[PATCH] libstdc++: constexpr flat_map and flat_multimap
Yuao Ma
addr2line@gmail.com
Fri Dec 19 15:34:38 GMT 2025
On Thu, Dec 18, 2025 at 11:15 PM Patrick Palka <ppalka@redhat.com> wrote:
>
> On Fri, 12 Dec 2025, Yuao Ma wrote:
>
> > Hi all,
> >
> > This patch is a follow-up to r16-6026-gbf9dd44a97400e. It makes
> > flat_map and flat_multimap constexpr as part of P3372R3.
> > Tested on x86_64-linux. OK for trunk?
> >
> > Yuao
> >
> > From c2a1c42266bdd87c97868735514b621cec3e30bd Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <c8ef@outlook.com>
> > Date: Fri, 12 Dec 2025 19:26:01 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_map and flat_multimap
> >
> > This patch makes flat_map and flat_multimap constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_map: Add constexpr.
> > * testsuite/23_containers/flat_map/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_multimap/1.cc: Add constexpr test.
>
> LGTM
>
Thanks for the review!
Hi Jonathan,
Could you take a look at this patch when you have a moment? I’ve
rebased it against the latest trunk and verified it in both debug and
release modes. Everything seems to be working correctly now.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 +
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_map | 157 +++++++++++++++++-
> > .../testsuite/23_containers/flat_map/1.cc | 43 ++++-
> > .../23_containers/flat_multimap/1.cc | 42 ++++-
> > 5 files changed, 245 insertions(+), 15 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> > index 5b95db19ac6..f97276d80f2 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1351,6 +1351,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_map;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_flat_set;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> > index eee9890a72b..97b37e9a62b 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1496,6 +1496,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_map)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_map 202502L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_flat_map)
> > +# define __cpp_lib_constexpr_flat_map 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_map) */
> > +#undef __glibcxx_want_constexpr_flat_map
> > +
> > #if !defined(__cpp_lib_constexpr_flat_set)
> > # if (__cplusplus > 202302L)
> > # define __glibcxx_constexpr_flat_set 202502L
> > diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
> > index 637c3b7fe0d..e270735a87b 100644
> > --- a/libstdc++-v3/include/std/flat_map
> > +++ b/libstdc++-v3/include/std/flat_map
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_map
> > #define __glibcxx_want_flat_map
> > #include <bits/version.h>
> >
> > @@ -108,9 +109,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > class value_compare
> > {
> > [[no_unique_address]] key_compare _M_comp;
> > + _GLIBCXX26_CONSTEXPR
> > value_compare(key_compare __c) : _M_comp(__c) { }
> >
> > public:
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return _M_comp(__x.first, __y.first); }
> > @@ -129,10 +132,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > containers* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(containers& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > @@ -142,24 +147,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_disable()
> > { _M_cont = nullptr; }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard
> > _M_make_clear_guard()
> > { return _ClearGuard{this->_M_cont}; }
> >
> > public:
> > // constructors
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl() : _Flat_map_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > const key_compare& __comp = key_compare())
> > @@ -169,6 +179,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_sort_uniq();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > @@ -180,12 +191,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > : _M_cont(), _M_comp(__comp)
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -193,20 +206,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_map_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_map_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -216,12 +233,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const _Alloc& __a)
> > : _Flat_map_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a),
> > std::make_obj_using_allocator<mapped_container_type>(__a)),
> > @@ -229,6 +248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const _Alloc& __a)
> > @@ -236,6 +256,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const key_compare& __comp,
> > @@ -249,6 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -257,6 +279,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -271,6 +294,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a, __x._M_cont.keys),
> > std::make_obj_using_allocator<mapped_container_type>(__a, __x._M_cont.values)),
> > @@ -278,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>
> > (__a, std::move(__x._M_cont.keys)),
> > @@ -288,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_map_impl(std::move(__first), std::move(__last), key_compare(), __a)
> > @@ -295,6 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -303,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -311,6 +339,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -320,6 +349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare(), __a)
> > @@ -327,18 +357,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp,
> > const _Alloc& __a)
> > : _Flat_map_impl(__comp, __a)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_map_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -346,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -353,6 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -360,6 +395,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_map_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -369,64 +405,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > begin() noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > end() noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rbegin() noexcept
> > { return reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rend() noexcept
> > { return reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return const_reverse_iterator(cend()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return const_reverse_iterator(cbegin()); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.keys.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.keys.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return std::min<size_type>(keys().max_size(), values().max_size()); }
> > @@ -436,6 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // modifiers
> > template<typename _Key2, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -491,6 +543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -503,6 +556,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > {
> > @@ -510,36 +564,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return _M_try_emplace(__position, std::move(__p.first), std::move(__p.second)).first;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(const value_type& __x)
> > { return emplace(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(value_type&& __x)
> > { return emplace(std::move(__x)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, const value_type& __x)
> > { return emplace_hint(__position, __x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, value_type&& __x)
> > { return emplace_hint(__position, std::move(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(_Arg&& __x)
> > { return emplace(std::forward<_Arg>(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, _Arg&& __x)
> > { return emplace_hint(__position, std::forward<_Arg>(__x)); }
> >
> > private:
> > template<typename _Iter, typename _Sent>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_insert(_Iter __first, _Sent __last)
> > {
> > @@ -577,11 +638,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > public:
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > { _M_insert(std::move(__first), std::move(__last)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -590,18 +653,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > { _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(initializer_list<value_type> __il)
> > { insert(__il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t __s, initializer_list<value_type> __il)
> > { insert(__s, __il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > containers
> > extract() &&
> > {
> > @@ -609,6 +676,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return {std::move(_M_cont.keys), std::move(_M_cont.values)};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(key_container_type&& __key_cont, mapped_container_type&& __mapped_cont)
> > {
> > @@ -622,10 +690,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // try_emplace and insert_or_assign defined directly in class flat_map only.
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(iterator __position)
> > { return erase(static_cast<const_iterator>(__position)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > {
> > @@ -637,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -646,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > || (__transparent_comparator<_Compare>
> > && !is_convertible_v<_Key2, iterator>
> > && !is_convertible_v<_Key2, const_iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(_Key2&& __x)
> > {
> > @@ -655,6 +727,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > {
> > @@ -667,6 +740,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __y) noexcept
> > {
> > @@ -675,6 +749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::swap(_M_cont.values, __y._M_cont.values);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > {
> > @@ -684,32 +759,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return value_compare(_M_comp); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const key_container_type&
> > keys() const noexcept
> > { return _M_cont.keys; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_container_type&
> > values() const noexcept
> > { return _M_cont.values; }
> >
> > // map operations
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const key_type& __x)
> > { return find<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const key_type& __x) const
> > { return find<key_type>(__x); }
> > @@ -717,6 +798,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -730,6 +812,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const _Key2& __x) const
> > {
> > @@ -741,6 +824,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -748,6 +832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const _Key2& __x) const
> > {
> > @@ -761,6 +846,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -768,16 +854,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const _Key2& __x) const
> > { return find(__x) != cend(); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const key_type& __x)
> > { return lower_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const key_type& __x) const
> > { return lower_bound<key_type>(__x); }
> > @@ -785,6 +874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > {
> > @@ -796,6 +886,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const _Key2& __x) const
> > {
> > @@ -805,11 +896,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const key_type& __x)
> > { return upper_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const key_type& __x) const
> > { return upper_bound<key_type>(__x); }
> > @@ -817,6 +910,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > {
> > @@ -828,6 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const _Key2& __x) const
> > {
> > @@ -837,11 +932,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const key_type& __x)
> > { return equal_range<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const key_type& __x) const
> > { return equal_range<key_type>(__x); }
> > @@ -849,6 +946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const _Key2& __x)
> > {
> > @@ -861,6 +959,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const _Key2& __x) const
> > {
> > @@ -871,7 +970,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > {
> > return __x._M_cont.keys == __y._M_cont.keys
> > @@ -880,7 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Up = value_type>
> > [[nodiscard]]
> > - friend __detail::__synth3way_t<_Up>
> > + friend _GLIBCXX26_CONSTEXPR __detail::__synth3way_t<_Up>
> > operator<=>(const _Derived& __x, const _Derived& __y)
> > {
> > return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
> > @@ -888,11 +987,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __detail::__synth3way);
> > }
> >
> > - friend void
> > + friend _GLIBCXX26_CONSTEXPR void
> > swap(_Derived& __x, _Derived& __y) noexcept
> > { return __x.swap(__y); }
> >
> > template<typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > _M_erase_if(_Predicate __pred)
> > {
> > @@ -912,6 +1012,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > containers _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -921,13 +1022,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_unique();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_unique() requires (!_Multi)
> > {
> > struct __key_equiv
> > {
> > + _GLIBCXX26_CONSTEXPR
> > __key_equiv(key_compare __c) : _M_comp(__c) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return !_M_comp(__x.first, __y.first) && !_M_comp(__y.first, __x.first); }
> > @@ -958,12 +1062,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::__maybe_const_t<_Const, mapped_type>&>;
> > using difference_type = ptrdiff_t;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator() = default;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Iterator<!_Const> __it) requires _Const
> > : _M_cont(__it._M_cont), _M_index(__it._M_index)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator*() const noexcept
> > {
> > @@ -975,19 +1082,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > reference __p;
> >
> > + _GLIBCXX26_CONSTEXPR
> > const reference*
> > operator->() const noexcept
> > { return std::__addressof(__p); }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > pointer
> > operator->() const
> > { return pointer{operator*()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator[](difference_type __n) const noexcept
> > { return *(*this + __n); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator++() noexcept
> > {
> > @@ -995,6 +1106,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator--() noexcept
