[PATCH] D86429: [X86] Make lowerShuffleAsLanePermuteAndShuffle use sublanes on AVX2

[TellowKrinkle via Phabricator via llvm-commits]

TellowKrinkle created this revision.
TellowKrinkle added reviewers: RKSimon, craig.topper.
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Extends lowerShuffleAsLanePermuteAndShuffle to search for opportunities to use vpermq (64-bit cross-lane shuffle) and vpermd (32-bit cross-lane shuffle) to get elements into the correct lane, in addition to the 128-bit full-lane permutes it previously searched for

This is especially helpful in cross-lane byte shuffles, where the alternative tends to be "vpshufb both lanes separately and blend them with a vpblendvb", which is very expensive, especially on Haswell where vpblendvb uses the same execution port as all the shuffles.

Addresses Bug 47262 <https://bugs.llvm.org/show_bug.cgi?id=47262>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D86429

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/bitcast-int-to-vector-bool-sext.ll
  llvm/test/CodeGen/X86/bitcast-int-to-vector-bool-zext.ll
  llvm/test/CodeGen/X86/bitcast-int-to-vector-bool.ll
  llvm/test/CodeGen/X86/oddshuffles.ll
  llvm/test/CodeGen/X86/vector-sext.ll
  llvm/test/CodeGen/X86/vector-shuffle-256-v16.ll
  llvm/test/CodeGen/X86/vector-shuffle-256-v32.ll
  llvm/test/CodeGen/X86/vector-shuffle-512-v32.ll
  llvm/test/CodeGen/X86/vector-shuffle-combining-avx2.ll
  llvm/test/CodeGen/X86/vector-shuffle-combining.ll

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