[PATCH] D48172: [CostModel][AArch64] Add some initial costs for SK_Select and SK_PermuteSingleSrc

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: mssimpso, evandro, rengolin, javed.absar, spatel.
Herald added a subscriber: kristof.beyls.

AArch64 was only setting costs for SK_Transpose, which meant that many of the simpler shuffles (e.g. SK_Select and SK_PermuteSingleSrc for larger vector elements) was being severely overestimated by the default shuffle expansion.

This patch adds costs to help improve SLP performance and avoid a regression in reductions in an upcoming patch that will allow SLP to recognise a lot more SK_Select shuffle patterns.

I'm not very knowledgable about AArch64 shuffle lowering so I've kept the extra costs to a minimum - someone who knows this code can add extra costs which should improve vectorization a lot more.


Repository:
  rL LLVM

https://reviews.llvm.org/D48172

Files:
  lib/Target/AArch64/AArch64TargetTransformInfo.cpp
  test/Analysis/CostModel/AArch64/shuffle-select.ll
  test/Transforms/SLPVectorizer/AArch64/transpose.ll

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