P0754R2 <version> header

	* include/Makefile.am: Add new header.
	* include/Makefile.in: Regenerate.
	* include/bits/c++config: Change doxygen comment to suggest <version>
	instead of <iosfwd>.
	* include/precompiled/stdc++.h: Include <cwchar> and <cwctype>
	unconditionally.  Add C++17 and C++20 headers.
	* include/std/version: New header.
	* testsuite/17_intro/headers/c++2017/all_attributes.cc: New.
	* testsuite/17_intro/headers/c++2017/all_no_exceptions.cc: New.
	* testsuite/17_intro/headers/c++2017/all_no_rtti.cc: New.
	* testsuite/17_intro/headers/c++2017/all_pedantic_errors.cc: New.
	* testsuite/17_intro/headers/c++2017/operator_names.cc: New.
	* testsuite/17_intro/headers/c++2017/stdc++.cc: New.
	* testsuite/17_intro/headers/c++2017/stdc++_multiple_inclusion.cc:
	New.
	* testsuite/17_intro/headers/c++2020/all_attributes.cc: New.
	* testsuite/17_intro/headers/c++2020/all_no_exceptions.cc: New.
	* testsuite/17_intro/headers/c++2020/all_no_rtti.cc: New.
	* testsuite/17_intro/headers/c++2020/all_pedantic_errors.cc: New.
	* testsuite/17_intro/headers/c++2020/operator_names.cc: New.
	* testsuite/17_intro/headers/c++2020/stdc++.cc: New.
	* testsuite/17_intro/headers/c++2020/stdc++_multiple_inclusion.cc:
	New.
	* testsuite/18_support/headers/version/macros.cc: New.
	* testsuite/18_support/headers/version/macros.cc: New.

From-SVN: r261706

21 files changed, 851 insertions, 5 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 6b2357a..d598558 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,32 @@
 2018-06-18  Jonathan Wakely  <jwakely@redhat.com>
 
+	P0754R2 <version> header
+	* include/Makefile.am: Add new header.
+	* include/Makefile.in: Regenerate.
+	* include/bits/c++config: Change doxygen comment to suggest <version>
+	instead of <iosfwd>.
+	* include/precompiled/stdc++.h: Include <cwchar> and <cwctype>
+	unconditionally.  Add C++17 and C++20 headers.
+	* include/std/version: New header.
+	* testsuite/17_intro/headers/c++2017/all_attributes.cc: New.
+	* testsuite/17_intro/headers/c++2017/all_no_exceptions.cc: New.
+	* testsuite/17_intro/headers/c++2017/all_no_rtti.cc: New.
+	* testsuite/17_intro/headers/c++2017/all_pedantic_errors.cc: New.
+	* testsuite/17_intro/headers/c++2017/operator_names.cc: New.
+	* testsuite/17_intro/headers/c++2017/stdc++.cc: New.
+	* testsuite/17_intro/headers/c++2017/stdc++_multiple_inclusion.cc:
+	New.
+	* testsuite/17_intro/headers/c++2020/all_attributes.cc: New.
+	* testsuite/17_intro/headers/c++2020/all_no_exceptions.cc: New.
+	* testsuite/17_intro/headers/c++2020/all_no_rtti.cc: New.
+	* testsuite/17_intro/headers/c++2020/all_pedantic_errors.cc: New.
+	* testsuite/17_intro/headers/c++2020/operator_names.cc: New.
+	* testsuite/17_intro/headers/c++2020/stdc++.cc: New.
+	* testsuite/17_intro/headers/c++2020/stdc++_multiple_inclusion.cc:
+	New.
+	* testsuite/18_support/headers/version/macros.cc: New.
+	* testsuite/18_support/headers/version/macros.cc: New.
+
 	* acinclude.m4 (GLIBCXX_CHECK_FILESYSTEM_DEPS): Only check when
 	enable_libstdcxx_filesystem_ts = yes. Check for link, readlink and
 	symlink.
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index 77e6dc2..f91907d 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -80,7 +80,8 @@ std_headers = \
 	${std_srcdir}/utility \
 	${std_srcdir}/valarray \
 	${std_srcdir}/variant \
-	${std_srcdir}/vector
+	${std_srcdir}/vector \
+	${std_srcdir}/version
 
