https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115028
Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
          Component|target                      |testsuite

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So the extra xor is due to an extra register move in the IR and then RA decides
to do slightly different register allocation.
```
/* PR middle-end/101950 */
/* { dg-do compile } */
/* { dg-options "-O2 -mlzcnt" } */
/* { dg-final { scan-assembler-not "call\[^\n\r]*__clrsb.i2" } } */
/* { dg-final { scan-assembler-times "\tlzcnt\[ql]\t" 2 } } */
/* { dg-final { scan-assembler-times "\txor\[ql]\t" 2 } } */
/* { dg-final { scan-assembler-times "\tsar\[ql]\t|\tcltd" 2 } } */

int
foo (long *x)
{
  return __builtin_clrsbl (*x);
}

int
bar (int *x)
{
  return __builtin_clrsb (*x);
}
```

I am just goign to change the testcase to avoid the register allocation
trouble.

Reply via email to