[PATCH] Mark <queue>, <deque> constexpr

Tomasz Kaminski tkaminsk@redhat.com
Thu Aug 21 11:45:00 GMT 2025


On Mon, Aug 11, 2025 at 3:22 PM Thor Preimesberger <
tcpreimesberger@gmail.com> wrote:

> libstdc++: Mark <queue>, <deque> constexpr.
>
> This patch makes partial progress towards P3372 by marking
> std::{deque, priority_queue, queue} and relevant internal helpers to be
> constexpr when using C++26.
>
> libstdc++-v3/ChangeLog:
>
>         * include/bits/deque.tcc: Mark nonmember functions constexpr.
>         * include/bits/stl_algobase.h: Mark some __equal_aux1 overloads
>         constexpr for deque nonmember functions.
>         * include/bits/stl_deque.h: Make deque and member functions
>         constexpr.
>         * include/bits/stl_queue.h: Make queue, priority_queue,
>         and respective member functions constexpr.
>         * include/bits/stl_uninitialized.h: Mark
>         __uninitialized_default_a constexpr for deque nonmember functions.
>         * include/bits/version.def: Add feature test macros for
>         __cpp_lib_constexpr_{queue, deque}.
>         * include/bits/version.h : Regenerate.
>         * include/std/deque: Mark nonmember functions constexpr and add
> macros.
>         * include/std/queue: Mark nonmember functions constexpr and add
> macros.
>         * testsuite/23_containers/deque/constexpr.cc: New test. Tries to
>         exhaust all possible features in standard.
>         * testsuite/23_containers/queue/constexpr.cc: New test. Ditto.
>         * testsuite/23_containers/priority_queue/constexpr.cc: New test.
> Ditto.
>
> Signed-off-by: Thor Preimesberger <tcpreimesberger@gmail.com>
>
> ---
>
Thank you very much for the patch.

I have few additional comments to the changes.
Firstly we also have libstdc++-v3/include/debug/deque file that is used in
debug mode,
you may test it by adding RUNTESTFLAGS="--target_board=-D_GLIBCXX_DEBUG".
Some additional comments below.


>  libstdc++-v3/include/bits/deque.tcc           |  34 +++
>  libstdc++-v3/include/bits/stl_algobase.h      |   3 +
>  libstdc++-v3/include/bits/stl_deque.h         | 166 ++++++++++-
>  libstdc++-v3/include/bits/stl_queue.h         |  73 ++++-
>  libstdc++-v3/include/bits/stl_uninitialized.h |   1 +
>  libstdc++-v3/include/bits/version.def         |  16 ++
>  libstdc++-v3/include/bits/version.h           |  20 ++
>  libstdc++-v3/include/std/deque                |   3 +
>  libstdc++-v3/include/std/queue                |   1 +
>  .../23_containers/deque/constexpr.cc          | 266 ++++++++++++++++++
>  .../23_containers/priority_queue/constexpr.cc | 233 +++++++++++++++
>  .../23_containers/queue/constexpr.cc          | 194 +++++++++++++
>  12 files changed, 1007 insertions(+), 3 deletions(-)
>  create mode 100644 libstdc++-v3/testsuite/23_containers/deque/constexpr.cc
>  create mode 100644
> libstdc++-v3/testsuite/23_containers/priority_queue/constexpr.cc
>  create mode 100644 libstdc++-v3/testsuite/23_containers/queue/constexpr.cc
>
> diff --git a/libstdc++-v3/include/bits/deque.tcc
> b/libstdc++-v3/include/bits/deque.tcc
> index dabb6ec5365..ae05bf3b4bc 100644
> --- a/libstdc++-v3/include/bits/deque.tcc
> +++ b/libstdc++-v3/include/bits/deque.tcc
> @@ -65,6 +65,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>  #if __cplusplus >= 201103L
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_default_initialize()
> @@ -91,6 +92,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #endif
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      deque<_Tp, _Alloc>&
>      deque<_Tp, _Alloc>::
>      operator=(const deque& __x)
> @@ -133,6 +135,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    template<typename _Tp, typename _Alloc>
>      template<typename... _Args>
>  #if __cplusplus > 201402L
> +      _GLIBCXX26_CONSTEXPR
>        typename deque<_Tp, _Alloc>::reference
>  #else
>        void
> @@ -157,6 +160,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    template<typename _Tp, typename _Alloc>
>      template<typename... _Args>
>  #if __cplusplus > 201402L
> +      _GLIBCXX26_CONSTEXPR
>        typename deque<_Tp, _Alloc>::reference
>  #else
>        void
> @@ -183,6 +187,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #if __cplusplus >= 201103L
>    template<typename _Tp, typename _Alloc>
>      template<typename... _Args>
> +      _GLIBCXX26_CONSTEXPR
>        typename deque<_Tp, _Alloc>::iterator
>        deque<_Tp, _Alloc>::
>        emplace(const_iterator __position, _Args&&... __args)
> @@ -206,6 +211,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #endif
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      typename deque<_Tp, _Alloc>::iterator
>      deque<_Tp, _Alloc>::
>  #if __cplusplus >= 201103L
> @@ -231,6 +237,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>     }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      typename deque<_Tp, _Alloc>::iterator
>      deque<_Tp, _Alloc>::
>      _M_erase(iterator __position)
> @@ -254,6 +261,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      typename deque<_Tp, _Alloc>::iterator
>      deque<_Tp, _Alloc>::
>      _M_erase(iterator __first, iterator __last)
> @@ -303,6 +311,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_fill_insert(iterator __pos, size_type __n, const value_type& __x)
> @@ -346,6 +355,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>  #if __cplusplus >= 201103L
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_default_append(size_type __n)
> @@ -370,6 +380,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      bool
>      deque<_Tp, _Alloc>::
>      _M_shrink_to_fit()
> @@ -389,6 +400,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #endif
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_fill_initialize(const value_type& __value)
> @@ -415,6 +427,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template <typename _Tp, typename _Alloc>
>      template <typename _InputIterator>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_range_initialize(_InputIterator __first, _InputIterator __last,
> @@ -439,6 +452,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template <typename _Tp, typename _Alloc>
>      template <typename _ForwardIterator>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_range_initialize(_ForwardIterator __first, _ForwardIterator
> __last,
> @@ -480,6 +494,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    template<typename _Tp, typename _Alloc>
>  #if __cplusplus >= 201103L
>      template<typename... _Args>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_push_back_aux(_Args&&... __args)
> @@ -519,6 +534,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    template<typename _Tp, typename _Alloc>
>  #if __cplusplus >= 201103L
>      template<typename... _Args>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_push_front_aux(_Args&&... __args)
> @@ -557,6 +573,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    // Called only if _M_impl._M_finish._M_cur ==
> _M_impl._M_finish._M_first.
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void deque<_Tp, _Alloc>::
>      _M_pop_back_aux()
>      {
> @@ -573,6 +590,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    //   _M_impl._M_start._M_cur == _M_impl._M_start._M_last,
>    // then the deque must have at least two nodes.
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void deque<_Tp, _Alloc>::
>      _M_pop_front_aux()
>      {
> @@ -585,6 +603,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template <typename _Tp, typename _Alloc>
>      template <typename _InputIterator, typename _Sentinel>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_range_prepend(_InputIterator __first, _Sentinel __last,
> @@ -607,6 +626,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template <typename _Tp, typename _Alloc>
>      template <typename _InputIterator, typename _Sentinel>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_range_append(_InputIterator __first, _Sentinel __last,
> @@ -630,6 +650,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template <typename _Tp, typename _Alloc>
>      template <typename _InputIterator>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_range_insert_aux(iterator __pos,
> @@ -639,6 +660,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template <typename _Tp, typename _Alloc>
>      template <typename _ForwardIterator>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        deque<_Tp, _Alloc>::
>        _M_range_insert_aux(iterator __pos,
> @@ -660,6 +682,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    template<typename _Tp, typename _Alloc>
>  #if __cplusplus >= 201103L
>      template<typename... _Args>
> +      _GLIBCXX26_CONSTEXPR
>        typename deque<_Tp, _Alloc>::iterator
>        deque<_Tp, _Alloc>::
>        _M_emplace_aux(iterator __pos, _Args&&... __args)
> @@ -907,6 +930,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    template<typename _Tp, typename _Alloc>
>      template<__detail::__container_compatible_range<_Tp> _Rg>
> +      _GLIBCXX26_CONSTEXPR
>        auto
>        deque<_Tp, _Alloc>::
>        insert_range(const_iterator __pos, _Rg&& __rg)
> @@ -947,6 +971,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>     template<typename _Tp, typename _Alloc>
>       template<__detail::__container_compatible_range<_Tp> _Rg>
> +      _GLIBCXX26_CONSTEXPR
>         void
>         deque<_Tp, _Alloc>::
>         prepend_range(_Rg&& __rg)
> @@ -989,6 +1014,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>     template<typename _Tp, typename _Alloc>
>       template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         deque<_Tp, _Alloc>::
>         append_range(_Rg&& __rg)
> @@ -1025,6 +1051,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #endif // containers_ranges
>
>     template<typename _Tp, typename _Alloc>
> +     _GLIBCXX26_CONSTEXPR
>       void
>       deque<_Tp, _Alloc>::
>       _M_destroy_data_aux(iterator __first, iterator __last)
> @@ -1047,6 +1074,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>       }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_new_elements_at_front(size_type __new_elems)
> @@ -1072,6 +1100,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_new_elements_at_back(size_type __new_elems)
> @@ -1097,6 +1126,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      }
>
>    template <typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      deque<_Tp, _Alloc>::
>      _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front)
> @@ -1371,6 +1401,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      }
>
>    template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
> +    _GLIBCXX26_CONSTEXPR
>      bool
>      __equal_dit(
>         const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>& __first1,
> @@ -1398,6 +1429,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      }
>
>    template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
> +    _GLIBCXX26_CONSTEXPR
>      typename __gnu_cxx::__enable_if<
>        __is_random_access_iter<_II>::__value, bool>::__type
>      __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>
> __first1,
> @@ -1407,6 +1439,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>
>    template<typename _Tp1, typename _Ref1, typename _Ptr1,
>            typename _Tp2, typename _Ref2, typename _Ptr2>
> +    _GLIBCXX26_CONSTEXPR
>      bool
>      __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>
> __first1,
>                  _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>
> __last1,
> @@ -1414,6 +1447,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      { return std::__equal_dit(__first1, __last1, __first2); }
>
>    template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
> +    _GLIBCXX26_CONSTEXPR
>      typename __gnu_cxx::__enable_if<
>        __is_random_access_iter<_II>::__value, bool>::__type
>      __equal_aux1(_II __first1, _II __last1,
> diff --git a/libstdc++-v3/include/bits/stl_algobase.h
> b/libstdc++-v3/include/bits/stl_algobase.h
> index b104ec2536a..6d82be2c5c3 100644
> --- a/libstdc++-v3/include/bits/stl_algobase.h
> +++ b/libstdc++-v3/include/bits/stl_algobase.h
> @@ -1216,6 +1216,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      };
>
>    template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
> +    _GLIBCXX26_CONSTEXPR
>      typename __gnu_cxx::__enable_if<
>        __is_random_access_iter<_II>::__value, bool>::__type
>      __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