 bits_srcdir = ${glibcxx_srcdir}/include/bits
 bits_builddir = ./bits
diff --git a/libstdc++-v3/include/Makefile.in b/libstdc++-v3/include/Makefile.in
index 948a5c1..aa8a0a4 100644
--- a/libstdc++-v3/include/Makefile.in
+++ b/libstdc++-v3/include/Makefile.in
@@ -374,7 +374,8 @@ std_headers = \
 	${std_srcdir}/utility \
 	${std_srcdir}/valarray \
 	${std_srcdir}/variant \
-	${std_srcdir}/vector
+	${std_srcdir}/vector \
+	${std_srcdir}/version
 
 bits_srcdir = ${glibcxx_srcdir}/include/bits
 bits_builddir = ./bits
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index 4a096a1..c0b89f4 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -24,7 +24,7 @@
 
 /** @file bits/c++config.h
  *  This is an internal header file, included by other library headers.
- *  Do not attempt to use it directly. @headername{iosfwd}
+ *  Do not attempt to use it directly. @headername{version}
  */
 
 #ifndef _GLIBCXX_CXX_CONFIG_H
diff --git a/libstdc++-v3/include/precompiled/stdc++.h b/libstdc++-v3/include/precompiled/stdc++.h
index adcd7bf..9b056bb 100644
--- a/libstdc++-v3/include/precompiled/stdc++.h
+++ b/libstdc++-v3/include/precompiled/stdc++.h
@@ -47,6 +47,8 @@
 #include <cstdlib>
 #include <cstring>
 #include <ctime>
+#include <cwchar>
+#include <cwctype>
 
 #if __cplusplus >= 201103L
 #include <ccomplex>
@@ -57,8 +59,6 @@
 #include <cstdint>
 #include <ctgmath>
 #include <cuchar>
-#include <cwchar>
-#include <cwctype>
 #endif
 
