[Bug tree-optimization/109959] `(a > 1) ? 0 : (a == 1)` is not optimized when spelled out at -O2+

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109959

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
here is another related testcase but this was the exactly reduced one from
bitmap_single_bit_set_p :

```
_Bool f(unsigned a, int t)
{
  void g(void);
  if (t)
    return 0;
  g();
  if (a > 1)
    return 0;
  return a == 1;
}
```

this should be optimized down to:
```
_Bool f(unsigned a, int t)
{
  void g(void);
  if (t)
    return 0;
  g();
  return a == 1;
}
```