[Bug tree-optimization/114092] New: ADD_OVERFLOW<a, 0> with resulting type of `_Complex unsigned:1` should be reduced to just `(unsigned)(a) <= 1`

[Bug tree-optimization/114092] New: ADD_OVERFLOW<a, 0> with resulting type of `_Complex unsigned:1` should be reduced to just `(unsigned)(a) <= 1`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114092

            Bug ID: 114092
           Summary: ADD_OVERFLOW<a, 0> with resulting type of `_Complex
                    unsigned:1` should be reduced to just `(unsigned)(a)
                    <= 1`
           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:
```
struct d
{
  unsigned i:1;
};
_Bool f(int a, struct d b)
{
        return __builtin_add_overflow_p(a, 0, b.i);
}


_Bool f1(int a, struct d b)
{
        return a != 1 && a != 0;
}
```

These 2 functions should produce the same. Here `a+0` overflows an `unsigned:1`
if the value of a is not 0 or 1.

We could extend this to any smaller types too if we want.

[Bug tree-optimization/114092] ADD_OVERFLOW<a, 0> with resulting type of `_Complex unsigned:1` should be reduced to just `(unsigned)(a) <= 1`

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114092

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I should note that LLVM (LLVM does not have __builtin_add_overflow_p) is able
to optimize:
```
_Bool f2(int a, struct d b, unsigned _BitInt(1) t)
{
        return __builtin_add_overflow(a, 0, &t);
}
```
into  f1.

[Bug tree-optimization/114092] ADD_OVERFLOW<a, 0> with resulting type of `_Complex unsigned:1` should be reduced to just `(unsigned)(a) <= 1`

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114092

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Guess all of .ADD_OVERFLOW (x, 0), .ADD_OVERFLOW (0, x) and .SUB_OVERFLOW (x,
0)
to REALPART_EXPR = (type) x and IMAGPART_EXPR to (type) x != x.  Just need to
figure out for which types it is beneficial and for which it isn't.