[libc++] Implement ranges::find_end, ranges::search{, _n}

Reviewed By: var-const, #libc, huixie90 Spies: thakis, h-vetinari, huixie90, libcxx-commits, mgorny Differential Revision: https://reviews.llvm.org/D124079
2022-07-13 18:07:26 +02:00
parent 9d24eba04d
commit 101d1e9b3c
22 changed files with 1834 additions and 168 deletions
--- a/libcxx/docs/Status/RangesAlgorithms.csv
+++ b/libcxx/docs/Status/RangesAlgorithms.csv
@@ -23,9 +23,9 @@ Search,max_element,Nikolas Klauser,`D117523 <https://llvm.org/D117523>`_,✅
 Search,minmax_element,Nikolas Klauser,`D120637 <https://llvm.org/D120637>`_,✅
 Search,count,Nikolas Klauser,`D121523 <https://llvm.org/D121523>`_,✅
 Search,count_if,Nikolas Klauser,`D121523 <https://llvm.org/D121523>`_,✅
-Search,search,Nikolas Klauser,`D124079 <https://llvm.org/D124079>`_,Under review
-Search,search_n,Nikolas Klauser,`D124079 <https://llvm.org/D124079>`_,Under review
-Search,find_end,Nikolas Klauser,`D124079 <https://llvm.org/D124079>`_,Under review
+Search,search,Nikolas Klauser,`D124079 <https://llvm.org/D124079>`_,✅
+Search,search_n,Nikolas Klauser,`D124079 <https://llvm.org/D124079>`_,✅
+Search,find_end,Nikolas Klauser,`D124079 <https://llvm.org/D124079>`_,✅
 Read-only,is_partitioned,Nikolas Klauser,`D124440 <https://llvm.org/D124440>`_,✅
 Read-only,is_sorted,Nikolas Klauser,`D125608 <https://llvm.org/D125608>`_,✅
 Read-only,is_sorted_until,Nikolas Klauser,`D125608 <https://llvm.org/D125608>`_,✅
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -83,6 +83,7 @@ set(files
  __algorithm/ranges_fill.h
  __algorithm/ranges_fill_n.h
  __algorithm/ranges_find.h
+  __algorithm/ranges_find_end.h
  __algorithm/ranges_find_first_of.h
  __algorithm/ranges_find_if.h
  __algorithm/ranges_find_if_not.h
@@ -129,6 +130,8 @@ set(files
  __algorithm/ranges_reverse.h
  __algorithm/ranges_reverse_copy.h
  __algorithm/ranges_rotate_copy.h
+  __algorithm/ranges_search.h
+  __algorithm/ranges_search_n.h
  __algorithm/ranges_set_difference.h
  __algorithm/ranges_set_intersection.h
  __algorithm/ranges_set_union.h
--- a/libcxx/include/__algorithm/find_end.h
+++ b/libcxx/include/__algorithm/find_end.h
@@ -11,8 +11,16 @@
 #define _LIBCPP___ALGORITHM_FIND_END_OF_H

 #include <__algorithm/comp.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/search.h>
 #include <__config>
+#include <__functional/identity.h>
+#include <__iterator/advance.h>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/reverse_iterator.h>
+#include <__utility/pair.h>
+#include <type_traits>

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -20,35 +28,52 @@

 _LIBCPP_BEGIN_NAMESPACE_STD

-template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1 __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
-                                                           _ForwardIterator2 __first2, _ForwardIterator2 __last2,
-                                                           _BinaryPredicate __pred, forward_iterator_tag,
-                                                           forward_iterator_tag) {
+template <
+    class _AlgPolicy,
+    class _Iter1,
+    class _Sent1,
+    class _Iter2,
+    class _Sent2,
+    class _Pred,
+    class _Proj1,
+    class _Proj2>
+_LIBCPP_HIDE_FROM_ABI inline _LIBCPP_CONSTEXPR_AFTER_CXX11 pair<_Iter1, _Iter1> __find_end_impl(
+    _Iter1 __first1,
+    _Sent1 __last1,
+    _Iter2 __first2,
+    _Sent2 __last2,
+    _Pred& __pred,
+    _Proj1& __proj1,
+    _Proj2& __proj2,
+    forward_iterator_tag,
+    forward_iterator_tag) {
  // modeled after search algorithm
-  _ForwardIterator1 __r = __last1; // __last1 is the "default" answer
+  _Iter1 __match_first = _IterOps<_AlgPolicy>::next(__first1, __last1); // __last1 is the "default" answer
+  _Iter1 __match_last = __match_first;
  if (__first2 == __last2)
-    return __r;
+    return pair<_Iter1, _Iter1>(__match_last, __match_last);
  while (true) {
    while (true) {
-      if (__first1 == __last1) // if source exhausted return last correct answer
-        return __r;            //    (or __last1 if never found)
-      if (__pred(*__first1, *__first2))
+      if (__first1 == __last1) // if source exhausted return last correct answer (or __last1 if never found)
+        return pair<_Iter1, _Iter1>(__match_first, __match_last);
+      if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
        break;
      ++__first1;
    }
    // *__first1 matches *__first2, now match elements after here
-    _ForwardIterator1 __m1 = __first1;
-    _ForwardIterator2 __m2 = __first2;
+    _Iter1 __m1 = __first1;
+    _Iter2 __m2 = __first2;
    while (true) {
      if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one
-        __r = __first1;
+        __match_first = __first1;
+        __match_last = ++__m1;
        ++__first1;
        break;
      }
      if (++__m1 == __last1) // Source exhausted, return last answer
-        return __r;
-      if (!__pred(*__m1, *__m2)) // mismatch, restart with a new __first
+        return pair<_Iter1, _Iter1>(__match_first, __match_last);
+       // mismatch, restart with a new __first
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2)))
      {
        ++__first1;
        break;
@@ -57,33 +82,52 @@ _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1 __find_end(_ForwardIterator1 __f
  }
 }

