[Bug c/83123] New: Int compare - different asm code for different return type

[bugzilla@poradnik-webmastera.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83123

            Bug ID: 83123
           Summary: Int compare - different asm code for different return
                    type
           Product: gcc
           Version: 7.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bugzilla@poradnik-webmastera.com
  Target Milestone: ---

int test1(int a, int b)
{
  return (a < 0) && (b < 0);
}
bool test2(int a, int b)
{
  return (a < 0) && (b < 0);
}

This produces following code, when compiled with -O2. For some reason 2nd
function performs shifts first, then and. This is not necessary, you can and
first, then shift. The same issue is for checking if any of numbers is negative
- or can be executed first, then shift.

test1(int, int):
  and esi, edi
  mov eax, esi
  shr eax, 31
  ret
test2(int, int):
  mov eax, edi
  shr esi, 31
  shr eax, 31
  and eax, esi
  ret