\frac{x}{1 + \sqrt{x + 1}}\begin{array}{l}
\mathbf{if}\;\frac{x}{1 + \sqrt{x + 1}} \le 1012629.646108792512677609920501708984375:\\
\;\;\;\;\frac{x}{{1}^{3} + {\left(\sqrt{x + 1}\right)}^{3}} \cdot \left(1 \cdot 1 + \left(\sqrt{x + 1} \cdot \sqrt{x + 1} - 1 \cdot \sqrt{x + 1}\right)\right)\\
\mathbf{else}:\\
\;\;\;\;\sqrt{x} \cdot \frac{\sqrt{x}}{1 + \sqrt{x + 1}}\\
\end{array}double f(double x) {
double r112645 = x;
double r112646 = 1.0;
double r112647 = r112645 + r112646;
double r112648 = sqrt(r112647);
double r112649 = r112646 + r112648;
double r112650 = r112645 / r112649;
return r112650;
}
double f(double x) {
double r112651 = x;
double r112652 = 1.0;
double r112653 = r112651 + r112652;
double r112654 = sqrt(r112653);
double r112655 = r112652 + r112654;
double r112656 = r112651 / r112655;
double r112657 = 1012629.6461087925;
bool r112658 = r112656 <= r112657;
double r112659 = 3.0;
double r112660 = pow(r112652, r112659);
double r112661 = pow(r112654, r112659);
double r112662 = r112660 + r112661;
double r112663 = r112651 / r112662;
double r112664 = r112652 * r112652;
double r112665 = r112654 * r112654;
double r112666 = r112652 * r112654;
double r112667 = r112665 - r112666;
double r112668 = r112664 + r112667;
double r112669 = r112663 * r112668;
double r112670 = sqrt(r112651);
double r112671 = r112670 / r112655;
double r112672 = r112670 * r112671;
double r112673 = r112658 ? r112669 : r112672;
return r112673;
}



Bits error versus x
Results
if (/ x (+ 1.0 (sqrt (+ x 1.0)))) < 1012629.6461087925Initial program 0.0
rmApplied flip3-+0.0
Applied associate-/r/0.0
if 1012629.6461087925 < (/ x (+ 1.0 (sqrt (+ x 1.0)))) Initial program 0.5
rmApplied *-un-lft-identity0.5
Applied add-sqr-sqrt0.1
Applied times-frac0.0
Simplified0.0
Final simplification0.0
herbie shell --seed 2019209
(FPCore (x)
:name "Numeric.Log:$clog1p from log-domain-0.10.2.1, B"
:precision binary64
(/ x (+ 1 (sqrt (+ x 1)))))