WIP: [libc++][ranges] Implement `ranges::stride_view`.

[hawkinsw]

Hello @ldionne and @philnik !! I am a *huge* fan of both of yours and really appreciate all the work that you devote to libc++. I saw a chance to contribute and wanted to try to help.

The code I have here is very rough and early, but I was hoping that you could provide some rough guidance! I have contributed small patches before but this is a new area for me and I have already learned a ton! I know that I need to complete the steps listed in the Pre-commit check list in docs/Contributing.rst and I am working on that now.

Thank you, again, for all the great work!

PS: I hope that you are the right ones to tag for review. I based the tag here on git blame output and I apologize if I am spamming you!

I hope that this contribution is the first of many (e.g., ranges::adjacent_view).
Will

[Mordante]

Thanks for working on this!

I'm not to familiar with ranges to I leave a real review to others. I mainly glossed over the patch.

Based on https://libcxx.llvm.org/Status/Ranges @H-G-Hristov is working on this too, @H-G-Hristov what is the status of your work?

If you want to work on a different view nobody is working on please let us know, we can put your name on it.

libcxx/include/__ranges/stride_view.h

188

This line is too long, please use clang-format to format the patch.

[hawkinsw]

In D156924#4555070, @Mordante wrote:

Thanks for working on this!

I'm not to familiar with ranges to I leave a real review to others. I mainly glossed over the patch.

Based on https://libcxx.llvm.org/Status/Ranges @H-G-Hristov is working on this too, @H-G-Hristov what is the status of your work?

If you want to work on a different view nobody is working on please let us know, we can put your name on it.

I am really eager to help however I can! I am a huge language geek and love open source. The past two days of coding on this little side project have been the most eye-opening C++ experience I have had since I started (mid 90s). If @H-G-Hristov wants to take over, that's great -- just assign me whatever needs to be done!

Will

libcxx/include/__ranges/stride_view.h

188

Will do!!

This is actually a meta question -- I ran clang-format (in the libcxx/ directory with the .clang-format file) and noticed that the result was nothing like what the other files looked like. I was worried that I had done something wrong.

[Mordante]

In D156924#4555100, @hawkinsw wrote:

In D156924#4555070, @Mordante wrote:

Thanks for working on this!

I'm not to familiar with ranges to I leave a real review to others. I mainly glossed over the patch.

Based on https://libcxx.llvm.org/Status/Ranges @H-G-Hristov is working on this too, @H-G-Hristov what is the status of your work?

If you want to work on a different view nobody is working on please let us know, we can put your name on it.

I am really eager to help however I can! I am a huge language geek and love open source. The past two days of coding on this little side project have been the most eye-opening C++ experience I have had since I started (mid 90s). If @H-G-Hristov wants to take over, that's great -- just assign me whatever needs to be done!

Will

I think nobody is working on the C++23 range based algorithms. I found some patches for other views. Unfortunately the Phabricator search is under heavy load so I can't search. Maybe visit our Discord channel and reach out to @varconst or @philnik they are most familiar in this area. If you don't know where our Discord is, the link is at the top of https://libcxx.llvm.org/Contributing.html

libcxx/include/__ranges/stride_view.h

188

Not all files are formatted. Currently we use clang-format-17. We like new files to be formatted.

[Mordante]

Pressed submit too fast ;-)

In D156924#4555100, @hawkinsw wrote:

I am really eager to help however I can! I am a huge language geek and love open source. The past two days of coding on this little side project have been the most eye-opening C++ experience I have had since I started (mid 90s).

Cool to hear! I too love to see the progress C++ has made over the years :-)

[hawkinsw]

Formatted patch using clang-format on @Mordante 's helpful suggestion.

[hawkinsw]

Thank you, @Mordante !

libcxx/include/__ranges/stride_view.h

53

Yes, I realize that this is crazy! It is dead code and I will eliminate it.

[H-G-Hristov]

@Mordante @hawkinsw My patch is about the same state like this one. I am still working on enumerate_view I need to add more tests before I submit it. I didn't have much time to work during the last month but I'd like to get it in Clang 18. Maybe its about time to submit a draft.

@hawkinsw You can continue working on it if you like or maybe you can pick some of the other view which are more useful and interesting but I think also more difficult (join_with and join).
You can update the status here: https://libcxx.llvm.org/Status/Ranges.html

[hawkinsw]

In D156924#4558613, @H-G-Hristov wrote:

@Mordante @hawkinsw My patch is about the same state like this one. I am still working on enumerate_view I need to add more tests before I submit it. I didn't have much time to work during the last month but I'd like to get it in Clang 18. Maybe its about time to submit a draft.

@hawkinsw You can continue working on it if you like or maybe you can pick some of the other view which are more useful and interesting but I think also more difficult (join_with and join).
You can update the status here: https://libcxx.llvm.org/Status/Ranges.html

Hello @H-G-Hristov !! As a warmup to working on others, I will continue to hammer on this (my next goal is to write tests!) I don't want to waste your time (obviously!) but it's been fun to work on this and a great learning experience. The next goal I have is to write tests (I will start on that tonight!)

