[Bug c/108296] __builtin_memcpy generating wrong code in some cases

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108296

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think all of the above snippets have UB, whether using memcpy,
__builtin_memcpy or
overlapping structure assignment.  It is all user error.
If you need overlapping copies, always use memmove/__builtin_memmove.