Use the --timeout flag to change the timeout.
\frac{-\left(f + n\right)}{f - n}double f(double f, double n) {
double r85435 = f;
double r85436 = n;
double r85437 = r85435 + r85436;
double r85438 = -r85437;
double r85439 = r85435 - r85436;
double r85440 = r85438 / r85439;
return r85440;
}
herbie shell --seed 2019235 +o rules:numerics
(FPCore (f n)
:name "subtraction fraction"
:precision binary64
(/ (- (+ f n)) (- f n)))