-template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator1 __find_end(
-    _BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1, _BidirectionalIterator2 __first2,
-    _BidirectionalIterator2 __last2, _BinaryPredicate __pred, bidirectional_iterator_tag, bidirectional_iterator_tag) {
+template <
+    class _IterOps,
+    class _Pred,
+    class _Iter1,
+    class _Sent1,
+    class _Iter2,
+    class _Sent2,
+    class _Proj1,
+    class _Proj2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _Iter1 __find_end(
+    _Iter1 __first1,
+    _Sent1 __sent1,
+    _Iter2 __first2,
+    _Sent2 __sent2,
+    _Pred& __pred,
+    _Proj1& __proj1,
+    _Proj2& __proj2,
+    bidirectional_iterator_tag,
+    bidirectional_iterator_tag) {
+  auto __last1 = _IterOps::next(__first1, __sent1);
+  auto __last2 = _IterOps::next(__first2, __sent2);
  // modeled after search algorithm (in reverse)
  if (__first2 == __last2)
    return __last1; // Everything matches an empty sequence
-  _BidirectionalIterator1 __l1 = __last1;
-  _BidirectionalIterator2 __l2 = __last2;
+  _Iter1 __l1 = __last1;
+  _Iter2 __l2 = __last2;
  --__l2;
  while (true) {
    // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
    while (true) {
      if (__first1 == __l1) // return __last1 if no element matches *__first2
        return __last1;
-      if (__pred(*--__l1, *__l2))
+      if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
        break;
    }
    // *__l1 matches *__l2, now match elements before here
-    _BidirectionalIterator1 __m1 = __l1;
-    _BidirectionalIterator2 __m2 = __l2;
+    _Iter1 __m1 = __l1;
+    _Iter2 __m2 = __l2;
    while (true) {
      if (__m2 == __first2) // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
        return __m1;
      if (__m1 == __first1) // Otherwise if source exhaused, pattern not found
        return __last1;
-      if (!__pred(*--__m1, *--__m2)) // if there is a mismatch, restart with a new __l1
+
+      // if there is a mismatch, restart with a new __l1
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(__proj2, *--__m2)))
      {
        break;
      } // else there is a match, check next elements
@@ -91,37 +135,53 @@ _LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator1 __find_end(
  }
 }

-template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1 __find_end(
-    _RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
-    _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag, random_access_iterator_tag) {
-  typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
-  typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
+template <
+    class _AlgPolicy,
+    class _Pred,
+    class _Iter1,
+    class _Sent1,
+    class _Iter2,
+    class _Sent2,
+    class _Proj1,
+    class _Proj2>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _Iter1 __find_end(
+    _Iter1 __first1,
+    _Sent1 __sent1,
+    _Iter2 __first2,
+    _Sent2 __sent2,
+    _Pred& __pred,
+    _Proj1& __proj1,
+    _Proj2& __proj2,
+    random_access_iterator_tag,
+    random_access_iterator_tag) {
+  typedef typename iterator_traits<_Iter1>::difference_type _D1;
+  auto __last1 = _IterOps<_AlgPolicy>::next(__first1, __sent1);
+  auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __sent2);
  // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
-  _D2 __len2 = __last2 - __first2;
+  auto __len2 = __last2 - __first2;
  if (__len2 == 0)
    return __last1;
-  _D1 __len1 = __last1 - __first1;
+  auto __len1 = __last1 - __first1;
  if (__len1 < __len2)
    return __last1;
-  const _RandomAccessIterator1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here
-  _RandomAccessIterator1 __l1 = __last1;
-  _RandomAccessIterator2 __l2 = __last2;
+  const _Iter1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here
+  _Iter1 __l1 = __last1;
+  _Iter2 __l2 = __last2;
  --__l2;
  while (true) {
    while (true) {
      if (__s == __l1)
        return __last1;
-      if (__pred(*--__l1, *__l2))
+      if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
        break;
    }
-    _RandomAccessIterator1 __m1 = __l1;
-    _RandomAccessIterator2 __m2 = __l2;
+    _Iter1 __m1 = __l1;
+    _Iter2 __m2 = __l2;
    while (true) {
      if (__m2 == __first2)
        return __m1;
      // no need to check range on __m1 because __s guarantees we have enough source
-      if (!__pred(*--__m1, *--__m2)) {
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(*--__m2))) {
        break;
      }
    }
@@ -129,20 +189,39 @@ _LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1 __find_end(
 }

 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
-find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2,
-         _BinaryPredicate __pred) {
-  return _VSTD::__find_end<_BinaryPredicate&>(
-      __first1, __last1, __first2, __last2, __pred, typename iterator_traits<_ForwardIterator1>::iterator_category(),
-      typename iterator_traits<_ForwardIterator2>::iterator_category());
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+_ForwardIterator1 __find_end_classic(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                                     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                                     _BinaryPredicate& __pred) {
+  auto __proj = __identity();
+  return std::__find_end_impl<_ClassicAlgPolicy>(
+             __first1,
+             __last1,
+             __first2,
+             __last2,
+             __pred,
+             __proj,
+             __proj,
+             typename iterator_traits<_ForwardIterator1>::iterator_category(),
+             typename iterator_traits<_ForwardIterator2>::iterator_category())
+      .first;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator1 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                           _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                           _BinaryPredicate __pred) {
+  return std::__find_end_classic(__first1, __last1, __first2, __last2, __pred);
 }

 template <class _ForwardIterator1, class _ForwardIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
-find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
-  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
-  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
-  return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator1 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                           _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  using __v1 = typename iterator_traits<_ForwardIterator1>::value_type;
+  using __v2 = typename iterator_traits<_ForwardIterator2>::value_type;
+  return std::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
 }

 _LIBCPP_END_NAMESPACE_STD
--- a/libcxx/include/__algorithm/iterator_operations.h
+++ b/libcxx/include/__algorithm/iterator_operations.h
@@ -39,6 +39,7 @@ struct _IterOps<_RangeAlgPolicy> {
  static constexpr auto __iter_move = ranges::iter_move;
  static constexpr auto iter_swap = ranges::iter_swap;
  static constexpr auto next = ranges::next;
+  static constexpr auto __advance_to = ranges::advance;
 };
 #endif

@@ -82,6 +83,11 @@ struct _IterOps<_ClassicAlgPolicy> {
  _Iterator next(_Iterator, _Iterator __last) {
    return __last;
  }
+
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_AFTER_CXX11 void __advance_to(_Iter& __first, _Iter __last) {
+    __first = __last;
+  }
 };

