[Bug tree-optimization/124267] False positive -Wrestrict with std::string::operator+ with -O3

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124267

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
>From r16-3077-g18c32a39168525 to r16-7532-g716ec14c573c7e (includes defaulting
to C++20).