[libcxx-commits] [libcxx] [libcxx] patch for implementing ranges::find_last (PR #67270)

via libcxx-commits libcxx-commits at lists.llvm.org
Mon Sep 25 13:02:06 PDT 2023


https://github.com/phyBrackets updated https://github.com/llvm/llvm-project/pull/67270

>From 392dff0b9d134233e2fe1807fd27133b682822d1 Mon Sep 17 00:00:00 2001
From: Shivam Kunwar <shivam.kunwar at kdab.com>
Date: Sun, 24 Sep 2023 23:35:51 +0530
Subject: [PATCH 1/5] follow up on implementing ranges::find_last

---
 libcxx/docs/FeatureTestMacroTable.rst         |   2 +
 libcxx/docs/ReleaseNotes/18.rst               |   2 +-
 libcxx/docs/Status/Cxx23Papers.csv            |   2 +-
 libcxx/include/CMakeLists.txt                 |   3 +
 libcxx/include/__algorithm/ranges_find_last.h |  62 +++
 .../include/__algorithm/ranges_find_last_if.h |  77 ++++
 .../__algorithm/ranges_find_last_if_not.h     |  69 ++++
 libcxx/include/algorithm                      |  33 ++
 libcxx/include/module.modulemap.in            |  12 +
 libcxx/include/version                        |   2 +
 ...obust_against_copying_comparators.pass.cpp |   4 +
 ...obust_against_copying_projections.pass.cpp |   6 +
 .../ranges.nodiscard_extensions.verify.cpp    |   4 +
 .../alg.find/ranges.find_last.pass.cpp        | 290 ++++++++++++++
 .../alg.find/ranges.find_last_if.pass.cpp     | 364 ++++++++++++++++++
 .../alg.find/ranges.find_last_if_not.pass.cpp | 327 ++++++++++++++++
 .../algorithm.version.compile.pass.cpp        |   1 +
 .../niebloid.compile.pass.cpp                 |   3 +
 libcxx/test/support/almost_satisfies_types.h  |   9 +
 .../generate_feature_test_macro_components.py |   5 +
 20 files changed, 1275 insertions(+), 2 deletions(-)
 create mode 100644 libcxx/include/__algorithm/ranges_find_last.h
 create mode 100644 libcxx/include/__algorithm/ranges_find_last_if.h
 create mode 100644 libcxx/include/__algorithm/ranges_find_last_if_not.h
 create mode 100644 libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last.pass.cpp
 create mode 100644 libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if.pass.cpp
 create mode 100644 libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if_not.pass.cpp

diff --git a/libcxx/docs/FeatureTestMacroTable.rst b/libcxx/docs/FeatureTestMacroTable.rst
index e1b4172b22c53da..e2224a5a0ce5cc6 100644
--- a/libcxx/docs/FeatureTestMacroTable.rst
+++ b/libcxx/docs/FeatureTestMacroTable.rst
@@ -322,6 +322,8 @@ Status
     --------------------------------------------------- -----------------
     ``__cpp_lib_expected``                              ``202211L``
     --------------------------------------------------- -----------------
+    ``__cpp_lib_find_last``                             ``202207L``
+    ------------------------------------------------- -------------------
     ``__cpp_lib_format_ranges``                         ``202207L``
     --------------------------------------------------- -----------------
     ``__cpp_lib_formatters``                            *unimplemented*
diff --git a/libcxx/docs/ReleaseNotes/18.rst b/libcxx/docs/ReleaseNotes/18.rst
index 8869d0b07d39f74..d6a57d8cac91a99 100644
--- a/libcxx/docs/ReleaseNotes/18.rst
+++ b/libcxx/docs/ReleaseNotes/18.rst
@@ -52,7 +52,7 @@ Implemented Papers
 - P2697R1 - Interfacing ``bitset`` with ``string_view``
 - P2443R1 - ``views::chunk_by``
 - P2538R1 - ADL-proof ``std::projected``
-
+- P1223R5 - ``find_last``
 
 Improvements and New Features
 -----------------------------
diff --git a/libcxx/docs/Status/Cxx23Papers.csv b/libcxx/docs/Status/Cxx23Papers.csv
index 9cb49fd5176ea5f..216aca3a5f2b3c8 100644
--- a/libcxx/docs/Status/Cxx23Papers.csv
+++ b/libcxx/docs/Status/Cxx23Papers.csv
@@ -55,7 +55,7 @@
 "`P0429R9 <https://wg21.link/P0429R9>`__","LWG","A Standard ``flat_map``","July 2022","",""
 "`P1169R4 <https://wg21.link/P1169R4>`__","LWG","``static operator()``","July 2022","|Complete|","16.0"
 "`P1222R4 <https://wg21.link/P1222R4>`__","LWG","A Standard ``flat_set``","July 2022","",""
-"`P1223R5 <https://wg21.link/P1223R5>`__","LWG","``ranges::find_last()``, ``ranges::find_last_if()``, and ``ranges::find_last_if_not()``","July 2022","","","|ranges|"
+"`P1223R5 <https://wg21.link/P1223R5>`__","LWG","``ranges::find_last()``, ``ranges::find_last_if()``, and ``ranges::find_last_if_not()``","July 2022","|Complete|","18.0","|ranges|"
 "`P1467R9 <https://wg21.link/P1467R9>`__","LWG","Extended ``floating-point`` types and standard names","July 2022","",""
 "`P1642R11 <https://wg21.link/P1642R11>`__","LWG","Freestanding ``[utilities]``, ``[ranges]``, and ``[iterators]``","July 2022","",""
 "`P1899R3 <https://wg21.link/P1899R3>`__","LWG","``stride_view``","July 2022","","","|ranges|"
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 2ec755236dbaee2..45083070acd4751 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -120,6 +120,9 @@ set(files
   __algorithm/ranges_find_first_of.h
   __algorithm/ranges_find_if.h
   __algorithm/ranges_find_if_not.h
+  __algorithm/ranges_find_last.h
+  __algorithm/ranges_find_last_if.h
+  __algorithm/ranges_find_last_if_not.h
   __algorithm/ranges_for_each.h
   __algorithm/ranges_for_each_n.h
   __algorithm/ranges_generate.h
diff --git a/libcxx/include/__algorithm/ranges_find_last.h b/libcxx/include/__algorithm/ranges_find_last.h
new file mode 100644
index 000000000000000..81c2caef413bbab
--- /dev/null
+++ b/libcxx/include/__algorithm/ranges_find_last.h
@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___ALGORITHM_RANGES_FIND_LAST_H
+#define _LIBCPP___ALGORITHM_RANGES_FIND_LAST_H
+
+#include <__algorithm/ranges_find_last_if.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__iterator/concepts.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __find_last {
+struct __fn {
+  template <forward_iterator _Ip, sentinel_for<_Ip> _Sp, class _Tp, class _Proj = identity>
+    requires indirect_binary_predicate <ranges::equal_to, projected<_Ip, _Proj>, const _Tp*>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
+               operator()(_Ip __first, _Sp __last, const _Tp& __value, _Proj __proj = {}) const {
+    auto __pred = [&](auto&& __e) { return std::forward<decltype(__e)>(__e) == __value; };
+    return ranges::__find_last_if_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+
+  template <forward_range _Rp, class _Tp, class _Proj = identity>
+    requires indirect_binary_predicate <ranges::equal_to, projected<iterator_t<_Rp>, _Proj>, const _Tp*> 
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
+               operator()(_Rp&& __r, const _Tp& __value, _Proj __proj = {}) const {
+    auto __pred = [&](auto&& __e) { return std::forward<decltype(__e)>(__e) == __value; };
+    return ranges::__find_last_if_impl(ranges::begin(__r), ranges::end(__r), __pred, __proj);
+  }
+};
+} // namespace __find_last
+
+inline namespace __cpo {
+inline constexpr auto find_last = __find_last::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 23
+
+#endif // _LIBCPP___ALGORITHM_RANGES_FIND_LAST_H
diff --git a/libcxx/include/__algorithm/ranges_find_last_if.h b/libcxx/include/__algorithm/ranges_find_last_if.h
new file mode 100644
index 000000000000000..894144fd6f2ea8e
--- /dev/null
+++ b/libcxx/include/__algorithm/ranges_find_last_if.h
@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___ALGORITHM_RANGES_FIND_LAST_IF_H
+#define _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_H
+
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__ranges/range_adaptor.h>
+#include <__ranges/subrange.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template <class _Ip, class _Sp, class _Pred, class _Proj>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Ip>
+__find_last_if_impl(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj) {
+  _Ip __result = __last;
+  while (__first != __last) {
+    if (std::invoke(__pred, std::invoke(__proj, *__first))) {
+      __result = __first;
+    }
+    ++__first;
+  }
+  return {__result, __last};
+}
+
+namespace __find_last_if {
+struct __fn {
+  template <forward_range _Rp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Rp>, _Proj>> _Pred>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
+  operator()(_Rp&& __r, _Pred __pred, _Proj __proj = {}) const {
+    return ranges::__find_last_if_impl(ranges::begin(__r), ranges::end(__r), __pred, __proj);
+  }
+
+  template <forward_iterator _Ip,
+            sentinel_for<_Ip> _Sp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Ip, _Proj>> _Pred>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
+  operator()(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj = {}) const {
+    return ranges::__find_last_if_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+};
+} // namespace __find_last_if
+
+inline namespace __cpo {
+inline constexpr auto find_last_if = __find_last_if::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 23
+
+#endif // _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_H
diff --git a/libcxx/include/__algorithm/ranges_find_last_if_not.h b/libcxx/include/__algorithm/ranges_find_last_if_not.h
new file mode 100644
index 000000000000000..e1b29d8f4870e1d
--- /dev/null
+++ b/libcxx/include/__algorithm/ranges_find_last_if_not.h
@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___ALGORITHM_RANGES_FIND_LAST_IF_NOT_H
+#define _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_NOT_H
+
+#include <__algorithm/ranges_find_last_if.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __find_last_if_not {
+struct __fn {
+  static constexpr auto __make_negate_pred = [](auto&& __pred) {
+    return [&__pred](auto&& __e) { return !std::invoke(__pred, std::forward<decltype(__e)>(__e)); };
+};
+
+  template <forward_iterator _Ip,
+            sentinel_for<_Ip> _Sp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Ip, _Proj>> _Pred>
+ _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
+  operator()(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj = {}) const {
+    auto __negate_pred = __make_negate_pred(__pred);
+    return ranges::__find_last_if_impl(std::move(__first), std::move(__last), __negate_pred, __proj);
+  }
+
+  template <forward_range _Rp,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Rp>, _Proj>> _Pred>
+ _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
+  operator()(_Rp&& __r, _Pred __pred, _Proj __proj = {}) const {
+    auto __negate_pred = __make_negate_pred(__pred);
+    return ranges::__find_last_if_impl(ranges::begin(__r), ranges::end(__r), __negate_pred, __proj);
+  }
+};
+} // namespace __find_last_if_not
+
+inline namespace __cpo {
+inline constexpr auto find_last_if_not = __find_last_if_not::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 23
+
+#endif // _LIBCPP___ALGORITHM_RANGES_FIND_LAST_IF_NOT_H
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 69ba9537dda6984..cfc4c09007c5b7f 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -99,6 +99,36 @@ namespace ranges {
     constexpr borrowed_iterator_t<R>
       find_if_not(R&& r, Pred pred, Proj proj = {});                                                      // since C++20
 