 _LIBCPP_END_NAMESPACE_STD
--- a/libcxx/include/__algorithm/ranges_find_end.h
+++ b/libcxx/include/__algorithm/ranges_find_end.h
@@ -0,0 +1,113 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_END_H
+#define _LIBCPP___ALGORITHM_RANGES_FIND_END_H
+
+#include <__algorithm/find_end.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/indirectly_comparable.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/subrange.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter>
+consteval auto __get_iterator_concept() {
+  if constexpr (contiguous_iterator<_Iter>)
+    return contiguous_iterator_tag();
+  else if constexpr (random_access_iterator<_Iter>)
+    return random_access_iterator_tag();
+  else if constexpr (bidirectional_iterator<_Iter>)
+    return bidirectional_iterator_tag();
+  else if constexpr (forward_iterator<_Iter>)
+    return forward_iterator_tag();
+  else if constexpr (input_iterator<_Iter>)
+    return input_iterator_tag();
+}
+
+template <class _Iter>
+using __iterator_concept = decltype(__get_iterator_concept<_Iter>());
+
+namespace ranges {
+namespace __find_end {
+struct __fn {
+  template <forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
+            forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
+            class _Pred = ranges::equal_to,
+            class _Proj1 = identity,
+            class _Proj2 = identity>
+    requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  subrange<_Iter1> operator()(_Iter1 __first1, _Sent1 __last1,
+                              _Iter2 __first2, _Sent2 __last2,
+                              _Pred __pred = {},
+                              _Proj1 __proj1 = {},
+                              _Proj2 __proj2 = {}) const {
+    auto __ret = std::__find_end_impl<_RangeAlgPolicy>(
+        __first1,
+        __last1,
+        __first2,
+        __last2,
+        __pred,
+        __proj1,
+        __proj2,
+        __iterator_concept<_Iter1>(),
+        __iterator_concept<_Iter2>());
+    return {__ret.first, __ret.second};
+  }
+
+  template <forward_range _Range1,
+            forward_range _Range2,
+            class _Pred = ranges::equal_to,
+            class _Proj1 = identity,
+            class _Proj2 = identity>
+    requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_subrange_t<_Range1> operator()(_Range1&& __range1,
+                                          _Range2&& __range2,
+                                          _Pred __pred = {},
+                                          _Proj1 __proj1 = {},
+                                          _Proj2 __proj2 = {}) const {
+    auto __ret = std::__find_end_impl<_RangeAlgPolicy>(
+        ranges::begin(__range1),
+        ranges::end(__range1),
+        ranges::begin(__range2),
+        ranges::end(__range2),
+        __pred,
+        __proj1,
+        __proj2,
+        __iterator_concept<iterator_t<_Range1>>(),
+        __iterator_concept<iterator_t<_Range2>>());
+    return {__ret.first, __ret.second};
+  }
+};
+} // namespace __find_end
+
+inline namespace __cpo {
+  inline constexpr auto find_end = __find_end::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP___ALGORITHM_RANGES_FIND_END_H
--- a/libcxx/include/__algorithm/ranges_search.h
+++ b/libcxx/include/__algorithm/ranges_search.h
@@ -0,0 +1,134 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_SEARCH_H
+#define _LIBCPP___ALGORITHM_RANGES_SEARCH_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/search.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/distance.h>
+#include <__iterator/indirectly_comparable.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/size.h>
+#include <__ranges/subrange.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __search {
+struct __fn {
+  template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
+  _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_impl(
+      _Iter1 __first1,
+      _Sent1 __last1,
+      _Iter2 __first2,
+      _Sent2 __last2,
+      _Pred& __pred,
+      _Proj1& __proj1,
+      _Proj2& __proj2) {
+    if constexpr (sized_sentinel_for<_Sent2, _Iter2>) {
+      auto __size2 = ranges::distance(__first2, __last2);
+      if (__size2 == 0)
+        return {__first1, __first1};
+
+      if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
+        auto __size1 = ranges::distance(__first1, __last1);
+        if (__size1 < __size2) {
+          ranges::advance(__first1, __last1);
+          return {__first1, __first1};
+        }
+
+        if constexpr (random_access_iterator<_Iter1> && random_access_iterator<_Iter2>) {
+          auto __ret = std::__search_random_access_impl<_RangeAlgPolicy>(
+              __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
+          return {__ret.first, __ret.second};
+        }
+      }
+    }
+
+    auto __ret =
+        std::__search_forward_impl<_RangeAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
+    return {__ret.first, __ret.second};
+  }
+
+  template <forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
+            forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
+            class _Pred = ranges::equal_to,
+            class _Proj1 = identity,
+            class _Proj2 = identity>
+    requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  subrange<_Iter1> operator()(_Iter1 __first1, _Sent1 __last1,
+                              _Iter2 __first2, _Sent2 __last2,
+                              _Pred __pred = {},
+                              _Proj1 __proj1 = {},
+                              _Proj2 __proj2 = {}) const {
+    return __ranges_search_impl(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
+  }
+
+  template <forward_range _Range1,
+            forward_range _Range2,
+            class _Pred = ranges::equal_to,
+            class _Proj1 = identity,
+            class _Proj2 = identity>
+    requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_subrange_t<_Range1> operator()(_Range1&& __range1,
+                                          _Range2&& __range2,
+                                          _Pred __pred = {},
+                                          _Proj1 __proj1 = {},
+                                          _Proj2 __proj2 = {}) const {
+    auto __first1 = ranges::begin(__range1);
+    if constexpr (sized_range<_Range2>) {
+      auto __size2 = ranges::size(__range2);
+      if (__size2 == 0)
+        return {__first1, __first1};
+      if constexpr (sized_range<_Range1>) {
+        auto __size1 = ranges::size(__range1);
+        if (__size1 < __size2) {
+          ranges::advance(__first1, ranges::end(__range1));
+          return {__first1, __first1};
+        }
+      }
+    }
+
+    return __ranges_search_impl(
+        ranges::begin(__range1),
+        ranges::end(__range1),
+        ranges::begin(__range2),
+        ranges::end(__range2),
+        __pred,
+        __proj1,
+        __proj2);
+  }
+
+};
+} // namespace __search
+
+inline namespace __cpo {
+  inline constexpr auto search = __search::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_H
--- a/libcxx/include/__algorithm/ranges_search_n.h
+++ b/libcxx/include/__algorithm/ranges_search_n.h
@@ -0,0 +1,120 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_SEARCH_N_H
+#define _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/search_n.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/distance.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/indirectly_comparable.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/size.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 > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __search_n {
+struct __fn {
+
+  template <class _Iter1, class _Sent1, class _SizeT, class _Type, class _Pred, class _Proj>
+  _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_n_impl(
+      _Iter1 __first, _Sent1 __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) {
+    if (__count == 0)
+      return {__first, __first};
+
+    if constexpr (sized_sentinel_for<_Sent1, _Iter1>) {
+      auto __size = ranges::distance(__first, __last);
+      if (__size < __count) {
+        ranges::advance(__first, __last);
+        return {__first, __first};
+      }
+
+      if constexpr (random_access_iterator<_Iter1>) {
+        auto __ret = __search_n_random_access_impl<_RangeAlgPolicy>(__first, __last,
+                                                                    __count,
+                                                                    __value,
+                                                                    __pred,
+                                                                    __proj,
+                                                                    __size);
+        return {std::move(__ret.first), std::move(__ret.second)};
+      }
+    }
+
+    auto __ret = std::__search_n_forward_impl<_RangeAlgPolicy>(__first, __last,
+                                                               __count,
+                                                               __value,
+                                                               __pred,
+                                                               __proj);
+    return {std::move(__ret.first), std::move(__ret.second)};
+  }
+
+  template <forward_iterator _Iter, sentinel_for<_Iter> _Sent,
+            class _Type,
+            class _Pred = ranges::equal_to,
+            class _Proj = identity>
+    requires indirectly_comparable<_Iter, const _Type*, _Pred, _Proj>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  subrange<_Iter> operator()(_Iter __first, _Sent __last,
+                             iter_difference_t<_Iter> __count,
+                             const _Type& __value,
+                             _Pred __pred = {},
+                             _Proj __proj = _Proj{}) const {
+    return __ranges_search_n_impl(__first, __last, __count, __value, __pred, __proj);
+  }
+
+  template <forward_range _Range, class _Type, class _Pred = ranges::equal_to, class _Proj = identity>
+    requires indirectly_comparable<iterator_t<_Range>, const _Type*, _Pred, _Proj>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_subrange_t<_Range> operator()(_Range&& __range,
+                                         range_difference_t<_Range> __count,
+                                         const _Type& __value,
+                                         _Pred __pred = {},
+                                         _Proj __proj = {}) const {
+    auto __first = ranges::begin(__range);
+    if (__count <= 0)
+      return {__first, __first};
+    if constexpr (sized_range<_Range>) {
+      auto __size1 = ranges::size(__range);
+      if (__size1 < static_cast<range_size_t<_Range>>(__count)) {
+        ranges::advance(__first, ranges::end(__range));
+        return {__first, __first};
+      }
+    }
+
+    return __ranges_search_n_impl(ranges::begin(__range), ranges::end(__range), __count, __value, __pred, __proj);
+  }
+};
+} // namespace __search_n
+
+inline namespace __cpo {
+  inline constexpr auto search_n = __search_n::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H
--- a/libcxx/include/__algorithm/search.h
+++ b/libcxx/include/__algorithm/search.h
@@ -11,9 +11,15 @@
 #define _LIBCPP___ALGORITHM_SEARCH_H

