@@ -961,6 +961,13 @@ requirements of the license of GCC.
is included by <code><array></code>.
</para></listitem></varlistentry>
+ <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2296">2296</link>:
+ <emphasis><code>std::addressof</code> should be constexpr</emphasis>
+ </term>
+ <listitem><para>Use <code>__builtin_addressof</code> and add
+ <code>constexpr</code> to <code>addressof</code> for C++17 and later.
+ </para></listitem></varlistentry>
+
<varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2313">2313</link>:
<emphasis><code>tuple_size</code> should always derive from <code>integral_constant<size_t, N></code></emphasis>
</term>
@@ -253,14 +253,13 @@ Feature-testing recommendations for C++</link>.
</row>
<row>
- <?dbhtml bgcolor="#C8B0B0" ?>
<entry> <code>std::addressof</code> should be constexpr </entry>
<entry>
<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0304r0.html#2296">
LWG2296
</link>
</entry>
- <entry align="center"> No </entry>
+ <entry align="center"> 7 </entry>
<entry><code> __cpp_lib_addressof_constexpr >= 201603 </code></entry>
</row>
@@ -43,12 +43,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @ingroup utilities
*/
template<typename _Tp>
- inline _Tp*
+ inline _GLIBCXX_CONSTEXPR _Tp*
__addressof(_Tp& __r) _GLIBCXX_NOEXCEPT
- {
- return reinterpret_cast<_Tp*>
- (&const_cast<char&>(reinterpret_cast<const volatile char&>(__r)));
- }
+ { return __builtin_addressof(__r); }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
@@ -123,6 +120,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// declval, from type_traits.
+#if __cplusplus > 201402L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 2296. std::addressof should be constexpr
+# define __cpp_lib_addressof_constexpr 201603
+#endif
/**
* @brief Returns the actual address of the object or function
* referenced by r, even in the presence of an overloaded
@@ -131,7 +133,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @return The actual address.
*/
template<typename _Tp>
- inline _Tp*
+ inline _GLIBCXX17_CONSTEXPR _Tp*
addressof(_Tp& __r) noexcept
{ return std::__addressof(__r); }
new file mode 100644
@@ -0,0 +1,55 @@
+// 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-options "-std=gnu++1z" }
+// { dg-do compile { target c++1z } }
+
+#include <utility>
+
+// LWG 2296 std::addressof should be constexpr
+
+#ifndef __cpp_lib_addressof_constexpr
+# error "Feature-test macro for constexpr addressof missing"
+#elif __cpp_lib_addressof_constexpr != 201603
+# error "Feature-test macro for constexpr addressof has wrong value"
+#endif
+
+int i;
+constexpr int* pi = std::addressof(i);
+static_assert( pi == &i, "&i" );
+
+struct X {
+ void operator&();
+ constexpr X* addr() { return this; }
+ constexpr const X* addr() const { return this; }
+};
+X x;
+constexpr X* px = std::addressof(x);
+static_assert( px == x.addr(), "x.addr()" );
+const X cx;
+constexpr const X* pcx = std::addressof(cx);
+static_assert( pcx == cx.addr(), "cx.addr()" );
+
+void
+test01()
+{
+ static int i2;
+ static_assert( std::addressof(i2) == &i2, "&i2" );
+
+ static X x2;
+ static_assert( std::addressof(x2) == x2.addr(), "x2.addr()" );
+}
@@ -17,7 +17,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
-// { dg-error "static assertion failed" "" { target *-*-* } 89 }
+// { dg-error "static assertion failed" "" { target *-*-* } 86 }
#include <list>
@@ -17,7 +17,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
-// { dg-error "static assertion failed" "" { target *-*-* } 89 }
+// { dg-error "static assertion failed" "" { target *-*-* } 86 }
#include <utility>
Thank to the new __builtin_addressof that Jakub added we can do this now. * doc/xml/manual/intro.xml: Document DR 2296 status. * doc/xml/manual/status_cxx2017.xml: Update status. * include/bits/move.h (__addressof): Add _GLIBCXX_CONSTEXPR and call __builtin_addressof. (addressof): Add _GLIBCXX17_CONSTEXPR. * testsuite/20_util/addressof/requirements/constexpr.cc: New test. * testsuite/20_util/forward/c_neg.cc: Adjust dg-error lineno. * testsuite/20_util/forward/f_neg.cc: Likewise. Tested powerpc64le-linux, committed to trunk. commit d450a86bff30b38464e440f6157c39b399b54cc1 Author: Jonathan Wakely <jwakely@redhat.com> Date: Thu Oct 6 18:53:28 2016 +0100 Implement constexpr std::addressof for C++17 * doc/xml/manual/intro.xml: Document DR 2296 status. * doc/xml/manual/status_cxx2017.xml: Update status. * include/bits/move.h (__addressof): Add _GLIBCXX_CONSTEXPR and call __builtin_addressof. (addressof): Add _GLIBCXX17_CONSTEXPR. * testsuite/20_util/addressof/requirements/constexpr.cc: New test. * testsuite/20_util/forward/c_neg.cc: Adjust dg-error lineno. * testsuite/20_util/forward/f_neg.cc: Likewise.