On Mon, 8 Dec 2025 at 14:47, Patrick Palka <[email protected]> wrote:
>
> On Mon, 8 Dec 2025, Yuao Ma wrote:
>
> > On Mon, Dec 8, 2025 at 6:52 PM Jonathan Wakely <[email protected]> wrote:
> > >
> > > On Mon, 1 Dec 2025 at 19:52, Patrick Palka <[email protected]> wrote:
> > > >
> > > > On Wed, 26 Nov 2025, Yuao Ma wrote:
> > > > > diff --git
> > > > > a/libstdc++-v3/testsuite/23_containers/flat_multiset/constexpr.cc
> > > > > b/libstdc++-v3/testsuite/23_containers/flat_multiset/constexpr.cc
> > > > > new file mode 100644
> > > > > index 00000000000..860b7660809
> > > > > --- /dev/null
> > > > > +++ b/libstdc++-v3/testsuite/23_containers/flat_multiset/constexpr.cc
> > > > > @@ -0,0 +1,239 @@
> > > > > +// { dg-do run { target c++26 } }
> > > >
> > > > I'd expect constexpr tests to be compile-only.
> > >
> > > The tests have a main() function which calls VERIFY(test()), which
> > > only has an effect at runtime.
> > >
> > > Either they should be dg-do run, or the main() function can be removed
> > > and just keep:
> > >
> > > static_assert( test() );
> > >
> > > Do these new tests add any checks which are not already covered by
> > > existing runtime tests for flat_set and flat_multiset?
> > >
> > > If they don't add anything new, then remove the main() function and
> > > just do static_assert(test());
> > >
> >
> > It turns out I misunderstood `target c++23`; I thought it would *only*
> > test C++23, but it actually tests against both 23 and 26. I’ve merged
> > the testcase and guarded it using __cplusplus > 202302L.
> > Please take another look, thanks!
>
> Works for me, it makes sense to just make the existing testcase constexpr.
> Also instantiating flat_set/map is quite compile time/memory heavy so
> reusing the existing test as much as possible is cheaper than having a
> separate test.
>
> >
> > From 821c14b7181940899b199ef21103efde59ebd1ae Mon Sep 17 00:00:00 2001
> > From: Yuao Ma <[email protected]>
> > Date: Mon, 8 Dec 2025 22:14:34 +0800
> > Subject: [PATCH] libstdc++: constexpr flat_set and flat_multiset
> >
> > This patch makes flat_set and flat_multiset constexpr as part of P3372R3.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/bits/version.def: Add FTM.
> > * include/bits/version.h: Regenerate.
> > * include/std/flat_set: Add constexpr.
> > * testsuite/23_containers/flat_multiset/1.cc: Add constexpr test.
> > * testsuite/23_containers/flat_set/1.cc: Add constexpr test.
> > ---
> > libstdc++-v3/include/bits/version.def | 8 ++
> > libstdc++-v3/include/bits/version.h | 10 ++
> > libstdc++-v3/include/std/flat_set | 103 +++++++++++++++++-
> > .../23_containers/flat_multiset/1.cc | 78 ++++++++++---
> > .../testsuite/23_containers/flat_set/1.cc | 79 +++++++++++---
> > 5 files changed, 243 insertions(+), 35 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/version.def
> > b/libstdc++-v3/include/bits/version.def
> > index 412b9ce96f8..6ff88f3072a 100644
> > --- a/libstdc++-v3/include/bits/version.def
> > +++ b/libstdc++-v3/include/bits/version.def
> > @@ -1347,6 +1347,14 @@ ftms = {
> > };
> > };
> >
> > +ftms = {
> > + name = constexpr_flat_set;
> > + values = {
> > + v = 202502;
> > + cxxmin = 26;
> > + };
> > +};
> > +
> > ftms = {
> > name = constexpr_string;
> > values = {
> > diff --git a/libstdc++-v3/include/bits/version.h
> > b/libstdc++-v3/include/bits/version.h
> > index 2b96934ca09..ae0df182572 100644
> > --- a/libstdc++-v3/include/bits/version.h
> > +++ b/libstdc++-v3/include/bits/version.h
> > @@ -1495,6 +1495,16 @@
> > #endif /* !defined(__cpp_lib_constexpr_dynamic_alloc) */
> > #undef __glibcxx_want_constexpr_dynamic_alloc
> >
> > +#if !defined(__cpp_lib_constexpr_flat_set)
> > +# if (__cplusplus > 202302L)
> > +# define __glibcxx_constexpr_flat_set 202502L
> > +# if defined(__glibcxx_want_all) ||
> > defined(__glibcxx_want_constexpr_flat_set)
> > +# define __cpp_lib_constexpr_flat_set 202502L
> > +# endif
> > +# endif
> > +#endif /* !defined(__cpp_lib_constexpr_flat_set) */
> > +#undef __glibcxx_want_constexpr_flat_set
> > +
> > #if !defined(__cpp_lib_constexpr_string)
> > # if (__cplusplus >= 202002L) && _GLIBCXX_USE_CXX11_ABI && _GLIBCXX_HOSTED
> > && (defined(__glibcxx_is_constant_evaluated))
> > # define __glibcxx_constexpr_string 201907L
> > diff --git a/libstdc++-v3/include/std/flat_set
> > b/libstdc++-v3/include/std/flat_set