 // C++
@@ -123,6 +123,19 @@
 #endif
 
 #if __cplusplus >= 201703L
+#include <any>
 #include <charconv>
+// #include <execution>
 #include <filesystem>
+#include <optional>
+// #include <memory_resource>
+#include <string_view>
+#include <variant>
+#endif
+
+#if __cplusplus > 201703L
+// #include <compare>
+// #include <span>
+// #include <syncstream>
+#include <version>
 #endif
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
new file mode 100644
index 0000000..08036ff
--- /dev/null
+++ b/libstdc++-v3/include/std/version
@@ -0,0 +1,134 @@
+// -*- C++ -*- Libstdc++ version details header.
+
+// Copyright (C) 2018 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file version
+ *  This is a Standard C++ Library file.  You should @c \#include this file
+ *  in your programs, rather than any of the @a *.h implementation files.
+ */
+
+#ifndef _GLIBCXX_VERSION_INCLUDED
+#define _GLIBCXX_VERSION_INCLUDED
+
+#pragma GCC system_header
+
+#include <bits/c++config.h>
+
+// c++03
+#define __cpp_lib_incomplete_container_elements 201505
+
+#if !defined(__STRICT_ANSI__)
+// gnu++03
+# define __cpp_lib_uncaught_exceptions 201411
+#endif
+
+#if __cplusplus >= 201103L
+// c++11
+#define __cpp_lib_allocator_is_always_equal 201411
+#define __cpp_lib_allocator_traits_is_always_equal 201411
+#define __cpp_lib_is_null_pointer 201309
+#define __cpp_lib_result_of_sfinae 201210
+#define __cpp_lib_shared_ptr_arrays 201603
+
+#if !defined(__STRICT_ANSI__)
+// gnu++11
+# define __cpp_lib_enable_shared_from_this 201603
+# define __cpp_lib_is_swappable 201603
+# define __cpp_lib_void_t 201411
+#endif
+
+// For C++11 and later we support ISO/IEC 29124 Mathematical Special Functions
+#define __STDCPP_MATH_SPEC_FUNCS__ 201003L
+
+#if __cplusplus >= 201402L
+// c++14
+#define __cpp_lib_chrono_udls 201304
+#define __cpp_lib_complex_udls 201309
+#define __cpp_lib_exchange_function 201304
+#define __cpp_lib_generic_associative_lookup 201304
+#define __cpp_lib_integer_sequence 201304
+#define __cpp_lib_integral_constant_callable 201304
+#define __cpp_lib_is_final 201402L
+#define __cpp_lib_make_reverse_iterator 201402
+#define __cpp_lib_make_unique 201304
+#define __cpp_lib_quoted_string_io 201304
+#define __cpp_lib_robust_nonmodifying_seq_ops 201304
+#define __cpp_lib_shared_timed_mutex 201402
+#define __cpp_lib_string_udls 201304
+#define __cpp_lib_transformation_trait_aliases 201304
+#define __cpp_lib_transparent_operators 201510
+#define __cpp_lib_tuple_element_t 201402L
+#define __cpp_lib_tuples_by_type 201304
+
+#if __cplusplus >= 201703L
+// c++17
+#define __cpp_lib_addressof_constexpr 201603
+#define __cpp_lib_apply 201603
+#define __cpp_lib_array_constexpr 201603
+#define __cpp_lib_as_const 201510
+#define __cpp_lib_atomic_is_always_lock_free 201603
+#define __cpp_lib_bool_constant 201505
+#define __cpp_lib_boyer_moore_searcher 201603
+#define __cpp_lib_byte 201603
+#define __cpp_lib_chrono 201611
+#define __cpp_lib_clamp 201603
+#define __cpp_lib_constexpr_char_traits 201611
+#define __cpp_lib_enable_shared_from_this 201603
+#define __cpp_lib_filesystem 201703
+#define __cpp_lib_gcd 201606
+#define __cpp_lib_gcd_lcm 201606
+#define __cpp_lib_has_unique_object_representations 201606
+#define __cpp_lib_hypot 201603
+#define __cpp_lib_invoke 201411
+#define __cpp_lib_is_aggregate 201703
+#define __cpp_lib_is_invocable 201703
+#define __cpp_lib_is_swappable 201603
+#define __cpp_lib_launder 201606
+#define __cpp_lib_lcm 201606
+#define __cpp_lib_logical_traits 201510
+#define __cpp_lib_make_from_tuple 201606
+#define __cpp_lib_map_insertion 201411
+#define __cpp_lib_map_try_emplace 201411
+#define __cpp_lib_math_special_functions 201603L
+#define __cpp_lib_node_extract 201606
+#define __cpp_lib_nonmember_container_access 201411
+#define __cpp_lib_not_fn 201603
+#define __cpp_lib_optional 201603
+#define __cpp_lib_sample 201603
+#define __cpp_lib_scoped_lock 201703
+#define __cpp_lib_shared_mutex 201505
+#define __cpp_lib_shared_ptr_weak_type 201606
+#define __cpp_lib_string_view 201603
+#define __cpp_lib_type_trait_variable_templates 201510L
+#define __cpp_lib_unordered_map_insertion 201411
+#define __cpp_lib_unordered_map_try_emplace 201411
+#define __cpp_lib_void_t 201411
+
+#if __cplusplus > 201703L
+// c++2a
+#endif // C++2a
+#endif // C++17
+#endif // C++14
+#endif // C++11
+
+#endif // _GLIBCXX_VERSION_INCLUDED