> @@ -1224,12 +1225,14 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>
>    template<typename _Tp1, typename _Ref1, typename _Ptr1,
>            typename _Tp2, typename _Ref2, typename _Ptr2>
> +    _GLIBCXX26_CONSTEXPR
>      bool
>      __equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
>                  _GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
>                  _GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
>
>    template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
> +    _GLIBCXX26_CONSTEXPR
>      typename __gnu_cxx::__enable_if<
>        __is_random_access_iter<_II>::__value, bool>::__type
>      __equal_aux1(_II, _II,
> diff --git a/libstdc++-v3/include/bits/stl_deque.h
> b/libstdc++-v3/include/bits/stl_deque.h
> index 7055641ad4e..e7997a2669b 100644
> --- a/libstdc++-v3/include/bits/stl_deque.h
> +++ b/libstdc++-v3/include/bits/stl_deque.h
> @@ -131,6 +131,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        typedef __ptr_rebind<_Ptr, _Elt_pointer>            _Map_pointer;
>  #endif
>
> +      _GLIBCXX26_CONSTEXPR
>        static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT
>        { return __deque_buf_size(sizeof(_Tp)); }
>
> @@ -147,10 +148,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        _Elt_pointer _M_last;
>        _Map_pointer _M_node;
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_iterator(_Elt_pointer __x, _Map_pointer __y)
> _GLIBCXX_NOEXCEPT
>        : _M_cur(__x), _M_first(*__y),
>         _M_last(*__y + _S_buffer_size()), _M_node(__y) { }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_iterator() _GLIBCXX_NOEXCEPT
>        : _M_cur(), _M_first(), _M_last(), _M_node() { }
>
> @@ -164,10 +167,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        template<typename _Iter,
>                typename = _Require<is_same<_Self, const_iterator>,
>                                    is_same<_Iter, iterator>>>
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_iterator(const _Iter& __x) noexcept
>         : _M_cur(__x._M_cur), _M_first(__x._M_first),
>          _M_last(__x._M_last), _M_node(__x._M_node) { }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_iterator(const _Deque_iterator& __x) noexcept
>         : _M_cur(__x._M_cur), _M_first(__x._M_first),
>          _M_last(__x._M_last), _M_node(__x._M_node) { }
> @@ -175,20 +180,24 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        _Deque_iterator& operator=(const _Deque_iterator&) = default;
>  #endif
>
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        _M_const_cast() const _GLIBCXX_NOEXCEPT
>        { return iterator(_M_cur, _M_node); }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        operator*() const _GLIBCXX_NOEXCEPT
>        { return *_M_cur; }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        pointer
>        operator->() const _GLIBCXX_NOEXCEPT
>        { return _M_cur; }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Self&
>        operator++() _GLIBCXX_NOEXCEPT
>        {
> @@ -201,6 +210,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return *this;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Self
>        operator++(int) _GLIBCXX_NOEXCEPT
>        {
> @@ -209,6 +219,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return __tmp;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Self&
>        operator--() _GLIBCXX_NOEXCEPT
>        {
> @@ -221,6 +232,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return *this;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Self
>        operator--(int) _GLIBCXX_NOEXCEPT
>        {
> @@ -229,6 +241,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return __tmp;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Self&
>        operator+=(difference_type __n) _GLIBCXX_NOEXCEPT
>        {
> @@ -248,11 +261,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return *this;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Self&
>        operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
>        { return *this += -__n; }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        operator[](difference_type __n) const _GLIBCXX_NOEXCEPT
>        { return *(*this + __n); }
> @@ -262,6 +277,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  _M_cur, which should therefore be set by the caller
>         *  immediately afterwards, based on _M_first and _M_last.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_set_node(_Map_pointer __new_node) _GLIBCXX_NOEXCEPT
>        {
> @@ -271,6 +287,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        friend bool
>        operator==(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
>        { return __x._M_cur == __y._M_cur; }
> @@ -280,6 +297,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        // operators are in scope (for additional details, see
> libstdc++/3628)
>        template<typename _RefR, typename _PtrR>
>         _GLIBCXX_NODISCARD
> +       _GLIBCXX26_CONSTEXPR
>         friend bool
>         operator==(const _Self& __x,
>                    const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
> @@ -288,6 +306,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>  #if __cpp_lib_three_way_comparison
>        [[nodiscard]]
> +      _GLIBCXX26_CONSTEXPR
>        friend strong_ordering
>        operator<=>(const _Self& __x, const _Self& __y) noexcept
>        {
> @@ -369,6 +388,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #endif // three-way comparison
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        friend difference_type
>        operator-(const _Self& __x, const _Self& __y) _GLIBCXX_NOEXCEPT
>        {
> @@ -384,6 +404,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        // parameters.
>        template<typename _RefR, typename _PtrR>
>         _GLIBCXX_NODISCARD
> +       _GLIBCXX26_CONSTEXPR
>         friend difference_type
>         operator-(const _Self& __x,
>                   const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
> @@ -396,6 +417,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        friend _Self
>        operator+(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
>        {
> @@ -405,6 +427,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        friend _Self
>        operator-(const _Self& __x, difference_type __n) _GLIBCXX_NOEXCEPT
>        {
> @@ -414,6 +437,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        friend _Self
>        operator+(difference_type __n, const _Self& __x) _GLIBCXX_NOEXCEPT
>        { return __x + __n; }
> @@ -451,6 +475,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>        typedef _Alloc             allocator_type;
>
> +      _GLIBCXX26_CONSTEXPR
>        allocator_type
>        get_allocator() const _GLIBCXX_NOEXCEPT
>        { return allocator_type(_M_get_Tp_allocator()); }
> @@ -458,23 +483,28 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        typedef _Deque_iterator<_Tp, _Tp&, _Ptr>   iterator;
>        typedef _Deque_iterator<_Tp, const _Tp&, _Ptr_const>
>  const_iterator;
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base()
>        : _M_impl()
>        { _M_initialize_map(0); }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base(size_t __num_elements)
>        : _M_impl()
>        { _M_initialize_map(__num_elements); }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base(const allocator_type& __a, size_t __num_elements)
>        : _M_impl(__a)
>        { _M_initialize_map(__num_elements); }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base(const allocator_type& __a)
>        : _M_impl(__a)
>        { /* Caller must initialize map. */ }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base(_Deque_base&& __x)
>        : _M_impl(std::move(__x._M_get_Tp_allocator()))
>        {
> @@ -483,10 +513,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>           this->_M_impl._M_swap_data(__x._M_impl);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base(_Deque_base&& __x, const allocator_type& __a)
>        : _M_impl(std::move(__x._M_impl), _Tp_alloc_type(__a))
>        { __x._M_initialize_map(0); }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Deque_base(_Deque_base&& __x, const allocator_type& __a, size_t
> __n)
>        : _M_impl(__a)
>        {
> @@ -505,6 +537,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>  #endif
>
> +      _GLIBCXX26_CONSTEXPR
>        ~_Deque_base() _GLIBCXX_NOEXCEPT;
>
>        typedef typename iterator::_Map_pointer _Map_pointer;
> @@ -516,20 +549,25 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         iterator _M_start;
>         iterator _M_finish;
>
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl_data() _GLIBCXX_NOEXCEPT
>         : _M_map(), _M_map_size(), _M_start(), _M_finish()
>         { }
>
>  #if __cplusplus >= 201103L
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl_data(const _Deque_impl_data&) = default;
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl_data&
>         operator=(const _Deque_impl_data&) = default;
>
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl_data(_Deque_impl_data&& __x) noexcept
>         : _Deque_impl_data(__x)
>         { __x = _Deque_impl_data(); }
>  #endif
>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         _M_swap_data(_Deque_impl_data& __x) _GLIBCXX_NOEXCEPT
>         {
> @@ -545,40 +583,49 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        struct _Deque_impl
>        : public _Tp_alloc_type, public _Deque_impl_data
>        {
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl() _GLIBCXX_NOEXCEPT_IF(
>           is_nothrow_default_constructible<_Tp_alloc_type>::value)
>         : _Tp_alloc_type()
>         { }
>
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
>         : _Tp_alloc_type(__a)
>         { }
>
>  #if __cplusplus >= 201103L
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl(_Deque_impl&&) = default;
>
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl(_Tp_alloc_type&& __a) noexcept
>         : _Tp_alloc_type(std::move(__a))
>         { }
>
> +       _GLIBCXX26_CONSTEXPR
>         _Deque_impl(_Deque_impl&& __d, _Tp_alloc_type&& __a)
>         : _Tp_alloc_type(std::move(__a)), _Deque_impl_data(std::move(__d))
>         { }
>  #endif
>        };
>
> +      _GLIBCXX26_CONSTEXPR
>        _Tp_alloc_type&
>        _M_get_Tp_allocator() _GLIBCXX_NOEXCEPT
>        { return this->_M_impl; }
>
> +      _GLIBCXX26_CONSTEXPR
>        const _Tp_alloc_type&
>        _M_get_Tp_allocator() const _GLIBCXX_NOEXCEPT
>        { return this->_M_impl; }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Map_alloc_type
>        _M_get_map_allocator() const _GLIBCXX_NOEXCEPT
>        { return _Map_alloc_type(_M_get_Tp_allocator()); }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Ptr
>        _M_allocate_node()
>        {
> @@ -586,6 +633,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return _Traits::allocate(_M_impl, __deque_buf_size(sizeof(_Tp)));
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_deallocate_node(_Ptr __p) _GLIBCXX_NOEXCEPT
>        {
> @@ -593,6 +641,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         _Traits::deallocate(_M_impl, __p, __deque_buf_size(sizeof(_Tp)));
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        _Map_pointer
>        _M_allocate_map(size_t __n)
>        {
> @@ -600,6 +649,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return _Map_alloc_traits::allocate(__map_alloc, __n);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_deallocate_map(_Map_pointer __p, size_t __n) _GLIBCXX_NOEXCEPT
>        {
> @@ -607,8 +657,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         _Map_alloc_traits::deallocate(__map_alloc, __p, __n);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        void _M_initialize_map(size_t);
> +      _GLIBCXX26_CONSTEXPR
>        void _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish);
> +      _GLIBCXX26_CONSTEXPR
>        void _M_destroy_nodes(_Map_pointer __nstart,
>                             _Map_pointer __nfinish) _GLIBCXX_NOEXCEPT;
>        enum { _S_initial_map_size = 8 };
> @@ -617,6 +670,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      };
>
>    template<typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      _Deque_base<_Tp, _Alloc>::
>      ~_Deque_base() _GLIBCXX_NOEXCEPT
>      {
> @@ -637,6 +691,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>     *  The initial underlying memory layout is a bit complicated...