> > index c48340d7980..3a1f5ba10da 100644
> > --- a/libstdc++-v3/include/std/flat_set
> > +++ b/libstdc++-v3/include/std/flat_set
> > @@ -33,6 +33,7 @@
> > #pragma GCC system_header
> > #endif
> >
> > +#define __glibcxx_want_constexpr_flat_set
> > #define __glibcxx_want_flat_set
> > #include <bits/version.h>
> >
> > @@ -100,50 +101,60 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > {
> > container_type* _M_cont;
> >
> > + _GLIBCXX26_CONSTEXPR
> > _ClearGuard(container_type& __cont)
> > : _M_cont(std::__addressof(__cont))
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > ~_ClearGuard()
> > {
> > if (_M_cont)
> > _M_cont->clear();
> > }
> >
> > + _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_set_impl() : _Flat_set_impl(key_compare()) { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_set_impl(const key_compare& __comp)
> > : _M_cont(), _M_comp(__comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(container_type __cont, const key_compare& __comp =
> > key_compare())
> > : _M_cont(std::move(__cont)), _M_comp(__comp)
> > { _M_sort_uniq(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t,
> > container_type __cont, const key_compare& __comp =
> > key_compare())
> > : _M_cont(std::move(__cont)), _M_comp(__comp)
> > { _GLIBCXX_DEBUG_ASSERT(ranges::is_sorted(_M_cont, _M_comp)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_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_set_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp = key_compare())
> > @@ -151,20 +162,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__s, __first, __last); }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(from_range_t, _Rg&& __rg)
> > : _Flat_set_impl(from_range, std::forward<_Rg>(__rg), key_compare())
> > { }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(from_range_t, _Rg&& __rg, const key_compare& __comp)
> > : _Flat_set_impl(__comp)
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > : _Flat_set_impl(__il.begin(), __il.end(), __comp)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp = key_compare())
> > @@ -174,23 +189,27 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > // constructors with allocators
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > explicit
> > _Flat_set_impl(const _Alloc& __a)
> > : _Flat_set_impl(key_compare(), __a)
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(const key_compare& __comp, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<container_type>(__a)),
> > _M_comp(__comp)
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(const container_type& __cont, const _Alloc& __a)
> > : _Flat_set_impl(__cont, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(const container_type& __cont, const key_compare&
> > __comp,
> > const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<container_type>(__a, __cont)),
> > @@ -198,11 +217,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { _M_sort_uniq(); }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t __s, const container_type& __cont, const
> > _Alloc& __a)
> > : _Flat_set_impl(__s, __cont, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t, const container_type& __cont, const
> > key_compare& __comp,
> > const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<container_type>(__a, __cont)),
> > @@ -210,24 +231,28 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { _GLIBCXX_DEBUG_ASSERT(ranges::is_sorted(_M_cont, _M_comp)); }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(const _Derived& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<container_type>(__a,
> > __x._M_cont)),
> > _M_comp(__x._M_comp)
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(_Derived&& __x, const _Alloc& __a)
> > : _M_cont(std::make_obj_using_allocator<container_type>(__a,
> > std::move(__x._M_cont))),
> > _M_comp(__x._M_comp)
> > { }
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(_InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > : _Flat_set_impl(std::move(__first), std::move(__last),
> > key_compare(), __a)
> > { }
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(_InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -235,6 +260,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert(__first, __last); }
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const _Alloc& __a)