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_attributes.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_attributes.cc
new file mode 100644
index 0000000..0a92ae6
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_attributes.cc
@@ -0,0 +1,41 @@
+// Copyright (C) 2015-2018 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-options "-std=gnu++17" }
+// { dg-do compile }
+
+// Ensure the library only uses the __name__ form for attributes.
+// Don't test 'const' and 'noreturn' because they are reserved anyway.
+#define abi_tag 1
+#define always_inline 1
+#ifndef __APPLE__
+// darwin headers use this, see PR 64883
+# define visibility 1
+#endif
+#define packed 1
+#define pure 1
+// glibc's sysdeps/unix/sysv/linux/arm/sys/ucontext.h uses this on ARM.
+#ifndef __arm__
+#define unused 1
+#endif
+
+#include <bits/extc++.h>
+
+int
+main()
+{
+}
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_no_exceptions.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_no_exceptions.cc
new file mode 100644
index 0000000..5b12b00
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_no_exceptions.cc
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++17 -fno-exceptions" }
+
+// Copyright (C) 2015-2018 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/>.
+
+#include <bits/extc++.h>
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_no_rtti.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_no_rtti.cc
new file mode 100644
index 0000000..3717ccf
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_no_rtti.cc
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++17 -fno-rtti" }
+
+// Copyright (C) 2015-2018 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/>.
+
+#include <bits/extc++.h>
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_pedantic_errors.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_pedantic_errors.cc
new file mode 100644
index 0000000..bf391d3
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/all_pedantic_errors.cc
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++17 -pedantic-errors" }
+
+// Copyright (C) 2015-2018 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/>.
+
+#include <bits/extc++.h>
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/operator_names.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/operator_names.cc
new file mode 100644
index 0000000..c0b94de
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/operator_names.cc
@@ -0,0 +1,30 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++17 -fno-operator-names" }
+
+// Copyright (C) 2015-2018 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/>.
+
+// libstdc++/47662
+
+// Avoid using PCH
+#include <cerrno>
+#include <bits/stdc++.h>
+#include <bits/stdtr1c++.h>
+#include <bits/extc++.h>
+
+int or, xor, and;
+
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/stdc++.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/stdc++.cc
new file mode 100644
index 0000000..bafc7d4
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/stdc++.cc
@@ -0,0 +1,70 @@
+// FreeBSD wants warning clean system headers:
+// { dg-options "-std=gnu++17" }
+// { dg-additional-options "-Wall -Wsystem-headers" { target *-*-freebsd* *-*-dragonfly* } }
+// { dg-do compile }
+
+// Copyright (C) 2015-2018 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/>.
+
+// 17.4.1.2 Headers
+
+#include <bits/stdc++.h>
+
+// "C" compatibility headers
+#include <assert.h>
+#ifdef _GLIBCXX_HAVE_COMPLEX_H
+#include <complex.h>
+#endif
+#include <ctype.h>
+#include <errno.h>
+#ifdef _GLIBCXX_HAVE_FENV_H
+#include <fenv.h>
+#endif
+#include <float.h>
+#ifdef _GLIBCXX_HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <iso646.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdarg.h>
+#ifdef _GLIBCXX_HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+#include <stddef.h>
+#ifdef _GLIBCXX_HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _GLIBCXX_HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+#include <time.h>
+#if __has_include(<uchar.h>)
+#include <uchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCTYPE_H
+#include <wctype.h>
+#endif
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2017/stdc++_multiple_inclusion.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2017/stdc++_multiple_inclusion.cc
new file mode 100644
index 0000000..5684558
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2017/stdc++_multiple_inclusion.cc
