[gcc r10-9679] libstdc++: Fix invalid constexpr function in C++11 mode [PR 99985]
Jonathan Wakely
redi@gcc.gnu.org
Fri Apr 9 15:15:03 GMT 2021
https://gcc.gnu.org/g:637418ec2c6f559d4fac074db3bafc34a728484b
commit r10-9679-g637418ec2c6f559d4fac074db3bafc34a728484b
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Fri Apr 9 12:05:39 2021 +0100
libstdc++: Fix invalid constexpr function in C++11 mode [PR 99985]
I keep forgetting that a constexpr function in C++11 has to be a single
return statement.
libstdc++-v3/ChangeLog:
PR libstdc++/99985
* include/bits/hashtable.h (_Hashtable::_S_nothrow_move()): Fix
to be a valid constexpr function in C++11.
* testsuite/23_containers/unordered_set/cons/99985.cc: New test.
(cherry picked from commit 40ccb47b505b528244ee305923681c0ae3b6f4d5)
Diff:
---
libstdc++-v3/include/bits/hashtable.h | 10 ++++-
.../23_containers/unordered_set/cons/99985.cc | 47 ++++++++++++++++++++++
2 files changed, 55 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 8705d1f33b8..e9a6cfe8b83 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -450,10 +450,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static constexpr bool
_S_nothrow_move()
{
- if _GLIBCXX17_CONSTEXPR (_No_realloc)
- if _GLIBCXX17_CONSTEXPR (is_nothrow_copy_constructible<_H1>())
+#if __cplusplus <= 201402L
+ return __and_<__bool_constant<_No_realloc>,
+ is_nothrow_copy_constructible<_H1>,
+ is_nothrow_copy_constructible<_Equal>>::value;
+#else
+ if constexpr (_No_realloc)
+ if constexpr (is_nothrow_copy_constructible<_H1>())
return is_nothrow_copy_constructible<_Equal>();
return false;
+#endif
}
_Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
diff --git a/libstdc++-v3/testsuite/23_containers/unordered_set/cons/99985.cc b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/99985.cc
new file mode 100644
index 00000000000..b209f7627f5
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/cons/99985.cc
@@ -0,0 +1,47 @@
+// Copyright (C) 2021 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" }
+// { dg-do compile { target c++11 } }
+
+#include <unordered_set>
+#include <testsuite_allocator.h>
+
+template<typename Alloc, typename T = typename Alloc::value_type>
+ using Set = std::unordered_set<T, std::hash<T>, std::equal_to<T>, Alloc>;
+
+// PR libstdc++/99985 - invalid constexpr function in C++11 mode
+
+void
+test01()
+{
+ using A = std::allocator<int>;
+ A a;
+ Set<A> s;
+ static_assert( noexcept( Set<A>(std::move(s)) ), "non-throwing" );
+ static_assert( noexcept( Set<A>(std::move(s), a) ), "non-throwing" );
+}
+
+void
+test02()
+{
+ using A = __gnu_test::uneq_allocator<long>;
+ A a;
+ Set<A> s;
+ static_assert( noexcept( Set<A>(std::move(s)) ), "non-throwing" );
+ static_assert( ! noexcept( Set<A>(std::move(s), a) ), "throwing" );
+}
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