https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70055
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- If some arch in glibc implements memcpy.S and does not implement mempcpy.S, then obviously the right fix is to add mempcpy.S for that arch, usually it is just a matter of #include memcpy.S with some define USE_AS_MEMPCPY, and change a couple of instructions in the assembly. You don't need to remember the original value of dest, usually you have the address to which you store bytes in some register, so it is just a matter of copying it to the return register.