> > {
> > @@ -1002,6 +1114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator++(int) noexcept
> > {
> > @@ -1010,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator--(int) noexcept
> > {
> > @@ -1018,6 +1132,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator+=(difference_type __n) noexcept
> > {
> > @@ -1025,6 +1140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator-=(difference_type __n) noexcept
> > {
> > @@ -1036,45 +1152,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > friend _Flat_map_impl;
> > friend _Iterator<!_Const>;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires (!_Const)
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(const _Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires _Const
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(_Iterator __it, difference_type __n) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(difference_type __n, _Iterator __it) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator-(_Iterator __it, difference_type __n) noexcept
> > {
> > __it -= __n;
> > return __it;
> > }
> >
> > - friend difference_type
> > + friend _GLIBCXX26_CONSTEXPR difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > return __x._M_index - __y._M_index;
> > }
> >
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1082,7 +1200,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __x._M_index == __y._M_index;
> > }
> >
> > - friend strong_ordering
> > + friend _GLIBCXX26_CONSTEXPR strong_ordering
> > operator<=>(const _Iterator& __x, const _Iterator& __y)
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1146,30 +1264,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using _Impl::max_size;
> >
> > // element access
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](const key_type& __x)
> > { return try_emplace(__x).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](key_type&& __x)
> > { return try_emplace(std::move(__x)).first->second; }
> >
> > template<typename _Key2>
> > requires __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](_Key2&& __x)
> > { return try_emplace(std::forward<_Key2>(__x)).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const key_type& __x)
> > { return at<key_type>(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const key_type& __x) const
> > { return at<key_type>(__x); }
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const _Key2& __x)
> > {
> > @@ -1181,6 +1305,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const _Key2& __x) const
> > {
> > @@ -1203,12 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(nullopt, __k, std::forward<_Args>(__args)...); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(key_type&& __k, _Args&&... __args)
> > {
> > @@ -1222,6 +1349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<mapped_type, _Args...>
> > && (!is_convertible_v<_Key2&&, const_iterator>)
> > && (!is_convertible_v<_Key2&&, iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(_Key2&& __k, _Args&&... __args)
> > {
> > @@ -1231,12 +1359,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(__hint, __k, std::forward<_Args>(__args)...).first; }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
> > {
> > @@ -1248,6 +1378,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > requires __transparent_comparator<_Compare>
> > && is_constructible_v<key_type, _Key2>
> > && is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -1258,6 +1389,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(const key_type& __k, _Mapped&& __obj)
> > { return insert_or_assign<const key_type&, _Mapped>(__k, std::forward<_Mapped>(__obj)); }
> > @@ -1265,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1277,6 +1410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(_Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1290,6 +1424,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, const key_type& __k, _Mapped&& __obj)
> > {
> > @@ -1300,6 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1312,6 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, _Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1422,6 +1559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > @@ -1590,6 +1728,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > index 5bcda3464f1..04c2101aab1 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > @@ -17,7 +17,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -76,6 +76,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -127,6 +128,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(20,42) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -158,6 +160,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -186,6 +189,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -218,6 +222,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -227,6 +232,7 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -243,6 +249,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -254,6 +261,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4}}) );
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > @@ -263,6 +271,7 @@ test08()
> > m[k] = 0;
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -274,8 +283,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -290,3 +299,31 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > index f143f3acd1b..00644c14061 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > @@ -11,7 +11,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -74,6 +74,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -111,6 +112,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(12,3) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -137,6 +139,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -165,6 +168,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -197,6 +201,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -205,6 +210,8 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
> > }
> > +
> > +constexpr
> > void
> > test06()
> > {
> > @@ -221,6 +228,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -232,6 +240,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4},{3,3}}) );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -243,8 +252,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -258,3 +267,30 @@ main()
> > test07();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > --
> > 2.52.0
> >
> > From c2a1c42266bdd87c97868735514b621cec3e30bd Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <c8ef@outlook.com>
> > Date: Fri, 12 Dec 2025 19:26:01 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_map and flat_multimap
> >
> > This patch makes flat_map and flat_multimap constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_map: Add constexpr.
> > * testsuite/23_containers/flat_map/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_multimap/1.cc: Add constexpr test.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 +
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_map | 157 +++++++++++++++++-
> > .../testsuite/23_containers/flat_map/1.cc | 43 ++++-
> > .../23_containers/flat_multimap/1.cc | 42 ++++-
> > 5 files changed, 245 insertions(+), 15 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> > index 5b95db19ac6..f97276d80f2 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1351,6 +1351,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_map;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_flat_set;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> > index eee9890a72b..97b37e9a62b 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1496,6 +1496,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_map)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_map 202502L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_flat_map)
> > +# define __cpp_lib_constexpr_flat_map 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_map) */
> > +#undef __glibcxx_want_constexpr_flat_map
> > +
> > #if !defined(__cpp_lib_constexpr_flat_set)
> > # if (__cplusplus > 202302L)
> > # define __glibcxx_constexpr_flat_set 202502L
> > diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
> > index 637c3b7fe0d..e270735a87b 100644
> > --- a/libstdc++-v3/include/std/flat_map
> > +++ b/libstdc++-v3/include/std/flat_map
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_map
> > #define __glibcxx_want_flat_map
> > #include <bits/version.h>
> >
> > @@ -108,9 +109,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > class value_compare
> > {
> > [[no_unique_address]] key_compare _M_comp;
> > + _GLIBCXX26_CONSTEXPR
> > value_compare(key_compare __c) : _M_comp(__c) { }
> >
> > public:
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return _M_comp(__x.first, __y.first); }
> > @@ -129,10 +132,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > containers* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(containers& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > @@ -142,24 +147,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_disable()
> > { _M_cont = nullptr; }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard
> > _M_make_clear_guard()
> > { return _ClearGuard{this->_M_cont}; }
> >
> > public:
> > // constructors
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl() : _Flat_map_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > const key_compare& __comp = key_compare())
> > @@ -169,6 +179,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_sort_uniq();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > @@ -180,12 +191,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > : _M_cont(), _M_comp(__comp)
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -193,20 +206,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_map_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_map_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -216,12 +233,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const _Alloc& __a)
> > : _Flat_map_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a),
> > std::make_obj_using_allocator<mapped_container_type>(__a)),
> > @@ -229,6 +248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const _Alloc& __a)
> > @@ -236,6 +256,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const key_compare& __comp,
> > @@ -249,6 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -257,6 +279,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -271,6 +294,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a, __x._M_cont.keys),
> > std::make_obj_using_allocator<mapped_container_type>(__a, __x._M_cont.values)),
> > @@ -278,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>
> > (__a, std::move(__x._M_cont.keys)),
> > @@ -288,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_map_impl(std::move(__first), std::move(__last), key_compare(), __a)
> > @@ -295,6 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -303,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -311,6 +339,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -320,6 +349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare(), __a)
> > @@ -327,18 +357,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp,
> > const _Alloc& __a)
> > : _Flat_map_impl(__comp, __a)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_map_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -346,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -353,6 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -360,6 +395,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_map_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -369,64 +405,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > begin() noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > end() noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rbegin() noexcept
> > { return reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rend() noexcept
> > { return reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return const_reverse_iterator(cend()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return const_reverse_iterator(cbegin()); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.keys.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.keys.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return std::min<size_type>(keys().max_size(), values().max_size()); }
> > @@ -436,6 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // modifiers
> > template<typename _Key2, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -491,6 +543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -503,6 +556,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > {
> > @@ -510,36 +564,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return _M_try_emplace(__position, std::move(__p.first), std::move(__p.second)).first;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(const value_type& __x)
> > { return emplace(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(value_type&& __x)
> > { return emplace(std::move(__x)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, const value_type& __x)
> > { return emplace_hint(__position, __x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, value_type&& __x)
> > { return emplace_hint(__position, std::move(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(_Arg&& __x)
> > { return emplace(std::forward<_Arg>(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, _Arg&& __x)
> > { return emplace_hint(__position, std::forward<_Arg>(__x)); }
> >
> > private:
> > template<typename _Iter, typename _Sent>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_insert(_Iter __first, _Sent __last)
> > {
> > @@ -577,11 +638,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > public:
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > { _M_insert(std::move(__first), std::move(__last)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -590,18 +653,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > { _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(initializer_list<value_type> __il)
> > { insert(__il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t __s, initializer_list<value_type> __il)
> > { insert(__s, __il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > containers
> > extract() &&
> > {
> > @@ -609,6 +676,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return {std::move(_M_cont.keys), std::move(_M_cont.values)};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(key_container_type&& __key_cont, mapped_container_type&& __mapped_cont)
> > {
> > @@ -622,10 +690,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // try_emplace and insert_or_assign defined directly in class flat_map only.
