[all-commits] [llvm/llvm-project] 0f59d0: [X86][AVX] combineVectorSignBitsTruncation - limit...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0f59d099571d3d803b54e2ce06aa94babb9b26db
      https://github.com/llvm/llvm-project/commit/0f59d099571d3d803b54e2ce06aa94babb9b26db
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-01-13 (Wed, 13 Jan 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    A llvm/test/CodeGen/X86/pr48727.ll
    M llvm/test/CodeGen/X86/vector-pack-256.ll

  Log Message:
  -----------
  [X86][AVX] combineVectorSignBitsTruncation - limit AVX512 truncations to 128-bits (PR48727)

rG73a44f437bf1 result in 256-bit packss/packus ops with additional shuffles that shuffle combining can sometimes try to convert back into a truncation.