>    */
>    template<typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      _Deque_base<_Tp, _Alloc>::
>      _M_initialize_map(size_t __num_elements)
> @@ -676,6 +731,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      }
>
>    template<typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      _Deque_base<_Tp, _Alloc>::
>      _M_create_nodes(_Map_pointer __nstart, _Map_pointer __nfinish)
> @@ -694,6 +750,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>      }
>
>    template<typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      void
>      _Deque_base<_Tp, _Alloc>::
>      _M_destroy_nodes(_Map_pointer __nstart,
> @@ -828,6 +885,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        typedef _Alloc                                   allocator_type;
>
>      private:
> +      _GLIBCXX26_CONSTEXPR
>        static size_t _S_buffer_size() _GLIBCXX_NOEXCEPT
>        { return __deque_buf_size(sizeof(_Tp)); }
>
> @@ -854,6 +912,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        /**
>         *  @brief  Creates a %deque with no elements.
>         */
> +      _GLIBCXX26_CONSTEXPR
>  #if __cplusplus >= 201103L
>        deque() = default;
>  #else
> @@ -864,6 +923,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  @brief  Creates a %deque with no elements.
>         *  @param  __a  An allocator object.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        explicit
>        deque(const allocator_type& __a)
>        : _Base(__a, 0) { }
> @@ -877,6 +937,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  This constructor fills the %deque with @a n default
>         *  constructed elements.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        explicit
>        deque(size_type __n, const allocator_type& __a = allocator_type())
>        : _Base(__a, _S_check_init_len(__n, __a))
> @@ -890,6 +951,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *
>         *  This constructor fills the %deque with @a __n copies of @a
> __value.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque(size_type __n, const value_type& __value,
>             const allocator_type& __a = allocator_type())
>        : _Base(__a, _S_check_init_len(__n, __a))
> @@ -917,6 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  The newly-created %deque uses a copy of the allocator object
> used
>         *  by @a __x (unless the allocator traits dictate a different
> object).
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque(const deque& __x)
>        : _Base(_Alloc_traits::_S_select_on_copy(__x._M_get_Tp_allocator()),
>               __x.size())
> @@ -933,9 +996,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  The contents of the moved instance are a valid, but unspecified
>         *  %deque.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque(deque&&) = default;
>
>        /// Copy constructor with alternative allocator
> +      _GLIBCXX26_CONSTEXPR
>        deque(const deque& __x, const __type_identity_t<allocator_type>&
> __a)
>        : _Base(__a, __x.size())
>        { std::__uninitialized_copy_a(__x.begin(), __x.end(),
> @@ -943,15 +1008,18 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>                                     _M_get_Tp_allocator()); }
>
>        /// Move constructor with alternative allocator
> +      _GLIBCXX26_CONSTEXPR
>        deque(deque&& __x, const __type_identity_t<allocator_type>& __a)
>        : deque(std::move(__x), __a, typename
> _Alloc_traits::is_always_equal{})
>        { }
>
>      private:
> +      _GLIBCXX26_CONSTEXPR
>        deque(deque&& __x, const allocator_type& __a, true_type)
>        : _Base(std::move(__x), __a)
>        { }
>
> +      _GLIBCXX26_CONSTEXPR
>        deque(deque&& __x, const allocator_type& __a, false_type)
>        : _Base(std::move(__x), __a, __x.size())
>        {
> @@ -976,6 +1044,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  This will call the element type's copy constructor N times
>         *  (where N is __l.size()) and do no memory reallocation.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque(initializer_list<value_type> __l,
>             const allocator_type& __a = allocator_type())
>        : _Base(__a)
> @@ -1003,6 +1072,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #if __cplusplus >= 201103L
>        template<typename _InputIterator,
>                typename = std::_RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         deque(_InputIterator __first, _InputIterator __last,
>               const allocator_type& __a = allocator_type())
>         : _Base(__a)
> @@ -1029,6 +1099,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         * @since C++23
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         deque(from_range_t, _Rg&& __rg, const allocator_type& __a =
> _Alloc())
>         : deque(__a)
>         { append_range(std::forward<_Rg>(__rg)); }
> @@ -1039,6 +1110,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  themselves are pointers, the pointed-to memory is not touched
> in any
>         *  way.  Managing the pointer is the user's responsibility.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        ~deque()
>        { _M_destroy_data(begin(), end(), _M_get_Tp_allocator()); }
>
> @@ -1051,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  The newly-created %deque uses a copy of the allocator object
> used
>         *  by @a __x (unless the allocator traits dictate a different
> object).
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque&
>        operator=(const deque& __x);
>
> @@ -1063,6 +1136,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  if the allocators permit it).
>         *  @a __x is a valid, but unspecified %deque.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque&
>        operator=(deque&& __x) noexcept(_Alloc_traits::_S_always_equal())
>        {
> @@ -1082,6 +1156,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  resulting %deque's size is the same as the number of elements
>         *  assigned.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        deque&
>        operator=(initializer_list<value_type> __l)
>        {
> @@ -1101,6 +1176,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  %deque and that the resulting %deque's size is the same as
>         *  the number of elements assigned.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        assign(size_type __n, const value_type& __val)
>        { _M_fill_assign(__n, __val); }
> @@ -1120,6 +1196,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>  #if __cplusplus >= 201103L
>        template<typename _InputIterator,
>                typename = std::_RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         assign(_InputIterator __first, _InputIterator __last)
>         { _M_assign_aux(__first, __last,
> std::__iterator_category(__first)); }
> @@ -1145,6 +1222,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  resulting %deque's size is the same as the number of elements
>         *  assigned.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        assign(initializer_list<value_type> __l)
>        { _M_assign_aux(__l.begin(), __l.end(),
> random_access_iterator_tag()); }
> @@ -1199,6 +1277,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>        /// Get a copy of the memory allocation object.
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        allocator_type
>        get_allocator() const _GLIBCXX_NOEXCEPT
>        { return _Base::get_allocator(); }
> @@ -1209,6 +1288,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  %deque.  Iteration is done in ordinary element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        begin() _GLIBCXX_NOEXCEPT
>        { return this->_M_impl._M_start; }
> @@ -1218,6 +1298,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element in the %deque.  Iteration is done in ordinary element
> order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_iterator
>        begin() const _GLIBCXX_NOEXCEPT
>        { return this->_M_impl._M_start; }
> @@ -1228,6 +1309,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        end() _GLIBCXX_NOEXCEPT
>        { return this->_M_impl._M_finish; }
> @@ -1238,6 +1320,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  ordinary element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_iterator
>        end() const _GLIBCXX_NOEXCEPT
>        { return this->_M_impl._M_finish; }
> @@ -1248,6 +1331,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reverse_iterator
>        rbegin() _GLIBCXX_NOEXCEPT
>        { return reverse_iterator(this->_M_impl._M_finish); }
> @@ -1258,6 +1342,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  reverse element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reverse_iterator
>        rbegin() const _GLIBCXX_NOEXCEPT
>        { return const_reverse_iterator(this->_M_impl._M_finish); }
> @@ -1268,6 +1353,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  in reverse element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reverse_iterator
>        rend() _GLIBCXX_NOEXCEPT
>        { return reverse_iterator(this->_M_impl._M_start); }
> @@ -1278,6 +1364,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  done in reverse element order.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reverse_iterator
>        rend() const _GLIBCXX_NOEXCEPT
>        { return const_reverse_iterator(this->_M_impl._M_start); }
> @@ -1288,6 +1375,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element in the %deque.  Iteration is done in ordinary element
> order.
>         */
>        [[__nodiscard__]]
> +      _GLIBCXX26_CONSTEXPR
>        const_iterator
>        cbegin() const noexcept
>        { return this->_M_impl._M_start; }
> @@ -1298,6 +1386,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  ordinary element order.
>         */
>        [[__nodiscard__]]
> +      _GLIBCXX26_CONSTEXPR
>        const_iterator
>        cend() const noexcept
>        { return this->_M_impl._M_finish; }
> @@ -1308,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  reverse element order.
>         */
>        [[__nodiscard__]]
> +      _GLIBCXX26_CONSTEXPR
>        const_reverse_iterator
>        crbegin() const noexcept
>        { return const_reverse_iterator(this->_M_impl._M_finish); }
> @@ -1318,6 +1408,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  done in reverse element order.
>         */
>        [[__nodiscard__]]
> +      _GLIBCXX26_CONSTEXPR
>        const_reverse_iterator
>        crend() const noexcept
>        { return const_reverse_iterator(this->_M_impl._M_start); }
> @@ -1326,6 +1417,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        // [23.2.1.2] capacity
>        /**  Returns the number of elements in the %deque.  */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        size_type
>        size() const _GLIBCXX_NOEXCEPT
>        {
> @@ -1337,6 +1429,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>        /**  Returns the size() of the largest possible %deque.  */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        size_type
>        max_size() const _GLIBCXX_NOEXCEPT
>        { return _S_max_size(_M_get_Tp_allocator()); }
> @@ -1351,6 +1444,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  %deque's current size the %deque is truncated, otherwise
>         *  default constructed elements are appended.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        resize(size_type __new_size)
>        {
> @@ -1373,6 +1467,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  %deque is extended and new elements are populated with given
>         *  data.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        resize(size_type __new_size, const value_type& __x)
>  #else
> @@ -1401,6 +1496,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>  #if __cplusplus >= 201103L
>        /**  A non-binding request to reduce memory use.  */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        shrink_to_fit() noexcept
>        { _M_shrink_to_fit(); }
> @@ -1410,7 +1506,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  Returns true if the %deque is empty.  (Thus begin() would
>         *  equal end().)
>         */
> -      _GLIBCXX_NODISCARD bool
> +      _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
> +      bool
>        empty() const _GLIBCXX_NOEXCEPT
>        { return this->_M_impl._M_finish == this->_M_impl._M_start; }
>
> @@ -1427,6 +1525,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  see at().)
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        operator[](size_type __n) _GLIBCXX_NOEXCEPT
>        {
> @@ -1446,6 +1545,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  see at().)
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        operator[](size_type __n) const _GLIBCXX_NOEXCEPT
>        {
> @@ -1477,6 +1577,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  is first checked that it is in the range of the deque.  The
>         *  function throws out_of_range if the check fails.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        at(size_type __n)
>        {
> @@ -1495,6 +1596,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  checked that it is in the range of the deque.  The function
> throws
>         *  out_of_range if the check fails.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        at(size_type __n) const
>        {
> @@ -1507,6 +1609,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element of the %deque.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        front() _GLIBCXX_NOEXCEPT
>        {
> @@ -1519,6 +1622,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element of the %deque.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        front() const _GLIBCXX_NOEXCEPT
>        {
> @@ -1531,6 +1635,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  %deque.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        back() _GLIBCXX_NOEXCEPT
>        {
> @@ -1545,6 +1650,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  element of the %deque.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        back() const _GLIBCXX_NOEXCEPT
>        {
> @@ -1564,6 +1670,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  data to it.  Due to the nature of a %deque this operation
>         *  can be done in constant time.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push_front(const value_type& __x)
>        {
> @@ -1579,12 +1686,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push_front(value_type&& __x)
>        { emplace_front(std::move(__x)); }
>
>        template<typename... _Args>
>  #if __cplusplus > 201402L
> +       _GLIBCXX26_CONSTEXPR
>         reference
>  #else
>         void
> @@ -1601,6 +1710,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  to it.  Due to the nature of a %deque this operation can be
>         *  done in constant time.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push_back(const value_type& __x)
>        {
> @@ -1616,12 +1726,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push_back(value_type&& __x)
>        { emplace_back(std::move(__x)); }
>
>        template<typename... _Args>
>  #if __cplusplus > 201402L
> +       _GLIBCXX26_CONSTEXPR
>         reference
>  #else
>         void
> @@ -1637,6 +1749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  Note that no data is returned, and if the first element's data
> is
>         *  needed, it should be retrieved before pop_front() is called.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        pop_front() _GLIBCXX_NOEXCEPT
>        {
> @@ -1660,6 +1773,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  Note that no data is returned, and if the last element's data is
>         *  needed, it should be retrieved before pop_back() is called.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        pop_back() _GLIBCXX_NOEXCEPT
>        {
> @@ -1686,6 +1800,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  with T(std::forward<Args>(args)...) before the specified
> location.