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(iterator __position)
> > { return erase(static_cast<const_iterator>(__position)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > {
> > @@ -637,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -646,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > || (__transparent_comparator<_Compare>
> > && !is_convertible_v<_Key2, iterator>
> > && !is_convertible_v<_Key2, const_iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(_Key2&& __x)
> > {
> > @@ -655,6 +727,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > {
> > @@ -667,6 +740,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __y) noexcept
> > {
> > @@ -675,6 +749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::swap(_M_cont.values, __y._M_cont.values);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > {
> > @@ -684,32 +759,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return value_compare(_M_comp); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const key_container_type&
> > keys() const noexcept
> > { return _M_cont.keys; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_container_type&
> > values() const noexcept
> > { return _M_cont.values; }
> >
> > // map operations
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const key_type& __x)
> > { return find<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const key_type& __x) const
> > { return find<key_type>(__x); }
> > @@ -717,6 +798,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -730,6 +812,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const _Key2& __x) const
> > {
> > @@ -741,6 +824,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -748,6 +832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const _Key2& __x) const
> > {
> > @@ -761,6 +846,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -768,16 +854,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const _Key2& __x) const
> > { return find(__x) != cend(); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const key_type& __x)
> > { return lower_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const key_type& __x) const
> > { return lower_bound<key_type>(__x); }
> > @@ -785,6 +874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > {
> > @@ -796,6 +886,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const _Key2& __x) const
> > {
> > @@ -805,11 +896,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const key_type& __x)
> > { return upper_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const key_type& __x) const
> > { return upper_bound<key_type>(__x); }
> > @@ -817,6 +910,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > {
> > @@ -828,6 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const _Key2& __x) const
> > {
> > @@ -837,11 +932,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const key_type& __x)
> > { return equal_range<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const key_type& __x) const
> > { return equal_range<key_type>(__x); }
> > @@ -849,6 +946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const _Key2& __x)
> > {
> > @@ -861,6 +959,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const _Key2& __x) const
> > {
> > @@ -871,7 +970,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > {
> > return __x._M_cont.keys == __y._M_cont.keys
> > @@ -880,7 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Up = value_type>
> > [[nodiscard]]
> > - friend __detail::__synth3way_t<_Up>
> > + friend _GLIBCXX26_CONSTEXPR __detail::__synth3way_t<_Up>
> > operator<=>(const _Derived& __x, const _Derived& __y)
> > {
> > return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
> > @@ -888,11 +987,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __detail::__synth3way);
> > }
> >
> > - friend void
> > + friend _GLIBCXX26_CONSTEXPR void
> > swap(_Derived& __x, _Derived& __y) noexcept
> > { return __x.swap(__y); }
> >
> > template<typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > _M_erase_if(_Predicate __pred)
> > {
> > @@ -912,6 +1012,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > containers _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -921,13 +1022,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_unique();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_unique() requires (!_Multi)
> > {
> > struct __key_equiv
> > {
> > + _GLIBCXX26_CONSTEXPR
> > __key_equiv(key_compare __c) : _M_comp(__c) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return !_M_comp(__x.first, __y.first) && !_M_comp(__y.first, __x.first); }
> > @@ -958,12 +1062,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::__maybe_const_t<_Const, mapped_type>&>;
> > using difference_type = ptrdiff_t;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator() = default;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Iterator<!_Const> __it) requires _Const
> > : _M_cont(__it._M_cont), _M_index(__it._M_index)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator*() const noexcept
> > {
> > @@ -975,19 +1082,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > reference __p;
> >
> > + _GLIBCXX26_CONSTEXPR
> > const reference*
> > operator->() const noexcept
> > { return std::__addressof(__p); }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > pointer
> > operator->() const
> > { return pointer{operator*()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator[](difference_type __n) const noexcept
> > { return *(*this + __n); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator++() noexcept
> > {
> > @@ -995,6 +1106,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator--() noexcept
> > {
> > @@ -1002,6 +1114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator++(int) noexcept
> > {
> > @@ -1010,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator--(int) noexcept
> > {
> > @@ -1018,6 +1132,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator+=(difference_type __n) noexcept
> > {
> > @@ -1025,6 +1140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator-=(difference_type __n) noexcept
> > {
> > @@ -1036,45 +1152,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > friend _Flat_map_impl;
> > friend _Iterator<!_Const>;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires (!_Const)
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(const _Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires _Const
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(_Iterator __it, difference_type __n) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(difference_type __n, _Iterator __it) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator-(_Iterator __it, difference_type __n) noexcept
> > {
> > __it -= __n;
> > return __it;
> > }
> >
> > - friend difference_type
> > + friend _GLIBCXX26_CONSTEXPR difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > return __x._M_index - __y._M_index;
> > }
> >
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1082,7 +1200,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __x._M_index == __y._M_index;
> > }
> >
> > - friend strong_ordering
> > + friend _GLIBCXX26_CONSTEXPR strong_ordering
> > operator<=>(const _Iterator& __x, const _Iterator& __y)
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1146,30 +1264,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using _Impl::max_size;
> >
> > // element access
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](const key_type& __x)
> > { return try_emplace(__x).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](key_type&& __x)
> > { return try_emplace(std::move(__x)).first->second; }
> >
> > template<typename _Key2>
> > requires __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](_Key2&& __x)
> > { return try_emplace(std::forward<_Key2>(__x)).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const key_type& __x)
> > { return at<key_type>(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const key_type& __x) const
> > { return at<key_type>(__x); }
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const _Key2& __x)
> > {
> > @@ -1181,6 +1305,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const _Key2& __x) const
> > {
> > @@ -1203,12 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(nullopt, __k, std::forward<_Args>(__args)...); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(key_type&& __k, _Args&&... __args)
> > {
> > @@ -1222,6 +1349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<mapped_type, _Args...>
> > && (!is_convertible_v<_Key2&&, const_iterator>)
> > && (!is_convertible_v<_Key2&&, iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(_Key2&& __k, _Args&&... __args)
> > {
> > @@ -1231,12 +1359,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(__hint, __k, std::forward<_Args>(__args)...).first; }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
> > {
> > @@ -1248,6 +1378,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > requires __transparent_comparator<_Compare>
> > && is_constructible_v<key_type, _Key2>
> > && is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -1258,6 +1389,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(const key_type& __k, _Mapped&& __obj)
> > { return insert_or_assign<const key_type&, _Mapped>(__k, std::forward<_Mapped>(__obj)); }
> > @@ -1265,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1277,6 +1410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(_Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1290,6 +1424,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, const key_type& __k, _Mapped&& __obj)
> > {
> > @@ -1300,6 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1312,6 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, _Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1422,6 +1559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > @@ -1590,6 +1728,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > index 5bcda3464f1..04c2101aab1 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > @@ -17,7 +17,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -76,6 +76,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -127,6 +128,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(20,42) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -158,6 +160,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -186,6 +189,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -218,6 +222,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -227,6 +232,7 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -243,6 +249,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -254,6 +261,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4}}) );
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > @@ -263,6 +271,7 @@ test08()
> > m[k] = 0;
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -274,8 +283,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -290,3 +299,31 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > index f143f3acd1b..00644c14061 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > @@ -11,7 +11,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -74,6 +74,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -111,6 +112,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(12,3) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -137,6 +139,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -165,6 +168,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -197,6 +201,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -205,6 +210,8 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
> > }
> > +
> > +constexpr
> > void
> > test06()
> > {
> > @@ -221,6 +228,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -232,6 +240,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4},{3,3}}) );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -243,8 +252,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -258,3 +267,30 @@ main()
> > test07();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > --
> > 2.52.0
> >
> > From c2a1c42266bdd87c97868735514b621cec3e30bd Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <c8ef@outlook.com>
> > Date: Fri, 12 Dec 2025 19:26:01 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_map and flat_multimap
> >
> > This patch makes flat_map and flat_multimap constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_map: Add constexpr.
> > * testsuite/23_containers/flat_map/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_multimap/1.cc: Add constexpr test.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 +
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_map | 157 +++++++++++++++++-
> > .../testsuite/23_containers/flat_map/1.cc | 43 ++++-
> > .../23_containers/flat_multimap/1.cc | 42 ++++-
> > 5 files changed, 245 insertions(+), 15 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> > index 5b95db19ac6..f97276d80f2 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1351,6 +1351,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_map;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_flat_set;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> > index eee9890a72b..97b37e9a62b 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1496,6 +1496,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_map)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_map 202502L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_flat_map)
> > +# define __cpp_lib_constexpr_flat_map 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_map) */
> > +#undef __glibcxx_want_constexpr_flat_map
> > +
> > #if !defined(__cpp_lib_constexpr_flat_set)
> > # if (__cplusplus > 202302L)
> > # define __glibcxx_constexpr_flat_set 202502L
> > diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
> > index 637c3b7fe0d..e270735a87b 100644
> > --- a/libstdc++-v3/include/std/flat_map
> > +++ b/libstdc++-v3/include/std/flat_map
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_map
> > #define __glibcxx_want_flat_map
> > #include <bits/version.h>
> >
> > @@ -108,9 +109,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > class value_compare
> > {
> > [[no_unique_address]] key_compare _M_comp;
> > + _GLIBCXX26_CONSTEXPR
> > value_compare(key_compare __c) : _M_comp(__c) { }
> >
> > public:
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return _M_comp(__x.first, __y.first); }
> > @@ -129,10 +132,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > containers* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(containers& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > @@ -142,24 +147,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_disable()
> > { _M_cont = nullptr; }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard
> > _M_make_clear_guard()
> > { return _ClearGuard{this->_M_cont}; }
> >
> > public:
> > // constructors
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl() : _Flat_map_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > const key_compare& __comp = key_compare())
> > @@ -169,6 +179,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_sort_uniq();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > @@ -180,12 +191,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > : _M_cont(), _M_comp(__comp)
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -193,20 +206,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_map_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_map_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -216,12 +233,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const _Alloc& __a)
> > : _Flat_map_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a),
> > std::make_obj_using_allocator<mapped_container_type>(__a)),
> > @@ -229,6 +248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const _Alloc& __a)
> > @@ -236,6 +256,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const key_compare& __comp,
> > @@ -249,6 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -257,6 +279,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -271,6 +294,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a, __x._M_cont.keys),
> > std::make_obj_using_allocator<mapped_container_type>(__a, __x._M_cont.values)),
> > @@ -278,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>
> > (__a, std::move(__x._M_cont.keys)),
> > @@ -288,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_map_impl(std::move(__first), std::move(__last), key_compare(), __a)
> > @@ -295,6 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -303,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -311,6 +339,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -320,6 +349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare(), __a)
> > @@ -327,18 +357,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp,
> > const _Alloc& __a)
> > : _Flat_map_impl(__comp, __a)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_map_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -346,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -353,6 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -360,6 +395,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_map_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -369,64 +405,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > begin() noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > end() noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rbegin() noexcept
> > { return reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rend() noexcept
> > { return reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return const_reverse_iterator(cend()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return const_reverse_iterator(cbegin()); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.keys.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.keys.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return std::min<size_type>(keys().max_size(), values().max_size()); }
> > @@ -436,6 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // modifiers
> > template<typename _Key2, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -491,6 +543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -503,6 +556,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > {
> > @@ -510,36 +564,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return _M_try_emplace(__position, std::move(__p.first), std::move(__p.second)).first;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(const value_type& __x)
> > { return emplace(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(value_type&& __x)
> > { return emplace(std::move(__x)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, const value_type& __x)
> > { return emplace_hint(__position, __x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, value_type&& __x)
> > { return emplace_hint(__position, std::move(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(_Arg&& __x)
> > { return emplace(std::forward<_Arg>(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, _Arg&& __x)
> > { return emplace_hint(__position, std::forward<_Arg>(__x)); }
> >
> > private:
> > template<typename _Iter, typename _Sent>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_insert(_Iter __first, _Sent __last)
> > {
> > @@ -577,11 +638,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > public:
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > { _M_insert(std::move(__first), std::move(__last)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -590,18 +653,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > { _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(initializer_list<value_type> __il)
> > { insert(__il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t __s, initializer_list<value_type> __il)
> > { insert(__s, __il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > containers
> > extract() &&
> > {
> > @@ -609,6 +676,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return {std::move(_M_cont.keys), std::move(_M_cont.values)};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(key_container_type&& __key_cont, mapped_container_type&& __mapped_cont)
> > {
> > @@ -622,10 +690,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // try_emplace and insert_or_assign defined directly in class flat_map only.
