Of course I forgot to replace one _M_ instance. This should work now.
Sorry about this.
-- 8< --------------------------------------------------------- >8 --
C++11: [meta.trans.other]
* libstdc++-v3/testsuite/20_util/aligned_union/1.cc: New file.
* libstdc++-v3/include/std/type_traits (__strictest_alignment): New
helper struct.
(aligned_union): New struct (C++11).
(aligned_union_t): New type alias (C++14).
---
libstdc++-v3/include/std/type_traits | 43 ++++++++++++++
libstdc++-v3/testsuite/20_util/aligned_union/1.cc | 72
+++++++++++++++++++++++
2 files changed, 115 insertions(+)
create mode 100644 libstdc++-v3/testsuite/20_util/aligned_union/1.cc
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-
v3/include/std/type_traits
index 4b434a6..7fb3b74 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1837,6 +1837,46 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
};
};
+ template <typename... _Types>
+ struct __strictest_alignment
+ {
+ static const size_t _S_alignment = 0;
+ static const size_t _S_size = 0;
+ };
+
+ template <typename _T, typename... _Types>
+ struct __strictest_alignment<_T, _Types...>
+ {
+ static const size_t _S_alignment =
+ alignof(_T) > __strictest_alignment<_Types...>::_S_alignment ?
+ alignof(_T) : __strictest_alignment<_Types...>::_S_alignment;
+ static const size_t _S_size =
+ sizeof(_T) > __strictest_alignment<_Types...>::_S_size ?
+ sizeof(_T) : __strictest_alignment<_Types...>::_S_size;
+ };
+
+ /**
+ * @brief Provide aligned storage for types.
+ *
+ * [meta.trans.other]
+ *
+ * Provides aligned storage for any of the provided types of at
+ * least size _Len.
+ *
+ * @see aligned_storage
+ */
+ template <size_t _Len, typename... _Types>
+ struct aligned_union
+ {
+ /// The value of the strictest alignment of _Types.
+ static const size_t alignment_value =
+ __strictest_alignment<_Types...>::_S_alignment;
+ static const size_t _S_len =
+ _Len > __strictest_alignment<_Types...>::_S_size ?
+ _Len : __strictest_alignment<_Types...>::_S_size;
+ /// The storage.
+ typedef typename aligned_storage<_S_len, alignment_value>::type type;
+ };
// Decay trait for arrays and functions, used for perfect forwarding
// in make_pair, make_tuple, etc.
@@ -2173,6 +2213,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__alignof__(typename __aligned_storage_msa<_Len>::__type)>
using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
+ template <size_t _Len, typename... _Types>
+ using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
+
/// Alias template for decay
template<typename _Tp>
using decay_t = typename decay<_Tp>::type;
diff --git a/libstdc++-v3/testsuite/20_util/aligned_union/1.cc b/libstdc++-
v3/testsuite/20_util/aligned_union/1.cc
new file mode 100644
index 0000000..5285bb0
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/aligned_union/1.cc
@@ -0,0 +1,72 @@
+// { dg-options " -std=gnu++11 " }
+// { dg-do compile }
+
+// 2014-04-16 Rüdiger Sonderfeld <ruedi...@c-plusplus.de>
+
+// Copyright (C) 2014 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/>.
+
+// C++11 [meta.trans.other] 20.9.7.6: aligned_union
+
+#include <type_traits>
+#include <testsuite_tr1.h>
+
+struct MSAlignType { } __attribute__((__aligned__));
+
+template<typename...T>
+ struct mymax
+ {
+ static const std::size_t alignment = 0;
+ static const std::size_t size = 0;
+ };
+
+template<typename L, typename...T>
+ struct mymax<L, T...>
+ {
+ static const std::size_t alignment = alignof(L) > mymax<T...>::alignment
+ ? alignof(L) : mymax<T...>::alignment;
+ static const std::size_t size = sizeof(L) > mymax<T...>::size
+ ? sizeof(L) : mymax<T...>::size;
+ };
+
+void test01()
+{
+ using std::aligned_union;
+ using std::alignment_of;
+ using std::size_t;
+ using namespace __gnu_test;
+
+ const size_t max_a = mymax<char, short, int, double, int[4],
+ ClassType, MSAlignType>::alignment;
+ const size_t max_s = mymax<char, short, int, double, int[4],
+ ClassType, MSAlignType>::size;
+
+ typedef aligned_union<0, char, short, int, double, int[4],
+ ClassType, MSAlignType> au_type;
+ static_assert(au_type::alignment_value == max_a, "Alignment value");
+ static_assert(sizeof(au_type::type) >= max_s, "Storage size");
+
+ typedef aligned_union<max_s+100, char, short, int, double, int[4],
+ ClassType, MSAlignType> au_type2;
+ static_assert(sizeof(au_type2::type) >= max_s+100,
+ "Storage size (at least len)");
+}
+
+int main()
+{
+ test01();
+}
--
1.9.2