>         */
>        template<typename... _Args>
> +       _GLIBCXX26_CONSTEXPR
>         iterator
>         emplace(const_iterator __position, _Args&&... __args);
>
> @@ -1698,6 +1813,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  This function will insert a copy of the given value before the
>         *  specified location.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        insert(const_iterator __position, const value_type& __x);
>  #else
> @@ -1724,6 +1840,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  This function will insert a copy of the given rvalue before the
>         *  specified location.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        insert(const_iterator __position, value_type&& __x)
>        { return emplace(__position, std::move(__x)); }
> @@ -1738,6 +1855,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  initializer_list @a __l into the %deque before the location
>         *  specified by @a __p.  This is known as <em>list insert</em>.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        insert(const_iterator __p, initializer_list<value_type> __l)
>        {
> @@ -1757,6 +1875,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  This function will insert a specified number of copies of the
> given
>         *  data before the location specified by @a __position.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        insert(const_iterator __position, size_type __n, const value_type&
> __x)
>        {
> @@ -1793,6 +1912,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         */
>        template<typename _InputIterator,
>                typename = std::_RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         iterator
>         insert(const_iterator __position, _InputIterator __first,
>                _InputIterator __last)
> @@ -1834,6 +1954,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         * @since C++23
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         iterator
>         insert_range(const_iterator __pos, _Rg&& __rg);
>
> @@ -1843,6 +1964,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         * @since C++23
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         prepend_range(_Rg&& __rg);
>
> @@ -1852,6 +1974,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         * @since C++23
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         append_range(_Rg&& __rg);
>  #endif // containers_ranges
> @@ -1871,6 +1994,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         */
>        iterator
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        erase(const_iterator __position)
>  #else
>        erase(iterator __position)
> @@ -1895,6 +2019,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         */
>        iterator
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        erase(const_iterator __first, const_iterator __last)
>  #else
>        erase(iterator __first, iterator __last)
> @@ -1912,6 +2037,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *
>         *  Whether the allocators are swapped depends on the allocator
> traits.
>         */
> +      // TODO: I don't know if we should poke this.
> +      _GLIBCXX26_CONSTEXPR
>        void
>        swap(deque& __x) _GLIBCXX_NOEXCEPT
>        {
> @@ -1930,6 +2057,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  pointed-to memory is not touched in any way.  Managing the
> pointer is
>         *  the user's responsibility.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        clear() _GLIBCXX_NOEXCEPT
>        { _M_erase_at_end(begin()); }
> @@ -1962,6 +2090,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         }
>  #endif
>
> +      _GLIBCXX26_CONSTEXPR
>        static size_t
>        _S_check_init_len(size_t __n, const allocator_type& __a)
>        {
> @@ -1971,6 +2100,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return __n;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        static size_type
>        _S_max_size(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
>        {
> @@ -1992,12 +2122,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  push_back on each value from the iterator.
>         */
>        template<typename _InputIterator>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         _M_range_initialize(_InputIterator __first, _InputIterator __last,
>                             std::input_iterator_tag);
>
>        // called by the second initialize_dispatch above
>        template<typename _ForwardIterator>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         _M_range_initialize(_ForwardIterator __first, _ForwardIterator
> __last,
>                             std::forward_iterator_tag);
> @@ -2013,11 +2145,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  This function is called only when the user provides an explicit
> size
>         *  (with or without an explicit exemplar value).
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_fill_initialize(const value_type& __value);
>
>  #if __cplusplus >= 201103L
>        // called by deque(n).
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_default_initialize();
>  #endif
> @@ -2093,14 +2227,18 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        void _M_push_front_aux(const value_type&);
>  #else
>        template<typename... _Args>
> +       _GLIBCXX26_CONSTEXPR
>         void _M_push_back_aux(_Args&&... __args);
>
>        template<typename... _Args>
> +       _GLIBCXX26_CONSTEXPR
>         void _M_push_front_aux(_Args&&... __args);
>  #endif
>
> +      _GLIBCXX26_CONSTEXPR
>        void _M_pop_back_aux();
>
> +      _GLIBCXX26_CONSTEXPR
>        void _M_pop_front_aux();
>        ///@}
>
> @@ -2132,22 +2270,26 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>        // insert [__first, __last) at the front, assumes distance(__first,
> __last) is n
>        template<typename _InputIterator, typename _Sentinel>
> +      _GLIBCXX26_CONSTEXPR
>        void _M_range_prepend(_InputIterator __first, _Sentinel __last,
>                             size_type __n);
>
>        // insert [__first, __last) at the back, assumes distance(__first,
> __last) is n
>        template<typename _InputIterator, typename _Sentinel>
> +      _GLIBCXX26_CONSTEXPR
>        void _M_range_append(_InputIterator __first, _Sentinel __last,
>                            size_type __n);
>
>        // called by the second insert_dispatch above
>        template<typename _InputIterator>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         _M_range_insert_aux(iterator __pos, _InputIterator __first,
>                             _InputIterator __last,
> std::input_iterator_tag);
>
>        // called by the second insert_dispatch above
>        template<typename _ForwardIterator>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         _M_range_insert_aux(iterator __pos, _ForwardIterator __first,
>                             _ForwardIterator __last,
> std::forward_iterator_tag);
> @@ -2155,6 +2297,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        // Called by insert(p,n,x), and the range insert when it turns out
> to be
>        // the same thing.  Can use fill functions in optimal situations,
>        // otherwise passes off to insert_aux(p,n,x).
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_fill_insert(iterator __pos, size_type __n, const value_type&
> __x);
>
> @@ -2163,11 +2306,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        iterator
>        _M_insert_aux(iterator __pos, const value_type& __x);
>  #else
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        _M_insert_aux(iterator __pos, const value_type& __x)
>        { return _M_emplace_aux(__pos, __x); }
>
>        template<typename... _Args>
> +       _GLIBCXX26_CONSTEXPR
>         iterator
>         _M_emplace_aux(iterator __pos, _Args&&... __args);
>  #endif
> @@ -2186,16 +2331,19 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>        // Internal erase functions follow.
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_destroy_data_aux(iterator __first, iterator __last);
>
>        // Called by ~deque().
>        // NB: Doesn't deallocate the nodes.
>        template<typename _Alloc1>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         _M_destroy_data(iterator __first, iterator __last, const _Alloc1&)
>         { _M_destroy_data_aux(__first, __last); }
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_destroy_data(iterator __first, iterator __last,
>                       const std::allocator<_Tp>&)
> @@ -2205,6 +2353,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>        }
>
>        // Called by erase(q1, q2).
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_erase_at_begin(iterator __pos)
>        {
> @@ -2215,6 +2364,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>        // Called by erase(q1, q2), resize(), clear(), _M_assign_aux,
>        // _M_fill_assign, operator=.
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_erase_at_end(iterator __pos)
>        {
> @@ -2224,23 +2374,28 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         this->_M_impl._M_finish = __pos;
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        _M_erase(iterator __pos);
>
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        _M_erase(iterator __first, iterator __last);
>
>  #if __cplusplus >= 201103L
>        // Called by resize(sz).
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_default_append(size_type __n);
>
> +      _GLIBCXX26_CONSTEXPR
>        bool
>        _M_shrink_to_fit();
>  #endif
>
>        ///@{
>        /// Memory-handling helpers for the previous internal insert
> functions.
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        _M_reserve_elements_at_front(size_type __n)
>        {
> @@ -2251,6 +2406,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return this->_M_impl._M_start - difference_type(__n);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        iterator
>        _M_reserve_elements_at_back(size_type __n)
>        {
> @@ -2261,9 +2417,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         return this->_M_impl._M_finish + difference_type(__n);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_new_elements_at_front(size_type __new_elements);
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_new_elements_at_back(size_type __new_elements);
>        ///@}
> @@ -2277,6 +2435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>         *  actually add the nodes.  Can invalidate _M_map pointers.
>         *  (And consequently, %deque iterators.)
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_reserve_map_at_back(size_type __nodes_to_add = 1)
>        {
> @@ -2285,6 +2444,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>           _M_reallocate_map(__nodes_to_add, false);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_reserve_map_at_front(size_type __nodes_to_add = 1)
>        {
> @@ -2293,6 +2453,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>           _M_reallocate_map(__nodes_to_add, true);
>        }
>
> +      _GLIBCXX26_CONSTEXPR
>        void
>        _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front);
>        ///@}
> @@ -2406,6 +2567,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    */
>    template<typename _Tp, typename _Alloc>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator==(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>&
> __y)
>      { return __x.size() == __y.size()
> @@ -2425,6 +2587,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>    */
>    template<typename _Tp, typename _Alloc>
>      [[nodiscard]]
> +    _GLIBCXX26_CONSTEXPR
>      inline __detail::__synth3way_t<_Tp>
>      operator<=>(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>&
> __y)
>      {
> @@ -2482,6 +2645,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
>
>    /// See std::deque::swap().
