On Thu, 12 Jun 2025, Patrick Palka wrote:
> On Thu, 12 Jun 2025, Patrick Palka wrote:
>
> > On Thu, 12 Jun 2025, Tomasz Kaminski wrote:
> >
> > >
> > >
> > >
> > > On Thu, Jun 12, 2025 at 5:06 PM Patrick Palka <ppa...@redhat.com> wrote:
> > > On Wed, 11 Jun 2025, Tomasz Kaminski wrote:
> > >
> > > >
> > > >
> > > > On Tue, Jun 10, 2025 at 3:08 AM Patrick Palka <ppa...@redhat.com>
> > > wrote:
> > > > As with the previous patch, this patch reimplements
> > > ranges::sort
> > > > directly instead of incorrectly forwarding to std::sort.
> > > In addition to
> > > > the compatibility changes listed in the previous patch we
> > > also:
> > > >
> > > > - use ranges::iter_swap instead of std::iter_swap
> > > > - use ranges::move_backward instead of std::move_backward
> > > > - use __bit_floor and __to_unsigned_like instead of __lg
> > > >
> > > > We also need to extend std::__lg to support integer-class
> > > types.
> > > >
> > > > PR libstdc++/100795
> > > > PR libstdc++/118209
> > > >
> > > > libstdc++-v3/ChangeLog:
> > > >
> > > > * include/bits/ranges_algo.h
> > > (__detail::__move_median_to_first):
> > > > New, based on the stl_algo.h implementation.
> > > > (__detail::__unguarded_liner_insert): Likewise.
> > > > (__detail::__insertion_sort): Likewise.
> > > > (__detail::__sort_threshold): Likewise.
> > > > (__detail::__unguarded_insertion_sort): Likewise.
> > > > (__detail::__final_insertion_sort): Likewise.
> > > > (__detail::__unguarded_partition): Likewise.
> > > > (__detail::__unguarded_partition_pivot): Likewise.
> > > > (__detail::__heap_select): Likewise.
> > > > (__detail::__partial_sort): Likewise.
> > > > (__detail::__introsort_loop): Likewise.
> > > > (__sort_fn::operator()): Reimplement in terms of
> > > the above.
> > > > *
> > > libstdc++-v3/testsuite/25_algorithms/sort/118209.cc: New test.
> > > > *
> > > libstdc++-v3/testsuite/25_algorithms/sort/constrained.cc
> > > > (test03): New test.
> > > > ---
> > > > libstdc++-v3/include/bits/ranges_algo.h | 210
> > > +++++++++++++++++-
> > > > .../testsuite/25_algorithms/sort/118209.cc | 23 ++
> > > > .../25_algorithms/sort/constrained.cc | 31 +++
> > > > 3 files changed, 260 insertions(+), 4 deletions(-)
> > > > create mode 100644
> > > libstdc++-v3/testsuite/25_algorithms/sort/118209.cc
> > > >
> > > > diff --git a/libstdc++-v3/include/bits/ranges_algo.h
> > > b/libstdc++-v3/include/bits/ranges_algo.h
> > > > index f84e0c42d76a..67bdf4287241 100644
> > > > --- a/libstdc++-v3/include/bits/ranges_algo.h
> > > > +++ b/libstdc++-v3/include/bits/ranges_algo.h
> > > > @@ -32,6 +32,7 @@
> > > >
> > > > #if __cplusplus > 201703L
> > > >
> > > > +#include <bit> // __bit_floor
> > > > #if __cplusplus > 202002L
> > > > #include <optional>
> > > > #endif
> > > > @@ -2166,6 +2167,184 @@ namespace ranges
> > > >
> > > > inline constexpr __is_heap_fn is_heap{};
> > > >
> > > > + namespace __detail
> > > > + {
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __move_median_to_first(_Iter __result, _Iter __a,
> > > _Iter __b, _Iter __c,
> > > > + _Comp __comp, _Proj __proj)
> > > > + {
> > > > + if (std::__invoke(__comp,
> > > > + std::__invoke(__proj, *__a),
> > > > + std::__invoke(__proj, *__b)))
> > > >
> > > > See all this __invoke calls, that are the same in each algo,
> > > maybe we could accept only _Comp here,
> > > > and then pass following lambda as comp [&](auto& __a, auto& __b).
