[Bug tree-optimization/105651] [12 Regression] bogus "may overlap" memcpy warning with std::string and operator+ at -O3

[redi at gcc dot gnu.org via Gcc-bugs]

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

--- Comment #29 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I've pushed the workaround from comment 17 to the gcc-12 branch.