[all-commits] [llvm/llvm-project] ee52af: [X86] Handle multiple use freeze(undef) in LowerAV...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ee52af74d8e5e3083cf5195d11c92f8df95b8072
      https://github.com/llvm/llvm-project/commit/ee52af74d8e5e3083cf5195d11c92f8df95b8072
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2023-04-26 (Wed, 26 Apr 2023)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/avx512-intrinsics.ll
    M llvm/test/CodeGen/X86/avx512fp16-intrinsics.ll

  Log Message:
  -----------
  [X86] Handle multiple use freeze(undef) in LowerAVXCONCAT_VECTORS as zero vectors

Replacement for D144903

If we're concatenating freeze(undef) subvector ops with multiple uses then we can't treat them as a wider freeze(undef), but we can replace them with a zero subvector, which is cheap on AVX

Differential Revision: https://reviews.llvm.org/D149249