https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105428
--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- If you can identify specific arguments passed to mpc_asin for which it is excessively slow, that should be reported as an MPC bug. Computing correctly rounded mpc_asin shouldn't need to be that slow - provided the algorithm used is appropriate to the input value. See for example how glibc implements casin / casinh / cacos / cacosh. Or https://dl.acm.org/doi/10.1145/275323.275324 (Hull et al, Implementing the complex arcsine and arccosine functions using exception handling, ACM TOMS vol. 23 no. 3 (Sep 1997) pp 299-335). That may require several different algorithms to be implemented, but each such algorithm is straightforward. That's different from the case of Bessel functions of high order - for which there is some literature about computational techniques that shouldn't take time proportional to the order, but where the algorithms are certainly a lot more complicated.