+  template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity>
+    requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
+    constexpr subrange<I>
+      ranges::find_last(I first, S last, const T& value, Proj proj = {});                                 // since C++23
+  
+  template<forward_range R, class T, class Proj = identity>
+    requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
+    constexpr borrowed_subrange_t<R>
+      ranges::find_last(R&& r, const T& value, Proj proj = {});                                           //since C++23
+
+  template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
+           indirect_unary_predicate<projected<I, Proj>> Pred>
+    constexpr subrange<I> 
+      ranges::find_last_if(I first, S last, Pred pred, Proj proj = {});                                   // since C++23
+
+  template<forward_range R, class Proj = identity,
+           indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
+    constexpr borrowed_subrange_t<R>
+      ranges::find_last_if(R&& r, Pred pred, Proj proj = {});                                             // since C++23
+
+  template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
+           indirect_unary_predicate<projected<I, Proj>> Pred>
+    constexpr subrange<I> 
+      ranges::find_last_if_not(I first, S last, Pred pred, Proj proj = {});                               // since C++23
+
+  template<forward_range R, class Proj = identity,
+           indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
+    constexpr borrowed_subrange_t<R>
+      ranges::find_last_if_not(R&& r, Pred pred, Proj proj = {});                                         // since C++23
+
   template<class T, class Proj = identity,
            indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
     constexpr const T& min(const T& a, const T& b, Comp comp = {}, Proj proj = {});                       // since C++20
@@ -1859,6 +1889,9 @@ template <class BidirectionalIterator, class Compare>
 #include <__algorithm/ranges_find_first_of.h>
 #include <__algorithm/ranges_find_if.h>
 #include <__algorithm/ranges_find_if_not.h>
+#include <__algorithm/ranges_find_last.h>
+#include <__algorithm/ranges_find_last_if.h>
+#include <__algorithm/ranges_find_last_if_not.h>
 #include <__algorithm/ranges_for_each.h>
 #include <__algorithm/ranges_for_each_n.h>
 #include <__algorithm/ranges_generate.h>
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index 6d9bb8653fcb5e9..eb42d6f59b138f4 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -842,6 +842,18 @@ module std_private_algorithm_ranges_find_end                             [system
 module std_private_algorithm_ranges_find_first_of                        [system] { header "__algorithm/ranges_find_first_of.h" }
 module std_private_algorithm_ranges_find_if                              [system] { header "__algorithm/ranges_find_if.h" }
 module std_private_algorithm_ranges_find_if_not                          [system] { header "__algorithm/ranges_find_if_not.h" }
+module std_private_algorithm_ranges_find_last                            [system] { 
+  header "__algorithm/ranges_find_last.h"
+  export std_private_ranges_subrange
+}
+module std_private_algorithm_ranges_find_last_if                         [system] { 
+  header "__algorithm/ranges_find_last_if.h"
+  export std_private_ranges_subrange
+}
+module std_private_algorithm_ranges_find_last_if_not                     [system] { 
+  header "__algorithm/ranges_find_last_if_not.h"
+  export std_private_ranges_subrange 
+}
 module std_private_algorithm_ranges_for_each                             [system] {
   header "__algorithm/ranges_for_each.h"
   export std_private_algorithm_in_fun_result
diff --git a/libcxx/include/version b/libcxx/include/version
index e5a995366a7aa48..2bacf36a6295cb7 100644
--- a/libcxx/include/version
+++ b/libcxx/include/version
@@ -90,6 +90,7 @@ __cpp_lib_execution                                     201902L <execution>
                                                         201603L // C++17
 __cpp_lib_expected                                      202211L <expected>
 __cpp_lib_filesystem                                    201703L <filesystem>
+__cpp_lib_find_last                                     202207L <algorithm>
 __cpp_lib_format                                        202106L <format>
 __cpp_lib_format_ranges                                 202207L <format>
 __cpp_lib_formatters                                    202302L <stacktrace> <thread>
@@ -422,6 +423,7 @@ __cpp_lib_within_lifetime                               202306L <type_traits>
 # define __cpp_lib_constexpr_memory                     202202L
 # define __cpp_lib_constexpr_typeinfo                   202106L
 # define __cpp_lib_expected                             202211L
+# define __cpp_lib_find_last                            202207L
 # define __cpp_lib_format_ranges                        202207L
 // # define __cpp_lib_formatters                           202302L
 # define __cpp_lib_forward_like                         202207L
diff --git a/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_comparators.pass.cpp b/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_comparators.pass.cpp
index eece9833f8a6357..85d5ba35d8184ba 100644
--- a/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_comparators.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_comparators.pass.cpp
@@ -118,6 +118,10 @@ constexpr bool all_the_algorithms()
     (void)std::ranges::find_if(a, UnaryTrue(&copies)); assert(copies == 0);
     (void)std::ranges::find_if_not(first, last, UnaryTrue(&copies)); assert(copies == 0);
     (void)std::ranges::find_if_not(a, UnaryTrue(&copies)); assert(copies == 0);
+    (void)std::ranges::find_last_if(first, last, UnaryTrue(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last_if(a, UnaryTrue(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last_if_not(first, last, UnaryTrue(&copies)); assert(copies == 0);
+    (void)std::ranges::find_last_if_not(a, UnaryTrue(&copies)); assert(copies == 0);
     (void)std::ranges::for_each(first, last, UnaryVoid(&copies)); assert(copies == 1); copies = 0;
     (void)std::ranges::for_each(a, UnaryVoid(&copies)); assert(copies == 1); copies = 0;
     (void)std::ranges::for_each_n(first, count, UnaryVoid(&copies)); assert(copies == 1); copies = 0;
diff --git a/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_projections.pass.cpp b/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_projections.pass.cpp
index afbbc224ea8644c..d3939881ab21ff6 100644
--- a/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_projections.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_projections.pass.cpp
@@ -104,6 +104,12 @@ constexpr bool all_the_algorithms()
     (void)std::ranges::find_if(a, UnaryTrue(), Proj(&copies)); assert(copies == 0);
     (void)std::ranges::find_if_not(first, last, UnaryTrue(), Proj(&copies)); assert(copies == 0);
     (void)std::ranges::find_if_not(a, UnaryTrue(), Proj(&copies)); assert(copies == 0);
+    (void)std::ranges::find_last(first, last, value, Proj(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last(a, value, Proj(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last_if(first, last, UnaryTrue(), Proj(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last_if(a, UnaryTrue(), Proj(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last_if_not(first, last, UnaryTrue(), Proj(&copies)); assert(copies == 1); copies = 0;
+    (void)std::ranges::find_last_if_not(a, UnaryTrue(), Proj(&copies)); assert(copies == 1); copies = 0;
     (void)std::ranges::for_each(first, last, UnaryVoid(), Proj(&copies)); assert(copies == 0);
     (void)std::ranges::for_each(a, UnaryVoid(), Proj(&copies)); assert(copies == 0);
     (void)std::ranges::for_each_n(first, count, UnaryVoid(), Proj(&copies)); assert(copies == 0);
diff --git a/libcxx/test/libcxx/diagnostics/ranges.nodiscard_extensions.verify.cpp b/libcxx/test/libcxx/diagnostics/ranges.nodiscard_extensions.verify.cpp
index 77ac5f3f7790357..7528acdae28dfb3 100644
--- a/libcxx/test/libcxx/diagnostics/ranges.nodiscard_extensions.verify.cpp
+++ b/libcxx/test/libcxx/diagnostics/ranges.nodiscard_extensions.verify.cpp
@@ -41,6 +41,10 @@ void test() {
   std::ranges::find_if_not(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::find_if(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::find_if(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_last_if(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_last_if(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_last_if_not(range, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::find_last_if_not(iter, iter, pred); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::find(range, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::find(iter, iter, 1); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::includes(range, range); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last.pass.cpp
new file mode 100644
index 000000000000000..03a37714d96c301
--- /dev/null
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last.pass.cpp
@@ -0,0 +1,290 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <algorithm>
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity>
+//   requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
+//  constexpr subrange<I> ranges::find_last(I first, S last, const T& value, Proj proj = {});
+// template<forward_range R, class T, class Proj = identity>
+//   requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
+//  constexpr borrowed_subrange_t<R>
+// ranges::find_last(R&& r, const T& value, Proj proj = {});
+
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <ranges>
+#include <concepts>
+
+#include "almost_satisfies_types.h"
+#include "boolean_testable.h"
+#include "test_iterators.h"
+
+struct NotEqualityComparable {};
+
+template <class It, class Sent = It>
+concept HasFindIt = requires(It it, Sent sent) {
+  std::ranges::find_last(it, sent, *it);
+};
+static_assert(HasFindIt<int*>);
+static_assert(!HasFindIt<NotEqualityComparable*>);
+static_assert(!HasFindIt<InputIteratorNotDerivedFrom>);
+static_assert(!HasFindIt<InputIteratorNotIndirectlyReadable>);
+static_assert(!HasFindIt<InputIteratorNotInputOrOutputIterator>);
+static_assert(!HasFindIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
+static_assert(!HasFindIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
+
+static_assert(!HasFindIt<int*, int>);
+static_assert(!HasFindIt<int, int*>);
+
+template <class Range, class ValT>
+concept HasFindR = requires(Range r) {
+  std::ranges::find_last(r, ValT{});
+};
+
+static_assert(HasFindR<std::array<int, 1>, int>);
+static_assert(!HasFindR<int, int>);
+static_assert(!HasFindR<std::array<NotEqualityComparable, 1>, NotEqualityComparable>);
+static_assert(!HasFindR<InputRangeNotDerivedFrom, int>);
+static_assert(!HasFindR<InputRangeNotIndirectlyReadable, int>);
+static_assert(!HasFindR<InputRangeNotInputOrOutputIterator, int>);
+static_assert(!HasFindR<InputRangeNotSentinelSemiregular, int>);
+static_assert(!HasFindR<InputRangeNotSentinelEqualityComparableWith, int>);
+
+struct OneWayComparable {
+  bool isLeft;
+  friend constexpr bool operator==(OneWayComparable l, OneWayComparable) { return l.isLeft; }
+};
+
+struct NonConstComparableLValue {
+  friend constexpr bool operator==(const NonConstComparableLValue&, const NonConstComparableLValue&) { return false; }
+  friend constexpr bool operator==(NonConstComparableLValue&, NonConstComparableLValue&) { return false; }
+  friend constexpr bool operator==(const NonConstComparableLValue&, NonConstComparableLValue&) { return false; }
+  friend constexpr bool operator==(NonConstComparableLValue&, const NonConstComparableLValue&) { return true; }
+};
+
+struct NonConstComparableRValue {
+  friend constexpr bool operator==(const NonConstComparableRValue&, const NonConstComparableRValue&) { return false; }
+  friend constexpr bool operator==(const NonConstComparableRValue&&, const NonConstComparableRValue&&) { return false; }
+  friend constexpr bool operator==(NonConstComparableRValue&&, NonConstComparableRValue&&) { return false; }
+  friend constexpr bool operator==(NonConstComparableRValue&&, const NonConstComparableRValue&) { return true; }
+};
+
+constexpr bool test() {
+
+  {// check that projections are used properly and called with the reference to the element the iterator is pointing to
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, a + 4, a + 3, [](int& i) { return &i; });
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, a + 3, [](int& i) { return &i; });
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  {// check that the end element is returned
+
+    {
+      struct S{
+        int comp;
+        int other;
+      };
+
+      S a[] = {{0, 0}, {0, 2}, {0, 1}};
+      std::same_as<std::ranges::borrowed_subrange_t<S (&)[3]>> auto ret = std::ranges::find_last(a, 0, &S::comp);
+      assert(ret.data() == a + 2);
+      assert(ret.data()->comp == 0);
+      assert(ret.data()->other == 1);
+    }
+
+    {
+      struct S {
+        int comp;
+        int other;
+      };
+
+      S a[] = {{0, 0}, {0, 2}, {0, 1}};
+      std::same_as<std::ranges::subrange<S*>> auto ret = std::ranges::find_last(a, a + 3, 0, &S::comp);
+      assert(ret.data() == a + 2);
+      assert(ret.data()->comp == 0);
+      assert(ret.data()->other == 1);
+    }
+
+  }
+
+  {// check that end + 1 iterator is returned with no match
+
+    {
+      int a[] = {1, 1, 1};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, a + 3, 0);
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      int a[] = {1, 1, 1};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, 0);
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  {// check that ranges::dangling is returned
+  [[maybe_unused]] std::same_as<std::ranges::dangling> auto ret = std::ranges::find_last(std::array{1, 2}, 3);
+  }
+
+  {// check that an iterator is returned with a borrowing range