 #include <__algorithm/comp.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
+#include <__functional/identity.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
 #include <__iterator/iterator_traits.h>
+#include <__type_traits/is_callable.h>
 #include <__utility/pair.h>
+#include <type_traits>

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -21,31 +27,43 @@

 _LIBCPP_BEGIN_NAMESPACE_STD

-template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
-pair<_ForwardIterator1, _ForwardIterator1>
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
-                                           _ForwardIterator2 __first2, _ForwardIterator2 __last2,
-                                           _BinaryPredicate __pred, forward_iterator_tag, forward_iterator_tag) {
+template <class _AlgPolicy,
+          class _Iter1, class _Sent1,
+          class _Iter2, class _Sent2,
+          class _Pred,
+          class _Proj1,
+          class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter1, _Iter1> __search_forward_impl(_Iter1 __first1, _Sent1 __last1,
+                                           _Iter2 __first2, _Sent2 __last2,
+                                           _Pred& __pred,
+                                           _Proj1& __proj1,
+                                           _Proj2& __proj2) {
  if (__first2 == __last2)
-    return _VSTD::make_pair(__first1, __first1); // Everything matches an empty sequence
+    return std::make_pair(__first1, __first1); // Everything matches an empty sequence
  while (true) {
    // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
    while (true) {
-      if (__first1 == __last1) // return __last1 if no element matches *__first2
-        return _VSTD::make_pair(__last1, __last1);
-      if (__pred(*__first1, *__first2))
+      if (__first1 == __last1) { // return __last1 if no element matches *__first2
+        _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
+        return std::make_pair(__first1, __first1);
+      }
+      if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
        break;
      ++__first1;
    }
    // *__first1 matches *__first2, now match elements after here
-    _ForwardIterator1 __m1 = __first1;
-    _ForwardIterator2 __m2 = __first2;
+    _Iter1 __m1 = __first1;
+    _Iter2 __m2 = __first2;
    while (true) {
      if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
-        return _VSTD::make_pair(__first1, __m1);
-      if (++__m1 == __last1) // Otherwise if source exhaused, pattern not found
-        return _VSTD::make_pair(__last1, __last1);
-      if (!__pred(*__m1, *__m2)) // if there is a mismatch, restart with a new __first1
+        return std::make_pair(__first1, ++__m1);
+      if (++__m1 == __last1) { // Otherwise if source exhaused, pattern not found
+        return std::make_pair(__m1, __m1);
+      }
+
+      // if there is a mismatch, restart with a new __first1
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2)))
      {
        ++__first1;
        break;
@@ -54,38 +72,42 @@ pair<_ForwardIterator1, _ForwardIterator1>
  }
 }

-template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
-_LIBCPP_CONSTEXPR_AFTER_CXX11 pair<_RandomAccessIterator1, _RandomAccessIterator1>
-__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
-         _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag,
-         random_access_iterator_tag) {
-  typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
-  typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
-  // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
-  const _D2 __len2 = __last2 - __first2;
-  if (__len2 == 0)
-    return _VSTD::make_pair(__first1, __first1);
-  const _D1 __len1 = __last1 - __first1;
-  if (__len1 < __len2)
-    return _VSTD::make_pair(__last1, __last1);
-  const _RandomAccessIterator1 __s = __last1 - _D1(__len2 - 1); // Start of pattern match can't go beyond here
+template <class _AlgPolicy,
+          class _Iter1, class _Sent1,
+          class _Iter2, class _Sent2,
+          class _Pred,
+          class _Proj1,
+          class _Proj2,
+          class _DiffT1,
+          class _DiffT2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter1, _Iter1> __search_random_access_impl(_Iter1 __first1, _Sent1 __last1,
+                                                 _Iter2 __first2, _Sent2 __last2,
+                                                 _Pred& __pred,
+                                                 _Proj1& __proj1,
+                                                 _Proj2& __proj2,
+                                                 _DiffT1 __size1,
+                                                 _DiffT2 __size2) {
+  const _Iter1 __s = __first1 + __size1 - _DiffT1(__size2 - 1); // Start of pattern match can't go beyond here

  while (true) {
    while (true) {
-      if (__first1 == __s)
-        return _VSTD::make_pair(__last1, __last1);
-      if (__pred(*__first1, *__first2))
+      if (__first1 == __s) {
+        _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
+        return std::make_pair(__first1, __first1);
+      }
+      if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
        break;
      ++__first1;
    }

