https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110906
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Well "math-errno" has no effect if -fno-math-errno is supplied on the command
line either, well can produce incorrect code too.
Take:
```
__attribute__((optimize("math-errno")))
void g(double x) {
__builtin_sqrt(x);
}
```
With `-O2`, a call happens but with `-O2 -fno-math-errno` does not happen. That
was true even in GCC 5.