>    template<typename _Tp, typename _Alloc>
> +    _GLIBCXX26_CONSTEXPR
>      inline void
>      swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>& __y)
>      _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
> diff --git a/libstdc++-v3/include/bits/stl_queue.h
> b/libstdc++-v3/include/bits/stl_queue.h
> index a3a8bc1f0ad..2ec1168c8a6 100644
> --- a/libstdc++-v3/include/bits/stl_queue.h
> +++ b/libstdc++-v3/include/bits/stl_queue.h
> @@ -115,15 +115,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>  #endif
>
>        template<typename _Tp1, typename _Seq1>
> +       _GLIBCXX26_CONSTEXPR
>         friend bool
>         operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
>
>        template<typename _Tp1, typename _Seq1>
> +       _GLIBCXX26_CONSTEXPR
>         friend bool
>         operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
>
>  #if __cpp_lib_three_way_comparison
>        template<typename _Tp1, three_way_comparable _Seq1>
> +       _GLIBCXX26_CONSTEXPR
>         friend compare_three_way_result_t<_Seq1>
>         operator<=>(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
>  #endif
> @@ -171,35 +174,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>  #else
>        template<typename _Seq = _Sequence, typename _Requires = typename
>                enable_if<is_default_constructible<_Seq>::value>::type>
> +       _GLIBCXX26_CONSTEXPR
>         queue()
>         : c() { }
>
> +      _GLIBCXX26_CONSTEXPR
>        explicit
>        queue(const _Sequence& __c)
>        : c(__c) { }
>
> +      _GLIBCXX26_CONSTEXPR
>        explicit
>        queue(_Sequence&& __c)
>        : c(std::move(__c)) { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         explicit
>         queue(const _Alloc& __a)
>         : c(__a) { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         queue(const _Sequence& __c, const _Alloc& __a)
>         : c(__c, __a) { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         queue(_Sequence&& __c, const _Alloc& __a)
>         : c(std::move(__c), __a) { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         queue(const queue& __q, const _Alloc& __a)
>         : c(__q.c, __a) { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         queue(queue&& __q, const _Alloc& __a)
>         : c(std::move(__q.c), __a) { }
>  #endif
> @@ -207,12 +218,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>  #ifdef __glibcxx_adaptor_iterator_pair_constructor // C++ >= 23 && HOSTED
>        template<typename _InputIterator,
>                typename = _RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         queue(_InputIterator __first, _InputIterator __last)
>         : c(__first, __last) { }
>
>        template<typename _InputIterator, typename _Alloc,
>                typename = _RequireInputIter<_InputIterator>,
>                typename = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         queue(_InputIterator __first, _InputIterator __last, const _Alloc&
> __a)
>         : c(__first, __last, __a) { }
>  #endif
> @@ -223,6 +236,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         * @since C++23
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         queue(from_range_t, _Rg&& __rg)
>         : c(ranges::to<_Sequence>(std::forward<_Rg>(__rg)))
>         { }
> @@ -233,6 +247,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg,
>                typename _Alloc>
> +       _GLIBCXX26_CONSTEXPR
>         queue(from_range_t, _Rg&& __rg, const _Alloc& __a)
>         : c(ranges::to<_Sequence>(std::forward<_Rg>(__rg), __a))
>         { }
> @@ -241,12 +256,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        /**
>         *  Returns true if the %queue is empty.
>         */
> -      _GLIBCXX_NODISCARD bool
> +      _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
> +      bool
>        empty() const
>        { return c.empty(); }
>
>        /**  Returns the number of elements in the %queue.  */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        size_type
>        size() const
>        { return c.size(); }
> @@ -256,6 +274,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  element of the %queue.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        front()
>        {
> @@ -268,6 +287,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  element of the %queue.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        front() const
>        {
> @@ -280,6 +300,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  element of the %queue.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        reference
>        back()
>        {
> @@ -292,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  element of the %queue.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        back() const
>        {
> @@ -308,17 +330,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  to it.  The time complexity of the operation depends on the
>         *  underlying sequence.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push(const value_type& __x)
>        { c.push_back(__x); }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push(value_type&& __x)
>        { c.push_back(std::move(__x)); }
>
>  #if __cplusplus > 201402L
>        template<typename... _Args>
> +       _GLIBCXX26_CONSTEXPR
>         decltype(auto)
>         emplace(_Args&&... __args)
>         { return c.emplace_back(std::forward<_Args>(__args)...); }
> @@ -332,6 +357,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>  #if __glibcxx_containers_ranges // C++ >= 23
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         push_range(_Rg&& __rg)
>         {
> @@ -353,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  data is needed, it should be retrieved before pop() is
>         *  called.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        pop()
>        {
> @@ -361,6 +388,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        void
>        swap(queue& __q)
>  #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
> @@ -430,6 +458,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    */
>    template<typename _Tp, typename _Seq>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return __x.c == __y.c; }
> @@ -449,6 +478,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    */
>    template<typename _Tp, typename _Seq>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return __x.c < __y.c; }
> @@ -456,6 +486,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    /// Based on operator==
>    template<typename _Tp, typename _Seq>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return !(__x == __y); }
> @@ -463,6 +494,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    /// Based on operator<
>    template<typename _Tp, typename _Seq>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return __y < __x; }
> @@ -470,6 +502,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    /// Based on operator<
>    template<typename _Tp, typename _Seq>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return !(__y < __x); }
> @@ -477,6 +510,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    /// Based on operator<
>    template<typename _Tp, typename _Seq>
>      _GLIBCXX_NODISCARD
> +    _GLIBCXX26_CONSTEXPR
>      inline bool
>      operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return !(__x < __y); }
> @@ -484,6 +518,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>  #if __cpp_lib_three_way_comparison
>    template<typename _Tp, three_way_comparable _Seq>
>      [[nodiscard]]
> +    _GLIBCXX26_CONSTEXPR
>      inline compare_three_way_result_t<_Seq>
>      operator<=>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
>      { return __x.c <=> __y.c; }
> @@ -491,6 +526,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>  #if __cplusplus >= 201103L
>    template<typename _Tp, typename _Seq>
> +    _GLIBCXX26_CONSTEXPR
>      inline
>  #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
>      // Constrained free swap overload, see p0185r1
> @@ -607,22 +643,28 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        template<typename _Seq = _Sequence, typename _Requires = typename
>                enable_if<__and_<is_default_constructible<_Compare>,
>
> is_default_constructible<_Seq>>::value>::type>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue()
>         : c(), comp() { }
>
> +      _GLIBCXX26_CONSTEXPR
>        explicit
>        priority_queue(const _Compare& __x, const _Sequence& __s)
>        : c(__s), comp(__x)
>        { std::make_heap(c.begin(), c.end(), comp); }
>
> +      _GLIBCXX26_CONSTEXPR
>        explicit
>        priority_queue(const _Compare& __x, _Sequence&& __s = _Sequence())
>        : c(std::move(__s)), comp(__x)
>        { std::make_heap(c.begin(), c.end(), comp); }
>
> +      _GLIBCXX26_CONSTEXPR
>        priority_queue(const priority_queue&) = default;
> +      _GLIBCXX26_CONSTEXPR
>        priority_queue& operator=(const priority_queue&) = default;
>
> +      _GLIBCXX26_CONSTEXPR
>        priority_queue(priority_queue&& __q)
>        noexcept(__and_<is_nothrow_move_constructible<_Sequence>,
>                       is_nothrow_move_constructible<_Compare>>::value)
> @@ -641,32 +683,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         explicit
>         priority_queue(const _Alloc& __a)
>         : c(__a), comp() { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(const _Compare& __x, const _Alloc& __a)
>         : c(__a), comp(__x) { }
>
>        // _GLIBCXX_RESOLVE_LIB_DEFECTS
>        // 2537. Constructors [...] taking allocators should call make_heap
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(const _Compare& __x, const _Sequence& __c,
>                        const _Alloc& __a)
>         : c(__c, __a), comp(__x)
>         { std::make_heap(c.begin(), c.end(), comp); }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(const _Compare& __x, _Sequence&& __c, const _Alloc&
> __a)
>         : c(std::move(__c), __a), comp(__x)
>         { std::make_heap(c.begin(), c.end(), comp); }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(const priority_queue& __q, const _Alloc& __a)
>         : c(__q.c, __a), comp(__q.comp) { }
>
>        template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(priority_queue&& __q, const _Alloc& __a)
>         : c(std::move(__q.c), __a), comp(std::move(__q.comp))
>         { __q.c.clear(); }
> @@ -702,6 +750,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        // 3529. priority_queue(first, last) should construct c with
> (first, last)
>        template<typename _InputIterator,
>                typename = std::_RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Compare& __x = _Compare())
>         : c(__first, __last), comp(__x)
> @@ -711,6 +760,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        // 3522. Missing requirement on InputIterator template parameter
>        template<typename _InputIterator,
>                typename = std::_RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Compare& __x, const _Sequence& __s)
>         : c(__s), comp(__x)
> @@ -722,6 +772,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>        template<typename _InputIterator,
>                typename = std::_RequireInputIter<_InputIterator>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Compare& __x, _Sequence&& __s)
>         : c(std::move(__s)), comp(__x)
> @@ -736,6 +787,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        template<typename _InputIterator, typename _Alloc,
>                typename = std::_RequireInputIter<_InputIterator>,
>                typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Alloc& __alloc)
>         : c(__first, __last, __alloc), comp()
> @@ -744,6 +796,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        template<typename _InputIterator, typename _Alloc,
>                typename = std::_RequireInputIter<_InputIterator>,
>                typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Compare& __x, const _Alloc& __alloc)
>         : c(__first, __last, __alloc), comp(__x)
> @@ -752,6 +805,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        template<typename _InputIterator, typename _Alloc,
>                typename = std::_RequireInputIter<_InputIterator>,
>                typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Compare& __x, const _Sequence& __s,
>                        const _Alloc& __alloc)
> @@ -764,6 +818,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>        template<typename _InputIterator, typename _Alloc,
>                typename _Requires = _Uses<_Alloc>>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(_InputIterator __first, _InputIterator __last,
>                        const _Compare& __x, _Sequence&& __s,
>                        const _Alloc& __alloc)
> @@ -783,18 +838,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         * @{
>         */
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(from_range_t, _Rg&& __rg,
>                        const _Compare& __x = _Compare())
>         : c(ranges::to<_Sequence>(std::forward<_Rg>(__rg))), comp(__x)
>         { std::make_heap(c.begin(), c.end(), comp); }
>
>        template<__detail::__container_compatible_range<_Tp> _Rg, typename
> _Alloc>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(from_range_t, _Rg&& __rg, const _Compare& __x,
>                        const _Alloc& __a)
>         : c(ranges::to<_Sequence>(std::forward<_Rg>(__rg), __a)), comp(__x)
>         { std::make_heap(c.begin(), c.end(), comp); }
>
>        template<__detail::__container_compatible_range<_Tp> _Rg, typename
> _Alloc>
> +       _GLIBCXX26_CONSTEXPR
>         priority_queue(from_range_t, _Rg&& __rg, const _Alloc& __a)
>         : c(ranges::to<_Sequence>(std::forward<_Rg>(__rg), __a)), comp()
>         { std::make_heap(c.begin(), c.end(), comp); }
> @@ -804,12 +862,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        /**
>         *  Returns true if the %queue is empty.
>         */
> -      _GLIBCXX_NODISCARD bool
> +      _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
> +      bool
>        empty() const
>        { return c.empty(); }
>
>        /**  Returns the number of elements in the %queue.  */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        size_type
>        size() const
>        { return c.size(); }
> @@ -819,6 +880,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  element of the %queue.
>         */
>        _GLIBCXX_NODISCARD
> +      _GLIBCXX26_CONSTEXPR
>        const_reference
>        top() const
>        {
> @@ -834,6 +896,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  The time complexity of the operation depends on the underlying
>         *  sequence.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push(const value_type& __x)
>        {
> @@ -842,6 +905,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        void
>        push(value_type&& __x)
>        {
> @@ -850,6 +914,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        }
>
>        template<typename... _Args>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         emplace(_Args&&... __args)
>         {
> @@ -860,6 +925,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>  #if __glibcxx_containers_ranges // C++ >= 23
>        template<__detail::__container_compatible_range<_Tp> _Rg>
> +       _GLIBCXX26_CONSTEXPR
>         void
>         push_range(_Rg&& __rg)
>         {
> @@ -882,6 +948,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         *  data is needed, it should be retrieved before pop() is
>         *  called.
