\[x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}\]
x - \frac{\log \left(\left(1 - y\right) + y \cdot e^{z}\right)}{t}
double f(double x, double y, double z, double t) {
        double r8902 = x;
        double r8903 = 1.0;
        double r8904 = y;
        double r8905 = r8903 - r8904;
        double r8906 = z;
        double r8907 = exp(r8906);
        double r8908 = r8904 * r8907;
        double r8909 = r8905 + r8908;
        double r8910 = log(r8909);
        double r8911 = t;
        double r8912 = r8910 / r8911;
        double r8913 = r8902 - r8912;
        return r8913;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 +o rules:numerics
(FPCore (x y z t)
  :name "System.Random.MWC.Distributions:truncatedExp from mwc-random-0.13.3.2"

  :herbie-target
  (if (< z -2.8874623088207947e+119) (- (- x (/ (/ (- 0.5) (* y t)) (* z z))) (* (/ (- 0.5) (* y t)) (/ (/ 2.0 z) (* z z)))) (- x (/ (log (+ 1.0 (* z y))) t)))

  (- x (/ (log (+ (- 1.0 y) (* y (exp z)))) t)))

Backtrace

get-representation: Unknown representation #fLC
loop/data/pavpan/nightlies/herbie/interface2/src/points.rkt1224
prepare-points/data/pavpan/nightlies/herbie/interface2/src/points.rkt1460
setup-prog!34/data/pavpan/nightlies/herbie/interface2/src/mainloop.rkt670
run-improve43/data/pavpan/nightlies/herbie/interface2/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