re PR libstdc++/56785 (std::tuple of two elements does not apply empty base class optimization when one of its elements is a std::tuple with two elements)
PR libstdc++/56785 * include/std/tuple (_Tuple_impl): Remove zero-element specialization and define one-element specialization. * testsuite/20_util/tuple/56785.cc: New. From-SVN: r219785
This commit is contained in:
Jonathan Wakely
Jonathan Wakely
parent
3c16c4238b
commit
3ecec1eff7
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@ -1,3 +1,10 @@
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2015-01-17 Jonathan Wakely <jwakely@redhat.com>
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PR libstdc++/56785
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* include/std/tuple (_Tuple_impl): Remove zero-element specialization
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and define one-element specialization.
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* testsuite/20_util/tuple/56785.cc: New.
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2015-01-17 Jonathan Wakely <jwakely@redhat.com>
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* testsuite/22_locale/codecvt/codecvt_utf8/requirements/1.cc:
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@ -158,30 +158,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<std::size_t _Idx, typename... _Elements>
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struct _Tuple_impl;
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/**
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* Zero-element tuple implementation. This is the basis case for the
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* inheritance recursion.
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*/
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template<std::size_t _Idx>
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struct _Tuple_impl<_Idx>
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{
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template<std::size_t, typename...> friend class _Tuple_impl;
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_Tuple_impl() = default;
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t, const _Alloc&) { }
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t, const _Alloc&, const _Tuple_impl&) { }
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t, const _Alloc&, _Tuple_impl&&) { }
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protected:
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void _M_swap(_Tuple_impl&) noexcept { /* no-op */ }
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};
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template<typename _Tp>
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struct __is_empty_non_tuple : is_empty<_Tp> { };
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@ -358,6 +334,130 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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}
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};
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// Basis case of inheritance recursion.
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template<std::size_t _Idx, typename _Head>
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struct _Tuple_impl<_Idx, _Head>
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: private _Head_base<_Idx, _Head, __empty_not_final<_Head>::value>
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{
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template<std::size_t, typename...> friend class _Tuple_impl;
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typedef _Head_base<_Idx, _Head, __empty_not_final<_Head>::value> _Base;
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static constexpr _Head&
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_M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
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static constexpr const _Head&
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_M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
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constexpr _Tuple_impl()
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: _Base() { }
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explicit
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constexpr _Tuple_impl(const _Head& __head)
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: _Base(__head) { }
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template<typename _UHead>
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explicit
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constexpr _Tuple_impl(_UHead&& __head)
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: _Base(std::forward<_UHead>(__head)) { }
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constexpr _Tuple_impl(const _Tuple_impl&) = default;
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constexpr
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_Tuple_impl(_Tuple_impl&& __in)
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noexcept(is_nothrow_move_constructible<_Head>::value)
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: _Base(std::forward<_Head>(_M_head(__in))) { }
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template<typename _UHead>
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constexpr _Tuple_impl(const _Tuple_impl<_Idx, _UHead>& __in)
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: _Base(_Tuple_impl<_Idx, _UHead>::_M_head(__in)) { }
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template<typename _UHead>
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constexpr _Tuple_impl(_Tuple_impl<_Idx, _UHead>&& __in)
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: _Base(std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in)))
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{ }
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
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: _Base(__tag, __use_alloc<_Head>(__a)) { }
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
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const _Head& __head)
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: _Base(__use_alloc<_Head, _Alloc, _Head>(__a), __head) { }
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template<typename _Alloc, typename _UHead>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
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_UHead&& __head)
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: _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
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std::forward<_UHead>(__head)) { }
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
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const _Tuple_impl& __in)
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: _Base(__use_alloc<_Head, _Alloc, _Head>(__a), _M_head(__in)) { }
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template<typename _Alloc>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
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_Tuple_impl&& __in)
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: _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
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std::forward<_Head>(_M_head(__in))) { }
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template<typename _Alloc, typename _UHead>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
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const _Tuple_impl<_Idx, _UHead>& __in)
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: _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
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_Tuple_impl<_Idx, _UHead>::_M_head(__in)) { }
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template<typename _Alloc, typename _UHead>
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_Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
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_Tuple_impl<_Idx, _UHead>&& __in)
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: _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
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std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in)))
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{ }
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_Tuple_impl&
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operator=(const _Tuple_impl& __in)
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{
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_M_head(*this) = _M_head(__in);
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return *this;
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}
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_Tuple_impl&
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operator=(_Tuple_impl&& __in)
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noexcept(is_nothrow_move_assignable<_Head>::value)
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{
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_M_head(*this) = std::forward<_Head>(_M_head(__in));
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return *this;
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}
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template<typename _UHead>
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_Tuple_impl&
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operator=(const _Tuple_impl<_Idx, _UHead>& __in)
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{
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_M_head(*this) = _Tuple_impl<_Idx, _UHead>::_M_head(__in);
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return *this;
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}
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template<typename _UHead>
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_Tuple_impl&
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operator=(_Tuple_impl<_Idx, _UHead>&& __in)
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{
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_M_head(*this)
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= std::forward<_UHead>(_Tuple_impl<_Idx, _UHead>::_M_head(__in));
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return *this;
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}
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protected:
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void
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_M_swap(_Tuple_impl& __in)
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noexcept(noexcept(swap(std::declval<_Head&>(), std::declval<_Head&>())))
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{
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using std::swap;
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swap(_M_head(*this), _M_head(__in));
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}
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};
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/// Primary class template, tuple
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template<typename... _Elements>
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class tuple : public _Tuple_impl<0, _Elements...>
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@ -0,0 +1,32 @@
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// Copyright (C) 2015 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// { dg-options "-std=gnu++11" }
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// { dg-do compile }
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#include <tuple>
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class Empty { };
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using std::tuple;
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using char_pair = tuple<char, char>;
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static_assert( sizeof(tuple<Empty, char_pair>) == sizeof(char_pair),
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"Nested tuple tuple<Empty, tuple<T,T>> is too big");
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static_assert( sizeof(tuple<char_pair, char_pair>) == (2 * sizeof(char_pair)),
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"Nested tuple<tuple<T,T, tuple<T,T>> is too big" );
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