[PATCH] D53573: [TTI] Fix uses of SK_ExtractSubvector shuffle costs (PR39368)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: ABataev, dtemirbulatov, fhahn, mssimpso, javed.absar, spatel.

Correct costings of SK_ExtractSubvector requires the SubTy argument to indicate the type/size of the extracted subvector.

Unlike the rest of the shuffle kinds this means that the main Ty argument represents the source vector type not the destination - if anyone wants to 'flip' this now is the time to ask before we start adding more reduction support!

I've done my best to fix a number of vectorizer uses:

SLP - AFAICT the reduction epilogue costs should be using a SK_PermuteSingleSrc shuffle as these all occur at the hardware vector width - we're not extracting (illegal) subvector types. This is causing the cost model diffs as SK_ExtractSubvector costs are poorly handled and tend to just return 1 at the moment.

LV - I'm not clear on what the SK_ExtractSubvector should represents for recurrences - I've used a <1 x ?> subvector extraction as that seems to match the VF delta but I need help here (@fhahn? @mssimpso?).


Repository:
  rL LLVM

https://reviews.llvm.org/D53573

Files:
  include/llvm/Analysis/TargetTransformInfo.h
  include/llvm/CodeGen/BasicTTIImpl.h
  lib/Transforms/Vectorize/LoopVectorize.cpp
  test/Analysis/CostModel/AArch64/vector-reduce.ll
  test/Analysis/CostModel/X86/reduce-add.ll
  test/Analysis/CostModel/X86/reduce-and.ll
  test/Analysis/CostModel/X86/reduce-mul.ll
  test/Analysis/CostModel/X86/reduce-or.ll
  test/Analysis/CostModel/X86/reduce-smax.ll
  test/Analysis/CostModel/X86/reduce-smin.ll
  test/Analysis/CostModel/X86/reduce-umax.ll
  test/Analysis/CostModel/X86/reduce-umin.ll
  test/Analysis/CostModel/X86/reduce-xor.ll
  test/Analysis/CostModel/X86/reduction.ll

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