Exception for fabs fraction 1

Math

\[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|\]

C

double f(double x, double y, double z) {
        double r8086 = x;
        double r8087 = 4.0;
        double r8088 = r8086 + r8087;
        double r8089 = y;
        double r8090 = r8088 / r8089;
        double r8091 = r8086 / r8089;
        double r8092 = z;
        double r8093 = r8091 * r8092;
        double r8094 = r8090 - r8093;
        double r8095 = fabs(r8094);
        return r8095;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x y z)
  :name "fabs fraction 1"
  (fabs (- (/ (+ x 4.0) y) (* (/ x y) z))))

Backtrace

get-representation: Unknown representation #f		L	C
loop	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	122	4
prepare-points	/data/pavpan/nightlies/herbie/interface2/src/points.rkt	146	0
setup-prog!34	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	67	0
run-improve43	/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt	339	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.0/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.0/collects/racket/private/more-scheme.rkt	261	28