From 3cb0c7cc160a50f830bfa9aa5a3264b773a28bf8 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Sat, 23 May 2020 18:27:35 +0100
Subject: [PATCH] libstdc++: Fix function that can't be constexpr in C++11 (PR
95289)
The body of this function isn't just a return statement, so it can't be
constexpr until C++14.
PR libstdc++/95289
* include/debug/helper_functions.h (__get_distance): Only declare
as a constexpr function for C++14 and up.
* testsuite/25_algorithms/copy/debug/95289.cc: New test.
---
libstdc++-v3/ChangeLog | 5 +++
libstdc++-v3/include/debug/helper_functions.h | 2 +-
.../25_algorithms/copy/debug/95289.cc | 31 +++++++++++++++++++
3 files changed, 37 insertions(+), 1 deletion(-)
create mode 100644 libstdc++-v3/testsuite/25_algorithms/copy/debug/95289.cc
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 08a2ad3330cb..167cb88b5920 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,10 @@
2020-05-23 Jonathan Wakely <jwakely@redhat.com>
+ PR libstdc++/95289
+ * include/debug/helper_functions.h (__get_distance): Only declare
+ as a constexpr function for C++14 and up.
+ * testsuite/25_algorithms/copy/debug/95289.cc: New test.
+
* include/bits/fs_path.h (__detail::_S_range_begin)
(__detail::_S_range_end, path::_S_string_from_iter): Replace with
overloaded function template __detail::__effective_range.
diff --git a/libstdc++-v3/include/debug/helper_functions.h b/libstdc++-v3/include/debug/helper_functions.h
index 251582d59220..62d5309257f2 100644
--- a/libstdc++-v3/include/debug/helper_functions.h
+++ b/libstdc++-v3/include/debug/helper_functions.h
@@ -96,7 +96,7 @@ namespace __gnu_debug
{ return std::make_pair(__rhs - __lhs, __dp_exact); }
template<typename _Iterator>
- _GLIBCXX_CONSTEXPR
+ _GLIBCXX14_CONSTEXPR
inline typename _Distance_traits<_Iterator>::__type
__get_distance(_Iterator __lhs, _Iterator __rhs,
std::input_iterator_tag)
diff --git a/libstdc++-v3/testsuite/25_algorithms/copy/debug/95289.cc b/libstdc++-v3/testsuite/25_algorithms/copy/debug/95289.cc
new file mode 100644
index 000000000000..bcdab19761f3
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/copy/debug/95289.cc
@@ -0,0 +1,31 @@
+// Copyright (C) 2020 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++11 -D_GLIBCXX_DEBUG" }
+// { dg-do compile { target c++11_only } }
+
+#include <algorithm>
+#include <iterator>
+#include <istream>
+
+// PR libstdc++/95289
+
+void
+test01(std::istream_iterator<char> i, char* out)
+{
+ std::copy(i, decltype(i){}, out);
+}
--
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