[Bug c++/81476] severe slow-down with range-v3 library compared to clang

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81476

--- Comment #8 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
Yeah, the

  target.insert(target.cbegin(), ranges::begin(concatenated),
ranges::end(concatenated));

appears to cause a bad case of Schlemiel-The-Painter, for each inserted char
the tail of target is memmove'd by 1 byte to the right...