> > >
> > > Seems this sentence was cut off; I guess you mean doing the
> > > equivalent
> > > of __detail::__make_comp_proj? That sounds good to me. Only
> > > in __move_median_to_first or throughout all the helpers?
> > >
> > > In all helpers, and also ones from the previous patch.
> >
> > Hmm, some of the helpers such as __heap_select and __partial_sort
> > directly call ranges algos (make_heap, sort_heap) that of course
> > take a projection. It feels a little iffy to me to pass only a composite
> > comparator+projection function to these algos from these helpers, and
> > omit the projection function. It should be safe for these particular
> > ranges algos that we're calling (make_heap, sort_heap), but in general
> > I don't think we can assume
> >
> > ranges::foo(..., __detail::__make_comp_proj(comp, proj));
> >
> > is equivalent to
> >
> > ranges::foo(..., __comp, __proj);
> >
> > So I'm not 100% sold on this refactoring anymore. What do you think?
>
> i.e. the refactoring makes the implementation of ranges::sort dependent
> on implementation details of ranges::make_heap/sort_heap in a subtle
> way.
I think I'm wrong,
ranges::foo(..., __detail::__make_comp_proj(comp, proj));
and
ranges::foo(..., __comp, __proj);
should always be equivalent as long as the constraints of the latter
form are met. I posted update patches that includes the refactoring to
use __make_comp_proj.
>
> >
> > >
> > > > }
> > > > + {
> > > > + if (std::__invoke(__comp,
> > > > + std::__invoke(__proj, *__b),
> > > > + std::__invoke(__proj, *__c)))
> > > > + ranges::iter_swap(__result, __b);
> > > > + else if (std::__invoke(__comp,
> > > > + std::__invoke(__proj,
> > > *__a),
> > > > + std::__invoke(__proj,
> > > *__c)))
> > > > + ranges::iter_swap(__result, __c);
> > > > + else
> > > > + ranges::iter_swap(__result, __a);
> > > > + }
> > > > + else if (std::__invoke(__comp,
> > > > + std::__invoke(__proj, *__a),
> > > > + std::__invoke(__proj, *__c)))
> > > > + ranges::iter_swap(__result, __a);
> > > > + else if (std::__invoke(__comp,
> > > > + std::__invoke(__proj, *__b),
> > > > + std::__invoke(__proj, *__c)))
> > > > + ranges::iter_swap(__result, __c);
> > > > + else
> > > > + ranges::iter_swap(__result, __b);
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __unguarded_linear_insert(_Iter __last, _Comp
> > > __comp, _Proj __proj)
> > > > + {
> > > > + iter_value_t<_Iter> __val =
> > > ranges::iter_move(__last);
> > > > + _Iter __next = __last;
> > > > + --__next;
> > > > + while (std::__invoke(__comp,
> > > > + std::__invoke(__proj, __val),
> > > > + std::__invoke(__proj,
> > > *__next)))
> > > > + {
> > > > + *__last = ranges::iter_move(__next);
> > > > + __last = __next;
> > > > + --__next;
> > > > + }
> > > > + *__last = std::move(__val);
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __insertion_sort(_Iter __first, _Iter __last, _Comp
> > > __comp, _Proj __proj)
> > > > + {
> > > > + if (__first == __last) return;
> > > > +
> > > > + for (_Iter __i = __first + 1; __i != __last; ++__i)
> > > > + {
> > > > + if (std::__invoke(__comp,
> > > > + std::__invoke(__proj, *__i),
> > > > + std::__invoke(__proj,
> > > *__first)))
> > > > + {
> > > > + iter_value_t<_Iter> __val =
> > > ranges::iter_move(__i);
> > > > + ranges::move_backward(__first, __i, __i +
> > > 1);
> > > > + *__first = std::move(__val);
> > > > + }
> > > > + else
> > > > + __detail::__unguarded_linear_insert(__i,
> > > __comp, __proj);
> > > > + }
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __unguarded_insertion_sort(_Iter __first, _Iter
> > > __last,
> > > > + _Comp __comp, _Proj __proj)
> > > > + {
> > > > + for (_Iter __i = __first; __i != __last; ++__i)
> > > > + __detail::__unguarded_linear_insert(__i, __comp,
> > > __proj);
> > > > + }
> > > > +
> > > > + inline constexpr int __sort_threshold = 16;
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __final_insertion_sort(_Iter __first, _Iter __last,
> > > > + _Comp __comp, _Proj __proj)
> > > > + {
> > > > + if (__last - __first > __sort_threshold)
> > > > + {
> > > > + __detail::__insertion_sort(__first, __first +