Does that sound okay?

[H-G-Hristov]

In D156924#4558648, @hawkinsw wrote:

In D156924#4558613, @H-G-Hristov wrote:

@Mordante @hawkinsw My patch is about the same state like this one. I am still working on enumerate_view I need to add more tests before I submit it. I didn't have much time to work during the last month but I'd like to get it in Clang 18. Maybe its about time to submit a draft.

@hawkinsw You can continue working on it if you like or maybe you can pick some of the other view which are more useful and interesting but I think also more difficult (join_with and join).
You can update the status here: https://libcxx.llvm.org/Status/Ranges.html

Hello @H-G-Hristov !! As a warmup to working on others, I will continue to hammer on this (my next goal is to write tests!) I don't want to waste your time (obviously!) but it's been fun to work on this and a great learning experience. The next goal I have is to write tests (I will start on that tonight!)

Does that sound okay?

Sure, please continue.

[hawkinsw]

Marked div_ceil as ABI invisible and removed caching.

[hawkinsw]

Fixed the commit against which this diff should be applied.

[hawkinsw]

Remove inclusion of spurious change to libcxx-lit.

[hawkinsw]

clang-tidy'd the code.

[hawkinsw]

Added a first, basic test and also did some more clang-tidy'ing.

[H-G-Hristov]

@hawkinsw You can look at my WIP for stuff you can easily copy: https://reviews.llvm.org/D157192

[hawkinsw]

In D156924#4563133, @H-G-Hristov wrote:

@hawkinsw You can look at my WIP for stuff you can easily copy: https://reviews.llvm.org/D157192

Thank you -- very kind of you! Two heads (especially yours -- which is smarter than mine!) are better than one!

[hawkinsw]

Fix some ADL warnings, compilation errors and implementation details.

[hawkinsw]

Bring in the awesome tests that @H-G-Hristov already wrote!

[hawkinsw]

More cargo crating from @H-G-Hristov's excellent work.

[hawkinsw]

Check in the modified feature test macro code.

[hawkinsw]

Adding some missing include files.

[hawkinsw]

Make div-ceil system only by adding __ prefix.

[hawkinsw]

Add initial tests for ::size

[hawkinsw]

(maybe) last clang-tidy/format and add base tests.

[hawkinsw]

Clean up the skeleton test file (remove references to std::ranges::enumerate).

[hawkinsw]

@H-G-Hristov Thank you for all the contributions -- your code was immensely helpful. I think that I am making some progress! If you have any thoughts on the way that things are going with the implementation, please let me know! Thanks again!

[H-G-Hristov]

In D156924#4573070, @hawkinsw wrote:

@H-G-Hristov Thank you for all the contributions -- your code was immensely helpful. I think that I am making some progress! If you have any thoughts on the way that things are going with the implementation, please let me know! Thanks again!

I'm also a rookie at this, so treat anything with a pinch of salt. This is may WIP patch for enumerate_view: https://reviews.llvm.org/D157193 I think it has some similarities to stride_view. It's missing a few converting constructor tests but after rebase it should get green. I do expect that it will get a lot of scrutiny and feedback in the review but I think you can check it for what tests you need to write. I've based my tests on already existing tests.

I am also going to update the status page with my patch soon: https://libcxx.llvm.org/Status/Ranges.html If you like I could update it for you too. Or you can do it yourself.

N.B. You should update the synopses. The implemented papers/issues, etc.

[hawkinsw]

Prevent __to_unsigned_like from using ADL.

[hawkinsw]

Add iterator operator== tests.

[hawkinsw]

Adding some tests (generally making progress).

[hawkinsw]

Add tests for enable_borrowed_range.

[var-const]

@hawkinsw First of all, thanks a ton for working on this! LLVM is currently in the process of moving away from Phabricator to GitHub reviews -- see https://discourse.llvm.org/t/logistics-of-the-transition-to-github-prs-for-libc-libc-abi-libunwind/73130. Since the review for this patch hasn't really started yet, I think it might be easier to open a new review on GitHub. Would that work for you? If you have a strong preference to keep the patch on Phabricator for now, that's ok, I can start the review here.

Btw, can you give a very brief outline on the current status of the patch? I notice it's still marked as WIP so I'm just curious which parts are still TODO. Would it make sense to start reviewing it now, or should I wait a bit? Let me know, and once again, thanks a lot for working on this!

[hawkinsw]

In D156924#4635672, @var-const wrote:

@hawkinsw First of all, thanks a ton for working on this! LLVM is currently in the process of moving away from Phabricator to GitHub reviews -- see https://discourse.llvm.org/t/logistics-of-the-transition-to-github-prs-for-libc-libc-abi-libunwind/73130. Since the review for this patch hasn't really started yet, I think it might be easier to open a new review on GitHub. Would that work for you? If you have a strong preference to keep the patch on Phabricator for now, that's ok, I can start the review here.

You got it!! I want to make sure that I do what the community wants! I will move it there and then comment back here and let you know where it lands!