+      int a[] = {1, 1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(std::views::all(a), 1);
+      assert(ret.data() == a + 1);
+      assert(*(ret.data()) == 1);
+  }
+
+  {// check that std::invoke is used
+
+    {
+      struct S{
+        int i;
+      };
+
+      S a[] = {S{1}, S{3}, S{2}};
+      std::same_as<std::ranges::borrowed_subrange_t<S (&)[3]>> auto ret = std::ranges::find_last(a, 4, &S::i);
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      struct S {
+        int i;
+      };
+
+      S a[] = {S{1}, S{3}, S{2}};
+      std::same_as<std::ranges::subrange<S*>> auto ret = std::ranges::find_last(a, a + 3, 4, &S::i);
+      assert(ret.data() == a + 3);
+    }
+  }
+
+  {// count invocations of the projection
+
+     {
+      int a[] = {1, 2, 2, 3, 4};
+      int projection_count = 0;
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, a + 5, 2, [&](int i) { ++projection_count; return i; });
+      assert(ret.data() == a + 2);
+      assert(*(ret.data()) == 2);
+      assert(projection_count == 5);
+    }
+
+    {
+      int a[] = {1, 2, 2, 3, 4};
+      int projection_count = 0;
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, 2, [&](int i) { ++projection_count; return i; });
+      assert(ret.data() == a + 2);
+      assert(*(ret.data()) == 2);
+      assert(projection_count == 5);
+    }
+
+  }
+
+  {// check comparison order
+
+    {
+      OneWayComparable a[] = {OneWayComparable{true}};
+      std::same_as<std::ranges::subrange<OneWayComparable*>> auto ret = std::ranges::find_last(a, a + 1, OneWayComparable{false});
+      assert(ret.data() == a);
+    }
+
+    {
+      OneWayComparable a[] = {OneWayComparable{true}};
+      std::same_as<std::ranges::borrowed_subrange_t<OneWayComparable(&)[1]>> auto ret = std::ranges::find_last(a, OneWayComparable{false});
+      assert(ret.data() == a);
+    }
+
+  }
+
+  {// check that the return type of `iter::operator*` doesn't change
+
+    {
+      NonConstComparableLValue a[] = {NonConstComparableLValue{}};
+      std::same_as<std::ranges::subrange<NonConstComparableLValue*>> auto ret = std::ranges::find_last(a, a + 1, NonConstComparableLValue{});
+      assert(ret.data() == a);
+    }
+
+    {
+      using It = std::move_iterator<NonConstComparableRValue*>;
+      NonConstComparableRValue a[] = {NonConstComparableRValue{}};
+      std::same_as<std::ranges::subrange<std::move_iterator<NonConstComparableRValue*>>> auto ret = std::ranges::find_last(It(a), It(a + 1), NonConstComparableRValue{});
+      assert(ret.begin().base() == a);
+    }
+
+    {
+      NonConstComparableLValue a[] = {NonConstComparableLValue{}};
+      std::same_as<std::ranges::borrowed_subrange_t<NonConstComparableLValue(&)[1]>> auto ret = std::ranges::find_last(a, NonConstComparableLValue{});
+      assert(ret.data() == a);
+    }
+
+    {
+      using It = std::move_iterator<NonConstComparableRValue*>;
+      NonConstComparableRValue a[] = {NonConstComparableRValue{}};
+      auto range = std::ranges::subrange(It(a), It(a + 1));
+      std::same_as<std::ranges::borrowed_subrange_t<std::ranges::subrange<std::move_iterator<NonConstComparableRValue*>,
+                                                                      std::move_iterator<NonConstComparableRValue*>,
+                                                                      std::ranges::subrange_kind::sized>&>> auto ret = std::ranges::find_last(range, NonConstComparableRValue{});
+      assert(ret.begin().base() == a);
+    }
+
+  }
+
+  {// check that an empty range works
+    {
+      std::array<int, 0> a = {};
+      int search_value = 1;
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a.begin(), a.end(), search_value);
+      assert(ret.data() == a.end());
+    }
+
+    {
+      std::array<int, 0> a = {};
+      int search_value = 1;
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(a, search_value);
+      assert(ret.data() == a.end());
+    }
+
+  }
+
+  {// check that the implicit conversion to bool works
+  
+    {
+      StrictComparable<int> a[] = {1, 2, 2, 3, 4};
+      std::same_as<std::ranges::subrange<StrictComparable<int>*>> auto ret = std::ranges::find_last(a, a + 4, StrictComparable<int>{2});
+      assert(ret.data() == a + 2);
+    }
+
+    {
+      StrictComparable<int> a[] = {1, 2, 2, 3, 4};
+      std::same_as<std::ranges::borrowed_subrange_t<StrictComparable<int>(&)[5]>> auto ret = std::ranges::find_last(a, StrictComparable<int>{2});
+      assert(ret.data() == a + 2);
+    }
+
+  }
+
+return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
\ No newline at end of file
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if.pass.cpp
new file mode 100644
index 000000000000000..6beb36f38f9cc49
--- /dev/null
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if.pass.cpp
@@ -0,0 +1,364 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <algorithm>
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
+//          indirect_unary_predicate<projected<I, Proj>> Pred>
+//  constexpr subrange<I> ranges::find_last_if(I first, S last, Pred pred, Proj proj = {});
+// template<forward_range R, class Proj = identity,
+//          indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
+//  constexpr borrowed_subrange_t<R>
+// ranges::find_last_if(R&& r, Pred pred, Proj proj = {});
+
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <ranges>
+
+#include "almost_satisfies_types.h"
+#include "boolean_testable.h"
+#include "test_iterators.h"
+
+struct Predicate {
+  bool operator()(int);
+};
+
+template <class It, class Sent = It>
+concept HasFindLastIfIt = requires(It it, Sent sent) {
+  std::ranges::find_last_if(it, sent, Predicate{});
+};
+static_assert(HasFindLastIfIt<int*>);
+static_assert(!HasFindLastIfIt<InputIteratorNotDerivedFrom>);
+static_assert(!HasFindLastIfIt<InputIteratorNotIndirectlyReadable>);
+static_assert(!HasFindLastIfIt<InputIteratorNotInputOrOutputIterator>);
+static_assert(!HasFindLastIfIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
+static_assert(!HasFindLastIfIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
+
+static_assert(!HasFindLastIfIt<int*, int>);
+static_assert(!HasFindLastIfIt<int, int*>);
+
+template <class Pred>
+concept HasFindLastIfPred = requires(int* it, Pred pred) {
+  std::ranges::find_last_if(it, it, pred);
+};
+
+static_assert(HasFindLastIfPred<IndirectUnaryPredicate>);
+static_assert(!HasFindLastIfPred<IndirectUnaryPredicateNotCopyConstructible>);
+static_assert(!HasFindLastIfPred<IndirectUnaryPredicateNotPredicate>);
+
+template <class R>
+concept HasFindLastIfR = requires(R r) {
+  std::ranges::find_last_if(r, Predicate{});
+};
+
+static_assert(HasFindLastIfR<std::array<int, 0>>);
+static_assert(!HasFindLastIfR<int>);
+static_assert(!HasFindLastIfR<InputRangeNotDerivedFrom>);
+static_assert(!HasFindLastIfR<InputRangeNotIndirectlyReadable>);
+static_assert(!HasFindLastIfR<InputRangeNotInputOrOutputIterator>);
+static_assert(!HasFindLastIfR<InputRangeNotSentinelSemiregular>);
+static_assert(!HasFindLastIfR<InputRangeNotSentinelEqualityComparableWith>);
+
+template <class It, class Sent = It>
+constexpr void test_iterators() {
+  {// Test with an empty range
+
+    {
+      int a[] = {};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(It(a), Sent(It(a)), [](int x) { return x == 4; });
+      assert(ret.empty());
+    }
+
+    {
+      int a[] = {};
+      auto range = std::ranges::subrange(It(a), Sent(It(a)));
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(range, [](int x) { return x == 4; });
+      assert(ret.empty());
+    }
+
+  }
+
+  {// Test with a single element range
+
+    {
+      int a[] = {4};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(It(a), Sent(It(a + 1)), [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a);
+      assert(*ret.begin() == 4);
+    }
+
+    {
+      int a[] = {4};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[1]>> auto ret = std::ranges::find_last_if(a, [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a);
+      assert(*ret.begin() == 4);
+    }
+
+  }
+
+  {// Test when no element satisfies the predicate
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(It(a), Sent(It(a + 4)), [](int x) { return x == 5; });
+      assert(ret.empty());
+    }
+   
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[4]>> auto ret = std::ranges::find_last_if(a, [](int x) { return x == 5; });
+      assert(ret.empty());
+    }
+
+  }
+
+  {// Test when all elements satisfy the predicate
+
+    {
+      int a[] = {4, 4, 4, 4};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(It(a), Sent(It(a + 4)), [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a + 3);
+      assert(*ret.begin() == 4);
+    }
+
+    {
+      int a[] = {4, 4, 4, 4};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[4]>> auto ret = std::ranges::find_last_if(a, [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a + 3);
+      assert(*ret.begin() == 4);
+    }
+
+  }
+
+  {// Test when the element being searched is the first one
+
+    {
+      int a[] = {4, 1, 2, 3};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(It(a), Sent(It(a + 4)), [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a);
+      assert(*ret.begin() == 4);
+    }
+
+    {
+      int a[] = {4, 1, 2, 3};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[4]>> auto ret = std::ranges::find_last_if(a, [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a);
+      assert(*ret.begin() == 4);
+    }
+
+  }
+
+  {// Test when the element being searched is the last one
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if(It(a), Sent(It(a + 4)), [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a + 3);
+      assert(*ret.begin() == 4);
+    }
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[4]>> auto ret = std::ranges::find_last_if(a, [](int x) { return x == 4; });
+      assert(base(ret.begin()) == a + 3);
+      assert(*ret.begin() == 4);
+    }
+
+  }
+
+
+  {// check that past-the-end iterator is returned with no match
+
+    {
+      int a[] = {1, 1, 1};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, a + 3, [](int) { return false; });
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      int a[]  = {1, 1, 1};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, [](int) { return false; });
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+}
+
+
+struct NonConstComparableValue {
+  friend constexpr bool operator==(const NonConstComparableValue&, const NonConstComparableValue&) { return false; }
+  friend constexpr bool operator==(NonConstComparableValue&, NonConstComparableValue&) { return false; }
+  friend constexpr bool operator==(const NonConstComparableValue&, NonConstComparableValue&) { return false; }
+  friend constexpr bool operator==(NonConstComparableValue&, const NonConstComparableValue&) { return true; }
+};
+
+constexpr bool test() {
+  test_iterators<const int*>();
+  test_iterators<int*>();
+  test_iterators<bidirectional_iterator<int*>>();
+  test_iterators<forward_iterator<int*>>();
+  test_iterators<random_access_iterator<int*>>();
+  test_iterators<contiguous_iterator<int*>>();
+
+  {// check that projections are used properly and called with the reference to the element the iterator is pointing to
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, a + 4, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; });
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; });
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  {// check that the last element is returned
+
+    {
+      struct S {
+        int comp;
+        int other;
+      };
+
+      S a[] = {{0, 0}, {0, 2}, {0, 1}};
+      std::same_as<std::ranges::borrowed_subrange_t<S (&)[3]>> auto ret = std::ranges::find_last_if(a, [](int i) { return i == 0; }, &S::comp);
+      assert(ret.data() == a + 2);
+      assert(ret.data()->comp == 0);
+      assert(ret.data()->other == 1);
+    }
+
+    {
+      struct S {
+        int comp;
+        int other;
+       };
+
+       S a[] = {{0, 0}, {0, 2}, {0, 1}};
+       std::same_as<std::ranges::subrange<S *>> auto ret = std::ranges::find_last_if(a, a + 3, [](int i) { return i == 0; }, &S::comp);
+       assert(ret.data() == a + 2);
+       assert(ret.data()->comp == 0);
+       assert(ret.data()->other == 1);
+    }
+
+  }
+
+  {// check that ranges::dangling is returned
+    [[maybe_unused]] std::same_as<std::ranges::dangling> auto ret = std::ranges::find_last_if(std::array{1, 2}, [](int) { return false; });
+  }
+
+  {// check that an iterator is returned with a borrowing range
+    int a[] = {1, 1, 2, 3, 4};
+    std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(std::views::all(a), [](int) { return true; });
+    assert(ret.data() == a + 4);
+  }
+
+  {// check that std::invoke is used
+
+    {
+      struct S {
+        int i;
+      };
+
+      S a[] = {S{1}, S{3}, S{2}};
+      std::same_as<std::ranges::borrowed_subrange_t<S (&)[3]>>  auto ret = std::ranges::find_last_if(a, [](int) { return false; }, &S::i);
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      struct S {
+        int i;
+      };
+
+      S a[] = {S{1}, S{3}, S{2}};
+      std::same_as<std::ranges::subrange<S*>> auto ret = std::ranges::find_last_if(a, a + 3, [](int) { return false; }, &S::i);
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  {// count projection and predicate invocation count
+
+    {
+      int a[] = {1, 2, 2, 3, 4};
+      int predicate_count  = 0;
+      int projection_count = 0;
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, a + 5, [&](int i) { ++predicate_count; return i == 2; }, [&](int i) {
+        ++projection_count;
+        return i;
+      });
+      assert(ret.data() == a + 2);
+      assert(*(ret.data()) == 2);
+      assert(predicate_count == 5);
+      assert(projection_count == 5);
+    }
+
+    {
+      int a[] = {1, 2, 2, 3, 4};
+      int predicate_count  = 0;
+      int projection_count = 0;
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, [&](int i) { ++predicate_count; return i == 2; }, [&](int i) {