> > > __sort_threshold,
> > > > + __comp, __proj);
> > > > + __detail::__unguarded_insertion_sort(__first +
> > > __sort_threshold, __last,
> > > > + __comp,
> > > __proj);
> > > > + }
> > > > + else
> > > > + __detail::__insertion_sort(__first, __last,
> > > __comp, __proj);
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr _Iter
> > > > + __unguarded_partition(_Iter __first, _Iter __last,
> > > _Iter __pivot,
> > > > + _Comp __comp, _Proj __proj)
> > > > + {
> > > > + while (true)
> > > > + {
> > > > + while (std::__invoke(__comp,
> > > > + std::__invoke(__proj,
> > > *__first),
> > > > + std::__invoke(__proj,
> > > *__pivot)))
> > > > + ++__first;
> > > > + --__last;
> > > > + while (std::__invoke(__comp,
> > > > + std::__invoke(__proj,
> > > *__pivot),
> > > > + std::__invoke(__proj,
> > > *__last)))
> > > > + --__last;
> > > > + if (!(__first < __last))
> > > > + return __first;
> > > > + ranges::iter_swap(__first, __last);
> > > > + ++__first;
> > > > + }
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr _Iter
> > > > + __unguarded_partition_pivot(_Iter __first, _Iter
> > > __last,
> > > > + _Comp __comp, _Proj
> > > __proj)
> > > > + {
> > > > + _Iter __mid = __first + (__last - __first) / 2;
> > > > + __detail::__move_median_to_first(__first, __first +
> > > 1, __mid, __last - 1,
> > > > + __comp, __proj);
> > > > + return __detail::__unguarded_partition(__first + 1,
> > > __last, __first,
> > > > + __comp,
> > > __proj);
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __heap_select(_Iter __first, _Iter __middle, _Iter
> > > __last,
> > > > + _Comp __comp, _Proj __proj)
> > > > + {
> > > > + ranges::make_heap(__first, __middle, __comp,
> > > __proj);
> > > > + for (_Iter __i = __middle; __i < __last; ++__i)
> > > > + if (std::__invoke(__comp,
> > > > + std::__invoke(__proj, *__i),
> > > > + std::__invoke(__proj,
> > > *__first)))
> > > > + __detail::__pop_heap(__first, __middle, __i,
> > > __comp, __proj);
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Compare, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __partial_sort(_Iter __first, _Iter __middle, _Iter
> > > __last,
> > > > + _Compare __comp, _Proj __proj)
> > > > + {
> > > > + __detail::__heap_select(__first, __middle, __last,
> > > __comp, __proj);
> > > > + ranges::sort_heap(__first, __middle, __comp,
> > > __proj);
> > > > + }
> > > > +
> > > > + template<typename _Iter, typename _Comp, typename
> > > _Proj>
> > > > + constexpr void
> > > > + __introsort_loop(_Iter __first, _Iter __last,
> > > unsigned __depth_limit,
> > > > + _Comp __comp, _Proj __proj)
> > > > + {
> > > > + while (__last - __first > __sort_threshold)
> > > > + {
> > > > + if (__depth_limit == 0)
> > > > + {
> > > > + __detail::__partial_sort(__first, __last,
> > > __last, __comp, __proj);
> > > > + return;
> > > > + }
> > > > + --__depth_limit;
> > > > + _Iter __cut =
> > > __detail::__unguarded_partition_pivot(__first, __last,
> > > > +
> > > __comp, __proj);
> > > > + __detail::__introsort_loop(__cut, __last,
> > > __depth_limit, __comp, __proj);
> > > > + __last = __cut;
> > > > + }
> > > > + }
> > > > + } // namespace __detail
> > > > +
> > > > struct __sort_fn
> > > > {
> > > > template<random_access_iterator _Iter,
> > > sentinel_for<_Iter> _Sent,
> > > > @@ -2175,10 +2354,33 @@ namespace ranges
> > > > operator()(_Iter __first, _Sent __last,
> > > > _Comp __comp = {}, _Proj __proj = {}) const
> > > > {
> > > > - auto __lasti = ranges::next(__first, __last);
> > > > - _GLIBCXX_STD_A::sort(std::move(__first), __lasti,
> > > > -
> > > __detail::__make_comp_proj(__comp, __proj));
> > > > - return __lasti;
> > > > + if constexpr (!same_as<_Iter, _Sent>)
> > > > + return (*this)(__first, ranges::next(__first,
> > > __last),
> > > > + std::move(__comp),
> > > std::move(__proj));
> > > > + else
> > > > + {
> > > > + if (__first != __last)
> > > > + {
> > > > + auto __n =
> > > __detail::__to_unsigned_like(__last - __first);
> > > > + unsigned __log_n;
> > > > + if constexpr
> > > (is_class_v<iter_difference_t<_Iter>>)
> > > > + {
> > > > + // FIXME: <bit> doesn't handle
> > > integer-class types.
