[all-commits] [llvm/llvm-project] 4b38ce: [X86] Remove MWAITX_SAVE_EBX pseudo instruction. A...

[topperc via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 4b38ceb0ebd7ed5fe1d5cbaf981060227515fb6e
      https://github.com/llvm/llvm-project/commit/4b38ceb0ebd7ed5fe1d5cbaf981060227515fb6e
  Author: Craig Topper <craig.topper at intel.com>
  Date:   2020-10-04 (Sun, 04 Oct 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ExpandPseudo.cpp
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/lib/Target/X86/X86InstrCompiler.td
    M llvm/test/CodeGen/X86/base-pointer-and-mwaitx.ll

  Log Message:
  -----------
  [X86] Remove MWAITX_SAVE_EBX pseudo instruction. Always save/restore the full %rbx register even in gnux32.

ebx/rbx only needs to be saved when 64-bit registers are supported
anyway. It should be fine to save/restore the whole rbx register
even in gnux32 where the base is technically just ebx.

This matches what we do for cmpxchg16b where rbx is saved/restored
regardless of gnux32.