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(iterator __position)
> > { return erase(static_cast<const_iterator>(__position)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > {
> > @@ -637,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -646,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > || (__transparent_comparator<_Compare>
> > && !is_convertible_v<_Key2, iterator>
> > && !is_convertible_v<_Key2, const_iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(_Key2&& __x)
> > {
> > @@ -655,6 +727,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > {
> > @@ -667,6 +740,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __y) noexcept
> > {
> > @@ -675,6 +749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::swap(_M_cont.values, __y._M_cont.values);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > {
> > @@ -684,32 +759,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return value_compare(_M_comp); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const key_container_type&
> > keys() const noexcept
> > { return _M_cont.keys; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_container_type&
> > values() const noexcept
> > { return _M_cont.values; }
> >
> > // map operations
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const key_type& __x)
> > { return find<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const key_type& __x) const
> > { return find<key_type>(__x); }
> > @@ -717,6 +798,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -730,6 +812,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const _Key2& __x) const
> > {
> > @@ -741,6 +824,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -748,6 +832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const _Key2& __x) const
> > {
> > @@ -761,6 +846,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -768,16 +854,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const _Key2& __x) const
> > { return find(__x) != cend(); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const key_type& __x)
> > { return lower_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const key_type& __x) const
> > { return lower_bound<key_type>(__x); }
> > @@ -785,6 +874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > {
> > @@ -796,6 +886,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const _Key2& __x) const
> > {
> > @@ -805,11 +896,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const key_type& __x)
> > { return upper_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const key_type& __x) const
> > { return upper_bound<key_type>(__x); }
> > @@ -817,6 +910,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > {
> > @@ -828,6 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const _Key2& __x) const
> > {
> > @@ -837,11 +932,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const key_type& __x)
> > { return equal_range<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const key_type& __x) const
> > { return equal_range<key_type>(__x); }
> > @@ -849,6 +946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const _Key2& __x)
> > {
> > @@ -861,6 +959,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const _Key2& __x) const
> > {
> > @@ -871,7 +970,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > {
> > return __x._M_cont.keys == __y._M_cont.keys
> > @@ -880,7 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Up = value_type>
> > [[nodiscard]]
> > - friend __detail::__synth3way_t<_Up>
> > + friend _GLIBCXX26_CONSTEXPR __detail::__synth3way_t<_Up>
> > operator<=>(const _Derived& __x, const _Derived& __y)
> > {
> > return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
> > @@ -888,11 +987,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __detail::__synth3way);
> > }
> >
> > - friend void
> > + friend _GLIBCXX26_CONSTEXPR void
> > swap(_Derived& __x, _Derived& __y) noexcept
> > { return __x.swap(__y); }
> >
> > template<typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > _M_erase_if(_Predicate __pred)
> > {
> > @@ -912,6 +1012,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > containers _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -921,13 +1022,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_unique();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_unique() requires (!_Multi)
> > {
> > struct __key_equiv
> > {
> > + _GLIBCXX26_CONSTEXPR
> > __key_equiv(key_compare __c) : _M_comp(__c) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return !_M_comp(__x.first, __y.first) && !_M_comp(__y.first, __x.first); }
> > @@ -958,12 +1062,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::__maybe_const_t<_Const, mapped_type>&>;
> > using difference_type = ptrdiff_t;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator() = default;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Iterator<!_Const> __it) requires _Const
> > : _M_cont(__it._M_cont), _M_index(__it._M_index)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator*() const noexcept
> > {
> > @@ -975,19 +1082,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > reference __p;
> >
> > + _GLIBCXX26_CONSTEXPR
> > const reference*
> > operator->() const noexcept
> > { return std::__addressof(__p); }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > pointer
> > operator->() const
> > { return pointer{operator*()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator[](difference_type __n) const noexcept
> > { return *(*this + __n); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator++() noexcept
> > {
> > @@ -995,6 +1106,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator--() noexcept
> > {
> > @@ -1002,6 +1114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator++(int) noexcept
> > {
> > @@ -1010,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator--(int) noexcept
> > {
> > @@ -1018,6 +1132,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator+=(difference_type __n) noexcept
> > {
> > @@ -1025,6 +1140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator-=(difference_type __n) noexcept
> > {
> > @@ -1036,45 +1152,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > friend _Flat_map_impl;
> > friend _Iterator<!_Const>;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires (!_Const)
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(const _Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires _Const
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(_Iterator __it, difference_type __n) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(difference_type __n, _Iterator __it) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator-(_Iterator __it, difference_type __n) noexcept
> > {
> > __it -= __n;
> > return __it;
> > }
> >
> > - friend difference_type
> > + friend _GLIBCXX26_CONSTEXPR difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > return __x._M_index - __y._M_index;
> > }
> >
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1082,7 +1200,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __x._M_index == __y._M_index;
> > }
> >
> > - friend strong_ordering
> > + friend _GLIBCXX26_CONSTEXPR strong_ordering
> > operator<=>(const _Iterator& __x, const _Iterator& __y)
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1146,30 +1264,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using _Impl::max_size;
> >
> > // element access
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](const key_type& __x)
> > { return try_emplace(__x).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](key_type&& __x)
> > { return try_emplace(std::move(__x)).first->second; }
> >
> > template<typename _Key2>
> > requires __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](_Key2&& __x)
> > { return try_emplace(std::forward<_Key2>(__x)).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const key_type& __x)
> > { return at<key_type>(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const key_type& __x) const
> > { return at<key_type>(__x); }
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const _Key2& __x)
> > {
> > @@ -1181,6 +1305,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const _Key2& __x) const
> > {
> > @@ -1203,12 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(nullopt, __k, std::forward<_Args>(__args)...); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(key_type&& __k, _Args&&... __args)
> > {
> > @@ -1222,6 +1349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<mapped_type, _Args...>
> > && (!is_convertible_v<_Key2&&, const_iterator>)
> > && (!is_convertible_v<_Key2&&, iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(_Key2&& __k, _Args&&... __args)
> > {
> > @@ -1231,12 +1359,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(__hint, __k, std::forward<_Args>(__args)...).first; }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
> > {
> > @@ -1248,6 +1378,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > requires __transparent_comparator<_Compare>
> > && is_constructible_v<key_type, _Key2>
> > && is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -1258,6 +1389,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(const key_type& __k, _Mapped&& __obj)
> > { return insert_or_assign<const key_type&, _Mapped>(__k, std::forward<_Mapped>(__obj)); }
> > @@ -1265,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1277,6 +1410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(_Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1290,6 +1424,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, const key_type& __k, _Mapped&& __obj)
> > {
> > @@ -1300,6 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1312,6 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, _Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1422,6 +1559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > @@ -1590,6 +1728,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > index 5bcda3464f1..04c2101aab1 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > @@ -17,7 +17,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -76,6 +76,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -127,6 +128,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(20,42) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -158,6 +160,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -186,6 +189,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -218,6 +222,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -227,6 +232,7 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -243,6 +249,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -254,6 +261,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4}}) );
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > @@ -263,6 +271,7 @@ test08()
> > m[k] = 0;
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -274,8 +283,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -290,3 +299,31 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > index f143f3acd1b..00644c14061 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > @@ -11,7 +11,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -74,6 +74,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -111,6 +112,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(12,3) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -137,6 +139,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -165,6 +168,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -197,6 +201,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -205,6 +210,8 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
> > }
> > +
> > +constexpr
> > void
> > test06()
> > {
> > @@ -221,6 +228,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -232,6 +240,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4},{3,3}}) );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -243,8 +252,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -258,3 +267,30 @@ main()
> > test07();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > --
> > 2.52.0
> >
> > From c2a1c42266bdd87c97868735514b621cec3e30bd Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <c8ef@outlook.com>
> > Date: Fri, 12 Dec 2025 19:26:01 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_map and flat_multimap
> >
> > This patch makes flat_map and flat_multimap constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_map: Add constexpr.