> > > > + __log_n = 0;
> > > > + while (__n != 1)
> > > > + {
> > > > + __n >>= 1;
> > > > + ++__log_n;
> > > > + }
> > > >
> > > > I would add overload for std::__bit_width for __max_size_type in
> > > max_size_type.h,
> > > > as it should be simple to implement:
> > > > if (_M_msb)
> > > > return numeric_limits<__rep>::digits + 1;
> > > > else
> > > > return std::__bit_width(_M_val);
> > >
> > > That's much better, fixed. I opted to use an explicit
> > > specialization of
> > > the existing overload of a new overload.
> > >
> > > -- >8 --
> > >
> > > Subject: [PATCH 2/2] libstdc++: Directly implement ranges::sort
> > > [PR100795]
> > >
> > > As with the previous patch, this patch reimplements ranges::sort
> > > directly instead of incorrectly forwarding to std::sort. In
> > > addition to
> > > the compatibility changes listed in the previous patch we also:
> > >
> > > - use ranges::iter_swap instead of std::iter_swap
> > > - use ranges::move_backward instead of std::move_backward
> > > - use __bit_width and __to_unsigned_like instead of __lg
> > >
> > > PR libstdc++/100795
> > > PR libstdc++/118209
> > >
> > > libstdc++-v3/ChangeLog:
> > >
> > > * include/bits/max_size_type.h (__bit_width): New explicit
> > > specializatino for __max_size_type.
> > > * include/bits/ranges_algo.h
> > > (__detail::__move_median_to_first):
> > > New, based on the stl_algo.h implementation.
> > > (__detail::__unguarded_liner_insert): Likewise.
> > > (__detail::__insertion_sort): Likewise.
> > > (__detail::__sort_threshold): Likewise.
> > > (__detail::__unguarded_insertion_sort): Likewise.
> > > (__detail::__final_insertion_sort): Likewise.
> > > (__detail::__unguarded_partition): Likewise.
> > > (__detail::__unguarded_partition_pivot): Likewise.
> > > (__detail::__heap_select): Likewise.
> > > (__detail::__partial_sort): Likewise.
> > > (__detail::__introsort_loop): Likewise.
> > > (__sort_fn::operator()): Reimplement in terms of the above.
> > > * libstdc++-v3/testsuite/25_algorithms/sort/118209.cc: New
> > > test.
> > > * libstdc++-v3/testsuite/25_algorithms/sort/constrained.cc
> > > (test03): New test.
