https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65409
--- Comment #8 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
The difference is that we go through a pseudo with my version, but the code is
optimal at -O1:
call _Z8copy_foo3Foo
movq %rax, a(%rip)
movb %dl, a+8(%rip)
and the change looks safe enough for all the branches.
