[Bug tree-optimization/114045] New: large _BitInt * _Bool (or having known boolean range) should be inlined instead of calling __mulbitint3

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114045

            Bug ID: 114045
           Summary: large _BitInt * _Bool (or having known boolean range)
                    should be inlined instead of calling __mulbitint3
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
unsigned _BitInt(1024) 
foo (unsigned _BitInt(1024) ub1024_0, _Bool b)
{
  unsigned _BitInt(1024) t  = ub1024_0 * b;
  return t;
}

unsigned _BitInt(1024) 
foo2 (unsigned _BitInt(1024) ub1024_0 , _Bool b)
{
  unsigned _BitInt(1024) t = (unsigned _BitInt(1024))b;
  return ub1024_0 & -t;
}

unsigned _BitInt(1024) 
foo1 (unsigned _BitInt(1024) ub1024_0 , _Bool b)
{
  if (b)
    return ub1024_0;
  else
    return 0;
}
```

These should be both optimized the same.
One thing I noticed also is the copy loop for the return not optimized to just
memcpy but that is for a different issue.

Noticed when looking into PR 114040.