https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114088
--- Comment #3 from Thiago Macieira <thiago at kde dot org> --- > But __builtin_strlen *does* get optimized when the input is a string literal. > Not sure about wcslen though. It appears not to, in the test above. std::char_trait<wchar_t>::length() calls wcslen() whereas the char specialisation uses __builtin_strlen() explicitly. But if the intrinsics are enabled, the two would be the same, wouldn't they? Anyway, in the absence of a library function to call, inserting the loop is fine; it's what is there already. Though it would be nice to be able to provide such a function. I wrote it for Qt (it's called qustrlen). I would try with __builtin_constant_p first to see if the string is a literal.
