368faacac7
This commit reverts5aaefa51(and also partly7f285f48e7andb6d75682f9, which were related to the original commit). As landed,5aaefa51had unintended consequences on some downstream bots and didn't have proper coverage upstream due to a few subtle things. Implementing this is something we should do in libc++, however we'll first need to address a few issues listed in https://reviews.llvm.org/D106124#3349710. Differential Revision: https://reviews.llvm.org/D120683
220 lines
6.7 KiB
C++
220 lines
6.7 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___MEMORY_POINTER_TRAITS_H
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#define _LIBCPP___MEMORY_POINTER_TRAITS_H
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#include <__config>
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#include <__memory/addressof.h>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Tp, class = void>
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struct __has_element_type : false_type {};
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template <class _Tp>
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struct __has_element_type<_Tp,
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typename __void_t<typename _Tp::element_type>::type> : true_type {};
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template <class _Ptr, bool = __has_element_type<_Ptr>::value>
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struct __pointer_traits_element_type;
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template <class _Ptr>
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struct __pointer_traits_element_type<_Ptr, true>
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{
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typedef _LIBCPP_NODEBUG typename _Ptr::element_type type;
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args>
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struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true>
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{
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typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::element_type type;
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args>
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struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false>
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{
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typedef _LIBCPP_NODEBUG _Tp type;
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};
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template <class _Tp, class = void>
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struct __has_difference_type : false_type {};
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template <class _Tp>
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struct __has_difference_type<_Tp,
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typename __void_t<typename _Tp::difference_type>::type> : true_type {};
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template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
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struct __pointer_traits_difference_type
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{
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typedef _LIBCPP_NODEBUG ptrdiff_t type;
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};
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template <class _Ptr>
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struct __pointer_traits_difference_type<_Ptr, true>
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{
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typedef _LIBCPP_NODEBUG typename _Ptr::difference_type type;
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};
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template <class _Tp, class _Up>
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struct __has_rebind
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{
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private:
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struct __two {char __lx; char __lxx;};
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template <class _Xp> static __two __test(...);
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_LIBCPP_SUPPRESS_DEPRECATED_PUSH
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template <class _Xp> static char __test(typename _Xp::template rebind<_Up>* = 0);
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_LIBCPP_SUPPRESS_DEPRECATED_POP
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public:
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static const bool value = sizeof(__test<_Tp>(0)) == 1;
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};
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template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
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struct __pointer_traits_rebind
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{
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#ifndef _LIBCPP_CXX03_LANG
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typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up> type;
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#else
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typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up>::other type;
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#endif
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
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struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true>
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{
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#ifndef _LIBCPP_CXX03_LANG
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typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
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#else
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typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
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#endif
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};
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template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
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struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false>
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{
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typedef _Sp<_Up, _Args...> type;
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};
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template <class _Ptr>
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struct _LIBCPP_TEMPLATE_VIS pointer_traits
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{
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typedef _Ptr pointer;
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typedef typename __pointer_traits_element_type<pointer>::type element_type;
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typedef typename __pointer_traits_difference_type<pointer>::type difference_type;
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#ifndef _LIBCPP_CXX03_LANG
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template <class _Up> using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
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#else
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template <class _Up> struct rebind
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{typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
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#endif // _LIBCPP_CXX03_LANG
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private:
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struct __nat {};
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public:
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_LIBCPP_INLINE_VISIBILITY
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static pointer pointer_to(typename conditional<is_void<element_type>::value,
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__nat, element_type>::type& __r)
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{return pointer::pointer_to(__r);}
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};
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template <class _Tp>
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struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
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{
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typedef _Tp* pointer;
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typedef _Tp element_type;
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typedef ptrdiff_t difference_type;
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#ifndef _LIBCPP_CXX03_LANG
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template <class _Up> using rebind = _Up*;
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#else
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template <class _Up> struct rebind {typedef _Up* other;};
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#endif
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private:
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struct __nat {};
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public:
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
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static pointer pointer_to(typename conditional<is_void<element_type>::value,
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__nat, element_type>::type& __r) _NOEXCEPT
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{return _VSTD::addressof(__r);}
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};
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template <class _From, class _To>
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struct __rebind_pointer {
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#ifndef _LIBCPP_CXX03_LANG
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typedef typename pointer_traits<_From>::template rebind<_To> type;
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#else
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typedef typename pointer_traits<_From>::template rebind<_To>::other type;
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#endif
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};
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// to_address
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template <class _Pointer, class = void>
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struct __to_address_helper;
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template <class _Tp>
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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_Tp* __to_address(_Tp* __p) _NOEXCEPT {
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static_assert(!is_function<_Tp>::value, "_Tp is a function type");
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return __p;
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}
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// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
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template <class _Pointer, class = __enable_if_t<
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!is_pointer<_Pointer>::value && !is_array<_Pointer>::value && !is_function<_Pointer>::value
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> >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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typename decay<decltype(__to_address_helper<_Pointer>::__call(declval<const _Pointer&>()))>::type
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__to_address(const _Pointer& __p) _NOEXCEPT {
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return __to_address_helper<_Pointer>::__call(__p);
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}
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template <class _Pointer, class>
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struct __to_address_helper {
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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static decltype(_VSTD::__to_address(declval<const _Pointer&>().operator->()))
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__call(const _Pointer& __p) _NOEXCEPT {
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return _VSTD::__to_address(__p.operator->());
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}
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};
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template <class _Pointer>
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struct __to_address_helper<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))> {
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
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static decltype(pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))
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__call(const _Pointer& __p) _NOEXCEPT {
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return pointer_traits<_Pointer>::to_address(__p);
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}
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};
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#if _LIBCPP_STD_VER > 17
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template <class _Tp>
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inline _LIBCPP_INLINE_VISIBILITY constexpr
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auto to_address(_Tp *__p) noexcept {
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return _VSTD::__to_address(__p);
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}
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template <class _Pointer>
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inline _LIBCPP_INLINE_VISIBILITY constexpr
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auto to_address(const _Pointer& __p) noexcept {
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return _VSTD::__to_address(__p);
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}
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#endif
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___MEMORY_POINTER_TRAITS_H
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