> > @@ -242,6 +268,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__has_input_iter_cat _InputIterator,
> > __allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t __s,
> > _InputIterator __first, _InputIterator __last,
> > const key_compare& __comp,
> > @@ -251,6 +278,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(from_range_t, _Rg&& __rg,
> > const _Alloc& __a)
> > : _Flat_set_impl(from_range, std::forward<_Rg>(__rg), key_compare(),
> > __a)
> > @@ -258,6 +286,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<__detail::__container_compatible_range<value_type> _Rg,
> > __allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(from_range_t, _Rg&& __rg,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -265,12 +294,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { insert_range(std::forward<_Rg>(__rg)); }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(initializer_list<value_type> __il,
> > const _Alloc& __a)
> > : _Flat_set_impl(__il, key_compare(), __a)
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(initializer_list<value_type> __il,
> > const key_compare& __comp,
> > const _Alloc& __a)
> > @@ -278,6 +309,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const _Alloc& __a)
> > @@ -285,6 +317,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > { }
> >
> > template<__allocator_for<container_type> _Alloc>
> > + _GLIBCXX26_CONSTEXPR
> > _Flat_set_impl(__sorted_t __s,
> > initializer_list<value_type> __il,
> > const key_compare& __comp,
> > @@ -292,6 +325,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > : _Flat_set_impl(__s, __il.begin(), __il.end(), __comp, __a)
> > { }
> >
> > + _GLIBCXX26_CONSTEXPR
> > _Derived&
> > operator=(initializer_list<value_type> __il)
> > {
> > @@ -303,54 +337,66 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > // iterators
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > begin() const noexcept
> > { return _M_cont.begin(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > end() const noexcept
> > { return _M_cont.end(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rbegin() const noexcept
> > { return const_reverse_iterator(end()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > rend() const noexcept
> > { return const_reverse_iterator(begin()); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cbegin() const noexcept
> > { return begin(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_iterator
> > cend() const noexcept
> > { return end(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crbegin() const noexcept
> > { return rbegin(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > const_reverse_iterator
> > crend() const noexcept
> > { return rend(); }
> >
> > // capacity
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > empty() const noexcept
> > { return _M_cont.empty(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > size() const noexcept
> > { return _M_cont.size(); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > max_size() const noexcept
> > { return _M_cont.max_size(); }
> >
> > // modifiers
> > template<typename _Arg, typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint, _Arg&& __arg,
> > _Args&&... __args)
> > {
> > @@ -410,12 +456,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > pair<iterator, bool>
> > _M_try_emplace(optional<const_iterator> __hint)
> > { return _M_try_emplace(__hint, value_type()); }
> >
> > template<typename... _Args>
> > requires is_constructible_v<value_type, _Args...>
> > + _GLIBCXX26_CONSTEXPR
> > __emplace_result_t
> > emplace(_Args&&... __args)
> > {
> > @@ -427,39 +475,47 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<typename... _Args>
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > emplace_hint(const_iterator __position, _Args&&... __args)
> > { return _M_try_emplace(__position,
> > std::forward<_Args>(__args)...).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)); }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(_InputIterator __first, _InputIterator __last)
> > {
> > @@ -473,6 +529,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__has_input_iter_cat _InputIterator>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert(__sorted_t, _InputIterator __first, _InputIterator __last)
> > {
> > @@ -485,6 +542,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > template<__detail::__container_compatible_range<value_type> _Rg>
