[all-commits] [llvm/llvm-project] 62e36b: [X86] canLowerByDroppingEvenElements - generalize ...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 62e36b1207497c4f7e1191a8d5407f4578c686e5
      https://github.com/llvm/llvm-project/commit/62e36b1207497c4f7e1191a8d5407f4578c686e5
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2022-01-18 (Tue, 18 Jan 2022)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/haddsub-shuf.ll
    M llvm/test/CodeGen/X86/phaddsub.ll
    M llvm/test/CodeGen/X86/shuffle-strided-with-offset-256.ll
    M llvm/test/CodeGen/X86/vector-interleaved-load-i16-stride-2.ll
    M llvm/test/CodeGen/X86/vector-shuffle-128-v8.ll
    M llvm/test/CodeGen/X86/x86-interleaved-access.ll

  Log Message:
  -----------
  [X86] canLowerByDroppingEvenElements - generalize to drop even or odd elements

This allows us to match shuffle<1,3,5,7,9,11,13,15> style shift+trunc/pack patterns as well as the existing shuffle<0,2,4,6,8,10,12,14> style shuffle trunc/pack patterns

In the future, interleaving patterns might benefit from an even more general implementation for higher strides