From d80f04d61e11a103e2e463a1a90a3d780b0fd99b Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 6 Mar 2019 11:32:42 +0000
Subject: [PATCH] Constexpr in std::pointer_traits (P1006R1)
* include/bits/ptr_traits.h [C++20] (pointer_traits<T*>::pointer_to):
Add constexpr.
* testsuite/20_util/pointer_traits/pointer_to_constexpr.cc: New test.
From-SVN: r269418
---
libstdc++-v3/ChangeLog | 6 +++++
libstdc++-v3/include/bits/ptr_traits.h | 2 +-
.../pointer_traits/pointer_to_constexpr.cc | 27 +++++++++++++++++++
3 files changed, 34 insertions(+), 1 deletion(-)
create mode 100644 libstdc++-v3/testsuite/20_util/pointer_traits/pointer_to_constexpr.cc
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 44bf6e72c650..053da2c25d8c 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2019-03-06 Jonathan Wakely <jwakely@redhat.com>
+
+ * include/bits/ptr_traits.h [C++20] (pointer_traits<T*>::pointer_to):
+ Add constexpr.
+ * testsuite/20_util/pointer_traits/pointer_to_constexpr.cc: New test.
+
2019-03-05 Jonathan Wakely <jwakely@redhat.com>
* include/c_compatibility/math.h [C++20] (lerp): Add using
diff --git a/libstdc++-v3/include/bits/ptr_traits.h b/libstdc++-v3/include/bits/ptr_traits.h
index 763558638527..c90a35080f12 100644
--- a/libstdc++-v3/include/bits/ptr_traits.h
+++ b/libstdc++-v3/include/bits/ptr_traits.h
@@ -137,7 +137,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* @param __r A reference to an object of type @c element_type
* @return @c addressof(__r)
*/
- static pointer
+ static _GLIBCXX20_CONSTEXPR pointer
pointer_to(__make_not_void<element_type>& __r) noexcept
{ return std::addressof(__r); }
};
diff --git a/libstdc++-v3/testsuite/20_util/pointer_traits/pointer_to_constexpr.cc b/libstdc++-v3/testsuite/20_util/pointer_traits/pointer_to_constexpr.cc
new file mode 100644
index 000000000000..ed4f2157adcc
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/pointer_traits/pointer_to_constexpr.cc
@@ -0,0 +1,27 @@
+// 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/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <memory>
+
+int i = 0;
+static_assert( std::pointer_traits<int*>::pointer_to(i) == &i );
+
+struct X { } x;
+static_assert( std::pointer_traits<X*>::pointer_to(x) == &x );
--
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