> > > ---
> > > libstdc++-v3/include/bits/max_size_type.h | 6 +
> > > libstdc++-v3/include/bits/ranges_algo.h | 198
> > > +++++++++++++++++-
> > > .../testsuite/25_algorithms/sort/118209.cc | 23 ++
> > > .../25_algorithms/sort/constrained.cc | 31 +++
> > > 4 files changed, 254 insertions(+), 4 deletions(-)
> > > create mode 100644
> > > libstdc++-v3/testsuite/25_algorithms/sort/118209.cc
> > >
> > > diff --git a/libstdc++-v3/include/bits/max_size_type.h
> > > b/libstdc++-v3/include/bits/max_size_type.h
> > > index e602b1b4bee5..915e59f22d52 100644
> > > --- a/libstdc++-v3/include/bits/max_size_type.h
> > > +++ b/libstdc++-v3/include/bits/max_size_type.h
> > > @@ -36,6 +36,7 @@
> > >
> > > #if __cplusplus > 201703L && __cpp_lib_concepts
> > > #include <ext/numeric_traits.h>
> > > +#include <bit> // __bit_width
> > > #include <numbers>
> > >
> > > // This header implements unsigned and signed integer-class types
> > > (as per
> > > @@ -818,6 +819,11 @@ namespace ranges
> > > { return min(); }
> > > };
> > >
> > > + template<>
> > > + inline constexpr int
> > > + __bit_width(ranges::__detail::__max_size_type __x) noexcept
> > > + { return std::__bit_width(__x._M_val) + __x._M_msb; }
> > >
> > > +
> > > _GLIBCXX_END_NAMESPACE_VERSION
> > > } // namespace
> > >
> > > diff --git a/libstdc++-v3/include/bits/ranges_algo.h
> > > b/libstdc++-v3/include/bits/ranges_algo.h
> > > index ca86f63812f4..819316fa79c3 100644
> > > --- a/libstdc++-v3/include/bits/ranges_algo.h
> > > +++ b/libstdc++-v3/include/bits/ranges_algo.h
> > > @@ -32,6 +32,7 @@
> > >
> > > #if __cplusplus > 201703L
> > >
> > > +#include <bit> // __bit_width
> > > #if __cplusplus > 202002L
> > > #include <optional>
> > > #endif
> > > @@ -2166,6 +2167,184 @@ namespace ranges
> > >
> > > inline constexpr __is_heap_fn is_heap{};
> > >
> > > + namespace __detail
> > > + {
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __move_median_to_first(_Iter __result, _Iter __a, _Iter __b,
> > > _Iter __c,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__a),
> > > + std::__invoke(__proj, *__b)))
> > > + {
> > > + if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__b),
> > > + std::__invoke(__proj, *__c)))
> > > + ranges::iter_swap(__result, __b);
> > > + else if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__a),
> > > + std::__invoke(__proj, *__c)))
> > > + ranges::iter_swap(__result, __c);
> > > + else
> > > + ranges::iter_swap(__result, __a);
> > > + }
> > > + else if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__a),
> > > + std::__invoke(__proj, *__c)))
> > > + ranges::iter_swap(__result, __a);
> > > + else if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__b),
> > > + std::__invoke(__proj, *__c)))
> > > + ranges::iter_swap(__result, __c);
> > > + else
> > > + ranges::iter_swap(__result, __b);
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __unguarded_linear_insert(_Iter __last, _Comp __comp, _Proj
> > > __proj)
> > > + {
> > > + iter_value_t<_Iter> __val = ranges::iter_move(__last);
> > > + _Iter __next = __last;
> > > + --__next;
> > > + while (std::__invoke(__comp,
> > > + std::__invoke(__proj, __val),
> > > + std::__invoke(__proj, *__next)))
> > > + {
> > > + *__last = ranges::iter_move(__next);
> > > + __last = __next;
> > > + --__next;
> > > + }
> > > + *__last = std::move(__val);
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __insertion_sort(_Iter __first, _Iter __last, _Comp __comp,
> > > _Proj __proj)
> > > + {
> > > + if (__first == __last) return;
> > > +
> > > + for (_Iter __i = __first + 1; __i != __last; ++__i)
> > > + {
> > > + if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__i),
> > > + std::__invoke(__proj, *__first)))
> > > + {
> > > + iter_value_t<_Iter> __val = ranges::iter_move(__i);
> > > + ranges::move_backward(__first, __i, __i + 1);
> > > + *__first = std::move(__val);
