\[\lambda_1 + \tan^{-1}_* \frac{\left(\sin theta \cdot \sin delta\right) \cdot \cos \phi_1}{\cos delta - \sin \phi_1 \cdot \sin \left(\sin^{-1} \left(\sin \phi_1 \cdot \cos delta + \left(\cos \phi_1 \cdot \sin delta\right) \cdot \cos theta\right)\right)}\]
\lambda_1 + \tan^{-1}_* \frac{\left(\sin theta \cdot \sin delta\right) \cdot \cos \phi_1}{\cos delta - \sin \phi_1 \cdot \sin \left(\sin^{-1} \left(\sin \phi_1 \cdot \cos delta + \left(\cos \phi_1 \cdot \sin delta\right) \cdot \cos theta\right)\right)}
double f(double lambda1, double phi1, double __attribute__((unused)) phi2, double delta, double theta) {
        double r8021 = lambda1;
        double r8022 = theta;
        double r8023 = sin(r8022);
        double r8024 = delta;
        double r8025 = sin(r8024);
        double r8026 = r8023 * r8025;
        double r8027 = phi1;
        double r8028 = cos(r8027);
        double r8029 = r8026 * r8028;
        double r8030 = cos(r8024);
        double r8031 = sin(r8027);
        double r8032 = r8031 * r8030;
        double r8033 = r8028 * r8025;
        double r8034 = cos(r8022);
        double r8035 = r8033 * r8034;
        double r8036 = r8032 + r8035;
        double r8037 = asin(r8036);
        double r8038 = sin(r8037);
        double r8039 = r8031 * r8038;
        double r8040 = r8030 - r8039;
        double r8041 = atan2(r8029, r8040);
        double r8042 = r8021 + r8041;
        return r8042;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019191 
(FPCore (lambda1 phi1 phi2 delta theta)
  :name "Destination given bearing on a great circle"
  (+ lambda1 (atan2 (* (* (sin theta) (sin delta)) (cos phi1)) (- (cos delta) (* (sin phi1) (sin (asin (+ (* (sin phi1) (cos delta)) (* (* (cos phi1) (sin delta)) (cos theta))))))))))

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