[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 #19 from fdlbxtqi <euloanty at live dot com> ---
Created attachment 47559
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47559&action=edit
An untested patch

From 1dfd714e1f29e229d69a0c7f6f84bf05dd4ee85d Mon Sep 17 00:00:00 2001
From: expnkx <unlvsur@live.com>
Date: Sun, 29 Dec 2019 09:49:19 -0500
Subject: [PATCH] Untested patch fix volatile bug of std::copyXXX and
 std::uninitialized_copyXXX Support custom contiguous_iterator Fix undefined
 behavior of &*end constexpr std::fill Greatly improve performance of
 std::copyXXX and std::uninitialized_copyXX for different types and apply
 pipeline optimization to reduce branch misprediction