+        ++projection_count;
+        return i;
+      });
+      assert(ret.data() == a + 2);
+      assert(*(ret.data()) == 2);
+      assert(predicate_count == 5);
+      assert(projection_count == 5);
+    }
+
+  }
+
+  {// check that the return type of `iter::operator*` doesn't change
+
+    {
+      NonConstComparableValue a[] = {NonConstComparableValue{}};
+      std::same_as<std::ranges::subrange<NonConstComparableValue *>> auto ret = std::ranges::find_last_if(a, a + 1, [](auto&& e) { return e == NonConstComparableValue{}; });
+      assert(ret.data() == a);
+    }
+
+    {
+      NonConstComparableValue a[] = {NonConstComparableValue{}};
+      std::same_as<std::ranges::borrowed_subrange_t<NonConstComparableValue (&)[1]>> auto ret = std::ranges::find_last_if(a, [](auto&& e) { return e == NonConstComparableValue{}; });
+      assert(ret.data() == a);
+    }
+
+  }
+
+  {// check that the implicit conversion to bool works
+    
+    {
+      int a[] = {1, 2, 3, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, a + 4, [](const int& i) { return BooleanTestable{i == 3}; });
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      int a[] = {1, 2, 3, 3, 4};
+      std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last_if(a, [](const int& b) { return BooleanTestable{b == 3}; });
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
\ No newline at end of file
diff --git a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if_not.pass.cpp b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if_not.pass.cpp
new file mode 100644
index 000000000000000..daca8e7c0d04f2e
--- /dev/null
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/ranges.find_last_if_not.pass.cpp
@@ -0,0 +1,327 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// <algorithm>
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
+//          indirect_unary_predicate<projected<I, Proj>> Pred>
+//  constexpr subrange<I> ranges::find_last_if_not(I first, S last, Pred pred, Proj proj = {});
+// template<forward_range R, class Proj = identity,
+//          indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
+//  constexpr borrowed_subrange_t<R>
+// ranges::find_last_if_not(R&& r, Pred pred, Proj proj = {});
+
+#include <algorithm>
+#include <array>
+#include <cassert>
+#include <ranges>
+
+#include "almost_satisfies_types.h"
+#include "boolean_testable.h"
+#include "test_iterators.h"
+
+struct Predicate {
+  bool operator()(int);
+};
+
+template <class It, class Sent = It>
+concept HasFindLastIfNotIt = requires(It it, Sent sent) {
+  std::ranges::find_last_if_not(it, sent, Predicate{});
+};
+static_assert(HasFindLastIfNotIt<int*>);
+static_assert(!HasFindLastIfNotIt<InputIteratorNotDerivedFrom>);
+static_assert(!HasFindLastIfNotIt<InputIteratorNotIndirectlyReadable>);
+static_assert(!HasFindLastIfNotIt<InputIteratorNotInputOrOutputIterator>);
+static_assert(!HasFindLastIfNotIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
+static_assert(!HasFindLastIfNotIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
+
+static_assert(!HasFindLastIfNotIt<int*, int>);
+static_assert(!HasFindLastIfNotIt<int, int*>);
+
+template <class Pred>
+concept HasFindLastIfNotPred = requires(int* it, Pred pred) {
+  std::ranges::find_last_if_not(it, it, pred);
+};
+
+static_assert(HasFindLastIfNotPred<IndirectUnaryPredicate>);
+static_assert(!HasFindLastIfNotPred<IndirectUnaryPredicateNotCopyConstructible>);
+static_assert(!HasFindLastIfNotPred<IndirectUnaryPredicateNotPredicate>);
+
+template <class R>
+concept HasFindLastIfNotR = requires(R r) {
+  std::ranges::find_last_if_not(r, Predicate{});
+};
+static_assert(HasFindLastIfNotR<std::array<int, 0>>);
+static_assert(!HasFindLastIfNotR<int>);
+static_assert(!HasFindLastIfNotR<InputRangeNotDerivedFrom>);
+static_assert(!HasFindLastIfNotR<InputRangeNotIndirectlyReadable>);
+static_assert(!HasFindLastIfNotR<InputRangeNotInputOrOutputIterator>);
+static_assert(!HasFindLastIfNotR<InputRangeNotSentinelSemiregular>);
+static_assert(!HasFindLastIfNotR<InputRangeNotSentinelEqualityComparableWith>);
+
+template <class It, class Sent = It>
+constexpr void test_iterators() {
+  
+  {// Test with an empty range
+  
+    {
+      int a[] = {};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if_not(It(a), Sent(It(a)), [](int) { return false; });
+      assert(ret.empty());
+    }
+
+    {
+      int a[] = {};
+      auto range = std::ranges::subrange(It(a), Sent(It(a)));
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if_not(range, [](int) { return false; });
+      assert(ret.empty());
+    }
+
+  }
+
+
+  {// Test with a single element range
+
+    {
+      int a[] = {1};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if_not(It(a), Sent(It(a + 1)), [](int) { return false; });
+      assert(base(ret.begin()) == a);
+      assert(*ret.begin() == 1);
+    }
+
+    {
+      int a[] = {1};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[1]>> auto ret = std::ranges::find_last_if_not(a, [](int) { return false; });
+      assert(base(ret.begin()) == a);
+      assert(*ret.begin() == 1);
+    }
+
+  }
+
+  {// Test with a range where each element satisfies the predicate
+
+    {
+      int a[] = {1, 2, 3, 4, 5};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if_not(It(a), Sent(It(a + 5)), [](int) { return false; });
+      assert(base(ret.begin()) == a + 4);
+      assert(*ret.begin() == 5);
+    }
+
+    {
+      int a[] = {1, 2, 3, 4, 5};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[5]>> auto ret = std::ranges::find_last_if_not(a, [](int) { return false; });
+      assert(base(ret.begin()) == a + 4);
+      assert(*ret.begin() == 5);
+    }
+
+  }
+
+  {// Test with a range where no element satisfies the predicate
+
+    {
+      int a[] = {1, 2, 3, 4, 5};
+      std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last_if_not(It(a), Sent(It(a + 5)), [](int) { return true; });
+      assert(base(ret.begin()) == a + 5);
+      assert(ret.empty());
+    }
+
+    {
+      int a[] = {1, 2, 3, 4, 5};
+      std::same_as<std::ranges::borrowed_subrange_t<int (&)[5]>> auto ret = std::ranges::find_last_if_not(a, [](int) { return true; });
+      assert(base(ret.begin()) == a + 5);
+      assert(ret.empty());
+    }
+
+  }
+
+}
+
+struct NonConstComparableValue {
+  friend constexpr bool operator==(const NonConstComparableValue&, const NonConstComparableValue&) { return false; }
+  friend constexpr bool operator==(NonConstComparableValue&, NonConstComparableValue&) { return false; }
+  friend constexpr bool operator==(const NonConstComparableValue&, NonConstComparableValue&) { return false; }
+  friend constexpr bool operator==(NonConstComparableValue&, const NonConstComparableValue&) { return true; }
+};
+
+constexpr bool test() {
+  test_iterators<const int*>();
+  test_iterators<int*>();
+  test_iterators<bidirectional_iterator<int*>>();
+  test_iterators<forward_iterator<int*>>();
+  test_iterators<random_access_iterator<int*>>();
+  test_iterators<contiguous_iterator<int*>>();
+
+  {// check that projections are used properly and called with the reference to the element the iterator is pointing to
+
+    {
+      int a[] = {1, 2, 3, 4, 5};
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a, a + 5, [&](int* i) { return i != a + 3; }, [](int& i) { return &i; });
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      int a[]  = {1, 2, 3, 4, 5};
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a, [&](int* i) { return i != a + 3; }, [](int& i) { return &i; });
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  {// check that the last element is returned
+
+    {
+      struct S{
+        int comp;
+        int other;
+      };
+
+      S a[] = {{0, 0}, {0, 2}, {0, 1}};
+      std::same_as<std::ranges::borrowed_subrange_t<S (&)[3]>> auto ret = std::ranges::find_last_if_not(a, [](int i) { return i != 0; }, &S::comp);
+      assert(ret.data() == a + 2);
+      assert(ret.data()->comp == 0);
+      assert(ret.data()->other == 1);
+    }  
+
+    {
+      struct S {
+        int comp;
+        int other;
+      };
+
+      S a[] = {{0, 0}, {0, 2}, {0, 1}};
+      std::same_as<std::ranges::subrange<S *>> auto ret = std::ranges::find_last_if_not(a, a + 3, [](int i) { return i != 0; }, &S::comp);
+      assert(ret.data() == a + 2);
+      assert(ret.data()->comp == 0);
+      assert(ret.data()->other == 1);
+    }
+
+  }
+
+  {// check that end iterator is returned with no match
+
+    {
+      int a[] = {1, 1, 1};
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a, a + 3, [](int) { return false; });
+      assert(ret.data() == a + 2);
+    }
+
+    {
+      int a[] = {1, 1, 1};
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a, [](int) { return false; });
+      assert(ret.data() == a + 2);
+    }
+
+  }
+
+  {// check that ranges::dangling is returned
+    [[maybe_unused]] std::same_as<std::ranges::dangling> auto ret =
+    std::ranges::find_last_if_not(std::array{1, 2}, [](int) { return true; });
+  }
+
+  {// check that an iterator is returned with a borrowing range
+    int a[] = {1, 2, 3, 4};
+    std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(std::views::all(a), [](int) { return false; });
+    assert(ret.data() == a + 3);
+    assert(*ret.data() == 4);
+  }
+
+  {// check that std::invoke is used
+
+    {
+      struct S {
+        int i;
+      };
+
+      S a[] = {S{1}, S{3}, S{2}};
+      std::same_as<std::ranges::borrowed_subrange_t<S (&)[3]>> auto ret = std::ranges::find_last_if_not(a, [](int) { return true; }, &S::i);
+      assert(ret.data() == a + 3);
+    }
+
+    {
+      struct S {
+        int i;
+      };
+
+      S a[] = {S{1}, S{3}, S{2}};
+      std::same_as<std::ranges::subrange<S *>> auto ret = std::ranges::find_last_if_not(a, a + 3, [](int) { return true; }, &S::i);
+      assert(ret.data() == a + 3);
+    }
+
+  }
+
+  {// count projection and predicate invocation count
+
+    {
+      int a[] = {1, 2, 3, 4};
+      int predicate_count  = 0;
+      int projection_count = 0;
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a,a + 4,
+                                      [&](int i) { ++predicate_count; return i != 2; },
+                                      [&](int i) { ++projection_count; return i; });
+      assert(ret.data() == a + 1);
+      assert(*ret.data() == 2);
+      assert(predicate_count == 4);
+      assert(projection_count == 4);
+    }
+
+    {
+      int a[] = {1, 2, 3, 4};
+      int predicate_count  = 0;
+      int projection_count = 0;
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a,
+                                      [&](int i) { ++predicate_count; return i != 2; },
+                                      [&](int i) { ++projection_count; return i; });
+      assert(ret.data() == a + 1);
+      assert(*ret.data() == 2);
+      assert(predicate_count == 4);
+      assert(projection_count == 4);
+    }
+
+  }
+
+  {// check that the return type of `iter::operator*` doesn't change
+    {
+      NonConstComparableValue a[] = {NonConstComparableValue{}};
+      std::same_as<std::ranges::subrange<NonConstComparableValue *>> auto ret = std::ranges::find_last_if_not(a, a + 1, [](auto&& e) { return e != NonConstComparableValue{}; });
+      assert(ret.data() == a);
+    }
+
+    {
+      NonConstComparableValue a[] = {NonConstComparableValue{}};
+      std::same_as<std::ranges::borrowed_subrange_t<NonConstComparableValue (&)[1]>> auto ret = std::ranges::find_last_if_not(a, [](auto&& e) { return e != NonConstComparableValue{}; });
+      assert(ret.data() == a);
+    }
+
+  }
+
+  {// check that the implicit conversion to bool works
+
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a, a + 4, [](const int& i) { return BooleanTestable{i != 3}; });
+       assert(ret.data() == a + 2);
+    }
+    {
+      int a[] = {1, 2, 3, 4};
+      std::same_as<std::ranges::subrange<int *>> auto ret = std::ranges::find_last_if_not(a, [](const int& b) { return BooleanTestable{b != 3}; });
+      assert(ret.data() == a + 2);
+    }
+
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp
index 1cd58f081952f4b..d3aa801f61171df 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp
@@ -18,6 +18,7 @@
 /*  Constant                                 Value
     __cpp_lib_clamp                          201603L [C++17]
     __cpp_lib_constexpr_algorithms           201806L [C++20]
+    __cpp_lib_find_last                      202207L [C++2b]
     __cpp_lib_parallel_algorithm             201603L [C++17]
     __cpp_lib_ranges                         202207L [C++20]
     __cpp_lib_ranges_starts_ends_with        202106L [C++23]
diff --git a/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp b/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp
index 683f88c19f67849..1b7eaec9a6417cd 100644
--- a/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp
+++ b/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp
@@ -83,6 +83,9 @@ static_assert(test(std::ranges::find_end, a, a));
 static_assert(test(std::ranges::find_first_of, a, a));
 static_assert(test(std::ranges::find_if, a, odd));
 static_assert(test(std::ranges::find_if_not, a, odd));
+static_assert(test(std::ranges::find_last, a, 42));
+static_assert(test(std::ranges::find_last_if, a, odd));
+static_assert(test(std::ranges::find_last_if_not, a, odd));
 static_assert(test(std::ranges::for_each, a, odd));
 static_assert(test(std::ranges::for_each_n, a, 10, odd));
 static_assert(test(std::ranges::generate, a, gen));
diff --git a/libcxx/test/support/almost_satisfies_types.h b/libcxx/test/support/almost_satisfies_types.h
index 296dbb6de618055..1444e5a89274619 100644
--- a/libcxx/test/support/almost_satisfies_types.h
+++ b/libcxx/test/support/almost_satisfies_types.h
@@ -83,6 +83,15 @@ static_assert(std::indirectly_readable<InputIteratorNotInputOrOutputIterator>);
 static_assert(!std::input_iterator<InputIteratorNotInputOrOutputIterator>);
 static_assert(!std::ranges::input_range<InputRangeNotInputOrOutputIterator>);
 
