[Bug libstdc++/50880] __complex_acosh() picks wrong complex branch

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50880

--- Comment #16 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-11-02 12:44:06 UTC ---
Well, I guess this would be most of it:

  template<typename _Tp>
    std::complex<_Tp>
    __complex_acosh(const std::complex<_Tp>& __z)
    {
      return _Tp(2.0) * std::log(std::sqrt(_Tp(0.5) * (__z + _Tp(1.0)))
                 + std::sqrt(_Tp(0.5) * (__z - _Tp(1.0))));
    }