[Bug tree-optimization/102958] std::u8string suboptimal compared to std::string

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102958

--- Comment #7 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
Created attachment 57016
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57016&action=edit
preprocessed testcase with GCC13

Compile with -O2 -std=c++20