-    _RandomAccessIterator1 __m1 = __first1;
-    _RandomAccessIterator2 __m2 = __first2;
+    _Iter1 __m1 = __first1;
+    _Iter2 __m2 = __first2;
    while (true) {
      if (++__m2 == __last2)
-        return _VSTD::make_pair(__first1, __first1 + _D1(__len2));
+        return std::make_pair(__first1, __first1 + _DiffT1(__size2));
      ++__m1; // no need to check range on __m1 because __s guarantees we have enough source
-      if (!__pred(*__m1, *__m2)) {
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
        ++__first1;
        break;
      }
@@ -93,22 +115,78 @@ __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _Rando
  }
 }

+template <class _Iter1, class _Sent1,
+          class _Iter2, class _Sent2,
+          class _Pred,
+          class _Proj1,
+          class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
+                                   _Iter2 __first2, _Sent2 __last2,
+                                   _Pred& __pred,
+                                   _Proj1& __proj1,
+                                   _Proj2& __proj2,
+                                   __enable_if_t<__is_cpp17_random_access_iterator<_Iter1>::value
+                                              && __is_cpp17_random_access_iterator<_Iter2>::value>* = nullptr) {
+
+  auto __size2 = __last2 - __first2;
+  if (__size2 == 0)
+    return std::make_pair(__first1, __first1);
+
+  auto __size1 = __last1 - __first1;
+  if (__size1 < __size2) {
+    return std::make_pair(__last1, __last1);
+  }
+
+  return std::__search_random_access_impl<_ClassicAlgPolicy>(__first1, __last1,
+                                                             __first2, __last2,
+                                                             __pred,
+                                                             __proj1,
+                                                             __proj2,
+                                                             __size1,
+                                                             __size2);
+}
+
+template <class _Iter1, class _Sent1,
+          class _Iter2, class _Sent2,
+          class _Pred,
+          class _Proj1,
+          class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
+                                   _Iter2 __first2, _Sent2 __last2,
+                                   _Pred& __pred,
+                                   _Proj1& __proj1,
+                                   _Proj2& __proj2,
+                                   __enable_if_t<__is_cpp17_forward_iterator<_Iter1>::value
+                                              && __is_cpp17_forward_iterator<_Iter2>::value
+                                              && !(__is_cpp17_random_access_iterator<_Iter1>::value
+                                                && __is_cpp17_random_access_iterator<_Iter2>::value)>* = nullptr) {
+  return std::__search_forward_impl<_ClassicAlgPolicy>(__first1, __last1,
+                                                       __first2, __last2,
+                                                       __pred,
+                                                       __proj1,
+                                                       __proj2);
+}
+
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
-search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2,
-       _BinaryPredicate __pred) {
-  return _VSTD::__search<_BinaryPredicate&>(
-             __first1, __last1, __first2, __last2, __pred,
-             typename iterator_traits<_ForwardIterator1>::iterator_category(),
-             typename iterator_traits<_ForwardIterator2>::iterator_category()).first;
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                         _BinaryPredicate __pred) {
+  static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
+                "BinaryPredicate has to be callable");
+  auto __proj = __identity();
+  return std::__search_impl(__first1, __last1, __first2, __last2, __pred, __proj, __proj).first;
 }

 template <class _ForwardIterator1, class _ForwardIterator2>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
-search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
-  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
-  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
-  return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  using __v1 = typename iterator_traits<_ForwardIterator1>::value_type;
+  using __v2 = typename iterator_traits<_ForwardIterator2>::value_type;
+  return std::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
 }

 #if _LIBCPP_STD_VER > 14
--- a/libcxx/include/__algorithm/search_n.h
+++ b/libcxx/include/__algorithm/search_n.h
@@ -11,8 +11,15 @@
 #define _LIBCPP___ALGORITHM_SEARCH_N_H

 #include <__algorithm/comp.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
+#include <__functional/identity.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
+#include <__ranges/concepts.h>
+#include <__utility/pair.h>
 #include <type_traits>  // __convert_to_integral

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -21,30 +28,39 @@

 _LIBCPP_BEGIN_NAMESPACE_STD

-template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
-_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator __search_n(_ForwardIterator __first, _ForwardIterator __last,
-                                                          _Size __count, const _Tp& __value, _BinaryPredicate __pred,
-                                                          forward_iterator_tag) {
+template <class _AlgPolicy, class _Pred, class _Iter, class _Sent, class _SizeT, class _Type, class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter, _Iter> __search_n_forward_impl(_Iter __first, _Sent __last,
+                                           _SizeT __count,
+                                           const _Type& __value,
+                                           _Pred& __pred,
+                                           _Proj& __proj) {
  if (__count <= 0)
-    return __first;
+    return std::make_pair(__first, __first);
  while (true) {
-    // Find first element in sequence that matchs __value_, with a mininum of loop checks
+    // Find first element in sequence that matchs __value, with a mininum of loop checks
    while (true) {
-      if (__first == __last) // return __last if no element matches __value_
-        return __last;
-      if (__pred(*__first, __value))
+      if (__first == __last) { // return __last if no element matches __value
+        _IterOps<_AlgPolicy>::__advance_to(__first, __last);
+        return std::make_pair(__first, __first);
+      }
+      if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value))
        break;
      ++__first;
    }
-    // *__first matches __value_, now match elements after here
-    _ForwardIterator __m = __first;
-    _Size __c(0);
+    // *__first matches __value, now match elements after here
+    _Iter __m = __first;
+    _SizeT __c(0);
    while (true) {
      if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
-        return __first;
-      if (++__m == __last) // Otherwise if source exhaused, pattern not found
-        return __last;
-      if (!__pred(*__m, __value)) // if there is a mismatch, restart with a new __first
+        return std::make_pair(__first, ++__m);
+      if (++__m == __last) { // Otherwise if source exhaused, pattern not found
+        _IterOps<_AlgPolicy>::__advance_to(__first, __last);
+        return std::make_pair(__first, __first);
+      }
+
+      // if there is a mismatch, restart with a new __first
+      if (!std::__invoke(__pred, std::__invoke(__proj, *__m), __value))
      {
        __first = __m;
        ++__first;
@@ -54,35 +70,44 @@ _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator __search_n(_ForwardIterator __fir
  }
 }

