\[\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)}\]

\sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) + \sqrt{g \cdot g - h \cdot h}\right)} + \sqrt[3]{\frac{1}{2 \cdot a} \cdot \left(\left(-g\right) - \sqrt{g \cdot g - h \cdot h}\right)}

double f(double g, double h, double a) {
        double r91377 = 1.0;
        double r91378 = 2.0;
        double r91379 = a;
        double r91380 = r91378 * r91379;
        double r91381 = r91377 / r91380;
        double r91382 = g;
        double r91383 = -r91382;
        double r91384 = r91382 * r91382;
        double r91385 = h;
        double r91386 = r91385 * r91385;
        double r91387 = r91384 - r91386;
        double r91388 = sqrt(r91387);
        double r91389 = r91383 + r91388;
        double r91390 = r91381 * r91389;
        double r91391 = cbrt(r91390);
        double r91392 = r91383 - r91388;
        double r91393 = r91381 * r91392;
        double r91394 = cbrt(r91393);
        double r91395 = r91391 + r91394;
        return r91395;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019323 
(FPCore (g h a)
  :name "2-ancestry mixing, positive discriminant"
  :precision binary64
  (+ (cbrt (* (/ 1 (* 2 a)) (+ (- g) (sqrt (- (* g g) (* h h)))))) (cbrt (* (/ 1 (* 2 a)) (- (- g) (sqrt (- (* g g) (* h h))))))))

Backtrace

get-representation: Unknown representation real		L	C
(unnamed)	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt	65	3
filter	/opt/racket-7.2/collects/racket/private/list.rkt	256	2
infer-splitpoints	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt	34	0
get-final-combination	/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt	369	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28
run	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	39	2
profile-thunk16	/opt/racket-7.2/share/pkgs/profile-lib/main.rkt	9	0
(unnamed)	/opt/racket-7.2/collects/racket/private/more-scheme.rkt	261	28