https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127348
Bug ID: 127348
Summary: [X86] (a & 1) == 0 not using test + sete
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: kaelfandrew at gmail dot com
Target Milestone: ---
https://godbolt.org/z/dEeozoKxd
With -O2:
```
bool
src (unsigned int a)
{
return (a & 1) == 0;
}
/* GCC trunk assembly
"src":
mov eax, edi
not eax
and eax, 1
ret
*/
/* Clang trunk assembly
src:
test dil, 1
sete al
ret
*/
```
As of r17-4177,
it shows up in GCC with some examples:
ada/gcc-interface/utils.cc:3646: while ((mask & 1) == 0 && i <
HOST_BITS_PER_WIDE_INT)
ada/gcc-interface/utils2.cc:647: if (mh != 0 && (d & 1) == 0)
ada/init.c:1523: if ((status & 1) != 1)
c/c-parser.cc:22296: if (((mask >> c_kind) & 1) == 0)