Btw, can you give a very brief outline on the current status of the patch? I notice it's still marked as WIP so I'm just curious which parts are still TODO. Would it make sense to start reviewing it now, or should I wait a bit? Let me know, and once again, thanks a lot for working on this!

Though I am a long-time C++ developer, I have only submitted minor optimizations to STL implementations to date. So, I _think_ that what is here is something that is roughly complete. What I am adding now are tests and it's taking a little longer than I had hoped. My day job as a teacher just ramped up again.

That is to say, I would love to start getting feedback on the patch and start refining it! I have had so much fun doing the implementation so far and learned a ton. I know that your review will help me learn even more!

Thank you for being so encouraging.

[hawkinsw]

In light of the transition to GitHub PRs, I am closing this revision in favor of https://github.com/llvm/llvm-project/pull/65200.

libcxx/docs/FeatureTestMacroTable.rst

.. table:: Current Status
     ``__cpp_lib_ranges_join_with``                      *unimplemented*
     --------------------------------------------------- -----------------
     ``__cpp_lib_ranges_repeat``                         ``202207L``
     --------------------------------------------------- -----------------
     ``__cpp_lib_ranges_slide``                          *unimplemented*
     --------------------------------------------------- -----------------
     ``__cpp_lib_ranges_starts_ends_with``               *unimplemented*
     --------------------------------------------------- -----------------
+    ``__cpp_lib_ranges_stride``                         ``202207L``
+    --------------------------------------------------- -----------------
     ``__cpp_lib_ranges_to_container``                   ``202202L``
     --------------------------------------------------- -----------------
     ``__cpp_lib_ranges_zip``                            *unimplemented*
     --------------------------------------------------- -----------------
     ``__cpp_lib_reference_from_temporary``              *unimplemented*
     --------------------------------------------------- -----------------
     ``__cpp_lib_spanstream``                            *unimplemented*
     --------------------------------------------------- -----------------

libcxx/include/CMakeLists.txt

set(files
   __ranges/rbegin.h
   __ranges/ref_view.h
   __ranges/rend.h
   __ranges/repeat_view.h
   __ranges/reverse_view.h
   __ranges/single_view.h
   __ranges/size.h
   __ranges/split_view.h
+  __ranges/stride_view.h
   __ranges/subrange.h
   __ranges/take_view.h
   __ranges/take_while_view.h
   __ranges/to.h
   __ranges/transform_view.h
   __ranges/view_interface.h
   __ranges/views.h
   __ranges/zip_view.h