+// Example predicate that satisfies HasFindLastIfPred
+class IndirectUnaryPredicate {
+  public:
+    bool operator()(int) const;
+};
+
+static_assert(std::predicate<IndirectUnaryPredicate, int&>);
+static_assert(std::indirect_unary_predicate<IndirectUnaryPredicate, int*>);
+
 // almost an indirect_unary_predicate
 class IndirectUnaryPredicateNotCopyConstructible {
 public:
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index ac342aff0beb701..3b715662407bacb 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -451,6 +451,11 @@ def add_version_header(tc):
             "test_suite_guard": "!defined(_LIBCPP_AVAILABILITY_HAS_NO_FILESYSTEM_LIBRARY)",
             "libcxx_guard": "!defined(_LIBCPP_AVAILABILITY_HAS_NO_FILESYSTEM_LIBRARY)",
         },
+        {
+            "name": "__cpp_lib_find_last",
+            "values": { "c++2b": 202207 },
+            "headers": ["algorithm"],
+        },
         {
             "name": "__cpp_lib_format",
             "values": {

>From 1c8a18f316299001234be5b04a6ab413cbaeadbc Mon Sep 17 00:00:00 2001
From: Shivam Kunwar <shivam.kunwar at kdab.com>
Date: Mon, 25 Sep 2023 00:41:20 +0530
Subject: [PATCH 2/5] fixing format

