/// RTLIB::Libcall enum - This enum defines all of the runtime library calls
/// the backend can emit. The various long double types cannot be merged,
/// because 80-bit library functions use "xf" and 128-bit use "tf".
/// RTLIB::Libcall enum - This enum defines all of the runtime library calls
/// the backend can emit. The various long double types cannot be merged,
/// because 80-bit library functions use "xf" and 128-bit use "tf".