> > * testsuite/23_containers/flat_map/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_multimap/1.cc: Add constexpr test.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 +
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_map | 157 +++++++++++++++++-
> > .../testsuite/23_containers/flat_map/1.cc | 43 ++++-
> > .../23_containers/flat_multimap/1.cc | 42 ++++-
> > 5 files changed, 245 insertions(+), 15 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> > index 5b95db19ac6..f97276d80f2 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1351,6 +1351,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_map;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_flat_set;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> > index eee9890a72b..97b37e9a62b 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1496,6 +1496,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_map)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_map 202502L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_flat_map)
> > +# define __cpp_lib_constexpr_flat_map 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_map) */
> > +#undef __glibcxx_want_constexpr_flat_map
> > +
> > #if !defined(__cpp_lib_constexpr_flat_set)
> > # if (__cplusplus > 202302L)
> > # define __glibcxx_constexpr_flat_set 202502L
> > diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
> > index 637c3b7fe0d..e270735a87b 100644
> > --- a/libstdc++-v3/include/std/flat_map
> > +++ b/libstdc++-v3/include/std/flat_map
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_map
> > #define __glibcxx_want_flat_map
> > #include <bits/version.h>
> >
> > @@ -108,9 +109,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > class value_compare
> > {
> > [[no_unique_address]] key_compare _M_comp;
> > + _GLIBCXX26_CONSTEXPR
> > value_compare(key_compare __c) : _M_comp(__c) { }
> >
> > public:
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return _M_comp(__x.first, __y.first); }
> > @@ -129,10 +132,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > containers* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(containers& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > @@ -142,24 +147,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_disable()
> > { _M_cont = nullptr; }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard
> > _M_make_clear_guard()
> > { return _ClearGuard{this->_M_cont}; }
> >
> > public:
> > // constructors
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl() : _Flat_map_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > const key_compare& __comp = key_compare())
> > @@ -169,6 +179,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_sort_uniq();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > @@ -180,12 +191,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > : _M_cont(), _M_comp(__comp)
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -193,20 +206,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_map_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_map_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -216,12 +233,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const _Alloc& __a)
> > : _Flat_map_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a),
> > std::make_obj_using_allocator<mapped_container_type>(__a)),
> > @@ -229,6 +248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const _Alloc& __a)
> > @@ -236,6 +256,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const key_compare& __comp,
> > @@ -249,6 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -257,6 +279,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -271,6 +294,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a, __x._M_cont.keys),
> > std::make_obj_using_allocator<mapped_container_type>(__a, __x._M_cont.values)),
> > @@ -278,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>
> > (__a, std::move(__x._M_cont.keys)),
> > @@ -288,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_map_impl(std::move(__first), std::move(__last), key_compare(), __a)
> > @@ -295,6 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -303,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -311,6 +339,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -320,6 +349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare(), __a)
> > @@ -327,18 +357,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp,
> > const _Alloc& __a)
> > : _Flat_map_impl(__comp, __a)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_map_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -346,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -353,6 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -360,6 +395,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_map_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -369,64 +405,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > begin() noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > end() noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rbegin() noexcept
> > { return reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rend() noexcept
> > { return reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return const_reverse_iterator(cend()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return const_reverse_iterator(cbegin()); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.keys.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.keys.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return std::min<size_type>(keys().max_size(), values().max_size()); }
> > @@ -436,6 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // modifiers
> > template<typename _Key2, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -491,6 +543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -503,6 +556,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > {
> > @@ -510,36 +564,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return _M_try_emplace(__position, std::move(__p.first), std::move(__p.second)).first;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(const value_type& __x)
> > { return emplace(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(value_type&& __x)
> > { return emplace(std::move(__x)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, const value_type& __x)
> > { return emplace_hint(__position, __x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, value_type&& __x)
> > { return emplace_hint(__position, std::move(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(_Arg&& __x)
> > { return emplace(std::forward<_Arg>(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, _Arg&& __x)
> > { return emplace_hint(__position, std::forward<_Arg>(__x)); }
> >
> > private:
> > template<typename _Iter, typename _Sent>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_insert(_Iter __first, _Sent __last)
> > {
> > @@ -577,11 +638,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > public:
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > { _M_insert(std::move(__first), std::move(__last)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -590,18 +653,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > { _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(initializer_list<value_type> __il)
> > { insert(__il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t __s, initializer_list<value_type> __il)
> > { insert(__s, __il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > containers
> > extract() &&
> > {
> > @@ -609,6 +676,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return {std::move(_M_cont.keys), std::move(_M_cont.values)};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(key_container_type&& __key_cont, mapped_container_type&& __mapped_cont)
> > {
> > @@ -622,10 +690,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // try_emplace and insert_or_assign defined directly in class flat_map only.
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(iterator __position)
> > { return erase(static_cast<const_iterator>(__position)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > {
> > @@ -637,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -646,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > || (__transparent_comparator<_Compare>
> > && !is_convertible_v<_Key2, iterator>
> > && !is_convertible_v<_Key2, const_iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(_Key2&& __x)
> > {
> > @@ -655,6 +727,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > {
> > @@ -667,6 +740,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __y) noexcept
> > {
> > @@ -675,6 +749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::swap(_M_cont.values, __y._M_cont.values);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > {
> > @@ -684,32 +759,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return value_compare(_M_comp); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const key_container_type&
> > keys() const noexcept
> > { return _M_cont.keys; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_container_type&
> > values() const noexcept
> > { return _M_cont.values; }
> >
> > // map operations
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const key_type& __x)
> > { return find<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const key_type& __x) const
> > { return find<key_type>(__x); }
> > @@ -717,6 +798,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -730,6 +812,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const _Key2& __x) const
> > {
> > @@ -741,6 +824,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -748,6 +832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const _Key2& __x) const
> > {
> > @@ -761,6 +846,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -768,16 +854,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const _Key2& __x) const
> > { return find(__x) != cend(); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const key_type& __x)
> > { return lower_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const key_type& __x) const
> > { return lower_bound<key_type>(__x); }
> > @@ -785,6 +874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > {
> > @@ -796,6 +886,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const _Key2& __x) const
> > {
> > @@ -805,11 +896,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const key_type& __x)
> > { return upper_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const key_type& __x) const
> > { return upper_bound<key_type>(__x); }
> > @@ -817,6 +910,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > {
> > @@ -828,6 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const _Key2& __x) const
> > {
> > @@ -837,11 +932,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const key_type& __x)
> > { return equal_range<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const key_type& __x) const
> > { return equal_range<key_type>(__x); }
> > @@ -849,6 +946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const _Key2& __x)
> > {
> > @@ -861,6 +959,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const _Key2& __x) const
> > {
> > @@ -871,7 +970,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > {
> > return __x._M_cont.keys == __y._M_cont.keys
> > @@ -880,7 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Up = value_type>
> > [[nodiscard]]
> > - friend __detail::__synth3way_t<_Up>
> > + friend _GLIBCXX26_CONSTEXPR __detail::__synth3way_t<_Up>
> > operator<=>(const _Derived& __x, const _Derived& __y)
> > {
> > return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
> > @@ -888,11 +987,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __detail::__synth3way);
> > }
> >
> > - friend void
> > + friend _GLIBCXX26_CONSTEXPR void
> > swap(_Derived& __x, _Derived& __y) noexcept
> > { return __x.swap(__y); }
> >
> > template<typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > _M_erase_if(_Predicate __pred)
> > {
> > @@ -912,6 +1012,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > containers _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -921,13 +1022,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_unique();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_unique() requires (!_Multi)
> > {
> > struct __key_equiv
> > {
> > + _GLIBCXX26_CONSTEXPR
> > __key_equiv(key_compare __c) : _M_comp(__c) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return !_M_comp(__x.first, __y.first) && !_M_comp(__y.first, __x.first); }
> > @@ -958,12 +1062,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::__maybe_const_t<_Const, mapped_type>&>;
> > using difference_type = ptrdiff_t;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator() = default;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Iterator<!_Const> __it) requires _Const
> > : _M_cont(__it._M_cont), _M_index(__it._M_index)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator*() const noexcept
> > {
> > @@ -975,19 +1082,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > reference __p;
> >
> > + _GLIBCXX26_CONSTEXPR
> > const reference*
> > operator->() const noexcept
> > { return std::__addressof(__p); }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > pointer
> > operator->() const
> > { return pointer{operator*()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator[](difference_type __n) const noexcept
> > { return *(*this + __n); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator++() noexcept
> > {
> > @@ -995,6 +1106,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator--() noexcept
> > {
> > @@ -1002,6 +1114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator++(int) noexcept
> > {
> > @@ -1010,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator--(int) noexcept
> > {
> > @@ -1018,6 +1132,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator+=(difference_type __n) noexcept
> > {
> > @@ -1025,6 +1140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator-=(difference_type __n) noexcept
> > {
> > @@ -1036,45 +1152,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > friend _Flat_map_impl;
> > friend _Iterator<!_Const>;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires (!_Const)
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(const _Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires _Const
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(_Iterator __it, difference_type __n) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(difference_type __n, _Iterator __it) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator-(_Iterator __it, difference_type __n) noexcept
> > {
> > __it -= __n;
> > return __it;
> > }
> >
> > - friend difference_type
> > + friend _GLIBCXX26_CONSTEXPR difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > return __x._M_index - __y._M_index;
> > }
> >
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1082,7 +1200,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __x._M_index == __y._M_index;
> > }
> >
> > - friend strong_ordering
> > + friend _GLIBCXX26_CONSTEXPR strong_ordering
> > operator<=>(const _Iterator& __x, const _Iterator& __y)
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1146,30 +1264,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using _Impl::max_size;
> >
> > // element access
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](const key_type& __x)
> > { return try_emplace(__x).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](key_type&& __x)
> > { return try_emplace(std::move(__x)).first->second; }
> >
> > template<typename _Key2>
> > requires __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](_Key2&& __x)
> > { return try_emplace(std::forward<_Key2>(__x)).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const key_type& __x)
> > { return at<key_type>(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const key_type& __x) const
> > { return at<key_type>(__x); }
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const _Key2& __x)
> > {
> > @@ -1181,6 +1305,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const _Key2& __x) const
> > {
> > @@ -1203,12 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(nullopt, __k, std::forward<_Args>(__args)...); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(key_type&& __k, _Args&&... __args)
> > {
> > @@ -1222,6 +1349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<mapped_type, _Args...>
> > && (!is_convertible_v<_Key2&&, const_iterator>)
> > && (!is_convertible_v<_Key2&&, iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(_Key2&& __k, _Args&&... __args)
> > {
> > @@ -1231,12 +1359,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(__hint, __k, std::forward<_Args>(__args)...).first; }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
> > {
> > @@ -1248,6 +1378,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > requires __transparent_comparator<_Compare>
> > && is_constructible_v<key_type, _Key2>
> > && is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -1258,6 +1389,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(const key_type& __k, _Mapped&& __obj)
> > { return insert_or_assign<const key_type&, _Mapped>(__k, std::forward<_Mapped>(__obj)); }
> > @@ -1265,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1277,6 +1410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(_Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1290,6 +1424,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, const key_type& __k, _Mapped&& __obj)
> > {
> > @@ -1300,6 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1312,6 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, _Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1422,6 +1559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > @@ -1590,6 +1728,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > index 5bcda3464f1..04c2101aab1 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > @@ -17,7 +17,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -76,6 +76,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -127,6 +128,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(20,42) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -158,6 +160,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -186,6 +189,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -218,6 +222,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -227,6 +232,7 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -243,6 +249,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -254,6 +261,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4}}) );
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > @@ -263,6 +271,7 @@ test08()
> > m[k] = 0;
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -274,8 +283,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -290,3 +299,31 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > index f143f3acd1b..00644c14061 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > @@ -11,7 +11,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -74,6 +74,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -111,6 +112,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(12,3) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -137,6 +139,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -165,6 +168,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -197,6 +201,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -205,6 +210,8 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
> > }
> > +
> > +constexpr
> > void
> > test06()
> > {
> > @@ -221,6 +228,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -232,6 +240,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4},{3,3}}) );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -243,8 +252,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -258,3 +267,30 @@ main()
> > test07();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > --
> > 2.52.0
> >
> > From c2a1c42266bdd87c97868735514b621cec3e30bd Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <c8ef@outlook.com>
> > Date: Fri, 12 Dec 2025 19:26:01 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_map and flat_multimap
> >
> > This patch makes flat_map and flat_multimap constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_map: Add constexpr.
