[Bug tree-optimization/114204] Missed optimization: -(a*!a) => 0 when a=-b-c

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114204

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
```
int f(int a, int b)
{
        if (a == -b)
          return a + b;
        return 0;
}
int f1(int a, int b)
{
        if (a == b)
          return a - b;
        return 0;
}
```

Should be both handled in phiopt basically.

Another one too:
```
int f1(int a, int b)
{
        if (a == b)
          return a / b;
        return 1;
}
```
Should be transformed into 1 also.