https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50856
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a full testcase (f3 is caught via fold_cond_expr_with_comparison):
```
int f(int a, int b)
{
int t = a - b;
if (t > 0) return t;
return b - a;
}
int f1(int a, int b)
{
if (a > b) return a - b;
return b - a;
}
int f2(int a, int b)
{
return (a > b) ? a - b : b - a;
}
int f3(int a, int b)
{
return (a - b) > 0 ? a - b : b - a;
}
```
I should note we currently have the following note in match.pd about not
folding `(a - b) > 0` because of catching f3:
/* Transform comparisons of the form X - Y CMP 0 to X CMP Y.
??? The transformation is valid for the other operators if overflow
is undefined for the type, but performing it here badly interacts
with the transformation in fold_cond_expr_with_comparison which
attempts to synthetize ABS_EXPR. */