---
 libcxx/include/__algorithm/ranges_find_last.h        | 4 ++--
 libcxx/include/__algorithm/ranges_find_last_if_not.h | 6 +++---
 libcxx/include/algorithm                             | 6 +++---
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/libcxx/include/__algorithm/ranges_find_last.h b/libcxx/include/__algorithm/ranges_find_last.h
index 81c2caef413bbab..4208110f5e78032 100644
--- a/libcxx/include/__algorithm/ranges_find_last.h
+++ b/libcxx/include/__algorithm/ranges_find_last.h
@@ -33,7 +33,7 @@ namespace ranges {
 namespace __find_last {
 struct __fn {
   template <forward_iterator _Ip, sentinel_for<_Ip> _Sp, class _Tp, class _Proj = identity>
-    requires indirect_binary_predicate <ranges::equal_to, projected<_Ip, _Proj>, const _Tp*>
+    requires indirect_binary_predicate<ranges::equal_to, projected<_Ip, _Proj>, const _Tp*>
   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
                operator()(_Ip __first, _Sp __last, const _Tp& __value, _Proj __proj = {}) const {
     auto __pred = [&](auto&& __e) { return std::forward<decltype(__e)>(__e) == __value; };
@@ -41,7 +41,7 @@ struct __fn {
   }
 