>         */
> +      _GLIBCXX26_CONSTEXPR
>        void
>        pop()
>        {
> @@ -891,6 +958,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        }
>
>  #if __cplusplus >= 201103L
> +      _GLIBCXX26_CONSTEXPR
>        void
>        swap(priority_queue& __pq)
>        noexcept(__and_<
> @@ -959,6 +1027,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>  #if __cplusplus >= 201103L
>    template<typename _Tp, typename _Sequence, typename _Compare>
> +    _GLIBCXX26_CONSTEXPR
>      inline
>  #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
>      // Constrained free swap overload, see p0185r1
> diff --git a/libstdc++-v3/include/bits/stl_uninitialized.h
> b/libstdc++-v3/include/bits/stl_uninitialized.h
> index 351c3a17457..6719c558a40 100644
> --- a/libstdc++-v3/include/bits/stl_uninitialized.h
> +++ b/libstdc++-v3/include/bits/stl_uninitialized.h
> @@ -987,6 +987,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>  #if _GLIBCXX_HOSTED
>    template<typename _ForwardIterator, typename _Tp>
> +    _GLIBCXX26_CONSTEXPR
>
I would make this function  _GLIBCXX20_CONSTEXPR to match rest of the file,
there is alo another overload for allocators other than std::allocator,
that should be marked.
(see my comments on test below).

>      inline void
>      __uninitialized_default_a(_ForwardIterator __first,
>                               _ForwardIterator __last,
> diff --git a/libstdc++-v3/include/bits/version.def
> b/libstdc++-v3/include/bits/version.def
> index dbe2cb8f175..b7fd4ec8bd2 100644
> --- a/libstdc++-v3/include/bits/version.def
> +++ b/libstdc++-v3/include/bits/version.def
> @@ -2069,6 +2069,22 @@ ftms = {
>    };
>  };
>
> +ftms = {
> +  name = constexpr_queue;
> +  values = {
> +    v = 202502;
> +    cxxmin = 26;
> +  };
> +};
> +
> +ftms = {
> +  name = constexpr_deque;
> +  values = {
> +    v = 202502;
> +    cxxmin = 26;
> +  };
> +};
> +
>  // Standard test specifications.
>  stds[97] = ">= 199711L";
>  stds[03] = ">= 199711L";
> diff --git a/libstdc++-v3/include/bits/version.h
> b/libstdc++-v3/include/bits/version.h
> index 7bb6016df68..96f08e580d2 100644
> --- a/libstdc++-v3/include/bits/version.h
> +++ b/libstdc++-v3/include/bits/version.h
> @@ -2318,4 +2318,24 @@
>  #endif /* !defined(__cpp_lib_constexpr_exceptions) &&
> defined(__glibcxx_want_constexpr_exceptions) */
>  #undef __glibcxx_want_constexpr_exceptions
>
> +#if !defined(__cpp_lib_constexpr_queue)
> +# if (__cplusplus >  202302L)
> +#  define __glibcxx_constexpr_queue 202502L
> +#  if defined(__glibcxx_want_all) ||
> defined(__glibcxx_want_constexpr_queue)
> +#   define __cpp_lib_constexpr_queue 202502L
> +#  endif
> +# endif
> +#endif /* !defined(__cpp_lib_constexpr_queue) &&
> defined(__glibcxx_want_constexpr_queue) */
> +#undef __glibcxx_want_constexpr_queue
> +
> +#if !defined(__cpp_lib_constexpr_deque)
> +# if (__cplusplus >  202302L)
> +#  define __glibcxx_constexpr_deque 202502L
> +#  if defined(__glibcxx_want_all) ||
> defined(__glibcxx_want_constexpr_deque)
> +#   define __cpp_lib_constexpr_deque 202502L
> +#  endif
> +# endif
> +#endif /* !defined(__cpp_lib_constexpr_deque) &&
> defined(__glibcxx_want_constexpr_deque) */
> +#undef __glibcxx_want_constexpr_deque
> +
>  #undef __glibcxx_want_all
> diff --git a/libstdc++-v3/include/std/deque
> b/libstdc++-v3/include/std/deque
> index 2badab80a6d..c8a3649d643 100644
> --- a/libstdc++-v3/include/std/deque
> +++ b/libstdc++-v3/include/std/deque
> @@ -75,6 +75,7 @@
>  #define __glibcxx_want_containers_ranges
>  #define __glibcxx_want_erase_if
>  #define __glibcxx_want_nonmember_container_access
> +#define __glibcxx_want_constexpr_deque
>  #include <bits/version.h>
>
>  #ifdef _GLIBCXX_DEBUG
> @@ -101,6 +102,7 @@ namespace std _GLIBCXX_VISIBILITY(default)
>  _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>    template<typename _Tp, typename _Alloc, typename _Predicate>
> +    _GLIBCXX26_CONSTEXPR
>      inline typename deque<_Tp, _Alloc>::size_type
>      erase_if(deque<_Tp, _Alloc>& __cont, _Predicate __pred)
>      {
> @@ -122,6 +124,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>    template<typename _Tp, typename _Alloc,
>            typename _Up _GLIBCXX26_DEF_VAL_T(_Tp)>
> +    _GLIBCXX26_CONSTEXPR
>      inline typename deque<_Tp, _Alloc>::size_type
>      erase(deque<_Tp, _Alloc>& __cont, const _Up& __value)
>      {
> diff --git a/libstdc++-v3/include/std/queue
> b/libstdc++-v3/include/std/queue
> index 1b76088b31b..721ec4c5bef 100644
> --- a/libstdc++-v3/include/std/queue
> +++ b/libstdc++-v3/include/std/queue
> @@ -63,6 +63,7 @@
>
>  #define __glibcxx_want_adaptor_iterator_pair_constructor
>  #define __glibcxx_want_containers_ranges
> +#define __glibcxx_want_constexpr_queue
>  #include <bits/version.h>
>
>  #include <deque>
> diff --git a/libstdc++-v3/testsuite/23_containers/deque/constexpr.cc
> b/libstdc++-v3/testsuite/23_containers/deque/constexpr.cc
> new file mode 100644
> index 00000000000..4689b04ee63
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/23_containers/deque/constexpr.cc
> @@ -0,0 +1,266 @@
> +// { dg-do compile { target c++26 } }
> +
> +#include <deque>
> +
> +#ifndef __cpp_lib_constexpr_deque
> +#error "Feature test macro for constexpr deque is missing in <deque>"
> +#elif __cpp_lib_constexpr_deque != 202502L
> +# error "Feature test macro for constexpr deque has wrong value in
> <deque>"
> +#endif
> +
> +#include <ranges>
> +#include <numeric>
> +#include <testsuite_hooks.h>
> +
> +template<typename T>
> +struct Alloc : std::allocator<T>
> +{
> +  using std::allocator<T>::allocator;
> +
> +  int personality = 0;
> +  constexpr explicit Alloc (int p) : personality(p) { }
> +
> +  template<typename U>
> +    constexpr Alloc(const Alloc<U>& a) : personality(a.personality) { }
> +};
> +
> +constexpr bool ctor_tests()
> +{
> +  std::deque<int> dq1 {};
> +
> +  Alloc<int> alloc (6);
> +  std::deque<int> dq2 (alloc);
>
Also here, you are just converting Alloc to std::allocator. To test custom
allocators,
you should also add allocator argument to deque:
std::deque<int, Alloc> dq1(alloc);

> +  std::deque<int> dq3 (4, alloc);
> +  VERIFY( dq3.front() == 0 );
> +  VERIFY( dq3.size() == 4 );
> +  std::deque<int> dq4 (4, 5, alloc);
> +  VERIFY( dq4.front() == 5 );
> +  VERIFY( dq4.size() == 4 );
> +
> +  auto rg = {2, 3, 5, 7};
> +  auto dq5 = std::deque(rg.begin(), rg.end());
> +  VERIFY( dq5.front() == 2 );
> +  VERIFY( dq5.back() == 7 );
> +  VERIFY( dq5.size() == 4 );
> +
> +  auto dq6 = std::deque<int>(std::from_range, rg);
> +  VERIFY( dq6 == dq5 );
> +
> +  std::deque<int> dq7 (dq1);
> +  VERIFY( dq7 == dq1 );
> +  std::deque<int>dq8 (std::move(dq1));
> +  VERIFY( dq8 == dq7 );
> +
> +  std::deque<int> dq9 (dq1, alloc);
> +  std::deque<int> dq10 (std::move(dq1), alloc);
> +  VERIFY ( dq9 == dq10 );
> +  std::deque<int> dq11 (rg, alloc);
> +  VERIFY( dq11 == dq5 );
> +
> +  return true;
> +}
> +
> +static_assert(ctor_tests());
> +
> +constexpr bool insert_tests()
> +{
> +  std::deque<int> dq1 {};
> +
> +  auto rg = {1, 2, 3, 4, 5};
> +
> +  dq1.insert(dq1.begin() , 1);
> +  dq1.insert(dq1.end(), 2);
> +  VERIFY( dq1.size() == 2 );
> +  VERIFY( dq1.front() == 1 );
> +  VERIFY( dq1.back() == 2 );
> +
> +  dq1.insert(dq1.end(), 1, 3);
> +
> +  dq1.insert(dq1.end(), rg.begin() + 3, rg.end());
> +
> +  VERIFY( dq1[0] == 1 );
> +  VERIFY( dq1[1] == 2 );
> +  VERIFY( dq1[2] == 3 );
> +  VERIFY( dq1[3] == 4 );
> +  VERIFY( dq1[4] == 5 );
> +  dq1.clear();
> +
> +  dq1.insert(dq1.begin(), rg.begin(), rg.end());
> +  VERIFY( dq1[0] == 1 );
> +  VERIFY( dq1[1] == 2 );
> +  VERIFY( dq1[2] == 3 );
> +  VERIFY( dq1[3] == 4 );
> +  VERIFY( dq1[4] == 5 );
> +
> +  dq1.insert_range(dq1.end(), rg);
> +  VERIFY( dq1[5] == 1 );
> +  VERIFY( dq1[6] == 2 );
> +  VERIFY( dq1[7] == 3 );
> +  VERIFY( dq1[8] == 4 );
> +  VERIFY( dq1[9] == 5 );
> +
> +  std::deque<int> dq2 {2, 3, 5, 7};
> +  dq2.erase(dq2.begin());
> +  VERIFY( dq2.size() == 3 );
> +  dq2.clear();
> +  VERIFY( dq2.size() == 0);
> +  VERIFY( dq2.empty() );
> +
> +  std::deque<int> dq3, dq4;
> +  dq3.insert_range(dq3.begin(), rg);
>
It would be good to test all the iterator categories, as we have different
code paths.
I have recently updated our test iterators to be constexpr, and updated the
range test for vector
here:
https://gcc.gnu.org/cgit/gcc/commit/?id=be6a864b25206dd85827c2960f38f36f49b38f31

I think you can do something similar for range tests for deque and
adaptors.
You can mark the test template constexpr (since C++23 templates can be
marked constexpr,
without having any possible instantations), and something like:
#ifdef __cpp_lib_constexpr_deque
  static_assert( test_all() );
#endif

Let me know if you have any questions here.


