[Bug tree-optimization/120283] `Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1` gimple depends on single use

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120283

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |93006

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I forgot to say this comes from gcc.dg/tree-ssa/vrp89.c  .

Reduced down to:
```
void g();

void
foo (unsigned int a, unsigned *b)
{
  a &= 63;
  a += 3;
  *b = a;
  if (a == 0)
    g();
}
```


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93006
[Bug 93006] Better code with a-- == 0 rather than --a == -1