   template <forward_range _Rp, class _Tp, class _Proj = identity>
-    requires indirect_binary_predicate <ranges::equal_to, projected<iterator_t<_Rp>, _Proj>, const _Tp*> 
+    requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<_Rp>, _Proj>, const _Tp*> 
   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
                operator()(_Rp&& __r, const _Tp& __value, _Proj __proj = {}) const {
     auto __pred = [&](auto&& __e) { return std::forward<decltype(__e)>(__e) == __value; };
diff --git a/libcxx/include/__algorithm/ranges_find_last_if_not.h b/libcxx/include/__algorithm/ranges_find_last_if_not.h
index e1b29d8f4870e1d..042812e7fe16b40 100644
--- a/libcxx/include/__algorithm/ranges_find_last_if_not.h
+++ b/libcxx/include/__algorithm/ranges_find_last_if_not.h
@@ -34,13 +34,13 @@ namespace __find_last_if_not {
 struct __fn {
   static constexpr auto __make_negate_pred = [](auto&& __pred) {
     return [&__pred](auto&& __e) { return !std::invoke(__pred, std::forward<decltype(__e)>(__e)); };
-};
+  };
 
   template <forward_iterator _Ip,
             sentinel_for<_Ip> _Sp,
             class _Proj = identity,
             indirect_unary_predicate<projected<_Ip, _Proj>> _Pred>
- _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
   operator()(_Ip __first, _Sp __last, _Pred __pred, _Proj __proj = {}) const {
     auto __negate_pred = __make_negate_pred(__pred);
     return ranges::__find_last_if_impl(std::move(__first), std::move(__last), __negate_pred, __proj);
@@ -49,7 +49,7 @@ struct __fn {
   template <forward_range _Rp,
             class _Proj = identity,
             indirect_unary_predicate<projected<iterator_t<_Rp>, _Proj>> _Pred>
- _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
   operator()(_Rp&& __r, _Pred __pred, _Proj __proj = {}) const {
     auto __negate_pred = __make_negate_pred(__pred);
     return ranges::__find_last_if_impl(ranges::begin(__r), ranges::end(__r), __negate_pred, __proj);
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index cfc4c09007c5b7f..82365311d264bc3 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -103,7 +103,7 @@ namespace ranges {
     requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
     constexpr subrange<I>
       ranges::find_last(I first, S last, const T& value, Proj proj = {});                                 // since C++23
-  
+
   template<forward_range R, class T, class Proj = identity>
     requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
     constexpr borrowed_subrange_t<R>
@@ -111,7 +111,7 @@ namespace ranges {
 
   template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
            indirect_unary_predicate<projected<I, Proj>> Pred>
-    constexpr subrange<I> 
+    constexpr subrange<I>
       ranges::find_last_if(I first, S last, Pred pred, Proj proj = {});                                   // since C++23
 
   template<forward_range R, class Proj = identity,
@@ -121,7 +121,7 @@ namespace ranges {
 
   template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
            indirect_unary_predicate<projected<I, Proj>> Pred>
-    constexpr subrange<I> 
+    constexpr subrange<I>
       ranges::find_last_if_not(I first, S last, Pred pred, Proj proj = {});                               // since C++23
 
   template<forward_range R, class Proj = identity,

>From 843fc8f9737793b92c466e1f7a866f68e1146604 Mon Sep 17 00:00:00 2001
From: Shivam Kunwar <shivam.kunwar at kdab.com>
Date: Mon, 25 Sep 2023 22:45:46 +0530
Subject: [PATCH 3/5] fix format issues