libcxx/include/__ranges/stride_view.h

+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANGES_STRIDE_VIEW_H
+#define _LIBCPP___RANGES_STRIDE_VIEW_H
+
+#include <__config>
+
+#include <__compare/three_way_comparable.h>
+#include <__concepts/constructible.h>
+#include <__concepts/convertible_to.h>
+#include <__concepts/derived_from.h>
+#include <__functional/bind_back.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/distance.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/reverse_iterator.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/non_propagating_cache.h>
+#include <__ranges/range_adaptor.h>
+#include <__ranges/size.h>
+#include <__ranges/subrange.h>
+#include <__ranges/view_interface.h>
+#include <__ranges/views.h>
+#include <__type_traits/conditional.h>
+#include <__type_traits/maybe_const.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 23
+
+namespace ranges {
+
+template <class _Value>
+_LIBCPP_HIDE_FROM_ABI constexpr _Value __div_ceil(_Value __left, _Value __right) {
+  _Value __r = __left / __right;
+  if (__left % __right) {
+    __r++;
+  }
+  return __r;
+}
+
+template <input_range _View>
+  requires view<_View>
+class stride_view : public view_interface<stride_view<_View>> {
+  _LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
+  range_difference_t<_View> __stride_     = 0;
+
+  template <bool _Const>
+  class __iterator;
+  template <bool _Const>
+  class __sentinel;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI constexpr explicit stride_view(_View __base, range_difference_t<_View> __stride)
+      : __base_(std::move(__base)), __stride_(__stride) {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr _View base() const&
+    requires copy_constructible<_View>
+  {
+    return __base_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return std::move(__base_); }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto stride() { return __stride_; }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto size()
+    requires ranges::sized_range<_View>
+  {
+    return std::__to_unsigned_like(ranges::__div_ceil(ranges::distance(__base_), __stride_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto size() const
+    requires ranges::sized_range<const _View>
+  {
+    return std::__to_unsigned_like(ranges::__div_ceil(ranges::distance(__base_), __stride_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto begin()
+    requires(!__simple_view<_View>)
+  {
+    return __iterator<false>{*this, ranges::begin(__base_)};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto begin() const
+    requires ranges::range<const _View>
+  {
+    return __iterator<true>{*this, ranges::begin(__base_)};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto end()
+    requires(!__simple_view<_View> && common_range<_View> && sized_range<_View> && forward_range<_View>)
+  {
+    auto __missing = (__stride_ - ranges::distance(__base_) % __stride_) % __stride_;
+    return __iterator<false>{*this, ranges::end(__base_), __missing};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto end()
+    requires(!__simple_view<_View> && common_range<_View> && !bidirectional_range<_View>)
+  {
+    return __iterator<false>{*this, ranges::end(__base_)};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto end()
+    requires(!__simple_view<_View>)
+  {
+    return std::default_sentinel;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
+    requires(range<const _View> && common_range<const _View> && sized_range<const _View> && forward_range<const _View>)
+  {
+    auto __missing = (__stride_ - ranges::distance(__base_) % __stride_) % __stride_;
+    return __iterator<true>{*this, ranges::end(__base_), __missing};
+  }
+  _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
+    requires(range<const _View> && common_range<_View> && !bidirectional_range<_View>)
+  {
+    return __iterator<true>{*this, ranges::end(__base_)};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr auto end() const
+    requires(range<const _View>)
+  {
+    return std::default_sentinel;
+  }
+}; // class stride_view
+
+template <class _View>
+struct __stride_iterator_category {};
+
+template <forward_range _View>
+struct __stride_iterator_category<_View> {
+  using _Cat = typename iterator_traits<iterator_t<_View>>::iterator_category;
+  using iterator_category =
+      _If<derived_from<_Cat, random_access_iterator_tag>,
+          random_access_iterator_tag,
+          /* else */ _Cat >;
+};
+
+template <input_range _View>
+  requires view<_View>
+template <bool _Const>
+class stride_view<_View>::__iterator : public __stride_iterator_category<_View> {
+  using _Parent = __maybe_const<_Const, stride_view<_View>>;
+  using _Base   = __maybe_const<_Const, _View>;
+
+public:
+  using difference_type = range_difference_t<_Base>;
+  using value_type      = range_value_t<_Base>;
+  using iterator_concept =
+      _If<random_access_range<_Base>,
+          random_access_iterator_tag,
+          _If<bidirectional_range<_Base>,
+              bidirectional_iterator_tag,
+              _If<forward_range<_Base>,
+                  forward_iterator_tag,
+                  /* else */ input_iterator_tag >>>;
+
+  _LIBCPP_NO_UNIQUE_ADDRESS iterator_t<_Base> __current_     = iterator_t<_Base>();
+  _LIBCPP_NO_UNIQUE_ADDRESS ranges::sentinel_t<_Base> __end_ = ranges::sentinel_t<_Base>();
+  difference_type __stride_                                  = 0;
+  difference_type __missing_                                 = 0;
+
+  // using iterator_category = inherited;
+  _LIBCPP_HIDE_FROM_ABI __iterator()
+    requires default_initializable<iterator_t<_Base>>
+  = default;
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator(__iterator<!_Const> __i)
+    requires _Const && std::convertible_to<ranges::iterator_t<_View>, ranges::iterator_t<_Base>> &&
+                 std::convertible_to<ranges::sentinel_t<_View>, ranges::sentinel_t<_Base>>
+      : __current_(std::move(__i.__current_)),
+        __end_(std::move(__i.__end_)),
+        __stride_(__i.__stride_),
+        __missing_(__i.__missing_) {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator(
+      _Parent& __parent, ranges::iterator_t<_Base> __current, difference_type __missing = 0)
+      : __current_(std::move(__current)),
+        __end_(ranges::end(__parent.__base_)),
+        __stride_(__parent.__stride_),
+        __missing_(__missing) {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_View> const& base() const& noexcept { return __current_; }
+  _LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_View> base() && { return std::move(__current_); }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const { return *__current_; }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator++() {
