[Bug tree-optimization/95929] Failure to optimize tautological comparisons of comparisons to a single one

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95929

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
On the GCC 13+ we get:
  _1 = a_5(D) != 0;
  _8 = a_5(D) == 0; // _1^1
  _2 = b_3(D) != 0;
  _13 = _2 ? _8 : _1;
  _6 = (int) _13;

or rather
_13 = _2 ? _1 ^ 1 : _1

But we don't match that.

We could dosoemthing like:
```
(for cmp
(for cmpN
(simplify
 (cond
  @0 
  (cmpN   @1 @2)
  (cmp@3  @1 @2))
 (if (inverseof(cmp, TREE_TYPE (@1)) == cmpN)
  (bit_xor (convert @0) @3)
 )
)
)
)
```
And that would fix this I think.