PR libstdc++/88996 Implement P0439R0

2019-03-04  Edward Smith-Rowland  <3dw4rd@verizon.net>

	PR libstdc++/88996 Implement P0439R0
	Make std::memory_order a scoped enumeration.
	* include/bits/atomic_base.h: For C++20 make memory_order a scoped enum,
	add variables for the old enumerators.  Adjust calls.
	* testsuite/29_atomics/headers/atomic/types_std_c++2a.cc: New test.
	* testsuite/29_atomics/headers/atomic/types_std_c++2a_neg.cc: New test.

From-SVN: r269372

libstdc++-v3/ChangeLog

+2019-03-04  Edward Smith-Rowland  <3dw4rd@verizon.net>
+
+	PR libstdc++/88996 Implement P0439R0
+	Make std::memory_order a scoped enumeration.
+	* include/bits/atomic_base.h: For C++20 make memory_order a scoped enum,
+	add variables for the old enumerators.  Adjust calls.
+	* testsuite/29_atomics/headers/atomic/types_std_c++2a.cc: New test.
+	* testsuite/29_atomics/headers/atomic/types_std_c++2a_neg.cc: New test.
+
 2019-03-04  Jonathan Wakely  <jwakely@redhat.com>
 
 	* testsuite/26_numerics/bit/bitops.rot/rotl.cc: Remove bogus dg-do

libstdc++-v3/testsuite/29_atomics/headers/atomic/types_std_c++2a.cc

+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+// Copyright (C) 2019 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 <atomic>
+
+void test01()
+{
+  using std::memory_order;
+  constexpr auto relaxed = memory_order::relaxed;
+  constexpr auto consume = memory_order::consume;
+  constexpr auto acquire = memory_order::acquire;
+  constexpr auto release = memory_order::release;
+  constexpr auto acq_rel = memory_order::acq_rel;
+  constexpr auto seq_cst = memory_order::seq_cst;
+}

libstdc++-v3/testsuite/29_atomics/headers/atomic/types_std_c++2a_neg.cc

+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+// Copyright (C) 2019 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 <atomic>
+
+void test01()
+{
+  // Not global scoped, only namespace std.
+  using memory_order; // { dg-error "expected nested-name-specifier" }
+  constexpr auto relaxed = memory_order::relaxed; // { dg-error "has not been declared" }
+  constexpr auto consume = memory_order::consume; // { dg-error "has not been declared" }
+  constexpr auto acquire = memory_order::acquire; // { dg-error "has not been declared" }
+  constexpr auto release = memory_order::release; // { dg-error "has not been declared" }
+  constexpr auto acq_rel = memory_order::acq_rel; // { dg-error "has not been declared" }
+  constexpr auto seq_cst = memory_order::seq_cst; // { dg-error "has not been declared" }
+}