> > > + }
> > > + else
> > > + __detail::__unguarded_linear_insert(__i, __comp,
> > > __proj);
> > > + }
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __unguarded_insertion_sort(_Iter __first, _Iter __last,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + for (_Iter __i = __first; __i != __last; ++__i)
> > > + __detail::__unguarded_linear_insert(__i, __comp, __proj);
> > > + }
> > > +
> > > + inline constexpr int __sort_threshold = 16;
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __final_insertion_sort(_Iter __first, _Iter __last,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + if (__last - __first > __sort_threshold)
> > > + {
> > > + __detail::__insertion_sort(__first, __first +
> > > __sort_threshold,
> > > + __comp, __proj);
> > > + __detail::__unguarded_insertion_sort(__first +
> > > __sort_threshold, __last,
> > > + __comp, __proj);
> > > + }
> > > + else
> > > + __detail::__insertion_sort(__first, __last, __comp,
> > > __proj);
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr _Iter
> > > + __unguarded_partition(_Iter __first, _Iter __last, _Iter
> > > __pivot,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + while (true)
> > > + {
> > > + while (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__first),
> > > + std::__invoke(__proj, *__pivot)))
> > > + ++__first;
> > > + --__last;
> > > + while (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__pivot),
> > > + std::__invoke(__proj, *__last)))
> > > + --__last;
> > > + if (!(__first < __last))
> > > + return __first;
> > > + ranges::iter_swap(__first, __last);
> > > + ++__first;
> > > + }
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr _Iter
> > > + __unguarded_partition_pivot(_Iter __first, _Iter __last,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + _Iter __mid = __first + (__last - __first) / 2;
> > > + __detail::__move_median_to_first(__first, __first + 1,
> > > __mid, __last - 1,
> > > + __comp, __proj);
> > > + return __detail::__unguarded_partition(__first + 1, __last,
> > > __first,
> > > + __comp, __proj);
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __heap_select(_Iter __first, _Iter __middle, _Iter __last,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + ranges::make_heap(__first, __middle, __comp, __proj);
> > > + for (_Iter __i = __middle; __i < __last; ++__i)
> > > + if (std::__invoke(__comp,
> > > + std::__invoke(__proj, *__i),
> > > + std::__invoke(__proj, *__first)))
> > > + __detail::__pop_heap(__first, __middle, __i, __comp,
> > > __proj);
> > > + }
> > > +
> > > + template<typename _Iter, typename _Compare, typename _Proj>
> > > + constexpr void
> > > + __partial_sort(_Iter __first, _Iter __middle, _Iter __last,
> > > + _Compare __comp, _Proj __proj)
> > > + {
> > > + __detail::__heap_select(__first, __middle, __last, __comp,
> > > __proj);
> > > + ranges::sort_heap(__first, __middle, __comp, __proj);
> > > + }
> > > +
> > > + template<typename _Iter, typename _Comp, typename _Proj>
> > > + constexpr void
> > > + __introsort_loop(_Iter __first, _Iter __last, unsigned
> > > __depth_limit,
> > > + _Comp __comp, _Proj __proj)
> > > + {
> > > + while (__last - __first > __sort_threshold)
> > > + {
> > > + if (__depth_limit == 0)
> > > + {
> > > + __detail::__partial_sort(__first, __last, __last,
> > > __comp, __proj);
> > > + return;
> > > + }
> > > + --__depth_limit;
> > > + _Iter __cut =
> > > __detail::__unguarded_partition_pivot(__first, __last,
> > > +
> > > __comp, __proj);
> > > + __detail::__introsort_loop(__cut, __last,
> > > __depth_limit, __comp, __proj);
> > > + __last = __cut;
> > > + }
> > > + }
> > > + } // namespace __detail
> > > +
> > > struct __sort_fn
> > > {
> > > template<random_access_iterator _Iter, sentinel_for<_Iter>
> > > _Sent,
> > > @@ -2175,10 +2354,21 @@ namespace ranges