> > * testsuite/23_containers/flat_map/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_multimap/1.cc: Add constexpr test.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 +
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_map | 157 +++++++++++++++++-
> > .../testsuite/23_containers/flat_map/1.cc | 43 ++++-
> > .../23_containers/flat_multimap/1.cc | 42 ++++-
> > 5 files changed, 245 insertions(+), 15 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> > index 5b95db19ac6..f97276d80f2 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1351,6 +1351,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_map;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_flat_set;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> > index eee9890a72b..97b37e9a62b 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1496,6 +1496,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_map)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_map 202502L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_flat_map)
> > +# define __cpp_lib_constexpr_flat_map 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_map) */
> > +#undef __glibcxx_want_constexpr_flat_map
> > +
> > #if !defined(__cpp_lib_constexpr_flat_set)
> > # if (__cplusplus > 202302L)
> > # define __glibcxx_constexpr_flat_set 202502L
> > diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
> > index 637c3b7fe0d..e270735a87b 100644
> > --- a/libstdc++-v3/include/std/flat_map
> > +++ b/libstdc++-v3/include/std/flat_map
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_map
> > #define __glibcxx_want_flat_map
> > #include <bits/version.h>
> >
> > @@ -108,9 +109,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > class value_compare
> > {
> > [[no_unique_address]] key_compare _M_comp;
> > + _GLIBCXX26_CONSTEXPR
> > value_compare(key_compare __c) : _M_comp(__c) { }
> >
> > public:
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return _M_comp(__x.first, __y.first); }
> > @@ -129,10 +132,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > containers* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(containers& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > @@ -142,24 +147,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_disable()
> > { _M_cont = nullptr; }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard
> > _M_make_clear_guard()
> > { return _ClearGuard{this->_M_cont}; }
> >
> > public:
> > // constructors
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl() : _Flat_map_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > const key_compare& __comp = key_compare())
> > @@ -169,6 +179,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_sort_uniq();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > @@ -180,12 +191,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > : _M_cont(), _M_comp(__comp)
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -193,20 +206,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_map_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_map_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -216,12 +233,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const _Alloc& __a)
> > : _Flat_map_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a),
> > std::make_obj_using_allocator<mapped_container_type>(__a)),
> > @@ -229,6 +248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const _Alloc& __a)
> > @@ -236,6 +256,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const key_compare& __comp,
> > @@ -249,6 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -257,6 +279,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -271,6 +294,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a, __x._M_cont.keys),
> > std::make_obj_using_allocator<mapped_container_type>(__a, __x._M_cont.values)),
> > @@ -278,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>
> > (__a, std::move(__x._M_cont.keys)),
> > @@ -288,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_map_impl(std::move(__first), std::move(__last), key_compare(), __a)
> > @@ -295,6 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -303,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -311,6 +339,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -320,6 +349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare(), __a)
> > @@ -327,18 +357,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp,
> > const _Alloc& __a)
> > : _Flat_map_impl(__comp, __a)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_map_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -346,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -353,6 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -360,6 +395,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_map_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -369,64 +405,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > begin() noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > end() noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rbegin() noexcept
> > { return reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rend() noexcept
> > { return reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return const_reverse_iterator(cend()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return const_reverse_iterator(cbegin()); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.keys.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.keys.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return std::min<size_type>(keys().max_size(), values().max_size()); }
> > @@ -436,6 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // modifiers
> > template<typename _Key2, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -491,6 +543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -503,6 +556,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > {
> > @@ -510,36 +564,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return _M_try_emplace(__position, std::move(__p.first), std::move(__p.second)).first;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(const value_type& __x)
> > { return emplace(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(value_type&& __x)
> > { return emplace(std::move(__x)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, const value_type& __x)
> > { return emplace_hint(__position, __x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, value_type&& __x)
> > { return emplace_hint(__position, std::move(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(_Arg&& __x)
> > { return emplace(std::forward<_Arg>(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, _Arg&& __x)
> > { return emplace_hint(__position, std::forward<_Arg>(__x)); }
> >
> > private:
> > template<typename _Iter, typename _Sent>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_insert(_Iter __first, _Sent __last)
> > {
> > @@ -577,11 +638,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > public:
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > { _M_insert(std::move(__first), std::move(__last)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -590,18 +653,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > { _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(initializer_list<value_type> __il)
> > { insert(__il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t __s, initializer_list<value_type> __il)
> > { insert(__s, __il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > containers
> > extract() &&
> > {
> > @@ -609,6 +676,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return {std::move(_M_cont.keys), std::move(_M_cont.values)};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(key_container_type&& __key_cont, mapped_container_type&& __mapped_cont)
> > {
> > @@ -622,10 +690,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // try_emplace and insert_or_assign defined directly in class flat_map only.
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(iterator __position)
> > { return erase(static_cast<const_iterator>(__position)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > {
> > @@ -637,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -646,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > || (__transparent_comparator<_Compare>
> > && !is_convertible_v<_Key2, iterator>
> > && !is_convertible_v<_Key2, const_iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(_Key2&& __x)
> > {
> > @@ -655,6 +727,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > {
> > @@ -667,6 +740,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __y) noexcept
> > {
> > @@ -675,6 +749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::swap(_M_cont.values, __y._M_cont.values);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > {
> > @@ -684,32 +759,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return value_compare(_M_comp); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const key_container_type&
> > keys() const noexcept
> > { return _M_cont.keys; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_container_type&
> > values() const noexcept
> > { return _M_cont.values; }
> >
> > // map operations
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const key_type& __x)
> > { return find<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const key_type& __x) const
> > { return find<key_type>(__x); }
> > @@ -717,6 +798,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -730,6 +812,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const _Key2& __x) const
> > {
> > @@ -741,6 +824,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -748,6 +832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const _Key2& __x) const
> > {
> > @@ -761,6 +846,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -768,16 +854,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const _Key2& __x) const
> > { return find(__x) != cend(); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const key_type& __x)
> > { return lower_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const key_type& __x) const
> > { return lower_bound<key_type>(__x); }
> > @@ -785,6 +874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > {
> > @@ -796,6 +886,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const _Key2& __x) const
> > {
> > @@ -805,11 +896,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const key_type& __x)
> > { return upper_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const key_type& __x) const
> > { return upper_bound<key_type>(__x); }
> > @@ -817,6 +910,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > {
> > @@ -828,6 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const _Key2& __x) const
> > {
> > @@ -837,11 +932,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const key_type& __x)
> > { return equal_range<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const key_type& __x) const
> > { return equal_range<key_type>(__x); }
> > @@ -849,6 +946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const _Key2& __x)
> > {
> > @@ -861,6 +959,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const _Key2& __x) const
> > {
> > @@ -871,7 +970,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > {
> > return __x._M_cont.keys == __y._M_cont.keys
> > @@ -880,7 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Up = value_type>
> > [[nodiscard]]
> > - friend __detail::__synth3way_t<_Up>
> > + friend _GLIBCXX26_CONSTEXPR __detail::__synth3way_t<_Up>
> > operator<=>(const _Derived& __x, const _Derived& __y)
> > {
> > return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
> > @@ -888,11 +987,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __detail::__synth3way);
> > }
> >
> > - friend void
> > + friend _GLIBCXX26_CONSTEXPR void
> > swap(_Derived& __x, _Derived& __y) noexcept
> > { return __x.swap(__y); }
> >
> > template<typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > _M_erase_if(_Predicate __pred)
> > {
> > @@ -912,6 +1012,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > containers _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -921,13 +1022,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_unique();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_unique() requires (!_Multi)
> > {
> > struct __key_equiv
> > {
> > + _GLIBCXX26_CONSTEXPR
> > __key_equiv(key_compare __c) : _M_comp(__c) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return !_M_comp(__x.first, __y.first) && !_M_comp(__y.first, __x.first); }
> > @@ -958,12 +1062,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::__maybe_const_t<_Const, mapped_type>&>;
> > using difference_type = ptrdiff_t;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator() = default;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Iterator<!_Const> __it) requires _Const
> > : _M_cont(__it._M_cont), _M_index(__it._M_index)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator*() const noexcept
> > {
> > @@ -975,19 +1082,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > reference __p;
> >
> > + _GLIBCXX26_CONSTEXPR
> > const reference*
> > operator->() const noexcept
> > { return std::__addressof(__p); }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > pointer
> > operator->() const
> > { return pointer{operator*()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator[](difference_type __n) const noexcept
> > { return *(*this + __n); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator++() noexcept
> > {
> > @@ -995,6 +1106,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator--() noexcept
> > {
> > @@ -1002,6 +1114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator++(int) noexcept
> > {
> > @@ -1010,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator--(int) noexcept
> > {
> > @@ -1018,6 +1132,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator+=(difference_type __n) noexcept
> > {
> > @@ -1025,6 +1140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator-=(difference_type __n) noexcept
> > {
> > @@ -1036,45 +1152,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > friend _Flat_map_impl;
> > friend _Iterator<!_Const>;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires (!_Const)
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(const _Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires _Const
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(_Iterator __it, difference_type __n) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(difference_type __n, _Iterator __it) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator-(_Iterator __it, difference_type __n) noexcept
