[Bug libstdc++/93059] char and char8_t does not talk with each other with memcpy. std::copy std::copy_n, std::fill, std::fill_n, std::uninitialized_copy std::uninitialized_copy_n, std::fill, std::uninitialized_fill_n fails to convert to memxxx functions

[euloanty at live dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93059

--- Comment #18 from fdlbxtqi <euloanty at live dot com> ---
(In reply to Marc Glisse from comment #17)
> (In reply to fdlbxtqi from comment #15)
> > What I am worried about is that whether revamping these functions would be a new wave of ABI breaking.
> 
> I don't foresee any ABI issue here. Do make sure your code doesn't break
> with -std=c++03, and run the testsuite before submitting it.

Also, I have found another bug??? in both libstdc++ and libc++????

memmove is not allowed for using volatile. Only MSVC passes the test.

libstdc++&libc++ are wrong.

https://godbolt.org/z/FoTCbk

I will fix this as well.