstream embedded benchmarks that run under LTO and can be quite fragile to phase ordering changes. There are some there that get better, some that get worse.

I think the main change in x264 is from this function: https://github.com/MasterNobody/x264/blob/eaa68fad9e5d201d42fde51665f2d137ae96baf0/common/quant.c#L64, which requires some vectorization to perform well. https://godbolt.org/z/oKG5onsna

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D156532/new/

https://reviews.llvm.org/D156532