\[\frac{a \cdot c + b \cdot d}{c \cdot c + d \cdot d}\]

\frac{a \cdot c + b \cdot d}{c \cdot c + d \cdot d}

double f(double a, double b, double c, double d) {
        double r12283716 = a;
        double r12283717 = c;
        double r12283718 = r12283716 * r12283717;
        double r12283719 = b;
        double r12283720 = d;
        double r12283721 = r12283719 * r12283720;
        double r12283722 = r12283718 + r12283721;
        double r12283723 = r12283717 * r12283717;
        double r12283724 = r12283720 * r12283720;
        double r12283725 = r12283723 + r12283724;
        double r12283726 = r12283722 / r12283725;
        return r12283726;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019173 
(FPCore (a b c d)
  :name "Complex division, real part"

  :herbie-target
  (if (< (fabs d) (fabs c)) (/ (+ a (* b (/ d c))) (+ c (* d (/ d c)))) (/ (+ b (* a (/ c d))) (+ d (* c (/ c d)))))

  (/ (+ (* a c) (* b d)) (+ (* c c) (* d d))))

Backtrace

hash-ref: no value found for key key: #<enode 276(276)>		L	C
for-loop	/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt	197	2
extractor-extract	/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt	196	0
for-loop	/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt	35	2
(unnamed)	/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt	26	0
simplify!	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	217	0
run-iter!	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	320	0
for-loop	/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt	354	4
run-improve43	/data/pavpan/nightlies/herbie/various-cleanup/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