Define std::owner_less<void> specialization (P0074R0)

	* include/bits/shared_ptr.h (owner_less): Add default template
	argument.
	* include/bits/shared_ptr_base.h (_Sp_owner_less<void, void>): Define
	specialization.
	(owner_less<void>): Define specialization.
	* include/bits/stl_function.h (__cpp_lib_transparent_operators):
	Update value.
	* testsuite/20_util/owner_less/void.cc: New test.
	* testsuite/experimental/feat-cxx14.cc: Update macro value tested.

From-SVN: r239089

libstdc++-v3/ChangeLog

 2016-08-03  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/shared_ptr.h (owner_less): Add default template
+	argument.
+	* include/bits/shared_ptr_base.h (_Sp_owner_less<void, void>): Define
+	specialization.
+	(owner_less<void>): Define specialization.
+	* include/bits/stl_function.h (__cpp_lib_transparent_operators):
+	Update value.
+	* testsuite/20_util/owner_less/void.cc: New test.
+	* testsuite/experimental/feat-cxx14.cc: Update macro value tested.
+
 	* include/bits/allocator.h (__cpp_lib_incomplete_container_elements):
 	Define feature-test macro.
 	* include/bits/range_access.h (__cpp_lib_array_constexpr): Likewise.

libstdc++-v3/include/bits/shared_ptr.h

@@ -535,9 +535,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 
   /// Primary template owner_less
-  template<typename _Tp>
+  template<typename _Tp = void>
     struct owner_less;
 
+  /// Void specialization of owner_less
+  template<>
+    struct owner_less<void> : _Sp_owner_less<void, void>
+    { };
+
   /// Partial specialization of owner_less for shared_ptr.
   template<typename _Tp>
     struct owner_less<shared_ptr<_Tp>>

libstdc++-v3/include/bits/shared_ptr_base.h

@@ -1506,6 +1506,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { return __lhs.owner_before(__rhs); }
     };
 
+  template<>
+    struct _Sp_owner_less<void, void>
+    {
+      template<typename _Tp, typename _Up>
+	auto
+	operator()(const _Tp& __lhs, const _Up& __rhs) const
+	-> decltype(__lhs.owner_before(__rhs))
+	{ return __lhs.owner_before(__rhs); }
+
+      using is_transparent = void;
+    };
+
   template<typename _Tp, _Lock_policy _Lp>
     struct owner_less<__shared_ptr<_Tp, _Lp>>
     : public _Sp_owner_less<__shared_ptr<_Tp, _Lp>, __weak_ptr<_Tp, _Lp>>

libstdc++-v3/include/bits/stl_function.h

@@ -224,7 +224,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #if __cplusplus > 201103L
 
-#define __cpp_lib_transparent_operators 201210
+#define __cpp_lib_transparent_operators 201510
 
   template<>
     struct plus<void>

libstdc++-v3/testsuite/20_util/owner_less/void.cc

+// Copyright (C) 2016 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 { target c++11 } }
+
+#include <memory>
+
+#if __cplusplus >= 201402L
+// The feature-test macro is only defined for C++14 and later.
+# if __cpp_lib_transparent_operators < 201510
+#  error "__cpp_lib_transparent_operators < 201510"
+# endif
+#endif
+
+void
+test01()
+{
+  using namespace std;
+
+  static_assert(is_same<owner_less<>, owner_less<void>>::value,
+                "owner_less<> uses void specialization");
+
+  shared_ptr<int> sp1;
+  shared_ptr<void> sp2;
+  shared_ptr<long> sp3;
+  weak_ptr<int> wp1;
+
+  owner_less<> cmp;
+  cmp(sp1, sp2);
+  cmp(sp1, wp1);
+  cmp(sp1, sp3);
+  cmp(wp1, sp1);
+  cmp(wp1, wp1);
+}

libstdc++-v3/testsuite/experimental/feat-cxx14.cc

@@ -40,8 +40,8 @@
 
 #ifndef  __cpp_lib_transparent_operators
 #  error "__cpp_lib_transparent_operators"
-#elif  __cpp_lib_transparent_operators != 201210
-#  error "__cpp_lib_transparent_operators != 201210"
+#elif  __cpp_lib_transparent_operators < 201210
+#  error "__cpp_lib_transparent_operators < 201210"
 #endif
 
 #ifndef  __cpp_lib_result_of_sfinae