> > {
> > __it -= __n;
> > return __it;
> > }
> >
> > - friend difference_type
> > + friend _GLIBCXX26_CONSTEXPR difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > return __x._M_index - __y._M_index;
> > }
> >
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1082,7 +1200,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __x._M_index == __y._M_index;
> > }
> >
> > - friend strong_ordering
> > + friend _GLIBCXX26_CONSTEXPR strong_ordering
> > operator<=>(const _Iterator& __x, const _Iterator& __y)
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1146,30 +1264,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using _Impl::max_size;
> >
> > // element access
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](const key_type& __x)
> > { return try_emplace(__x).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](key_type&& __x)
> > { return try_emplace(std::move(__x)).first->second; }
> >
> > template<typename _Key2>
> > requires __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](_Key2&& __x)
> > { return try_emplace(std::forward<_Key2>(__x)).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const key_type& __x)
> > { return at<key_type>(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const key_type& __x) const
> > { return at<key_type>(__x); }
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const _Key2& __x)
> > {
> > @@ -1181,6 +1305,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const _Key2& __x) const
> > {
> > @@ -1203,12 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(nullopt, __k, std::forward<_Args>(__args)...); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(key_type&& __k, _Args&&... __args)
> > {
> > @@ -1222,6 +1349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<mapped_type, _Args...>
> > && (!is_convertible_v<_Key2&&, const_iterator>)
> > && (!is_convertible_v<_Key2&&, iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(_Key2&& __k, _Args&&... __args)
> > {
> > @@ -1231,12 +1359,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(__hint, __k, std::forward<_Args>(__args)...).first; }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
> > {
> > @@ -1248,6 +1378,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > requires __transparent_comparator<_Compare>
> > && is_constructible_v<key_type, _Key2>
> > && is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -1258,6 +1389,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(const key_type& __k, _Mapped&& __obj)
> > { return insert_or_assign<const key_type&, _Mapped>(__k, std::forward<_Mapped>(__obj)); }
> > @@ -1265,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1277,6 +1410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(_Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1290,6 +1424,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, const key_type& __k, _Mapped&& __obj)
> > {
> > @@ -1300,6 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1312,6 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, _Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1422,6 +1559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > @@ -1590,6 +1728,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > index 5bcda3464f1..04c2101aab1 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > @@ -17,7 +17,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -76,6 +76,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -127,6 +128,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(20,42) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -158,6 +160,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -186,6 +189,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -218,6 +222,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -227,6 +232,7 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -243,6 +249,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -254,6 +261,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4}}) );
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > @@ -263,6 +271,7 @@ test08()
> > m[k] = 0;
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -274,8 +283,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -290,3 +299,31 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > index f143f3acd1b..00644c14061 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > @@ -11,7 +11,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -74,6 +74,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -111,6 +112,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(12,3) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -137,6 +139,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -165,6 +168,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -197,6 +201,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -205,6 +210,8 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
> > }
> > +
> > +constexpr
> > void
> > test06()
> > {
> > @@ -221,6 +228,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -232,6 +240,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4},{3,3}}) );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -243,8 +252,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -258,3 +267,30 @@ main()
> > test07();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > --
> > 2.52.0
> >
> > From c2a1c42266bdd87c97868735514b621cec3e30bd Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <c8ef@outlook.com>
> > Date: Fri, 12 Dec 2025 19:26:01 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_map and flat_multimap
> >
> > This patch makes flat_map and flat_multimap constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_map: Add constexpr.
> > * testsuite/23_containers/flat_map/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_multimap/1.cc: Add constexpr test.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 +
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_map | 157 +++++++++++++++++-
> > .../testsuite/23_containers/flat_map/1.cc | 43 ++++-
> > .../23_containers/flat_multimap/1.cc | 42 ++++-
> > 5 files changed, 245 insertions(+), 15 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> > index 5b95db19ac6..f97276d80f2 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1351,6 +1351,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_map;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_flat_set;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> > index eee9890a72b..97b37e9a62b 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1496,6 +1496,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_map)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_map 202502L
> > +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_flat_map)
> > +# define __cpp_lib_constexpr_flat_map 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_map) */
> > +#undef __glibcxx_want_constexpr_flat_map
> > +
> > #if !defined(__cpp_lib_constexpr_flat_set)
> > # if (__cplusplus > 202302L)
> > # define __glibcxx_constexpr_flat_set 202502L
> > diff --git a/libstdc++-v3/include/std/flat_map b/libstdc++-v3/include/std/flat_map
> > index 637c3b7fe0d..e270735a87b 100644
> > --- a/libstdc++-v3/include/std/flat_map
> > +++ b/libstdc++-v3/include/std/flat_map
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_map
> > #define __glibcxx_want_flat_map
> > #include <bits/version.h>
> >
> > @@ -108,9 +109,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > class value_compare
> > {
> > [[no_unique_address]] key_compare _M_comp;
> > + _GLIBCXX26_CONSTEXPR
> > value_compare(key_compare __c) : _M_comp(__c) { }
> >
> > public:
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return _M_comp(__x.first, __y.first); }
> > @@ -129,10 +132,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > containers* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(containers& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > @@ -142,24 +147,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_disable()
> > { _M_cont = nullptr; }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard
> > _M_make_clear_guard()
> > { return _ClearGuard{this->_M_cont}; }
> >
> > public:
> > // constructors
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl() : _Flat_map_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > const key_compare& __comp = key_compare())
> > @@ -169,6 +179,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_sort_uniq();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > key_container_type __key_cont,
> > mapped_container_type __mapped_cont,
> > @@ -180,12 +191,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > : _M_cont(), _M_comp(__comp)
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -193,20 +206,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_map_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_map_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -216,12 +233,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_map_impl(const _Alloc& __a)
> > : _Flat_map_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a),
> > std::make_obj_using_allocator<mapped_container_type>(__a)),
> > @@ -229,6 +248,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const _Alloc& __a)
> > @@ -236,6 +256,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > const key_compare& __comp,
> > @@ -249,6 +270,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -257,6 +279,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t,
> > const key_container_type& __key_cont,
> > const mapped_container_type& __mapped_cont,
> > @@ -271,6 +294,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>(__a, __x._M_cont.keys),
> > std::make_obj_using_allocator<mapped_container_type>(__a, __x._M_cont.values)),
> > @@ -278,6 +302,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<key_container_type>
> > (__a, std::move(__x._M_cont.keys)),
> > @@ -288,6 +313,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_map_impl(std::move(__first), std::move(__last), key_compare(), __a)
> > @@ -295,6 +321,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -303,6 +330,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -311,6 +339,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -320,6 +349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_map_impl(from_range, std::forward<_Rg>(__rg), key_compare(), __a)
> > @@ -327,18 +357,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(from_range_t, _Rg&& __rg, const key_compare& __comp,
> > const _Alloc& __a)
> > : _Flat_map_impl(__comp, __a)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_map_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -346,6 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -353,6 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<key_container_type, mapped_container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_map_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -360,6 +395,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_map_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -369,64 +405,79 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > begin() noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > end() noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rbegin() noexcept
> > { return reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reverse_iterator
> > rend() noexcept
> > { return reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return {this, _M_cont.keys.cbegin()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return {this, _M_cont.keys.cend()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return const_reverse_iterator(cend()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return const_reverse_iterator(cbegin()); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.keys.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.keys.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return std::min<size_type>(keys().max_size(), values().max_size()); }
> > @@ -436,6 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // modifiers
> > template<typename _Key2, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -491,6 +543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -503,6 +556,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > {
> > @@ -510,36 +564,43 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return _M_try_emplace(__position, std::move(__p.first), std::move(__p.second)).first;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(const value_type& __x)
> > { return emplace(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(value_type&& __x)
> > { return emplace(std::move(__x)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, const value_type& __x)
> > { return emplace_hint(__position, __x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, value_type&& __x)
> > { return emplace_hint(__position, std::move(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > insert(_Arg&& __x)
> > { return emplace(std::forward<_Arg>(__x)); }
> >
> > template<typename _Arg>
> > requires is_constructible_v<value_type, _Arg>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert(const_iterator __position, _Arg&& __x)
> > { return emplace_hint(__position, std::forward<_Arg>(__x)); }
> >
> > private:
> > template<typename _Iter, typename _Sent>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_insert(_Iter __first, _Sent __last)
> > {
> > @@ -577,11 +638,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > public:
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > { _M_insert(std::move(__first), std::move(__last)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -590,18 +653,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > { _M_insert(ranges::begin(__rg), ranges::end(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(initializer_list<value_type> __il)
> > { insert(__il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t __s, initializer_list<value_type> __il)
> > { insert(__s, __il.begin(), __il.end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > containers
> > extract() &&
> > {
> > @@ -609,6 +676,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return {std::move(_M_cont.keys), std::move(_M_cont.values)};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(key_container_type&& __key_cont, mapped_container_type&& __mapped_cont)
> > {
> > @@ -622,10 +690,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // try_emplace and insert_or_assign defined directly in class flat_map only.
