\sqrt{\frac{e^{2 \cdot x} - 1}{e^{x} - 1}}\begin{array}{l}
\mathbf{if}\;x \le -9.627556263318037368709352563644898737039 \cdot 10^{-6}:\\
\;\;\;\;\sqrt{\frac{\mathsf{fma}\left({\left(e^{2}\right)}^{\left(\frac{x}{2}\right)}, {\left(e^{2}\right)}^{\left(\frac{x}{2}\right)}, -1\right)}{e^{x} - 1}}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{\sqrt[3]{{\left(\mathsf{fma}\left(x, \mathsf{fma}\left(x, 0.5, 1\right), 2\right)\right)}^{3}}}\\
\end{array}double f(double x) {
double r24161 = 2.0;
double r24162 = x;
double r24163 = r24161 * r24162;
double r24164 = exp(r24163);
double r24165 = 1.0;
double r24166 = r24164 - r24165;
double r24167 = exp(r24162);
double r24168 = r24167 - r24165;
double r24169 = r24166 / r24168;
double r24170 = sqrt(r24169);
return r24170;
}
double f(double x) {
double r24171 = x;
double r24172 = -9.627556263318037e-06;
bool r24173 = r24171 <= r24172;
double r24174 = 2.0;
double r24175 = exp(r24174);
double r24176 = 2.0;
double r24177 = r24171 / r24176;
double r24178 = pow(r24175, r24177);
double r24179 = 1.0;
double r24180 = -r24179;
double r24181 = fma(r24178, r24178, r24180);
double r24182 = exp(r24171);
double r24183 = r24182 - r24179;
double r24184 = r24181 / r24183;
double r24185 = sqrt(r24184);
double r24186 = 0.5;
double r24187 = fma(r24171, r24186, r24179);
double r24188 = fma(r24171, r24187, r24174);
double r24189 = 3.0;
double r24190 = pow(r24188, r24189);
double r24191 = cbrt(r24190);
double r24192 = sqrt(r24191);
double r24193 = r24173 ? r24185 : r24192;
return r24193;
}



Bits error versus x
if x < -9.627556263318037e-06Initial program 0.1
Simplified0.1
rmApplied sqr-pow0.1
Applied fma-neg0.0
if -9.627556263318037e-06 < x Initial program 34.4
Simplified34.5
Taylor expanded around 0 6.2
Simplified6.2
rmApplied add-cbrt-cube6.3
Simplified6.3
Final simplification0.8
herbie shell --seed 2019196 +o rules:numerics
(FPCore (x)
:name "sqrtexp (problem 3.4.4)"
(sqrt (/ (- (exp (* 2.0 x)) 1.0) (- (exp x) 1.0))))