Cannot sample enough valid points. (more)

\[\left(\left(\left(\sqrt{x + 1.0} - \sqrt{x}\right) + \left(\sqrt{y + 1.0} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1.0} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1.0} - \sqrt{t}\right)\]
\left(\left(\left(\sqrt{x + 1.0} - \sqrt{x}\right) + \left(\sqrt{y + 1.0} - \sqrt{y}\right)\right) + \left(\sqrt{z + 1.0} - \sqrt{z}\right)\right) + \left(\sqrt{t + 1.0} - \sqrt{t}\right)
double f(double x, double y, double z, double t) {
        double r19090926 = x;
        double r19090927 = 1.0;
        double r19090928 = r19090926 + r19090927;
        double r19090929 = sqrt(r19090928);
        double r19090930 = sqrt(r19090926);
        double r19090931 = r19090929 - r19090930;
        double r19090932 = y;
        double r19090933 = r19090932 + r19090927;
        double r19090934 = sqrt(r19090933);
        double r19090935 = sqrt(r19090932);
        double r19090936 = r19090934 - r19090935;
        double r19090937 = r19090931 + r19090936;
        double r19090938 = z;
        double r19090939 = r19090938 + r19090927;
        double r19090940 = sqrt(r19090939);
        double r19090941 = sqrt(r19090938);
        double r19090942 = r19090940 - r19090941;
        double r19090943 = r19090937 + r19090942;
        double r19090944 = t;
        double r19090945 = r19090944 + r19090927;
        double r19090946 = sqrt(r19090945);
        double r19090947 = sqrt(r19090944);
        double r19090948 = r19090946 - r19090947;
        double r19090949 = r19090943 + r19090948;
        return r19090949;
}