> +  dq4.append_range(rg);
> +  VERIFY( dq3 == dq4 );
> +  dq3.erase(dq3.begin(), dq3.end());
> +  dq3.prepend_range(rg);
> +  VERIFY( dq3 == dq4 );
> +
> +
> +  struct S {
> +    int foo;
> +    constexpr S (int i, int j) : foo{i + j} {}
> +  };
> +  std::deque<S> dq5 {};
> +  dq5.emplace(dq5.end(), 0, 1);
> +  const S& s1 = dq5.emplace_back(1, 1);
> +  const S& s2 = dq5.emplace_front(2, 1);
> +  VERIFY( dq5.front().foo == 3 );
> +  VERIFY( dq5.back().foo == 2 );
> +  VERIFY( dq5[1].foo == 1 );
> +
> +  std::deque<int> dq6 {2, 3};
> +  dq6.push_front(1);
> +  dq6.push_back(4);
> +  VERIFY( dq6.front() == 1);
> +  VERIFY( dq6.back() == 4 );
> +  dq6.pop_front();
> +  dq6.pop_back();
> +
> +  std::deque<int> dq7 {1, 2};
> +  dq7.resize(4);
> +  VERIFY( dq7.back() == 0 );
> +  dq7.resize(2);
> +  VERIFY( dq7.front() == 1 );
> +  VERIFY( dq7.back() == 2 );
> +  dq7.clear();
> +  dq7.resize(2);
> +  VERIFY( dq7.front() == 0 );
> +  VERIFY( dq7.back() == 0 );
> +
> +  std::deque<int> dq8 {1, 4};
> +  dq8.swap(dq6);
> +  VERIFY( dq6.front() == 1 );
> +  VERIFY( dq6.back() == 4 );
> +  VERIFY( dq8.front() == 2 );
> +  VERIFY( dq8.back() == 3 );
> +
> +  return true;
> +}
> +
> +static_assert(insert_tests());
> +
> +constexpr bool iterators_tests()
> +{
> +  std::deque<int> dq0 {};
> +  VERIFY( dq0.begin() == dq0.end() );
> +  dq0.resize(1);
> +  VERIFY( dq0.begin() != dq0.end() );
> +  dq0.resize(2);
> +  VERIFY( dq0.begin() != dq0.end() );
> +  VERIFY( dq0.cbegin() == dq0.begin() );
> +  VERIFY( dq0.crbegin() == dq0.rbegin() );
> +  VERIFY( dq0.cend() == dq0.end() );
> +  VERIFY( dq0.crend() == dq0.rend() );
> +
> +  auto it = dq0.begin();
> +  VERIFY( it[0] == 0 );
> +  VERIFY( &*it == &dq0.front() );
> +  VERIFY( &it[1] == &dq0[1] );
> +  VERIFY( it++ == dq0.begin() );
> +  VERIFY( ++it == dq0.end() );
> +  VERIFY( (it - 2) == dq0.begin() );
> +  VERIFY( (it - dq0.begin()) == 2 );
> +  it -= 2;
> +  it += 1;
> +  VERIFY( (it + 1) == dq0.end() );
> +  VERIFY( (1 + it) == dq0.end() );
> +  it = it + 1;
> +  auto it2 = dq0.begin();
> +  std::swap(it, it2);
> +  VERIFY( it == dq0.begin() );
> +  VERIFY( it2 == dq0.end() );
> +
> +  auto rit = dq0.rbegin();
> +  VERIFY( rit[0] == 0 );
> +  VERIFY( &*rit == &dq0.back() );
> +  VERIFY( &rit[1] == &dq0[0] );
> +  VERIFY( rit++ == dq0.rbegin() );
> +  VERIFY( ++rit == dq0.rend() );
> +  VERIFY( (rit - 2) == dq0.rbegin() );
> +  VERIFY( (rit - dq0.rbegin()) == 2 );
> +  rit -= 2;
> +  rit += 1;
> +  VERIFY( (rit + 1) == dq0.rend() );
> +  VERIFY( (1 + rit) == dq0.rend() );
> +  rit = rit + 1;
> +  auto rit2 = dq0.rbegin();
> +  std::swap(rit, rit2);
> +  VERIFY( rit == dq0.rbegin() );
> +  VERIFY( rit2 == dq0.rend() );
> +
> +  return true;
> +}
> +
> +static_assert(iterators_tests());
> +
> +constexpr bool capacity_tests()
> +{
> +  std::deque<int> dq0 {};
> +  VERIFY( dq0.empty() );
> +  VERIFY( dq0.max_size() );
> +  dq0.push_front(0);
> +  VERIFY( dq0.size() == 1 );
> +  dq0.erase(dq0.begin());
> +  dq0.shrink_to_fit();
> +
> +  return true;
> +}
> +
> +static_assert(capacity_tests());
> +
> +constexpr bool nonmember_tests()
> +{
> +  std::deque<int> dq0 {0, 1};
> +  std::deque<int> dq1 {0, 1};
> +
> +  VERIFY( (dq0 == dq1) == true );
> +  VERIFY( (dq0 != dq1) == false );
> +  VERIFY( (dq0 <= dq1) == true );
> +  VERIFY( (dq0 >= dq1) == true );
> +  VERIFY( (dq0  < dq1) == false );
> +  VERIFY( (dq0  > dq1) == false );
> +  VERIFY( (dq0 <=> dq1) == 0 );
> +  VERIFY( (dq0 <=> dq1) <= 0 );
> +  VERIFY( (dq0 <=> dq1) >= 0 );
> +
> +  std::deque<int> dq2 {2, 4};
> +  std::swap(dq1, dq2);
> +
> +  VERIFY( (dq0 == dq1) == false );
> +  VERIFY( (dq0 != dq1) == true );
> +  VERIFY( (dq0 <= dq1) == true );
> +  VERIFY( (dq0 >= dq1) == false );
> +  VERIFY( (dq0  < dq1) == true );
> +  VERIFY( (dq0  > dq1) == false );
> +  VERIFY( (dq0 <=> dq1) != 0 );
> +  VERIFY( (dq0 <=> dq1) <= 0 );
> +  VERIFY( (dq0 <=> dq1)  < 0 );
> +
> +  std::erase(dq0, 0);
> +  VERIFY( dq0.front() == 1 );
> +
> +  std::erase_if(dq1, [](int x) { return x % 2 == 0; });
> +  VERIFY( dq1.empty() );
> +  return true;
> +}
> +
> +static_assert(nonmember_tests());
> diff --git
> a/libstdc++-v3/testsuite/23_containers/priority_queue/constexpr.cc
> b/libstdc++-v3/testsuite/23_containers/priority_queue/constexpr.cc
> new file mode 100644
> index 00000000000..ae4529a9aa8
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/23_containers/priority_queue/constexpr.cc
> @@ -0,0 +1,233 @@
> +// { dg-do compile { target c++26 } }
> +
> +#include <queue>
> +
> +#ifndef __cpp_lib_constexpr_queue
> +#error "Feature test macro for constexpr queue is missing in <queue>"
> +#elif __cpp_lib_constexpr_queue != 202502L
> +# error "Feature test macro for constexpr queue has wrong value in
> <queue>"
> +#endif
> +
> +#include <ranges>
> +#include <functional>
> +#include <vector>
> +#include <numeric>
> +#include <testsuite_hooks.h>
> +
> +template<typename T>
> +struct Alloc : std::allocator<T>
> +{
> +  using std::allocator<T>::allocator;
> +
> +  int personality = 0;
> +  constexpr explicit Alloc (int p) : personality(p) { }
> +
> +  template<typename U>
> +    constexpr Alloc(const Alloc<U>& a) : personality(a.personality) { }
> +};
> +
> +constexpr bool ctor_tests()
> +{
> +  auto rg = {2, 3, 5, 7};
> +  std::vector<int> v0 {std::from_range, rg};
> +
> +  std::priority_queue<int> pq1;
> +  VERIFY( pq1.size() == 0 && pq1.empty() );
> +
> +  std::priority_queue<int> pq2 {std::less<int>()};
> +  VERIFY( pq2.size() == 0 && pq2.empty() );
> +
> +  std::priority_queue<int> pq3 {std::less<int>(), v0};
> +  VERIFY( pq3.size() == 4 && pq3.top() == 7 );
> +
> +  std::priority_queue<int> pq4 {std::less<int>(), std::move(v0)};
> +  VERIFY( pq4.size() == 4 && pq4.top() == 7 );
> +
> +  std::priority_queue<int> pq5 (pq3);
> +  VERIFY( pq5.top() == pq3.top() );
> +  VERIFY( pq5.size() == pq3.size() );
> +
> +  std::priority_queue<int> pq6 (std::move(pq3));
> +  VERIFY( pq6.top() == pq5.top() );
> +  VERIFY( pq6.size() == pq5.size() );
> +
> +  std::vector<int> v1 {};
> +
> +  std::priority_queue<int> pq10(std::begin(rg), std::end(rg),
> +                              std::less<int>());
> +  VERIFY( pq10.size() == std::size(rg) );
> +  VERIFY( pq10.top() == 7 );
> +  pq10.pop();
> +  VERIFY( pq10.top() == 5 );
> +  pq10.pop();
> +  VERIFY( pq10.top() == 3 );
> +  pq10.pop();
> +  VERIFY( pq10.top() == 2 );
> +  pq10.pop();
> +
> +  std::priority_queue<int> pq11(std::begin(rg), std::end(rg),
> +                              std::less<int>(), v1);
> +  VERIFY( pq11.size() == std::size(rg));
> +  VERIFY( pq11.top() == 7 );
> +  pq11.pop();
> +  VERIFY( pq11.top() == 5 );
> +  pq11.pop();
> +  VERIFY( pq11.top() == 3 );
> +  pq11.pop();
> +  VERIFY( pq11.top() == 2 );
> +  pq11.pop();
> +
> +  std::priority_queue<int> pq12(std::begin(rg), std::end(rg),
> +                              std::less<int>(), std::move(v1));
> +  VERIFY( pq12.size() == std::size(rg));
> +  VERIFY( pq12.top() == 7 );
> +  pq12.pop();
> +  VERIFY( pq12.top() == 5 );
> +  pq12.pop();
> +  VERIFY( pq12.top() == 3 );
> +  pq12.pop();
> +  VERIFY( pq12.top() == 2 );
> +  pq12.pop();
> +
> +  auto pq13 = std::priority_queue<int>(std::from_range,
> std::ranges::views::iota(0, 7), std::less<int>());
> +  VERIFY( pq13.size() == 7 );
> +
> +  return true;
> +}
> +
> +static_assert( ctor_tests() );
> +
> +constexpr bool alloc_aware_ctor_tests()
> +{
> +  std::allocator<int> alloc;
> +  auto rg = {1, 0};
> +  constexpr std::vector<int> v0 {};
> +  std::priority_queue<int> pq14 (alloc);
> +
> +  std::priority_queue<int> pq15 (std::less<int>(), alloc);
> +  pq15.push(0);
> +  pq15.push(1);
> +  VERIFY( pq15.top() == 1 );
> +
> +  std::priority_queue<int> pq16 (std::less<int>(), v0, alloc);
> +  pq16.push(0);
> +  pq16.push(1);
> +  VERIFY( pq16.top() == 1 );
> +
> +  std::priority_queue<int> pq17 (std::less<int>(), std::move(v0), alloc);
> +  pq17.push(0);
> +  pq17.push(1);
> +  VERIFY( pq17.top() == 1 );
> +
> +  std::priority_queue<int> pq18 (pq17, alloc);
> +  VERIFY( pq18.size() == pq17.size());
> +  VERIFY( pq18.top() == 1 );
> +