-template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
-_LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator __search_n(_RandomAccessIterator __first,
-                                                               _RandomAccessIterator __last, _Size __count,
-                                                               const _Tp& __value, _BinaryPredicate __pred,
-                                                               random_access_iterator_tag) {
-  typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
-  if (__count <= 0)
-    return __first;
-  _Size __len = static_cast<_Size>(__last - __first);
-  if (__len < __count)
-    return __last;
-  const _RandomAccessIterator __s = __last - difference_type(__count - 1); // Start of pattern match can't go beyond here
+template <class _AlgPolicy, class _Pred, class _Iter, class _Sent, class _SizeT, class _Type, class _Proj, class _DiffT>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+std::pair<_Iter, _Iter> __search_n_random_access_impl(_Iter __first, _Sent __last,
+                                                      _SizeT __count,
+                                                      const _Type& __value,
+                                                      _Pred& __pred,
+                                                      _Proj& __proj,
+                                                      _DiffT __size1) {
+  using difference_type = typename iterator_traits<_Iter>::difference_type;
+  if (__count == 0)
+    return std::make_pair(__first, __first);
+  if (__size1 < static_cast<_DiffT>(__count)) {
+    _IterOps<_AlgPolicy>::__advance_to(__first, __last);
+    return std::make_pair(__first, __first);
+  }
+
+  const auto __s = __first + __size1 - difference_type(__count - 1); // Start of pattern match can't go beyond here
  while (true) {
-    // Find first element in sequence that matchs __value_, with a mininum of loop checks
+    // Find first element in sequence that matchs __value, with a mininum of loop checks
    while (true) {
-      if (__first >= __s) // return __last if no element matches __value_
-        return __last;
-      if (__pred(*__first, __value))
+      if (__first >= __s) { // return __last if no element matches __value
+        _IterOps<_AlgPolicy>::__advance_to(__first, __last);
+        return std::make_pair(__first, __first);
+      }
+      if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value))
        break;
      ++__first;
    }
    // *__first matches __value_, now match elements after here
-    _RandomAccessIterator __m = __first;
-    _Size __c(0);
+    auto __m = __first;
+    _SizeT __c(0);
    while (true) {
      if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
-        return __first;
-      ++__m;                       // no need to check range on __m because __s guarantees we have enough source
-      if (!__pred(*__m, __value)) // if there is a mismatch, restart with a new __first
+        return std::make_pair(__first, __first + _DiffT(__count));
+      ++__m; // no need to check range on __m because __s guarantees we have enough source
+
+      // if there is a mismatch, restart with a new __first
+      if (!std::__invoke(__pred, std::__invoke(__proj, *__m), __value))
      {
        __first = __m;
        ++__first;
@@ -92,19 +117,63 @@ _LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator __search_n(_RandomAccessIter
  }
 }

+template <class _Iter, class _Sent,
+          class _DiffT,
+          class _Type,
+          class _Pred,
+          class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter, _Iter> __search_n_impl(_Iter __first, _Sent __last,
+                                   _DiffT __count,
+                                   const _Type& __value,
+                                   _Pred& __pred,
+                                   _Proj& __proj,
+                                   __enable_if_t<__is_cpp17_random_access_iterator<_Iter>::value>* = nullptr) {
+  return std::__search_n_random_access_impl<_ClassicAlgPolicy>(__first, __last,
+                                                               __count,
+                                                               __value,
+                                                               __pred,
+                                                               __proj,
+                                                               __last - __first);
+}
+
+template <class _Iter1, class _Sent1,
+          class _DiffT,
+          class _Type,
+          class _Pred,
+          class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Iter1, _Iter1> __search_n_impl(_Iter1 __first, _Sent1 __last,
+                                     _DiffT __count,
+                                     const _Type& __value,
+                                     _Pred& __pred,
+                                     _Proj& __proj,
+                                     __enable_if_t<__is_cpp17_forward_iterator<_Iter1>::value
+                                               && !__is_cpp17_random_access_iterator<_Iter1>::value>* = nullptr) {
+  return std::__search_n_forward_impl<_ClassicAlgPolicy>(__first, __last,
+                                                         __count,
+                                                         __value,
+                                                         __pred,
+                                                         __proj);
+}
+
 template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator search_n(
-    _ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value, _BinaryPredicate __pred) {
-  return _VSTD::__search_n<_BinaryPredicate&>(
-      __first, __last, _VSTD::__convert_to_integral(__count), __value, __pred,
-      typename iterator_traits<_ForwardIterator>::iterator_category());
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator search_n(_ForwardIterator __first, _ForwardIterator __last,
+                          _Size __count,
+                          const _Tp& __value,
+                          _BinaryPredicate __pred) {
+  static_assert(__is_callable<_BinaryPredicate, decltype(*__first), decltype(*__last)>::value,
+                "BinaryPredicate has to be callable");
+  auto __proj = __identity();
+  return std::__search_n_impl(__first, __last, std::__convert_to_integral(__count), __value, __pred, __proj).first;
 }

 template <class _ForwardIterator, class _Size, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
-search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value) {
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value) {
  typedef typename iterator_traits<_ForwardIterator>::value_type __v;
-  return _VSTD::search_n(__first, __last, _VSTD::__convert_to_integral(__count), __value, __equal_to<__v, _Tp>());
+  return std::search_n(__first, __last, std::__convert_to_integral(__count), __value, __equal_to<__v, _Tp>());
 }

 _LIBCPP_END_NAMESPACE_STD
--- a/libcxx/include/__algorithm/set_intersection.h
+++ b/libcxx/include/__algorithm/set_intersection.h
@@ -14,6 +14,7 @@
 #include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
 #include <__utility/move.h>

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
--- a/libcxx/include/__functional/default_searcher.h
+++ b/libcxx/include/__functional/default_searcher.h
@@ -12,6 +12,7 @@

 #include <__algorithm/search.h>
 #include <__config>
+#include <__functional/identity.h>
 #include <__functional/operations.h>
 #include <__iterator/iterator_traits.h>
 #include <__utility/pair.h>
@@ -38,16 +39,15 @@ public:
    pair<_ForwardIterator2, _ForwardIterator2>
    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
    {
-        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
-            typename iterator_traits<_ForwardIterator>::iterator_category(),
-            typename iterator_traits<_ForwardIterator2>::iterator_category());
+        auto __proj = __identity();
+        return std::__search_impl(__f, __l, __first_, __last_, __pred_, __proj, __proj);
    }

 private:
    _ForwardIterator __first_;
    _ForwardIterator __last_;
    _BinaryPredicate __pred_;
-    };
+};

 #endif // _LIBCPP_STD_VER > 14

--- a/libcxx/include/__iterator/iterator_traits.h
+++ b/libcxx/include/__iterator/iterator_traits.h
@@ -481,6 +481,12 @@ struct __is_exactly_cpp17_forward_iterator
         __has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value &&
        !__has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag>::value> {};

