[Bug target/95235] New: Failure to properly optimize out register use in bit-twiddling code

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95235

            Bug ID: 95235
           Summary: Failure to properly optimize out register use in
                    bit-twiddling code
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

int f(int a, int b)
{
    return ((a & 1) != 0) != (b != 0);
}

With -O3, GCC outputs this :

f(int, int):
  test esi, esi
  setne al
  xor edi, eax
  mov eax, edi
  and eax, 1
  ret

GCC should be able of outputting this instead :

f(int, int):
  test esi, esi
  setne al
  xor eax, edi
  and eax, 1
  ret

But it does not do so.