[PATCH] D89162: [SVE] Lower fixed length VECREDUCE_SEQ_FADD operation

[Cameron McInally via Phabricator via llvm-commits]

cameron.mcinally updated this revision to Diff 300321.
cameron.mcinally marked an inline comment as done.
cameron.mcinally added a comment.

Updating patch, but not ready for a serious review yet as I haven't started the splitting work. I'm still not convinced we can handle splitting appropriately with the current setup, but will comment on that seperately.

I caused a big misunderstanding here, so let me try to unwind it. Paul is correct. The legalizations are NOT necessary for SVE support. I made a mistake when preparing this patch. I.e. I built the legalization changes out before I finalized the shouldExpandReduction(...) changes, so ended up in a weird state with NEON.

The ExpandReductions pass is somewhat unusual and that threw me off. It's an IR pass that runs early in llc, before legalisation. I've never seen one of those, so it tripped me up. I apologize for the confusion. That said, I wonder if the reductions should really be expanded during legalization. That would have been a more natural choice to me.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D89162/new/

https://reviews.llvm.org/D89162

Files:
  llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/lib/Target/AArch64/AArch64ISelLowering.h
  llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
  llvm/test/CodeGen/AArch64/sve-fixed-length-fp-reduce.ll

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