> > + _GLIBCXX26_CONSTEXPR
> > void
> > insert_range(_Rg&& __rg)
> > {
> > @@ -511,14 +569,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __guard._M_disable();
> > }
> >
> > + _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
> > container_type
> > extract() &&
> > {
> > @@ -526,6 +587,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return std::move(_M_cont);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > replace(container_type&& __cont)
> > {
> > @@ -535,10 +597,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > __guard._M_disable();
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __position)
> > { return _M_cont.erase(__position); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > erase(const key_type& __x)
> > { return erase<const key_type&>(__x); }
> > @@ -548,6 +612,7 @@ _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)
> > {
> > @@ -557,10 +622,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > return __n;
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > erase(const_iterator __first, const_iterator __last)
> > { return _M_cont.erase(__first, __last); }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > swap(_Derived& __x) noexcept
> > {
> > @@ -569,28 +636,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > swap(_M_comp, __x._M_comp);
> > }
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > clear() noexcept
> > { _M_cont.clear(); }
> >
> > // observers
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > key_compare
> > key_comp() const
> > { return _M_comp; }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > value_compare
> > value_comp() const
> > { return _M_comp; }
> >
> > // set 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); }
> > @@ -598,6 +670,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > find(const _Key2& __x)
> > {
> > @@ -611,6 +684,7 @@ _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
> > {
> > @@ -622,6 +696,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > size_type
> > count(const key_type& __x) const
> > { return count<key_type>(__x); }
> > @@ -629,6 +704,7 @@ _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
> > {
> > @@ -642,6 +718,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > }
> >
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > bool
> > contains(const key_type& __x) const
> > { return contains<key_type>(__x); }
> > @@ -649,16 +726,19 @@ _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); }
> > @@ -666,6 +746,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > lower_bound(const _Key2& __x)
> > { return std::lower_bound(begin(), end(), __x, _M_comp); }
> > @@ -673,16 +754,19 @@ _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
> > { return std::lower_bound(begin(), end(), __x, _M_comp); }
> >
> > [[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); }
> > @@ -690,6 +774,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > template<typename _Key2>
> > requires same_as<_Key2, _Key> || __transparent_comparator<_Compare>
> > [[nodiscard]]
> > + _GLIBCXX26_CONSTEXPR
> > iterator
> > upper_bound(const _Key2& __x)
> > { return std::upper_bound(begin(), end(), __x, _M_comp); }
> > @@ -697,16 +782,19 @@ _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
> > { return std::upper_bound(begin(), end(), __x, _M_comp); }
> >
> > [[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); }
> > @@ -714,6 +802,7 @@ _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)
> > { return std::equal_range(begin(), end(), __x, _M_comp); }
> > @@ -721,18 +810,19 @@ _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
> > { return std::equal_range(begin(), end(), __x, _M_comp); }
> >
> > [[nodiscard]]
> > - friend bool
> > + friend _GLIBCXX26_CONSTEXPR bool
> > operator==(const _Derived& __x, const _Derived& __y)
> > { return std::equal(__x.begin(), __x.end(), __y.begin(), __y.end());
> > }
> >
> > 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(),
> > @@ -740,11 +830,12 @@ _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)
> > {
> > @@ -762,6 +853,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > container_type _M_cont;
> > [[no_unique_address]] _Compare _M_comp;
> >
> > + _GLIBCXX26_CONSTEXPR
> > void
> > _M_sort_uniq()
> > {
> > @@ -770,13 +862,16 @@ _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, __y) && !_M_comp(__y, __x); }
