[gcc r11-1722] Revert "Add a __nonnnull__ attribute to std::string's _CharT* constructor"

[Ville Voutilainen <ville@gcc.gnu.org>]

https://gcc.gnu.org/g:2635f9e5086318f4560997d9741fdda496b9c801

commit r11-1722-g2635f9e5086318f4560997d9741fdda496b9c801
Author: Ville Voutilainen <ville.voutilainen@gmail.com>
Date:   Tue Jun 30 01:59:34 2020 +0300

    Revert "Add a __nonnnull__ attribute to std::string's _CharT* constructor"
    
    This reverts commit b26fd416fb0a734d3f3e56629b6dff2e3c25dd40.

Diff:
---
 libstdc++-v3/include/bits/basic_string.h           |  1 -
 .../21_strings/basic_string/cons/char/nonnull.cc   | 29 ----------------------
 .../basic_string/cons/wchar_t/nonnull.cc           | 29 ----------------------
 3 files changed, 59 deletions(-)

diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index d5e5eb06e1b..bc0c256b65e 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -522,7 +522,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       // 3076. basic_string CTAD ambiguity
       template<typename = _RequireAllocator<_Alloc>>
 #endif
-      __attribute__((__nonnull__))
       basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
       : _M_dataplus(_M_local_data(), __a)
       { _M_construct(__s, __s ? __s + traits_type::length(__s) : __s+npos); }
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/nonnull.cc
deleted file mode 100644
index 1c09a1d2207..00000000000
--- a/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/nonnull.cc
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright (C) 2020 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-// { dg-additional-options "-Wnonnull" }
-// { dg-do compile { target c++11 } }
-
-#include <string>
-
-void
-test01()
-{
-  std::string s((const char*)nullptr); // { dg-warning "null arg" }
-  std::string t((char*)nullptr);       // { dg-warning "null arg" }
-  std::string u(nullptr);	       // { dg-warning "null arg" }
-}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/nonnull.cc
deleted file mode 100644
index 456efed6c8c..00000000000
--- a/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/nonnull.cc
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright (C) 2020 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-// { dg-additional-options "-Wnonnull" }
-// { dg-do compile { target c++11 } }
-
-#include <string>
-
-void
-test01()
-{
-  std::wstring s((const wchar_t*)nullptr); // { dg-warning "null arg" }
-  std::wstring t((wchar_t*)nullptr);	   // { dg-warning "null arg" }
-  std::wstring u(nullptr);		   // { dg-warning "null arg" }
-}