---
 libcxx/docs/FeatureTestMacroTable.rst                  | 2 +-
 libcxx/include/__algorithm/ranges_find_last.h          | 8 ++++----
 libcxx/utils/generate_feature_test_macro_components.py | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libcxx/docs/FeatureTestMacroTable.rst b/libcxx/docs/FeatureTestMacroTable.rst
index e2224a5a0ce5cc6..d7a077d29860a6f 100644
--- a/libcxx/docs/FeatureTestMacroTable.rst
+++ b/libcxx/docs/FeatureTestMacroTable.rst
@@ -323,7 +323,7 @@ Status
     ``__cpp_lib_expected``                              ``202211L``
     --------------------------------------------------- -----------------
     ``__cpp_lib_find_last``                             ``202207L``
-    ------------------------------------------------- -------------------
+    --------------------------------------------------- -----------------
     ``__cpp_lib_format_ranges``                         ``202207L``
     --------------------------------------------------- -----------------
     ``__cpp_lib_formatters``                            *unimplemented*
diff --git a/libcxx/include/__algorithm/ranges_find_last.h b/libcxx/include/__algorithm/ranges_find_last.h
index 4208110f5e78032..80baa6eaea4fbcd 100644
--- a/libcxx/include/__algorithm/ranges_find_last.h
+++ b/libcxx/include/__algorithm/ranges_find_last.h
@@ -12,8 +12,8 @@
 #include <__algorithm/ranges_find_last_if.h>
 #include <__config>
 #include <__functional/identity.h>
-#include <__iterator/concepts.h>
 #include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
 #include <__iterator/projected.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
@@ -35,15 +35,15 @@ struct __fn {
   template <forward_iterator _Ip, sentinel_for<_Ip> _Sp, class _Tp, class _Proj = identity>
     requires indirect_binary_predicate<ranges::equal_to, projected<_Ip, _Proj>, const _Tp*>
   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Ip>
-               operator()(_Ip __first, _Sp __last, const _Tp& __value, _Proj __proj = {}) const {
+  operator()(_Ip __first, _Sp __last, const _Tp& __value, _Proj __proj = {}) const {
     auto __pred = [&](auto&& __e) { return std::forward<decltype(__e)>(__e) == __value; };
     return ranges::__find_last_if_impl(std::move(__first), std::move(__last), __pred, __proj);
   }
 
   template <forward_range _Rp, class _Tp, class _Proj = identity>
-    requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<_Rp>, _Proj>, const _Tp*> 
+    requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<_Rp>, _Proj>, const _Tp*>
   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Rp>
-               operator()(_Rp&& __r, const _Tp& __value, _Proj __proj = {}) const {
+  operator()(_Rp&& __r, const _Tp& __value, _Proj __proj = {}) const {
     auto __pred = [&](auto&& __e) { return std::forward<decltype(__e)>(__e) == __value; };
     return ranges::__find_last_if_impl(ranges::begin(__r), ranges::end(__r), __pred, __proj);
   }
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index 3b715662407bacb..b4e97c99c40de92 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -453,7 +453,7 @@ def add_version_header(tc):
         },
         {
             "name": "__cpp_lib_find_last",
-            "values": { "c++2b": 202207 },
+            "values": {"c++2b": 202207},
             "headers": ["algorithm"],
         },
         {

>From 175777fdf6fa4bf3efa9013b98f4507aef9ccc63 Mon Sep 17 00:00:00 2001
From: Shivam Kunwar <shivam.kunwar at kdab.com>
Date: Mon, 25 Sep 2023 22:45:46 +0530
Subject: [PATCH 4/5] fix format issues

---
 libcxx/utils/generate_feature_test_macro_components.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
index b4e97c99c40de92..0602126f0e1e1e1 100755
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -453,7 +453,7 @@ def add_version_header(tc):
         },
         {
             "name": "__cpp_lib_find_last",
-            "values": {"c++2b": 202207},
+            "values": {"c++23": 202207},
             "headers": ["algorithm"],
         },
         {

>From cd2fdf1ced7fdcd491f9548deaa0f46de618c88e Mon Sep 17 00:00:00 2001
From: Shivam Kunwar <shivam.kunwar at kdab.com>
Date: Mon, 25 Sep 2023 22:45:46 +0530
Subject: [PATCH 5/5] fix format issues

---
 .../algorithm.version.compile.pass.cpp        | 32 ++++++++++++++++++-
 .../version.version.compile.pass.cpp          | 31 ++++++++++++++++++
 2 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp
index d3aa801f61171df..24ffdcf505bbd73 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/algorithm.version.compile.pass.cpp
@@ -18,7 +18,7 @@
 /*  Constant                                 Value
     __cpp_lib_clamp                          201603L [C++17]
     __cpp_lib_constexpr_algorithms           201806L [C++20]
-    __cpp_lib_find_last                      202207L [C++2b]
+    __cpp_lib_find_last                      202207L [C++23]
     __cpp_lib_parallel_algorithm             201603L [C++17]
     __cpp_lib_ranges                         202207L [C++20]
     __cpp_lib_ranges_starts_ends_with        202106L [C++23]
@@ -40,6 +40,10 @@
 #   error "__cpp_lib_constexpr_algorithms should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_parallel_algorithm
 #   error "__cpp_lib_parallel_algorithm should not be defined before c++17"
 # endif
@@ -74,6 +78,10 @@
 #   error "__cpp_lib_constexpr_algorithms should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_parallel_algorithm
 #   error "__cpp_lib_parallel_algorithm should not be defined before c++17"
 # endif
@@ -114,6 +122,10 @@
 #   error "__cpp_lib_constexpr_algorithms should not be defined before c++20"
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_parallel_algorithm
 #     error "__cpp_lib_parallel_algorithm should be defined in c++17"
@@ -169,6 +181,10 @@
 #   error "__cpp_lib_constexpr_algorithms should have the value 201806L in c++20"
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_parallel_algorithm
 #     error "__cpp_lib_parallel_algorithm should be defined in c++20"
@@ -230,6 +246,13 @@
 #   error "__cpp_lib_constexpr_algorithms should have the value 201806L in c++23"
 # endif
 
+# ifndef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should be defined in c++23"
+# endif
+# if __cpp_lib_find_last != 202207L
+#   error "__cpp_lib_find_last should have the value 202207L in c++23"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_parallel_algorithm
 #     error "__cpp_lib_parallel_algorithm should be defined in c++23"
@@ -300,6 +323,13 @@
 #   error "__cpp_lib_constexpr_algorithms should have the value 201806L in c++26"
 # endif
 
+# ifndef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should be defined in c++26"
+# endif
+# if __cpp_lib_find_last != 202207L
+#   error "__cpp_lib_find_last should have the value 202207L in c++26"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_parallel_algorithm
 #     error "__cpp_lib_parallel_algorithm should be defined in c++26"
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
index 566c595d8c30823..a5629b22d689f3c 100644
--- a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
+++ b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
@@ -83,6 +83,7 @@
                                                      201902L [C++20]
     __cpp_lib_expected                               202211L [C++23]
     __cpp_lib_filesystem                             201703L [C++17]
+    __cpp_lib_find_last                              202207L [C++23]
     __cpp_lib_format                                 202106L [C++20]
     __cpp_lib_format_ranges                          202207L [C++23]
     __cpp_lib_formatters                             202302L [C++23]
@@ -461,6 +462,10 @@
 #   error "__cpp_lib_filesystem should not be defined before c++17"
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
@@ -1192,6 +1197,10 @@
 #   error "__cpp_lib_filesystem should not be defined before c++17"
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
@@ -2037,6 +2046,10 @@
 #   endif
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # ifdef __cpp_lib_format
 #   error "__cpp_lib_format should not be defined before c++20"
 # endif
@@ -3152,6 +3165,10 @@
 #   endif
 # endif
 
+# ifdef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should not be defined before c++23"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_format
 #     error "__cpp_lib_format should be defined in c++20"
@@ -4471,6 +4488,13 @@
 #   endif
 # endif
 
+# ifndef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should be defined in c++23"
+# endif
+# if __cpp_lib_find_last != 202207L
+#   error "__cpp_lib_find_last should have the value 202207L in c++23"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_format
 #     error "__cpp_lib_format should be defined in c++23"
@@ -5985,6 +6009,13 @@
 #   endif
 # endif
 
+# ifndef __cpp_lib_find_last
+#   error "__cpp_lib_find_last should be defined in c++26"
+# endif
+# if __cpp_lib_find_last != 202207L
+#   error "__cpp_lib_find_last should have the value 202207L in c++26"
+# endif
+
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_format
 #     error "__cpp_lib_format should be defined in c++26"



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