[all-commits] [llvm/llvm-project] a047df: [AArch64][GISel] Lower EXT of 0 to a COPY

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a047dfe0d54294973913b5d93967501c9ed15fa5
      https://github.com/llvm/llvm-project/commit/a047dfe0d54294973913b5d93967501c9ed15fa5
  Author: David Green <david.green at arm.com>
  Date:   2023-08-16 (Wed, 16 Aug 2023)

  Changed paths:
    M llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
    M llvm/test/CodeGen/AArch64/GlobalISel/postlegalizer-lowering-shuffle-splat.mir
    M llvm/test/CodeGen/AArch64/GlobalISel/postlegalizer-lowering-zip.mir
    M llvm/test/CodeGen/AArch64/arm64-dup.ll
    M llvm/test/CodeGen/AArch64/arm64-neon-add-pairwise.ll
    M llvm/test/CodeGen/AArch64/arm64-vabs.ll

  Log Message:
  -----------
  [AArch64][GISel] Lower EXT of 0 to a COPY

This allows us to select G_SHUFFLE_VECTOR with identity masks (possibly
including undef elements), but avoid the actual EXT instruction if the shift
amount is 0.