\[\frac{x.re \cdot y.re + x.im \cdot y.im}{y.re \cdot y.re + y.im \cdot y.im}\]
\frac{x.re \cdot y.re + x.im \cdot y.im}{y.re \cdot y.re + y.im \cdot y.im}
double f(double x_re, double x_im, double y_re, double y_im) {
        double r4725989 = x_re;
        double r4725990 = y_re;
        double r4725991 = r4725989 * r4725990;
        double r4725992 = x_im;
        double r4725993 = y_im;
        double r4725994 = r4725992 * r4725993;
        double r4725995 = r4725991 + r4725994;
        double r4725996 = r4725990 * r4725990;
        double r4725997 = r4725993 * r4725993;
        double r4725998 = r4725996 + r4725997;
        double r4725999 = r4725995 / r4725998;
        return r4725999;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019173 +o rules:numerics
(FPCore (x.re x.im y.re y.im)
  :name "_divideComplex, real part"
  (/ (+ (* x.re y.re) (* x.im y.im)) (+ (* y.re y.re) (* y.im y.im))))

Backtrace

hash-ref: no value found for key key: #<enode 137(137)>LC
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt1972
extractor-extract/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt1960
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt352
(unnamed)/data/pavpan/nightlies/herbie/various-cleanup/src/core/simplify.rkt260
simplify!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt2170
run-iter!/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3200
for-loop/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3544
run-improve43/data/pavpan/nightlies/herbie/various-cleanup/src/mainloop.rkt3390
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.0/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.0/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.0/collects/racket/private/more-scheme.rkt26128