[Bug tree-optimization/105651] bogus "may overlap" memcpy warning with std::string

[mckelvey at maskull dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105651

--- Comment #4 from James McKelvey <mckelvey at maskull dot com> ---
Still fails with gcc-12-20220521 and gcc-13-20220522, but not gcc-11-20220520.