+    __missing_ = ranges::advance(__current_, __stride_, __end_);
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++*this; }
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator++(int)
+    requires forward_range<_Base>
+  {
+    auto __tmp = *this;
+    ++*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator--()
+    requires bidirectional_range<_Base>
+  {
+    ranges::advance(__current_, __missing_ - __stride_);
+    __missing_ = 0;
+    return *this;
+  }
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator operator--(int)
+    requires bidirectional_range<_Base>
+  {
+    auto __tmp = *this;
+    --*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator+=(difference_type __s)
+    requires random_access_range<_Base>
+  {
+    if (__s > 0) {
+      ranges::advance(__current_, __stride_ * (__s - 1));
+      __missing_ = ranges::advance(__current_, __stride_, __end_);
+    } else if (__s < 0) {
+      ranges::advance(__current_, __stride_ * __s + __missing_);
+      __missing_ = 0;
+    }
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator-=(difference_type __s)
+    requires random_access_range<_Base>
+  {
+    return *this += -__s;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __iterator& operator[](difference_type __s) const
+    requires random_access_range<_Base>
+  {
+    return *(*this + __s);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(__iterator const& __x, default_sentinel_t) {
+    return __x.__current_ == __x.__end_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(__iterator const& __x, __iterator const& __y)
+    requires equality_comparable<iterator_t<_Base>>
+  {
+    return __x.__current_ == __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(__iterator const& __x, __iterator const& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ < __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(__iterator const& __x, __iterator const& __y)
+    requires random_access_range<_Base>
+  {
+    return __y < __x;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(__iterator const& __x, __iterator const& __y)
+    requires random_access_range<_Base>
+  {
+    return !(__y < __x);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(__iterator const& __x, __iterator const& __y)
+    requires random_access_range<_Base>
+  {
+    return !(__x < __y);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=>(__iterator const& __x, __iterator const& __y)
+    requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>
+  {
+    return __x.__current_ <=> __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(__iterator const& __i, difference_type __s)
+    requires random_access_range<_Base>
+  {
+    auto __r = __i;
+    __r += __s;
+    return __r;
+  }
+  _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator+(difference_type __s, __iterator const& __i)
+    requires random_access_range<_Base>
+  {
+    auto __r = __i;
+    __r += __s;
+    return __r;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr __iterator operator-(__iterator const& __i, difference_type __s)
+    requires random_access_range<_Base>
+  {
+    auto __r = __i;
+    __r -= __s;
+    return __r;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(__iterator const& __x, __iterator const& __y)
+    requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>> && forward_range<_Base>
+  {
+    auto __n = __x.__current_ - __y.__current_;
+    return (__n + __x.__missing_ - __y.__missing_) / __x.__stride_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(__iterator const& __x, __iterator const& __y)
+    requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
+  {
+    auto __n = __x.__current_ - __y.__current_;
+    if (__n < 0) {
+      return -ranges::__div_ceil(-__n, __x.__stride_);
+    }
+    return ranges::__div_ceil(__n, __x.__stride_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(default_sentinel_t, __iterator const& __x)
+    requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
+  {
+    return ranges::__div_ceil(__x.__end_ - __x.__current_, __x.__stride_);
+  }
+  _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(__iterator const& __x, default_sentinel_t __y)
+    requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>>
+  {
+    return -(__y - __x);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr range_rvalue_reference_t<_Base>
+  iter_move(__iterator const& __it) noexcept(noexcept(ranges::iter_move(__it.__current_))) {
+    return ranges::iter_move(__it.__current_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr void
+  iter_swap(__iterator const& __x,
+            __iterator const& __y) noexcept(noexcept(ranges::iter_swap(__x.__current_, __y.__current_)))
+    requires indirectly_swappable<iterator_t<_Base>>
+  {
+    return ranges::iter_swap(__x.__current_, __y.__current_);
+  }
+}; // class stride_view::__iterator
+
+template <input_range _View>
+  requires view<_View>
+template <bool _Const>
+class stride_view<_View>::__sentinel {
+public:
+  sentinel_t<_View> __end_ = sentinel_t<_View>();
+
+  _LIBCPP_HIDE_FROM_ABI __sentinel() = default;
+
+  _LIBCPP_HIDE_FROM_ABI constexpr explicit __sentinel(stride_view<_View>& __parent)
+      : __end_(ranges::end(__parent.__base_)) {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_View> base() const { return __end_; }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(__iterator<true> const& __x, __sentinel const& __y) {
+    return __x.__current_ == __y.__end_;
+  }
+}; // class stride_view::__sentinel
+
+template <class _Range>
+stride_view(_Range&&) -> stride_view<views::all_t<_Range>>;
+
+template <class _Tp>
+inline constexpr bool enable_borrowed_range<stride_view<_Tp>> = enable_borrowed_range<_Tp>;
+
+namespace views {
+namespace __stride {
+// removed this.
+struct __fn {
+  template <viewable_range _Range>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Range&& __range, range_difference_t<_Range> __n) const
+      noexcept(noexcept(stride_view{std::forward<_Range>(__range), __n}))
+          -> decltype(stride_view{std::forward<_Range>(__range), __n}) {
+    return stride_view{std::forward<_Range>(__range), __n};
+  }
+
+  template <class _Np>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Np&& __n) const {
+    return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Np>(__n)));
+  }
+};
+} // namespace __stride
+
+inline namespace __cpo {
+inline constexpr auto stride = __stride::__fn{};
+} // namespace __cpo
+} // namespace views
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 23
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_STRIDE_VIEW_H

