https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94236
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- A patch for -mlong-calls was posted a long time ago but never made it in: https://gcc.gnu.org/legacy-ml/gcc-patches/2014-10/msg02933.html You should not need -mlong-calls really because the linker should insert stubs to do the long calls in the end. Why do you think you need full 64bit addressing for calls rather than the stubs?
