__attribute__((noipa,noinline))
int t(double a, double b)
{
	double c = a - b;
	if (!__builtin_isfinite(c)) {
		if (__builtin_isnan(c)) {
			if (!__builtin_isnan(a) && !__builtin_isnan(b))
				return 1;
		} else if (__builtin_isfinite(a) && __builtin_isfinite(b))
			return 2;
	} else if (c == 0 && a != b)
		return 3;
	return 4;
}

int main()
{
	double a = __builtin_inf();
	if (t(a, a) != 1)
		__builtin_abort();
}