[all-commits] [llvm/llvm-project] 445bc8: [BOLT] Use 32-bit MOV to zero 64-bit register in i...

[Amir Ayupov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 445bc88501f8f3e55293910dddd6c5fed87b0a0b
      https://github.com/llvm/llvm-project/commit/445bc88501f8f3e55293910dddd6c5fed87b0a0b
  Author: Amir Ayupov <aaupov at fb.com>
  Date:   2022-06-19 (Sun, 19 Jun 2022)

  Changed paths:
    M bolt/lib/Target/X86/X86MCPlusBuilder.cpp

  Log Message:
  -----------
  [BOLT] Use 32-bit MOV to zero 64-bit register in instrumentation code

Instead of `movabsq $0x0, %rax` emit shorter equivalent `movl $0x0, %eax`.
Intel SDM, 3.4.1.1 General-Purpose Registers in 64-Bit Mode:
>32-bit operands generate a 32-bit result, zero-extended to a 64-bit result in
> the destination general-purpose register.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D127045