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(iterator __position)
> > { return erase(static_cast<const_iterator>(__position)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > {
> > @@ -637,6 +707,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -646,6 +717,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > || (__transparent_comparator<_Compare>
> > && !is_convertible_v<_Key2, iterator>
> > && !is_convertible_v<_Key2, const_iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(_Key2&& __x)
> > {
> > @@ -655,6 +727,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > {
> > @@ -667,6 +740,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return iterator{this, __it};
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __y) noexcept
> > {
> > @@ -675,6 +749,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::swap(_M_cont.values, __y._M_cont.values);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > {
> > @@ -684,32 +759,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return value_compare(_M_comp); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const key_container_type&
> > keys() const noexcept
> > { return _M_cont.keys; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_container_type&
> > values() const noexcept
> > { return _M_cont.values; }
> >
> > // map operations
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const key_type& __x)
> > { return find<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const key_type& __x) const
> > { return find<key_type>(__x); }
> > @@ -717,6 +798,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -730,6 +812,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > find(const _Key2& __x) const
> > {
> > @@ -741,6 +824,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -748,6 +832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const _Key2& __x) const
> > {
> > @@ -761,6 +846,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -768,16 +854,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const _Key2& __x) const
> > { return find(__x) != cend(); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const key_type& __x)
> > { return lower_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const key_type& __x) const
> > { return lower_bound<key_type>(__x); }
> > @@ -785,6 +874,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > {
> > @@ -796,6 +886,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > lower_bound(const _Key2& __x) const
> > {
> > @@ -805,11 +896,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const key_type& __x)
> > { return upper_bound<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const key_type& __x) const
> > { return upper_bound<key_type>(__x); }
> > @@ -817,6 +910,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > {
> > @@ -828,6 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > upper_bound(const _Key2& __x) const
> > {
> > @@ -837,11 +932,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const key_type& __x)
> > { return equal_range<key_type>(__x); }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const key_type& __x) const
> > { return equal_range<key_type>(__x); }
> > @@ -849,6 +946,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, iterator>
> > equal_range(const _Key2& __x)
> > {
> > @@ -861,6 +959,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > pair<const_iterator, const_iterator>
> > equal_range(const _Key2& __x) const
> > {
> > @@ -871,7 +970,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > {
> > return __x._M_cont.keys == __y._M_cont.keys
> > @@ -880,7 +979,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Up = value_type>
> > [[nodiscard]]
> > - friend __detail::__synth3way_t<_Up>
> > + friend _GLIBCXX26_CONSTEXPR __detail::__synth3way_t<_Up>
> > operator<=>(const _Derived& __x, const _Derived& __y)
> > {
> > return std::lexicographical_compare_three_way(__x.begin(), __x.end(),
> > @@ -888,11 +987,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __detail::__synth3way);
> > }
> >
> > - friend void
> > + friend _GLIBCXX26_CONSTEXPR void
> > swap(_Derived& __x, _Derived& __y) noexcept
> > { return __x.swap(__y); }
> >
> > template<typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > _M_erase_if(_Predicate __pred)
> > {
> > @@ -912,6 +1012,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > containers _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -921,13 +1022,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > _M_unique();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_unique() requires (!_Multi)
> > {
> > struct __key_equiv
> > {
> > + _GLIBCXX26_CONSTEXPR
> > __key_equiv(key_compare __c) : _M_comp(__c) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > operator()(const_reference __x, const_reference __y) const
> > { return !_M_comp(__x.first, __y.first) && !_M_comp(__y.first, __x.first); }
> > @@ -958,12 +1062,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > ranges::__maybe_const_t<_Const, mapped_type>&>;
> > using difference_type = ptrdiff_t;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator() = default;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Iterator<!_Const> __it) requires _Const
> > : _M_cont(__it._M_cont), _M_index(__it._M_index)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator*() const noexcept
> > {
> > @@ -975,19 +1082,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > reference __p;
> >
> > + _GLIBCXX26_CONSTEXPR
> > const reference*
> > operator->() const noexcept
> > { return std::__addressof(__p); }
> > };
> >
> > + _GLIBCXX26_CONSTEXPR
> > pointer
> > operator->() const
> > { return pointer{operator*()}; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > reference
> > operator[](difference_type __n) const noexcept
> > { return *(*this + __n); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator++() noexcept
> > {
> > @@ -995,6 +1106,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator--() noexcept
> > {
> > @@ -1002,6 +1114,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator++(int) noexcept
> > {
> > @@ -1010,6 +1123,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator
> > operator--(int) noexcept
> > {
> > @@ -1018,6 +1132,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __tmp;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator+=(difference_type __n) noexcept
> > {
> > @@ -1025,6 +1140,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return *this;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator&
> > operator-=(difference_type __n) noexcept
> > {
> > @@ -1036,45 +1152,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > friend _Flat_map_impl;
> > friend _Iterator<!_Const>;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(_Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires (!_Const)
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Iterator(const _Flat_map_impl* __fm, typename key_container_type::const_iterator __it)
> > requires _Const
> > : _M_cont(std::__addressof(__fm->_M_cont)), _M_index(__it - __fm->keys().cbegin())
> > { }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(_Iterator __it, difference_type __n) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator+(difference_type __n, _Iterator __it) noexcept
> > {
> > __it += __n;
> > return __it;
> > }
> >
> > - friend _Iterator
> > + friend _GLIBCXX26_CONSTEXPR _Iterator
> > operator-(_Iterator __it, difference_type __n) noexcept
> > {
> > __it -= __n;
> > return __it;
> > }
> >
> > - friend difference_type
> > + friend _GLIBCXX26_CONSTEXPR difference_type
> > operator-(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > return __x._M_index - __y._M_index;
> > }
> >
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Iterator& __x, const _Iterator& __y) noexcept
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1082,7 +1200,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __x._M_index == __y._M_index;
> > }
> >
> > - friend strong_ordering
> > + friend _GLIBCXX26_CONSTEXPR strong_ordering
> > operator<=>(const _Iterator& __x, const _Iterator& __y)
> > {
> > __glibcxx_assert(__x._M_cont == __y._M_cont);
> > @@ -1146,30 +1264,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using _Impl::max_size;
> >
> > // element access
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](const key_type& __x)
> > { return try_emplace(__x).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](key_type&& __x)
> > { return try_emplace(std::move(__x)).first->second; }
> >
> > template<typename _Key2>
> > requires __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > operator[](_Key2&& __x)
> > { return try_emplace(std::forward<_Key2>(__x)).first->second; }
> >
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const key_type& __x)
> > { return at<key_type>(__x); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const key_type& __x) const
> > { return at<key_type>(__x); }
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > mapped_type&
> > at(const _Key2& __x)
> > {
> > @@ -1181,6 +1305,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > + _GLIBCXX26_CONSTEXPR
> > const mapped_type&
> > at(const _Key2& __x) const
> > {
> > @@ -1203,12 +1328,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(nullopt, __k, std::forward<_Args>(__args)...); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(key_type&& __k, _Args&&... __args)
> > {
> > @@ -1222,6 +1349,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<mapped_type, _Args...>
> > && (!is_convertible_v<_Key2&&, const_iterator>)
> > && (!is_convertible_v<_Key2&&, iterator>)
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > try_emplace(_Key2&& __k, _Args&&... __args)
> > {
> > @@ -1231,12 +1359,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, const key_type& __k, _Args&&... __args)
> > { return _Impl::_M_try_emplace(__hint, __k, std::forward<_Args>(__args)...).first; }
> >
> > template<typename... _Args>
> > requires is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, key_type&& __k, _Args&&... __args)
> > {
> > @@ -1248,6 +1378,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > requires __transparent_comparator<_Compare>
> > && is_constructible_v<key_type, _Key2>
> > && is_constructible_v<mapped_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > try_emplace(const_iterator __hint, _Key2&& __k, _Args&&... __args)
> > {
> > @@ -1258,6 +1389,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(const key_type& __k, _Mapped&& __obj)
> > { return insert_or_assign<const key_type&, _Mapped>(__k, std::forward<_Mapped>(__obj)); }
> > @@ -1265,6 +1397,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1277,6 +1410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > insert_or_assign(_Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1290,6 +1424,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, const key_type& __k, _Mapped&& __obj)
> > {
> > @@ -1300,6 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Mapped>
> > requires is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, key_type&& __k, _Mapped&& __obj)
> > {
> > @@ -1312,6 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > && is_constructible_v<key_type, _Key2>
> > && is_assignable_v<mapped_type&, _Mapped>
> > && is_constructible_v<mapped_type, _Mapped>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > insert_or_assign(const_iterator __hint, _Key2&& __k, _Mapped&& __obj)
> > {
> > @@ -1422,6 +1559,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_map<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > @@ -1590,6 +1728,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Tp, typename _Compare,
> > typename _KeyContainer, typename _MappedContainer, typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>::size_type
> > erase_if(flat_multimap<_Key, _Tp, _Compare, _KeyContainer, _MappedContainer>& __c,
> > _Predicate __pred)
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > index 5bcda3464f1..04c2101aab1 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_map/1.cc
> > @@ -17,7 +17,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -76,6 +76,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -127,6 +128,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(20,42) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -158,6 +160,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -186,6 +189,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -218,6 +222,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -227,6 +232,7 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, -4, -5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -243,6 +249,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -254,6 +261,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4}}) );
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > @@ -263,6 +271,7 @@ test08()
> > m[k] = 0;
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -274,8 +283,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -290,3 +299,31 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > index f143f3acd1b..00644c14061 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multimap/1.cc
> > @@ -11,7 +11,7 @@
> >
> > struct Gt {
> > template<typename T, typename U>
> > - bool operator()(T const& l, U const & r) const
> > + constexpr bool operator()(T const& l, U const & r) const
> > { return l > r; }
> > };
> >
> > @@ -74,6 +74,7 @@ test_deduction_guide()
> > }
> >
> > template<template<typename> class KeyContainer, template<typename> class MappedContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -111,6 +112,7 @@ test01()
> > VERIFY( m.end()[-1] == std::pair(12,3) );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -137,6 +139,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -165,6 +168,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (std::pair<int, int>[]){{5, 6}}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -197,6 +201,7 @@ test04()
> > VERIFY( m5.values().get_allocator().get_personality() == 44 );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -205,6 +210,8 @@ test05()
> > VERIFY( std::ranges::equal(m | std::views::keys, (int[]){1, 2, 3, 3, 4, 5}) );
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){-1, -2, -3, 3, -4, -5}) );
> > }
> > +
> > +constexpr
> > void
> > test06()
> > {
> > @@ -221,6 +228,7 @@ test06()
> > VERIFY( std::ranges::equal(m | std::views::values, (int[]){2, 3, 4, 5, 6}) );
> > }
> >
> > +constexpr
> > void
> > test07()
> > {
> > @@ -232,6 +240,7 @@ test07()
> > VERIFY( std::ranges::equal(m, (std::pair<int,int>[]){{3,4},{3,3}}) );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -243,8 +252,8 @@ test09()
> > using value_type = std::pair<int, int>;
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector, std::vector>();
> > test01<std::deque, std::deque>();
> > @@ -258,3 +267,30 @@ main()
> > test07();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector, std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test05();
> > + test06();
> > + test07();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
> > + static_assert(test_constexpr());
> > +#if __cpp_lib_constexpr_flat_map != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_map has wrong value in <flat_map>"
> > +#endif
> > +#endif
> > +}
> > --
> > 2.52.0
> >
>
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