[all-commits] [llvm/llvm-project] ae0f41: [X86] LowerBUILD_VECTOR - fold build_vector(undef, ...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ae0f41d186e6e851161fe0bad37a1c207b845859
      https://github.com/llvm/llvm-project/commit/ae0f41d186e6e851161fe0bad37a1c207b845859
  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/build-vector-128.ll
    M llvm/test/CodeGen/X86/freeze-vector.ll

  Log Message:
  -----------
  [X86] LowerBUILD_VECTOR - fold build_vector(undef,freeze(undef),zero) -> zero vector

426db6b4eb2e9298598 added the build_vector(undef,freeze(undef)) -> freeze(undef) fold, but failed to account for cases where the scalar freeze(undef) had multiple uses, in those cases we can only only safely fold to a zero vector

https://alive2.llvm.org/ce/z/87jG8K