[Bug middle-end/86471] GCC/libstdc++ outputs inferior code for std::fill and std::fill_n vs std::memset on c-style arrays

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86471

--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
__is_pointer_helper and __is_integral_helper are not available in C++98 and are
not supposed to be used directly anyway, they're just implementation details
for is_pointer and is_integral.