https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105428
--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- What MPC version are you using? There have been a few fixes for slowness in the MPC inverse trigonometric and hyperbolic functions over the years, though there may still be scope for substantial further improvements by choosing different algorithms for different ranges of inputs. If you're using current MPC then this case should probably be reported to the MPC maintainers.