+template <class _Tp>
+struct __is_exactly_cpp17_bidirectional_iterator
+    : public integral_constant<bool,
+         __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag>::value &&
+        !__has_iterator_category_convertible_to<_Tp, random_access_iterator_tag>::value> {};
+
 template<class _InputIterator>
 using __iter_value_type = typename iterator_traits<_InputIterator>::value_type;

--- a/libcxx/include/__string/char_traits.h
+++ b/libcxx/include/__string/char_traits.h
@@ -802,9 +802,7 @@ __str_rfind(const _CharT *__p, _SizeT __sz,
        __pos += __n;
    else
        __pos = __sz;
-    const _CharT* __r = _VSTD::__find_end(
-                  __p, __p + __pos, __s, __s + __n, _Traits::eq,
-                        random_access_iterator_tag(), random_access_iterator_tag());
+    const _CharT* __r = std::__find_end_classic(__p, __p + __pos, __s, __s + __n, _Traits::eq);
    if (__n > 0 && __r == __p + __pos)
        return __npos;
    return static_cast<_SizeT>(__r - __p);
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -649,6 +649,49 @@ namespace ranges {
    constexpr ranges::rotate_copy_result<borrowed_iterator_t<R>, O>
      ranges::rotate_copy(R&& r, iterator_t<R> middle, O result);                                   // since C++20

+  template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2,
+           sentinel_for<I2> S2, class Pred = ranges::equal_to,
+           class Proj1 = identity, class Proj2 = identity>
+    requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
+    constexpr subrange<I1>
+      ranges::search(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
+                     Proj1 proj1 = {}, Proj2 proj2 = {});                                           // since C++20
+
+  template<forward_range R1, forward_range R2, class Pred = ranges::equal_to,
+           class Proj1 = identity, class Proj2 = identity>
+    requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
+    constexpr borrowed_subrange_t<R1>
+      ranges::search(R1&& r1, R2&& r2, Pred pred = {},
+                     Proj1 proj1 = {}, Proj2 proj2 = {});                                           // since C++20
+
+  template<forward_iterator I, sentinel_for<I> S, class T,
+           class Pred = ranges::equal_to, class Proj = identity>
+    requires indirectly_comparable<I, const T*, Pred, Proj>
+    constexpr subrange<I>
+      ranges::search_n(I first, S last, iter_difference_t<I> count,
+                       const T& value, Pred pred = {}, Proj proj = {});                             // since C++20
+
+  template<forward_range R, class T, class Pred = ranges::equal_to,
+           class Proj = identity>
+    requires indirectly_comparable<iterator_t<R>, const T*, Pred, Proj>
+    constexpr borrowed_subrange_t<R>
+      ranges::search_n(R&& r, range_difference_t<R> count,
+                       const T& value, Pred pred = {}, Proj proj = {});                             // since C++20
+
+  template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2, sentinel_for<I2> S2,
+           class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
+    requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
+    constexpr subrange<I1>
+      ranges::find_end(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
+                       Proj1 proj1 = {}, Proj2 proj2 = {});                                         // since C++20
+
+  template<forward_range R1, forward_range R2,
+           class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
+    requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
+    constexpr borrowed_subrange_t<R1>
+      ranges::find_end(R1&& r1, R2&& r2, Pred pred = {},
+                       Proj1 proj1 = {}, Proj2 proj2 = {});                                         // since C++20
+
 }

    constexpr bool     // constexpr in C++20
@@ -1392,6 +1435,7 @@ template <class BidirectionalIterator, class Compare>
 #include <__algorithm/ranges_fill.h>
 #include <__algorithm/ranges_fill_n.h>
 #include <__algorithm/ranges_find.h>
+#include <__algorithm/ranges_find_end.h>
 #include <__algorithm/ranges_find_first_of.h>
 #include <__algorithm/ranges_find_if.h>
 #include <__algorithm/ranges_find_if_not.h>
@@ -1424,6 +1468,8 @@ template <class BidirectionalIterator, class Compare>
 #include <__algorithm/ranges_reverse.h>
 #include <__algorithm/ranges_reverse_copy.h>
 #include <__algorithm/ranges_rotate_copy.h>
+#include <__algorithm/ranges_search.h>
+#include <__algorithm/ranges_search_n.h>
 #include <__algorithm/ranges_set_difference.h>
 #include <__algorithm/ranges_set_intersection.h>
 #include <__algorithm/ranges_sort.h>
--- a/libcxx/include/experimental/functional
+++ b/libcxx/include/experimental/functional
@@ -62,6 +62,7 @@ inline namespace fundamentals_v1 {

 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__debug>
+#include <__functional/identity.h>
 #include <__memory/uses_allocator.h>
 #include <array>
 #include <experimental/__config>
@@ -104,9 +105,8 @@ public:
    pair<_ForwardIterator2, _ForwardIterator2>
    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
    {
-        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
-            typename iterator_traits<_ForwardIterator>::iterator_category(),
-            typename iterator_traits<_ForwardIterator2>::iterator_category());
+        auto __proj = __identity();
+        return std::__search_impl(__f, __l, __first_, __last_, __pred_, __proj, __proj);
    }