libcxx/include/module.modulemap.in

 module std_private_ranges_repeat_view                [system] { header "__ranges/repeat_view.h" }
 module std_private_ranges_reverse_view               [system] { header "__ranges/reverse_view.h" }
 module std_private_ranges_single_view                [system] { header "__ranges/single_view.h" }
 module std_private_ranges_size                       [system] {
   header "__ranges/size.h"
   export std_private_type_traits_make_unsigned
 }
 module std_private_ranges_split_view                 [system] { header "__ranges/split_view.h" }
+module std_private_ranges_stride_view                 [system] { header "__ranges/stride_view.h" }
 module std_private_ranges_subrange                   [system] {
   header "__ranges/subrange.h"
   export std_private_ranges_subrange_fwd
 }
 module std_private_ranges_subrange_fwd               [system] {
   header "__fwd/subrange.h"
   export std_private_iterator_concepts
 }

libcxx/include/ranges

 #include <__ranges/rbegin.h>
 #include <__ranges/ref_view.h>
 #include <__ranges/rend.h>
 #include <__ranges/repeat_view.h>
 #include <__ranges/reverse_view.h>
 #include <__ranges/single_view.h>
 #include <__ranges/size.h>
 #include <__ranges/split_view.h>
+#include <__ranges/stride_view.h>
 #include <__ranges/subrange.h>
 #include <__ranges/take_view.h>
 #include <__ranges/take_while_view.h>
 #include <__ranges/to.h>
 #include <__ranges/transform_view.h>
 #include <__ranges/view_interface.h>
 #include <__ranges/views.h>
 #include <__ranges/zip_view.h>

libcxx/include/version

 __cpp_lib_ranges_as_rvalue                              202207L <ranges>
 __cpp_lib_ranges_chunk                                  202202L <ranges>
 __cpp_lib_ranges_chunk_by                               202202L <ranges>
 __cpp_lib_ranges_iota                                   202202L <numeric>
 __cpp_lib_ranges_join_with                              202202L <ranges>
 __cpp_lib_ranges_repeat                                 202207L <ranges>
 __cpp_lib_ranges_slide                                  202202L <ranges>
 __cpp_lib_ranges_starts_ends_with                       202106L <algorithm>
+__cpp_lib_ranges_stride                                 202207L <ranges>
 __cpp_lib_ranges_to_container                           202202L <deque> <forward_list> <list>
                                                                 <map> <queue> <ranges>
                                                                 <set> <stack> <string>
                                                                 <unordered_map> <unordered_set> <vector>
 __cpp_lib_ranges_zip                                    202110L <ranges> <tuple> <utility>
 __cpp_lib_ratio                                         202306L <ratio>
 __cpp_lib_raw_memory_algorithms                         201606L <memory>
 __cpp_lib_rcu                                           202306L <rcu>

 # define __cpp_lib_ranges_as_rvalue                     202207L
 // # define __cpp_lib_ranges_chunk                         202202L
 // # define __cpp_lib_ranges_chunk_by                      202202L
 // # define __cpp_lib_ranges_iota                          202202L
 // # define __cpp_lib_ranges_join_with                     202202L
 # define __cpp_lib_ranges_repeat                        202207L
 // # define __cpp_lib_ranges_slide                         202202L
 // # define __cpp_lib_ranges_starts_ends_with              202106L
+# define __cpp_lib_ranges_stride                        202207L
 # define __cpp_lib_ranges_to_container                  202202L
 // # define __cpp_lib_ranges_zip                           202110L
 // # define __cpp_lib_reference_from_temporary             202202L
 // # define __cpp_lib_spanstream                           202106L
 // # define __cpp_lib_stacktrace                           202011L
 # define __cpp_lib_stdatomic_h                          202011L
 # define __cpp_lib_string_contains                      202011L
 # define __cpp_lib_string_resize_and_overwrite          202110L

libcxx/modules/std/ranges.cppm

#endif
 
     // [range.zip], zip view
     using std::ranges::zip_view;
 
     namespace views {
       using std::ranges::views::zip;
     } // namespace views
 
+    // [range.stride], stride view
+    using std::ranges::stride_view;
+
+    namespace views {
+      using std::ranges::views::stride;
+    }
+
 #if 0
     // [range.zip.transform], zip transform view
     using std::ranges::zip_transform_view;
 
     namespace views {
       using std::ranges::views::zip_transform;
     }
 
#if 0
 
     // [range.chunk.by], chunk by view
     using std::ranges::chunk_by_view;
 
     namespace views {
       using std::ranges::views::chunk_by;
     }
 
-    // [range.stride], stride view
-    using std::ranges::stride_view;
-
-    namespace views {
-      using std::ranges::views::stride;
-    }
-
     using std::ranges::cartesian_product_view;
 
     namespace views {
       using std::ranges::views::cartesian_product;
     }
 #endif
   } // namespace ranges
 
   namespace views = ranges::views;
 
   using std::tuple_element;
   using std::tuple_size;
 
   using std::from_range;
   using std::from_range_t;
 } // namespace std

libcxx/test/std/language.support/support.limits/support.limits.general/ranges.version.compile.pass.cpp

 /*  Constant                         Value
     __cpp_lib_ranges                 202207L [C++20]
     __cpp_lib_ranges_as_rvalue       202207L [C++23]
     __cpp_lib_ranges_chunk           202202L [C++23]
     __cpp_lib_ranges_chunk_by        202202L [C++23]
     __cpp_lib_ranges_join_with       202202L [C++23]
     __cpp_lib_ranges_repeat          202207L [C++23]
     __cpp_lib_ranges_slide           202202L [C++23]
+    __cpp_lib_ranges_stride          202207L [C++23]
     __cpp_lib_ranges_to_container    202202L [C++23]
     __cpp_lib_ranges_zip             202110L [C++23]
 */
 
 #include <ranges>
 #include "test_macros.h"
 
