[Bug tree-optimization/112659] missed-optimization: if (exp) return exp; else return 0;

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112659

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is the pattern I added for the plus case:
```
(for cnd (cond vec_cond)
...
 /* (a != CST1) ? (a + CST2) : 0 -> (a + CST2) iff CST1 == -CST2 */
 (simplify
  (cnd (ne @0 uniform_integer_cst_p@1)
       (plus@3 @0 uniform_integer_cst_p@2)
       integer_zerop)
  (if (wi::to_wide (uniform_integer_cst_p (@1))
       == -wi::to_wide (uniform_integer_cst_p (@2)))
   @3))
)
```

The division one is harder, I think I might only handle unsigned. Or maybe
decide that division is not a good idea to do ...