@@ -0,0 +1,117 @@
+// FreeBSD wants warning clean system headers:
+// { dg-options "-std=gnu++17" }
+// { dg-additional-options "-Wall -Wsystem-headers" { target *-*-freebsd* *-*-dragonfly* } }
+// { dg-do compile }
+
+// Copyright (C) 2015-2018 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/>.
+
+// 17.4.1.2 Headers
+
+#include <bits/stdc++.h>
+
+// "C" compatibility headers
+#include <assert.h>
+#ifdef _GLIBCXX_HAVE_COMPLEX_H
+#include <complex.h>
+#endif
+#include <ctype.h>
+#include <errno.h>
+#ifdef _GLIBCXX_HAVE_FENV_H
+#include <fenv.h>
+#endif
+#include <float.h>
+#ifdef _GLIBCXX_HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <iso646.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdarg.h>
+#ifdef _GLIBCXX_HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+#include <stddef.h>
+#ifdef _GLIBCXX_HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _GLIBCXX_HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+#include <time.h>
+#if __has_include(<uchar.h>)
+#include <uchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCTYPE_H
+#include <wctype.h>
+#endif
+
+#include <bits/stdc++.h>
+
+// "C" compatibility headers
+#include <assert.h>
+#ifdef _GLIBCXX_HAVE_COMPLEX_H
+#include <complex.h>
+#endif
+#include <ctype.h>
+#include <errno.h>
+#ifdef _GLIBCXX_HAVE_FENV_H
+#include <fenv.h>
+#endif
+#include <float.h>
+#ifdef _GLIBCXX_HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <iso646.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdarg.h>
+#ifdef _GLIBCXX_HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+#include <stddef.h>
+#ifdef _GLIBCXX_HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _GLIBCXX_HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+#include <time.h>
+#if __has_include(<uchar.h>)
+#include <uchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCTYPE_H
+#include <wctype.h>
+#endif
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_attributes.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_attributes.cc
new file mode 100644
index 0000000..766c7b6
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_attributes.cc
@@ -0,0 +1,41 @@
+// Copyright (C) 2015-2018 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-options "-std=gnu++2a" }
+// { dg-do compile }
+
+// Ensure the library only uses the __name__ form for attributes.
+// Don't test 'const' and 'noreturn' because they are reserved anyway.
+#define abi_tag 1
+#define always_inline 1
+#ifndef __APPLE__
+// darwin headers use this, see PR 64883
+# define visibility 1
+#endif
+#define packed 1
+#define pure 1
+// glibc's sysdeps/unix/sysv/linux/arm/sys/ucontext.h uses this on ARM.
+#ifndef __arm__
+#define unused 1
+#endif
+
+#include <bits/extc++.h>
+
+int
+main()
+{
+}
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_no_exceptions.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_no_exceptions.cc
new file mode 100644
index 0000000..2d2b824
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_no_exceptions.cc
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++2a -fno-exceptions" }
+
+// Copyright (C) 2015-2018 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/>.
+
+#include <bits/extc++.h>
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_no_rtti.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_no_rtti.cc
new file mode 100644
index 0000000..be518b0
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_no_rtti.cc
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++2a -fno-rtti" }
+
+// Copyright (C) 2015-2018 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/>.
+
+#include <bits/extc++.h>
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_pedantic_errors.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_pedantic_errors.cc
new file mode 100644
index 0000000..20fe03b
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/all_pedantic_errors.cc
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++2a -pedantic-errors" }
+
+// Copyright (C) 2015-2018 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/>.
+
+#include <bits/extc++.h>
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/operator_names.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/operator_names.cc
new file mode 100644
index 0000000..b6052d4
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/operator_names.cc
@@ -0,0 +1,30 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++2a -fno-operator-names" }