 #if TEST_STD_VER < 14

 # ifdef __cpp_lib_ranges_repeat
 #   error "__cpp_lib_ranges_repeat should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 # ifdef __cpp_lib_ranges_repeat
 #   error "__cpp_lib_ranges_repeat should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 # ifdef __cpp_lib_ranges_repeat
 #   error "__cpp_lib_ranges_repeat should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 # ifdef __cpp_lib_ranges_repeat
 #   error "__cpp_lib_ranges_repeat should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 #     error "__cpp_lib_ranges_slide should have the value 202202L in c++23"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_ranges_slide
 #     error "__cpp_lib_ranges_slide should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# ifndef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should be defined in c++23"
+# endif
+# if __cpp_lib_ranges_stride != 202207L
+#   error "__cpp_lib_ranges_stride should have the value 202207L in c++23"
+# endif
+
 # ifndef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should be defined in c++23"
 # endif
 # if __cpp_lib_ranges_to_container != 202202L
 #   error "__cpp_lib_ranges_to_container should have the value 202202L in c++23"
 # endif
 
 # if !defined(_LIBCPP_VERSION)

 #     error "__cpp_lib_ranges_slide should have the value 202202L in c++26"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_ranges_slide
 #     error "__cpp_lib_ranges_slide should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# ifndef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should be defined in c++26"
+# endif
+# if __cpp_lib_ranges_stride != 202207L
+#   error "__cpp_lib_ranges_stride should have the value 202207L in c++26"
+# endif
+
 # ifndef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should be defined in c++26"
 # endif
 # if __cpp_lib_ranges_to_container != 202202L
 #   error "__cpp_lib_ranges_to_container should have the value 202202L in c++26"
 # endif
 
 # if !defined(_LIBCPP_VERSION)

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp

/*  Constant                                         Value
     __cpp_lib_ranges_as_rvalue                       202207L [C++23]
     __cpp_lib_ranges_chunk                           202202L [C++23]
     __cpp_lib_ranges_chunk_by                        202202L [C++23]
     __cpp_lib_ranges_iota                            202202L [C++23]
     __cpp_lib_ranges_join_with                       202202L [C++23]
     __cpp_lib_ranges_repeat                          202207L [C++23]
     __cpp_lib_ranges_slide                           202202L [C++23]
     __cpp_lib_ranges_starts_ends_with                202106L [C++23]
+    __cpp_lib_ranges_stride                          202207L [C++23]
     __cpp_lib_ranges_to_container                    202202L [C++23]
     __cpp_lib_ranges_zip                             202110L [C++23]
     __cpp_lib_ratio                                  202306L [C++26]
     __cpp_lib_raw_memory_algorithms                  201606L [C++17]
     __cpp_lib_rcu                                    202306L [C++26]
     __cpp_lib_reference_from_temporary               202202L [C++23]
     __cpp_lib_remove_cvref                           201711L [C++20]
     __cpp_lib_result_of_sfinae                       201210L [C++14]

 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_starts_ends_with
 #   error "__cpp_lib_ranges_starts_ends_with should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_starts_ends_with
 #   error "__cpp_lib_ranges_starts_ends_with should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_starts_ends_with
 #   error "__cpp_lib_ranges_starts_ends_with should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 # ifdef __cpp_lib_ranges_slide
 #   error "__cpp_lib_ranges_slide should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_starts_ends_with
 #   error "__cpp_lib_ranges_starts_ends_with should not be defined before c++23"
 # endif
 
+# ifdef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should not be defined before c++23"
 # endif
 
 # ifdef __cpp_lib_ranges_zip
 #   error "__cpp_lib_ranges_zip should not be defined before c++23"
 # endif
 

 #     error "__cpp_lib_ranges_starts_ends_with should have the value 202106L in c++23"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_ranges_starts_ends_with
 #     error "__cpp_lib_ranges_starts_ends_with should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# ifndef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should be defined in c++23"
+# endif
+# if __cpp_lib_ranges_stride != 202207L
+#   error "__cpp_lib_ranges_stride should have the value 202207L in c++23"
+# endif
+
 # ifndef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should be defined in c++23"
 # endif
 # if __cpp_lib_ranges_to_container != 202202L
 #   error "__cpp_lib_ranges_to_container should have the value 202202L in c++23"
 # endif
 
 # if !defined(_LIBCPP_VERSION)

 #     error "__cpp_lib_ranges_starts_ends_with should have the value 202106L in c++26"
 #   endif
 # else // _LIBCPP_VERSION
 #   ifdef __cpp_lib_ranges_starts_ends_with
 #     error "__cpp_lib_ranges_starts_ends_with should not be defined because it is unimplemented in libc++!"
 #   endif
 # endif
 
+# ifndef __cpp_lib_ranges_stride
+#   error "__cpp_lib_ranges_stride should be defined in c++26"
+# endif
+# if __cpp_lib_ranges_stride != 202207L
+#   error "__cpp_lib_ranges_stride should have the value 202207L in c++26"
+# endif
+
 # ifndef __cpp_lib_ranges_to_container
 #   error "__cpp_lib_ranges_to_container should be defined in c++26"
 # endif
 # if __cpp_lib_ranges_to_container != 202202L
 #   error "__cpp_lib_ranges_to_container should have the value 202202L in c++26"
 # endif
 