> +  std::priority_queue<int> pq19 (std::move(pq17), alloc);
> +  VERIFY( pq19.size() == pq18.size() );
> +  VERIFY( pq18.top() == 1 );
> +
> +  constexpr std::vector<int> v1 {};
> +
> +  std::priority_queue<int> pq20(std::begin(rg), std::end(rg),
> +                              std::less<int>(), alloc);
> +  VERIFY( pq20.top() == 1 );
> +  VERIFY( pq20.size() == std::size(rg) );
> +
> +  std::priority_queue<int> pq21(std::begin(rg), std::end(rg),
> +                              std::less<int>(), v1, alloc);
> +  VERIFY( pq21.top() == 1 );
> +  VERIFY( pq21.size() == std::size(rg) );
> +
> +  std::priority_queue<int> pq22(std::begin(rg), std::end(rg),
> +                              std::less<int>(), std::move(v1), alloc);
> +  VERIFY( pq21.top() == 1 );
> +  VERIFY( pq22.size() == std::size(rg) );
> +
> +  auto pq23 = std::priority_queue<int>(std::from_range,
> std::ranges::views::iota(0, 7), alloc);
> +  VERIFY( pq23.size() == 7 );
> +
> +  auto pq24 = std::priority_queue<int>(std::from_range,
> std::ranges::views::iota(0, 7), std::less<int>(), alloc);
> +  VERIFY( pq24.size() == 7 );
> +
> +  return true;
> +}
> +
> +static_assert( alloc_aware_ctor_tests() );
> +
> +constexpr bool push_and_pop_test()
> +{
> +  std::priority_queue<int> a;
> +  a.push(1);
> +  a.pop();
> +
> +  return true;
> +}
> +
> +static_assert( push_and_pop_test() );
> +
> +constexpr bool top_test ()
> +{
> +  std::priority_queue<int> a;
> +  a.push(2);
> +  a.push(4);
> +  VERIFY( a.top() == 4 );
> +
> +  return true;
> +}
> +
> +static_assert( top_test() );
> +
> +constexpr int push_range_test()
> +{
> +  std::priority_queue<int> pq;
> +  const auto rg = {2, 3, 5, 7};
> +  pq.push_range(rg);
> +  VERIFY( pq.size() == 4);
> +  VERIFY( pq.top() == 7);
> +  pq.pop();
> +  VERIFY( pq.top() == 5);
> +  pq.pop();
> +  VERIFY( pq.top() == 3);
> +  pq.pop();
> +  VERIFY( pq.top() == 2);
> +  pq.pop();
> +  VERIFY( pq.size() == 0);
> +  return true;
> +}
> +
> +static_assert( push_range_test() );
> +
> +constexpr int swap_test()
> +{
> +  std::priority_queue<int> a,b;
> +  a.push(2);
> +  b.push(4);
> +  std::swap(a, b);
> +  VERIFY( a.top() == 4 );
> +  VERIFY( b.top() == 2 );
> +  return true;
> +}
> +
> +static_assert (swap_test());
> +
> +struct S
> +{
> +  int foo;
> +  constexpr S(int i, int j) : foo{i + j} {}
> +  constexpr friend bool operator< (S const &x, S const &y) { return x.foo
> < y.foo; }
> +};
> +
> +constexpr bool emplace_test()
> +{
> +  std::priority_queue<S> pq;
> +  pq.emplace(0, 0);
> +  pq.emplace(1, 0);
> +  VERIFY( pq.size() == 2 );
> +  VERIFY( pq.top().foo == 1 );
> +  pq.pop();
> +  VERIFY ( pq.top().foo == 0 );
> +  return true;
> +}
> +
> +static_assert( emplace_test() );
> diff --git a/libstdc++-v3/testsuite/23_containers/queue/constexpr.cc
> b/libstdc++-v3/testsuite/23_containers/queue/constexpr.cc
> new file mode 100644
> index 00000000000..8a00ba83c46
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/23_containers/queue/constexpr.cc
> @@ -0,0 +1,194 @@
> +// { dg-do compile { target c++26 } }
> +
> +#include <queue>
> +
> +#ifndef __cpp_lib_constexpr_queue
> +#error "Feature test macro for constexpr queue is missing in <queue>"
> +#elif __cpp_lib_constexpr_queue != 202502L
> +# error "Feature test macro for constexpr queue has wrong value in
> <queue>"
> +#endif
> +
> +#include <ranges>
> +#include <numeric>
> +#include <testsuite_hooks.h>
> +
> +template<typename T>
> +struct Alloc : std::allocator<T>
> +{
> +  using std::allocator<T>::allocator;
> +
> +  int personality = 0;
> +  constexpr explicit Alloc (int p) : personality(p) { }
> +
> +  template<typename U>
> +    constexpr Alloc(const Alloc<U>& a) : personality(a.personality) { }
> +};
> +
> +constexpr bool ctor_tests()
> +{
> +  std::queue<int> q1;
> +  VERIFY( q1.size() == 0 && q1.empty() );
> +  q1.push(1);
> +  q1.push(2);
> +  VERIFY( q1.size() == 2) ;
> +
> +  std::queue<int> q2 (q1);
> +  VERIFY( q2.size() == q1.size() );
> +  VERIFY( q2.front() == q1.front() );
> +  VERIFY( q2.back() == q1.back() );
> +
> +  std::queue<int> q3 (std::move(q2));
> +  VERIFY( q3.size() == q1.size() );
> +  VERIFY( q3.front() == q1.front() );
> +  VERIFY( q3.back() == q1.back() );
> +  VERIFY( q2.empty() );
> +
> +  std::allocator<int> alloc;
> +  std::queue<int> q4 (alloc);
> +  q4.push(1);
> +  q4.push(2);
> +  VERIFY( q4.size() == 2 );
> +
> +  std::queue<int> q5 (q4, alloc);
> +  VERIFY( q5 == q4 );
> +  VERIFY( q5.size() == q4.size() );
> +  VERIFY( q5.front() == q4.front() );
> +  VERIFY( q5.back() == q4.back() );
> +
> +  std::queue<int> q6 (std::move(q5), alloc);
> +  VERIFY( q6 == q4 );
> +  VERIFY( q6.size() == q4.size() );
> +  VERIFY( q5.empty() );
> +
> +  Alloc<int> aa(5);
>
You are using a custom allocator here, but you do not specify the
allocator argument for queue, thus it is just converted to std::alocator
(this is also why you haven't triggered other overload).
You should replace this (and for all adaptors) with:
std::queue<int, std::deque<int, Alloc>> q;

> +  std::queue<int> q7 (aa);
> +  VERIFY( q7.size() == 0 );
> +
> +  int rg[4] = {2, 3, 5, 7};
> +  std::queue<int> q8(std::begin(rg), std::end(rg));
> +  VERIFY( q8.size() == std::size(rg));
> +  VERIFY( q8.front() == 2 );
> +  q8.pop();
> +  VERIFY( q8.front() == 3 );
> +  q8.pop();
> +  VERIFY( q8.front() == 5 );
> +  q8.pop();
> +  VERIFY( q8.front() == 7 );
> +  q8.pop();
> +
> +  std::queue<int> q9(std::begin(rg), std::end(rg), aa);
> +  VERIFY( q9.size() == std::size(rg));
> +  VERIFY( q9.front() == 2 );
> +  q9.pop();
> +  VERIFY( q9.front() == 3 );
> +  q9.pop();
> +  VERIFY( q9.front() == 5 );
> +  q9.pop();
> +  VERIFY( q9.front() == 7 );
> +  q9.pop();
> +
> +  auto q10 = std::queue<int>(std::from_range, std::ranges::views::iota(0,
> 7));
> +  VERIFY( q10.size() == 7 );
> +
> +  auto q11 = std::queue<int>(std::from_range, std::ranges::views::iota(0,
> 7), alloc);
> +  VERIFY( q11.size() == 7 );
> +
> +  auto q12 = std::queue<int>(std::from_range, std::ranges::views::iota(0,
> 7), aa);
> +  VERIFY( q12.size() == 7 );
> +
> +  return true;
> +}
> +
> +static_assert( ctor_tests() );
> +
> +constexpr bool push_and_pop_test()
> +{
> +  std::queue<int> a;
> +  a.push(1);
> +  a.pop();
> +
> +  return true;
> +}
> +
> +static_assert( push_and_pop_test() );
> +
> +constexpr bool front_and_back_test()
> +{
> +  std::queue<int> a;
> +  a.push(2);
> +  a.push(4);
> +  VERIFY ( a.front() == 2 && a.back() == 4);
> +  return true;
> +}
> +
> +static_assert( front_and_back_test() );
> +
> +constexpr int push_range_test()
> +{
> +  std::queue<int> a;
> +  const auto rg = {2, 3, 5, 7};
> +  a.push_range(rg);
> +  VERIFY( a.size() == 4 );
> +  VERIFY( a.front() == 2 );
> +  a.pop();
> +  VERIFY( a.front() == 3 );
> +  a.pop();
> +  VERIFY( a.front() == 5 );
> +  a.pop();
> +  VERIFY( a.front() == 7 );
> +  a.pop();
> +  VERIFY( a.size() == 0 );
> +  return true;
> +}
> +
> +static_assert (push_range_test());
> +
> +constexpr int swap_test()
> +{
> +  std::queue<int> a,b;
> +  a.push(1);
> +  b.push(2);
> +  std::swap(a, b);
> +  VERIFY( a.front() == 2 );
> +  VERIFY( b.front() == 1 );
> +  return true;
> +}
> +
> +static_assert (swap_test());
> +
> +struct S
> +{
> +  int foo;
> +  constexpr S(int i, int j) : foo{i + j} {}
> +};
> +
> +constexpr bool emplace_test()
> +{
> +  std::queue<S> a;
> +  const S& s = a.emplace(196883, 1);
> +  VERIFY ( a.size() == 1 );
> +  VERIFY ( a.front().foo == 196884 );
> +  return true;
> +}
> +
> +static_assert( emplace_test() );
> +
> +constexpr bool operator_test()
> +{
> +  std::queue<int> a, b;
> +  a.push(1);
> +  b.push(1);
> +  VERIFY ( a == b );
> +  VERIFY ( a <= b );
> +  VERIFY ( a >= b );
> +  b.pop();
> +  b.push(2);
> +  VERIFY ( a < b );
> +  VERIFY ( !(a > b) );
> +  VERIFY ( a <= b );
> +  VERIFY ( !(a >= b) );
> +  VERIFY ( a != b );
> +  return true;
> +}
> +
> +static_assert( operator_test() );
> --
> 2.34.1
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://gcc.gnu.org/pipermail/libstdc++/attachments/20250821/1d2c8952/attachment-0001.htm>


More information about the Libstdc++ mailing list