\[\frac{\pi}{\sin \left(\pi \cdot z\right)} \cdot \left(\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}^{\left(\left(\left(1 - z\right) - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.99999999999980993 + \frac{676.520368121885099}{\left(\left(1 - z\right) - 1\right) + 1}\right) + \frac{-1259.13921672240281}{\left(\left(1 - z\right) - 1\right) + 2}\right) + \frac{771.32342877765313}{\left(\left(1 - z\right) - 1\right) + 3}\right) + \frac{-176.615029162140587}{\left(\left(1 - z\right) - 1\right) + 4}\right) + \frac{12.5073432786869052}{\left(\left(1 - z\right) - 1\right) + 5}\right) + \frac{-0.138571095265720118}{\left(\left(1 - z\right) - 1\right) + 6}\right) + \frac{9.98436957801957158 \cdot 10^{-6}}{\left(\left(1 - z\right) - 1\right) + 7}\right) + \frac{1.50563273514931162 \cdot 10^{-7}}{\left(\left(1 - z\right) - 1\right) + 8}\right)\right)\]

\frac{\pi}{\sin \left(\pi \cdot z\right)} \cdot \left(\left(\left(\sqrt{\pi \cdot 2} \cdot {\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}^{\left(\left(\left(1 - z\right) - 1\right) + 0.5\right)}\right) \cdot e^{-\left(\left(\left(\left(1 - z\right) - 1\right) + 7\right) + 0.5\right)}\right) \cdot \left(\left(\left(\left(\left(\left(\left(\left(0.99999999999980993 + \frac{676.520368121885099}{\left(\left(1 - z\right) - 1\right) + 1}\right) + \frac{-1259.13921672240281}{\left(\left(1 - z\right) - 1\right) + 2}\right) + \frac{771.32342877765313}{\left(\left(1 - z\right) - 1\right) + 3}\right) + \frac{-176.615029162140587}{\left(\left(1 - z\right) - 1\right) + 4}\right) + \frac{12.5073432786869052}{\left(\left(1 - z\right) - 1\right) + 5}\right) + \frac{-0.138571095265720118}{\left(\left(1 - z\right) - 1\right) + 6}\right) + \frac{9.98436957801957158 \cdot 10^{-6}}{\left(\left(1 - z\right) - 1\right) + 7}\right) + \frac{1.50563273514931162 \cdot 10^{-7}}{\left(\left(1 - z\right) - 1\right) + 8}\right)\right)

double f(double z) {
        double r102708 = atan2(1.0, 0.0);
        double r102709 = z;
        double r102710 = r102708 * r102709;
        double r102711 = sin(r102710);
        double r102712 = r102708 / r102711;
        double r102713 = 2.0;
        double r102714 = r102708 * r102713;
        double r102715 = sqrt(r102714);
        double r102716 = 1.0;
        double r102717 = r102716 - r102709;
        double r102718 = r102717 - r102716;
        double r102719 = 7.0;
        double r102720 = r102718 + r102719;
        double r102721 = 0.5;
        double r102722 = r102720 + r102721;
        double r102723 = r102718 + r102721;
        double r102724 = pow(r102722, r102723);
        double r102725 = r102715 * r102724;
        double r102726 = -r102722;
        double r102727 = exp(r102726);
        double r102728 = r102725 * r102727;
        double r102729 = 0.9999999999998099;
        double r102730 = 676.5203681218851;
        double r102731 = r102718 + r102716;
        double r102732 = r102730 / r102731;
        double r102733 = r102729 + r102732;
        double r102734 = -1259.1392167224028;
        double r102735 = r102718 + r102713;
        double r102736 = r102734 / r102735;
        double r102737 = r102733 + r102736;
        double r102738 = 771.3234287776531;
        double r102739 = 3.0;
        double r102740 = r102718 + r102739;
        double r102741 = r102738 / r102740;
        double r102742 = r102737 + r102741;
        double r102743 = -176.6150291621406;
        double r102744 = 4.0;
        double r102745 = r102718 + r102744;
        double r102746 = r102743 / r102745;
        double r102747 = r102742 + r102746;
        double r102748 = 12.507343278686905;
        double r102749 = 5.0;
        double r102750 = r102718 + r102749;
        double r102751 = r102748 / r102750;
        double r102752 = r102747 + r102751;
        double r102753 = -0.13857109526572012;
        double r102754 = 6.0;
        double r102755 = r102718 + r102754;
        double r102756 = r102753 / r102755;
        double r102757 = r102752 + r102756;
        double r102758 = 9.984369578019572e-06;
        double r102759 = r102758 / r102720;
        double r102760 = r102757 + r102759;
        double r102761 = 1.5056327351493116e-07;
        double r102762 = 8.0;
        double r102763 = r102718 + r102762;
        double r102764 = r102761 / r102763;
        double r102765 = r102760 + r102764;
        double r102766 = r102728 * r102765;
        double r102767 = r102712 * r102766;
        return r102767;
}

Reproduce

herbie shell --seed 2019199 
(FPCore (z)
  :name "Jmat.Real.gamma, branch z less than 0.5"
  (* (/ PI (sin (* PI z))) (* (* (* (sqrt (* PI 2.0)) (pow (+ (+ (- (- 1.0 z) 1.0) 7.0) 0.5) (+ (- (- 1.0 z) 1.0) 0.5))) (exp (- (+ (+ (- (- 1.0 z) 1.0) 7.0) 0.5)))) (+ (+ (+ (+ (+ (+ (+ (+ 0.9999999999998099 (/ 676.5203681218851 (+ (- (- 1.0 z) 1.0) 1.0))) (/ -1259.1392167224028 (+ (- (- 1.0 z) 1.0) 2.0))) (/ 771.3234287776531 (+ (- (- 1.0 z) 1.0) 3.0))) (/ -176.6150291621406 (+ (- (- 1.0 z) 1.0) 4.0))) (/ 12.507343278686905 (+ (- (- 1.0 z) 1.0) 5.0))) (/ -0.13857109526572012 (+ (- (- 1.0 z) 1.0) 6.0))) (/ 9.984369578019572e-06 (+ (- (- 1.0 z) 1.0) 7.0))) (/ 1.5056327351493116e-07 (+ (- (- 1.0 z) 1.0) 8.0))))))

Timeout in 10.0m

Reproduce