> > @@ -934,6 +1029,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Compare, typename _KeyContainer,
> > typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_set<_Key, _Compare, _KeyContainer>::size_type
> > erase_if(flat_set<_Key, _Compare, _KeyContainer>& __c, _Predicate
> > __pred)
> > { return __c._M_erase_if(std::move(__pred)); }
> > @@ -1081,6 +1177,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> > template<typename _Key, typename _Compare, typename _KeyContainer,
> > typename _Predicate>
> > + _GLIBCXX26_CONSTEXPR
> > typename flat_multiset<_Key, _Compare, _KeyContainer>::size_type
> > erase_if(flat_multiset<_Key, _Compare, _KeyContainer>& __c, _Predicate
> > __pred)
> > { return __c._M_erase_if(std::move(__pred)); }
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
> > b/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
> > index 63855e07065..d1a81c65762 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_multiset/1.cc
> > @@ -8,6 +8,7 @@
> > #include <testsuite_hooks.h>
> >
> > template<template<class> class Sequence>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -42,6 +43,7 @@ test01()
> > VERIFY( m.size() == 5 );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -67,6 +69,7 @@ test02()
> > VERIFY( m.count(3) == 2 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -95,6 +98,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (int[]){5}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -121,6 +125,7 @@ test04()
> > VERIFY( std::move(m5).extract().get_allocator().get_personality() == 44
> > );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -129,6 +134,7 @@ test05()
> > VERIFY( std::ranges::equal(m, (int[]){1, 2, 3, 3, 4, 5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -156,25 +162,25 @@ struct NoCatIterator {
> > using difference_type = int;
> > using value_type = int;
> >
> > - NoCatIterator() : v(0) {}
> > - NoCatIterator(int x) : v(x) {}
> > + constexpr NoCatIterator() : v(0) {}
> > + constexpr NoCatIterator(int x) : v(x) {}
> >
> > - int operator*() const
> > + constexpr int operator*() const
> > { return v; }
> >
> > - NoCatIterator& operator++()
> > + constexpr NoCatIterator& operator++()
> > {
> > ++v;
> > return *this;
> > }
> >
> > - NoCatIterator operator++(int)
> > + constexpr NoCatIterator operator++(int)
> > {
> > ++v;
> > return NoCatIterator(v-1);
> > }
> >
> > - bool operator==(const NoCatIterator& rhs) const
> > + constexpr bool operator==(const NoCatIterator& rhs) const
> > { return v == rhs.v; }
> >
> > private:
> > @@ -189,7 +195,9 @@ struct std::iterator_traits<NoCatIterator> {
> > // no iterator_category, happens also for common_iterator
> > };
> >
> > -void test07()
> > +constexpr
> > +void
> > +test07()
> > {
> > std::flat_multiset<int> s;
> > std::flat_multiset<int, std::less<int>, NoInsertRange<int>> s2;
> > @@ -214,27 +222,39 @@ void test07()
> > #endif
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > // PR libstdc++/119620 -- flat_set::emplace always constructs element on
> > the stack
> > - static int copy_counter;
> > + int copy_counter = 0;
> > +
> > struct A {
> > - A() { }
> > - A(const A&) { ++copy_counter; }
> > - A& operator=(const A&) { ++copy_counter; return *this; }
> > - auto operator<=>(const A&) const = default;
> > + int *counter;
> > + constexpr A(int &c) : counter(&c) {}
> > +
> > + constexpr A(const A &other) : counter(other.counter) { ++(*counter); }
> > +
> > + constexpr A &operator=(const A &other) {
> > + counter = other.counter;
> > + ++(*counter);
> > + return *this;
> > + }
> > +
> > + constexpr auto operator<=>(const A &) const = default;
> > };
> > +
> > std::vector<A> v;
> > v.reserve(2);
> > std::flat_multiset<A> s(std::move(v));
> > - A a;
> > + A a(copy_counter);
> > s.emplace(a);
> > - VERIFY( copy_counter == 1 );
> > + VERIFY(copy_counter == 1);
> > s.emplace(a);
> > - VERIFY( copy_counter == 2 );
> > + VERIFY(copy_counter == 2);
These whitespace changes seem unnecessary.
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -245,8 +265,8 @@ test09()
> > VERIFY( std::ranges::equal(s, (int[]){2,2,4}) );
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector>();
> > test01<std::deque>();
> > @@ -259,3 +279,27 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
Please test the __cpp_lib_constexpr_flat_set macro here instead.