> > > operator()(_Iter __first, _Sent __last,
> > > _Comp __comp = {}, _Proj __proj = {}) const
> > > {
> > > - auto __lasti = ranges::next(__first, __last);
> > > - _GLIBCXX_STD_A::sort(std::move(__first), __lasti,
> > > - __detail::__make_comp_proj(__comp,
> > > __proj));
> > > - return __lasti;
> > > + if constexpr (!same_as<_Iter, _Sent>)
> > > + return (*this)(__first, ranges::next(__first, __last),
> > > + std::move(__comp), std::move(__proj));
> > > + else
> > > + {
> > > + if (__first != __last)
> > > + {
> > > + auto __n = __detail::__to_unsigned_like(__last -
> > > __first);
> > > + unsigned __depth_limit = (std::__bit_width(__n) -
> > > 1) * 2;
> > > + __detail::__introsort_loop(__first, __last,
> > > __depth_limit,
> > > + __comp, __proj);
> > > + __detail::__final_insertion_sort(__first, __last,
> > > __comp, __proj);
> > > + }
> > > + return __last;
> > > + }
> > > }
> > >
> > > template<random_access_range _Range,
> > > diff --git a/libstdc++-v3/testsuite/25_algorithms/sort/118209.cc
> > > b/libstdc++-v3/testsuite/25_algorithms/sort/118209.cc
> > > new file mode 100644
> > > index 000000000000..6dedbde75173
> > > --- /dev/null
> > > +++ b/libstdc++-v3/testsuite/25_algorithms/sort/118209.cc
> > > @@ -0,0 +1,23 @@
> > > +// PR libstdc++ - ranges::sort doesn't use iter_move, cannot sort
> > > zip of move-only type
> > > +// { dg-do compile { target c++23 } }
> > > +
> > > +#include <algorithm>
> > > +#include <ranges>
> > > +#include <vector>
> > > +
> > > +struct F {
> > > + int a = -1;
> > > + explicit F(int d) : a(d) { }
> > > + F(const F&) = delete;
> > > + F(F&& o) : a(o.a) { }
> > > + void operator=(const F&) = delete;
> > > + F& operator=(F&& o) { return *this; }
> > > + auto operator<=>(const F&) const = default;
> > > +};
> > > +
> > > +int main () {
> > > + int a[] = {3,2,1};
> > > + std::vector<F> v(a, a+3);
> > > + std::ranges::sort(v); // OK
> > > + std::ranges::sort(std::views::zip(v)); // didn't compile
> > > +}
> > > diff --git
> > > a/libstdc++-v3/testsuite/25_algorithms/sort/constrained.cc
> > > b/libstdc++-v3/testsuite/25_algorithms/sort/constrained.cc
> > > index 82754af96430..930dbd77a376 100644
> > > --- a/libstdc++-v3/testsuite/25_algorithms/sort/constrained.cc
> > > +++ b/libstdc++-v3/testsuite/25_algorithms/sort/constrained.cc
> > > @@ -20,6 +20,7 @@
> > >
> > > #include <algorithm>
> > > #include <random>
> > > +#include <ranges>
> > > #include <vector>
> > > #include <testsuite_hooks.h>
> > > #include <testsuite_iterators.h>
> > > @@ -72,9 +73,39 @@ test02()
> > > && ranges::equal(x, y, {}, &X::i, &X::i));
> > > }
> > >
> > > +constexpr bool
> > > +test03()
> > > +{
> > > + // PR libstdc++/100795 - ranges::sort should not use std::sort
> > > directly
> > > +#if __SIZEOF_INT128__
> > > + auto v = std::views::iota(__int128(0), __int128(20));
> > > +#else
> > > + auto v = std::views::iota(0ll, 20ll);
> > > +#endif
> > > +
> > > + int storage[20] =
> > > {2,5,4,3,1,6,7,9,10,8,11,14,12,13,15,16,18,0,19,17};
> > > + auto w = v | std::views::transform([&](auto i) -> int& { return
> > > storage[i]; });
> > > + using type = decltype(w);
> > > + using cat =
> > > std::iterator_traits<std::ranges::iterator_t<type>>::iterator_category;
> > > + static_assert( std::same_as<cat, std::output_iterator_tag> );
> > > + static_assert( std::ranges::random_access_range<type> );
> > > +
> > > + ranges::sort(w);
> > > + VERIFY( ranges::equal(w, v) );
> > > +
> > > + ranges::sort(w, std::ranges::greater{});
> > > + VERIFY( ranges::equal(w, v | std::views::reverse) );
> > > +
> > > + ranges::sort(w, std::ranges::greater{}, std::negate{});
> > > + VERIFY( ranges::equal(w, v) );
> > > +
> > > + return true;
> > > +}
> > > +
> > > int
> > > main()
> > > {
> > > test01();
> > > static_assert(test02());
> > > + static_assert(test03());
> > > }
> > > --
> > > 2.50.0.rc2
> > >
> > >
> > >
