[PATCH] D125712: [SLP][X86] Improve reordering to consider alternate instruction bundles

[Vasileios Porpodas via Phabricator via llvm-commits]

vporpo added inline comments.


================
Comment at: llvm/include/llvm/Analysis/TargetTransformInfo.h:684
+  bool isLegalAltInstr(VectorType *VecTy, unsigned EvenOpcode,
+                       unsigned OddOpcode) const;
+
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RKSimon wrote:
> If we're going to do this (and I'm still not convinced we should) we're going to need a shuffle mask - otherwise addsub matching is not going to be accurate.
I agree, the shuffle mask will make matching a lot more accurate, I will update the patches.

Why do you think we should not be going ahead with this? To me this is very similar to the shuffle-reducing transformations that we already have, so it looks like it fits pretty well the scope of the SLP pass.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D125712/new/

https://reviews.llvm.org/D125712