> > + static_assert(test_constexpr());
> > +#endif
> > +}
> > diff --git a/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
> > b/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
> > index b1d9002caba..65848271c07 100644
> > --- a/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
> > +++ b/libstdc++-v3/testsuite/23_containers/flat_set/1.cc
> > @@ -6,6 +6,12 @@
> > # error "Feature-test macro __cpp_lib_flat_set has wrong value in
> > <flat_set>"
> > #endif
> >
> > +#if __cplusplus > 202302L
> > +#if __cpp_lib_constexpr_flat_set != 202502L
> > +#error "Feature-test macro __cpp_lib_constexpr_flat_set has wrong value in
> > <flat_set>"
> > +#endif
> > +#endif
> > +
> > #include <deque>
> > #include <ranges>
> > #include <vector>
> > @@ -13,6 +19,7 @@
> > #include <testsuite_hooks.h>
> >
> > template<template<typename> class KeyContainer>
> > +constexpr
> > void
> > test01()
> > {
> > @@ -56,6 +63,7 @@ test01()
> > VERIFY( m_copy == m );
> > }
> >
> > +constexpr
> > void
> > test02()
> > {
> > @@ -82,6 +90,7 @@ test02()
> > VERIFY( m.count(3) == 1 );
> > }
> >
> > +constexpr
> > void
> > test03()
> > {
> > @@ -110,6 +119,7 @@ test03()
> > VERIFY( std::ranges::equal(m, (int[]){5}) );
> > }
> >
> > +constexpr
> > void
> > test04()
> > {
> > @@ -136,6 +146,7 @@ test04()
> > VERIFY( std::move(m5).extract().get_allocator().get_personality() == 44
> > );
> > }
> >
> > +constexpr
> > void
> > test05()
> > {
> > @@ -144,6 +155,7 @@ test05()
> > VERIFY( std::ranges::equal(m, (int[]){1, 2, 3, 4, 5}) );
> > }
> >
> > +constexpr
> > void
> > test06()
> > {
> > @@ -171,25 +183,25 @@ struct NoCatIterator {
> > using difference_type = int;
> > using value_type = int;
> >
> > - NoCatIterator() : v(0) {}
> > - NoCatIterator(int x) : v(x) {}
> > + constexpr NoCatIterator() : v(0) {}
> > + constexpr NoCatIterator(int x) : v(x) {}
> >
> > - int operator*() const
> > + constexpr int operator*() const
> > { return v; }
> >
> > - NoCatIterator& operator++()
> > + constexpr NoCatIterator& operator++()
> > {
> > ++v;
> > return *this;
> > }
> >
> > - NoCatIterator operator++(int)
> > + constexpr NoCatIterator operator++(int)
> > {
> > ++v;
> > return NoCatIterator(v-1);
> > }
> >
> > - bool operator==(const NoCatIterator& rhs) const
> > + constexpr bool operator==(const NoCatIterator& rhs) const
> > { return v == rhs.v; }
> >
> > private:
> > @@ -204,7 +216,9 @@ struct std::iterator_traits<NoCatIterator> {
> > // no iterator_category, happens also for common_iterator
> > };
> >
> > -void test07()
> > +constexpr
> > +void
> > +test07()
> > {
> > std::flat_set<int> s;
> > std::flat_set<int, std::less<int>, NoInsertRange<int>> s2;
> > @@ -229,25 +243,36 @@ void test07()
> > #endif
> > }
> >
> > +constexpr
> > void
> > test08()
> > {
> > // PR libstdc++/119620 -- flat_set::emplace always constructs element on
> > the stack
> > - static int copy_counter;
> > + int copy_counter = 0;
> > +
> > struct A {
> > - A() { }
> > - A(const A&) { ++copy_counter; }
> > - A& operator=(const A&) { ++copy_counter; return *this; }
> > - auto operator<=>(const A&) const = default;
> > + int *counter;
> > + constexpr A(int &c) : counter(&c) {}
> > +
> > + constexpr A(const A &other) : counter(other.counter) { ++(*counter); }
> > +
> > + constexpr A &operator=(const A &other) {
> > + counter = other.counter;
> > + ++(*counter);
> > + return *this;
> > + }
> > +
> > + constexpr auto operator<=>(const A &) const = default;
> > };
> > std::flat_set<A> s;
> > - A a;
> > + A a(copy_counter);
> > s.emplace(a);
> > VERIFY( copy_counter == 1 );
> > s.emplace(a);
> > VERIFY( copy_counter == 1 );
> > }
> >
> > +constexpr
> > void
> > test09()
> > {
> > @@ -258,8 +283,8 @@ test09()
> > VERIFY( std::ranges::equal(s, (int[]){2,4}) );
> > }
> >
> > -int
> > -main()
> > +void
> > +test()
> > {
> > test01<std::vector>();
> > test01<std::deque>();
> > @@ -272,3 +297,27 @@ main()
> > test08();
> > test09();
> > }
> > +
> > +constexpr
> > +bool
> > +test_constexpr()
> > +{
> > + test01<std::vector>();
> > + test02();
> > + test03();
> > + test04();
> > + test06();
> > + test07();
> > + test08();
> > + test09();
> > + return true;
> > +}
> > +
> > +int
> > +main()
> > +{
> > + test();
> > +#if __cplusplus > 202302L
And test __cpp_lib_constexpr_flat_set here too.
OK with those changes, thanks!
> > + static_assert(test_constexpr());
> > +#endif
> > +}
> > --
> > 2.52.0
> >