+
+// Copyright (C) 2015-2018 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/>.
+
+// libstdc++/47662
+
+// Avoid using PCH
+#include <cerrno>
+#include <bits/stdc++.h>
+#include <bits/stdtr1c++.h>
+#include <bits/extc++.h>
+
+int or, xor, and;
+
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/stdc++.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/stdc++.cc
new file mode 100644
index 0000000..14e3270
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/stdc++.cc
@@ -0,0 +1,70 @@
+// FreeBSD wants warning clean system headers:
+// { dg-options "-std=gnu++2a" }
+// { dg-additional-options "-Wall -Wsystem-headers" { target *-*-freebsd* *-*-dragonfly* } }
+// { dg-do compile }
+
+// Copyright (C) 2015-2018 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/>.
+
+// 17.4.1.2 Headers
+
+#include <bits/stdc++.h>
+
+// "C" compatibility headers
+#include <assert.h>
+#ifdef _GLIBCXX_HAVE_COMPLEX_H
+#include <complex.h>
+#endif
+#include <ctype.h>
+#include <errno.h>
+#ifdef _GLIBCXX_HAVE_FENV_H
+#include <fenv.h>
+#endif
+#include <float.h>
+#ifdef _GLIBCXX_HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <iso646.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdarg.h>
+#ifdef _GLIBCXX_HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+#include <stddef.h>
+#ifdef _GLIBCXX_HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _GLIBCXX_HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+#include <time.h>
+#if __has_include(<uchar.h>)
+#include <uchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCTYPE_H
+#include <wctype.h>
+#endif
diff --git a/libstdc++-v3/testsuite/17_intro/headers/c++2020/stdc++_multiple_inclusion.cc b/libstdc++-v3/testsuite/17_intro/headers/c++2020/stdc++_multiple_inclusion.cc
new file mode 100644
index 0000000..36105af
--- /dev/null
+++ b/libstdc++-v3/testsuite/17_intro/headers/c++2020/stdc++_multiple_inclusion.cc
@@ -0,0 +1,117 @@
+// FreeBSD wants warning clean system headers:
+// { dg-options "-std=gnu++2a" }
+// { dg-additional-options "-Wall -Wsystem-headers" { target *-*-freebsd* *-*-dragonfly* } }
+// { dg-do compile }
+
+// Copyright (C) 2015-2018 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/>.
+
+// 17.4.1.2 Headers
+
+#include <bits/stdc++.h>
+
+// "C" compatibility headers
+#include <assert.h>
+#ifdef _GLIBCXX_HAVE_COMPLEX_H
+#include <complex.h>
+#endif
+#include <ctype.h>
+#include <errno.h>
+#ifdef _GLIBCXX_HAVE_FENV_H
+#include <fenv.h>
+#endif
+#include <float.h>
+#ifdef _GLIBCXX_HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <iso646.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdarg.h>
+#ifdef _GLIBCXX_HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+#include <stddef.h>
+#ifdef _GLIBCXX_HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _GLIBCXX_HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+#include <time.h>
+#if __has_include(<uchar.h>)
+#include <uchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCTYPE_H
+#include <wctype.h>
+#endif
+
+#include <bits/stdc++.h>
+
+// "C" compatibility headers
+#include <assert.h>
+#ifdef _GLIBCXX_HAVE_COMPLEX_H
+#include <complex.h>
+#endif
+#include <ctype.h>
+#include <errno.h>
+#ifdef _GLIBCXX_HAVE_FENV_H
+#include <fenv.h>
+#endif
+#include <float.h>
+#ifdef _GLIBCXX_HAVE_INTTYPES_H
+#include <inttypes.h>
+#endif
+#include <iso646.h>
+#include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdarg.h>
+#ifdef _GLIBCXX_HAVE_STDBOOL_H
+#include <stdbool.h>
+#endif
+#include <stddef.h>
+#ifdef _GLIBCXX_HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _GLIBCXX_HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+#include <time.h>
+#if __has_include(<uchar.h>)
+#include <uchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCHAR_H
+#include <wchar.h>
+#endif
+#ifdef _GLIBCXX_HAVE_WCTYPE_H
+#include <wctype.h>
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/version/macros.cc b/libstdc++-v3/testsuite/18_support/headers/version/macros.cc
new file mode 100644
index 0000000..70a8beb
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/headers/version/macros.cc
@@ -0,0 +1,28 @@
+// Copyright (C) 2018 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-do compile }
+
+#include <version>
+
+#ifndef _GLIBCXX_RELEASE
+# error "_GLIBCXX_RELEASE is not defined by <version>"
+#endif
+
+#ifndef __GLIBCXX__
+# error "__GLIBCXX__ is not defined by <version>"
+#endif