[PATCH] D31426: [DAGCombine] Combine shuffle of splat with multiple uses

[Zvi Rackover via Phabricator via llvm-commits]

zvi added a comment.

I initially tried handling all cases of shuffle of shuffle-splat but the improvements from https://reviews.llvm.org/D27793 regressed, so this is what i came up with.
Should i change this to an X86-specific combine to follow the spirit of https://reviews.llvm.org/D27793?

About doing this in instcombine, yes, i plan to look into that too, but the pattern optimized by this patch is born out of thin air in another patch I'm working on that improves the combine of BUILD_VECTOR into composed shuffles.


Repository:
  rL LLVM

https://reviews.llvm.org/D31426