 # if !defined(_LIBCPP_VERSION)

libcxx/test/std/ranges/range.adaptors/range.stride.view/adaptor.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/base.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+#include "test.h"
+#include <cassert>
+#include <ranges>
+
+template <typename T>
+concept can_call_base_on = requires(T t) { std::forward<T>(t).base(); };
+
+constexpr bool test() {
+  int buff[] = {1, 2, 3, 4, 5, 6, 7, 8};
+
+  // Check the const& overload
+  {
+    Range range(buff, buff + 8);
+    std::ranges::stride_view<Range> const view(range, 3);
+    std::same_as<Range> decltype(auto) result = view.base();
+    assert(result.wasCopyInitialized);
+    assert(result.begin() == buff);
+    assert(result.end() == buff + 8);
+  }
+
+  // Check the && overload
+  {
+    Range range(buff, buff + 8);
+    std::ranges::stride_view<Range> view(range, 3);
+    std::same_as<Range> decltype(auto) result = std::move(view).base();
+    assert(result.wasMoveInitialized);
+    assert(result.begin() == buff);
+    assert(result.end() == buff + 8);
+  }
+
+  // Check the && overload (again)
+  {
+    Range range(buff, buff + 8);
+    std::same_as<Range> decltype(auto) result = std::ranges::stride_view<Range>(range, 3).base();
+    assert(result.wasMoveInitialized);
+    assert(result.begin() == buff);
+    assert(result.end() == buff + 8);
+  }
+
+  // Ensure the const& overload is not considered when the base is not copy-constructible
+  {
+    static_assert(!can_call_base_on<std::ranges::stride_view<NoCopyRange> const&>);
+    static_assert(!can_call_base_on<std::ranges::stride_view<NoCopyRange>&>);
+    static_assert(can_call_base_on<std::ranges::stride_view<NoCopyRange>&&>);
+    static_assert(can_call_base_on<std::ranges::stride_view<NoCopyRange>>);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/begin.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/ctad.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/enable_borrowed_range.compile.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/end.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/iterator/ctor.default.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/iterator/equal.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/sentinel/ctor.default.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/sentinel/equal.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::views::stride_view
+
+constexpr bool test() { return true; }
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/size.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// ranges
+
+// std::ranges::stride_view
+
+#include <cassert>
+#include <ranges>
+
+bool runtime_test() {
+  auto iot    = std::views::iota(1, 22);
+  auto str    = std::views::stride(iot, 3);
+  auto result = str.size();
+  assert(result == 7);
+  return true;
+}
+
+constexpr bool test() {
+  {
+    constexpr auto iot = std::views::iota(1, 12);
+    constexpr auto str = std::views::stride(iot, 3);
+    assert(4 == str.size());
+    static_assert(4 == str.size(), "Striding by 3 through a 12 member list has size 4.");
+  }
+  {
+    constexpr auto iot = std::views::iota(1, 22);
+    constexpr auto str = std::views::stride(iot, 3);
+    assert(7 == str.size());
+    static_assert(7 == str.size(), "Striding by 3 through a 12 member list has size 4.");
+  }
+  return true;
+}
+
+int main(int, char**) {
+  runtime_test();
+  static_assert(test());
+  return 0;
+}

libcxx/test/std/ranges/range.adaptors/range.stride.view/test.h

+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_STRIDE_TYPES_H
+#define TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_STRIDE_TYPES_H
+
+#include <ranges>
+
+struct Range : std::ranges::view_base {
+  constexpr explicit Range(int* b, int* e) : begin_(b), end_(e) {}
+  constexpr Range(Range const& other) : begin_(other.begin_), end_(other.end_), wasCopyInitialized(true) {}
+  constexpr Range(Range&& other) : begin_(other.begin_), end_(other.end_), wasMoveInitialized(true) {}
+  Range& operator=(Range const&) = default;
+  Range& operator=(Range&&)      = default;
+  constexpr int* begin() const { return begin_; }
+  constexpr int* end() const { return end_; }
+
+  int* begin_;
+  int* end_;
+  bool wasCopyInitialized = false;
+  bool wasMoveInitialized = false;
+};
+
+struct NoCopyRange : std::ranges::view_base {
+  explicit NoCopyRange(int*, int*);
+  NoCopyRange(NoCopyRange const&)            = delete;
+  NoCopyRange(NoCopyRange&&)                 = default;
+  NoCopyRange& operator=(NoCopyRange const&) = default;
+  NoCopyRange& operator=(NoCopyRange&&)      = default;
+  int* begin() const;
+  int* end() const;
+};
+
+#endif // TEST_STD_RANGES_RANGE_ADAPTORS_RANGE_STRIDE_TYPES_H

libcxx/utils/generate_feature_test_macro_components.py

for x in [
         },
         {
             "name": "__cpp_lib_ranges_starts_ends_with",
             "values": {"c++23": 202106},
             "headers": ["algorithm"],
             "unimplemented": True,
         },
         {
+            "name": "__cpp_lib_ranges_stride",
+            "values": {"c++23": 202207},
+            "headers": ["ranges"],
+        },
+        {
             "name": "__cpp_lib_ranges_to_container",
             "values": {"c++23": 202202},
             "headers": [
                 "deque",
                 "forward_list",
                 "list",
                 "map",
                 "queue",