[Bug target/110588] New: btl (on x86_64) not always generated

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110588

            Bug ID: 110588
           Summary: btl (on x86_64) not always generated
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---
            Target: x86_64-linux-gnu

Take C+ code (since I am too lazy to figure out the types):
```
unsigned char clr1_bb (unsigned char x, int y)
{
  return (x & (1<<y)) == 0;
}


unsigned char clr1_bb1 (unsigned char x, int y)
{
  auto  _1 = (int) x;
 auto _2 = _1 >> y;
 auto _3 = _2 & 1;
 auto _8 = (unsigned char) _3;
auto  _6 = _8 ^ 1;

  return _6;
}

unsigned char clr1_bb2 (unsigned char x, int y)
{
  auto  _1 = (int) x;
 auto _2 = _1 >> y;
 auto _3 = _2 & 1;
auto  _6 = _3 ^ 1;
 auto _8 = (unsigned char) _6;

  return _6;
}
```

Right now clr1_bb and clr1_bb2 produce the btl/setnc but clr1_bb1 does not.

Note I noticed this while working on PR 110539 (I changed my patch to put the
cast after the ^1 rather than before so this is not blocking that patch).