 private:
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -322,6 +322,7 @@ module std [system] {
      module ranges_fill                     { private header "__algorithm/ranges_fill.h" }
      module ranges_fill_n                   { private header "__algorithm/ranges_fill_n.h" }
      module ranges_find                     { private header "__algorithm/ranges_find.h" }
+      module ranges_find_end                 { private header "__algorithm/ranges_find_end.h" }
      module ranges_find_first_of            { private header "__algorithm/ranges_find_first_of.h" }
      module ranges_find_if                  { private header "__algorithm/ranges_find_if.h" }
      module ranges_find_if_not              { private header "__algorithm/ranges_find_if_not.h" }
@@ -368,6 +369,8 @@ module std [system] {
      module ranges_reverse                  { private header "__algorithm/ranges_reverse.h" }
      module ranges_reverse_copy             { private header "__algorithm/ranges_reverse_copy.h" }
      module ranges_rotate_copy              { private header "__algorithm/ranges_rotate_copy.h" }
+      module ranges_search                   { private header "__algorithm/ranges_search.h" }
+      module ranges_search_n                 { private header "__algorithm/ranges_search_n.h" }
      module ranges_set_difference           { private header "__algorithm/ranges_set_difference.h" }
      module ranges_set_intersection         { private header "__algorithm/ranges_set_intersection.h" }
      module ranges_set_union                { private header "__algorithm/ranges_set_union.h" }
--- a/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_comparators.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/ranges_robust_against_copying_comparators.pass.cpp
@@ -84,7 +84,7 @@ constexpr bool all_the_algorithms()
    void **mid = a+5;
    void **last = a+10;
    void **first2 = b;
-    //void **mid2 = b+5;
+    void **mid2 = b+5;
    void **last2 = b+10;
    void *value = nullptr;
    int count = 1;
@@ -110,8 +110,8 @@ constexpr bool all_the_algorithms()
    (void)std::ranges::equal(a, b, Equal(&copies)); assert(copies == 0);
    //(void)std::ranges::equal_range(first, last, value, Less(&copies)); assert(copies == 0);
    //(void)std::ranges::equal_range(a, value, Less(&copies)); assert(copies == 0);
-    //(void)std::ranges::find_end(first, last, first2, mid2, Equal(&copies)); assert(copies == 0);
-    //(void)std::ranges::find_end(a, b, Equal(&copies)); assert(copies == 0);
+    (void)std::ranges::find_end(first, last, first2, mid2, Equal(&copies)); assert(copies == 0);
+    (void)std::ranges::find_end(a, b, Equal(&copies)); assert(copies == 0);
    (void)std::ranges::find_first_of(first, last, first2, last2, Equal(&copies)); assert(copies == 0);
    (void)std::ranges::find_first_of(a, b, Equal(&copies)); assert(copies == 0);
    (void)std::ranges::find_if(first, last, UnaryTrue(&copies)); assert(copies == 0);
@@ -195,10 +195,10 @@ constexpr bool all_the_algorithms()
    //(void)std::ranges::replace_copy_if(a, first2, UnaryTrue(&copies), value); assert(copies == 0);
    (void)std::ranges::replace_if(first, last, UnaryTrue(&copies), value); assert(copies == 0);
    (void)std::ranges::replace_if(a, UnaryTrue(&copies), value); assert(copies == 0);
-    //(void)std::ranges::search(first, last, first2, mid2, Equal(&copies)); assert(copies == 0);
-    //(void)std::ranges::search(a, b, Equal(&copies)); assert(copies == 0);
-    //(void)std::ranges::search_n(first, last, count, value, Equal(&copies)); assert(copies == 0);
-    //(void)std::ranges::search_n(a, count, value, Equal(&copies)); assert(copies == 0);
+    (void)std::ranges::search(first, last, first2, mid2, Equal(&copies)); assert(copies == 0);
+    (void)std::ranges::search(a, b, Equal(&copies)); assert(copies == 0);
+    (void)std::ranges::search_n(first, last, count, value, Equal(&copies)); assert(copies == 0);
+    (void)std::ranges::search_n(a, count, value, Equal(&copies)); assert(copies == 0);
    (void)std::ranges::set_difference(first, mid, mid, last, first2, Less(&copies)); assert(copies == 0);
    (void)std::ranges::set_difference(a, b, first2, Less(&copies)); assert(copies == 0);
    (void)std::ranges::set_intersection(first, mid, mid, last, first2, Less(&copies)); assert(copies == 0);
--- a/libcxx/test/libcxx/private_headers.verify.cpp
+++ b/libcxx/test/libcxx/private_headers.verify.cpp
@@ -120,6 +120,7 @@ END-SCRIPT
 #include <__algorithm/ranges_fill.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_fill.h'}}
 #include <__algorithm/ranges_fill_n.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_fill_n.h'}}
 #include <__algorithm/ranges_find.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_find.h'}}
+#include <__algorithm/ranges_find_end.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_find_end.h'}}
 #include <__algorithm/ranges_find_first_of.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_find_first_of.h'}}
 #include <__algorithm/ranges_find_if.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_find_if.h'}}
 #include <__algorithm/ranges_find_if_not.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_find_if_not.h'}}
@@ -166,6 +167,8 @@ END-SCRIPT
 #include <__algorithm/ranges_reverse.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_reverse.h'}}
 #include <__algorithm/ranges_reverse_copy.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_reverse_copy.h'}}
 #include <__algorithm/ranges_rotate_copy.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_rotate_copy.h'}}
+#include <__algorithm/ranges_search.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_search.h'}}
+#include <__algorithm/ranges_search_n.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_search_n.h'}}
 #include <__algorithm/ranges_set_difference.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_set_difference.h'}}
 #include <__algorithm/ranges_set_intersection.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_set_intersection.h'}}
 #include <__algorithm/ranges_set_union.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_set_union.h'}}
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/ranges.find_end.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.find.end/ranges.find_end.pass.cpp
@@ -0,0 +1,354 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2, sentinel_for<I2> S2,
+//          class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
+//   requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
+//   constexpr subrange<I1>
+//     ranges::find_end(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
+//                      Proj1 proj1 = {}, Proj2 proj2 = {});
+// template<forward_range R1, forward_range R2,
+//          class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
+//   requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
+//   constexpr borrowed_subrange_t<R1>
+//     ranges::find_end(R1&& r1, R2&& r2, Pred pred = {},
+//                      Proj1 proj1 = {}, Proj2 proj2 = {});
+
+#include <algorithm>
+#include <array>
+#include <ranges>
+
+#include "almost_satisfies_types.h"
+#include "test_iterators.h"
+
+template <class Iter1, class Sent1 = Iter1, class Iter2 = int*, class Sent2 = Iter2>
+concept HasFindEndIt = requires (Iter1 first1, Sent1 last1, Iter2 first2, Sent2 last2) {
+  std::ranges::find_end(first1, last1, first2, last2);
+};
+
+static_assert(HasFindEndIt<int*>);
+static_assert(!HasFindEndIt<ForwardIteratorNotDerivedFrom>);
+static_assert(!HasFindEndIt<ForwardIteratorNotIncrementable>);
+static_assert(!HasFindEndIt<int*, SentinelForNotSemiregular>);
+static_assert(!HasFindEndIt<int*, int*, int**>); // not indirectly comparable
+static_assert(!HasFindEndIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
+static_assert(!HasFindEndIt<int*, int*, ForwardIteratorNotDerivedFrom>);
+static_assert(!HasFindEndIt<int*, int*, ForwardIteratorNotIncrementable>);
+static_assert(!HasFindEndIt<int*, int*, int*, SentinelForNotSemiregular>);
+static_assert(!HasFindEndIt<int*, int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
+
+template <class Range1, class Range2 = UncheckedRange<int*>>
+concept HasFindEndR = requires (Range1 range1, Range2 range2) {
+  std::ranges::find_end(range1, range2);
+};
+
+static_assert(HasFindEndR<UncheckedRange<int*>>);
+static_assert(!HasFindEndR<ForwardRangeNotDerivedFrom>);
+static_assert(!HasFindEndR<ForwardIteratorNotIncrementable>);
+static_assert(!HasFindEndR<ForwardRangeNotSentinelSemiregular>);
+static_assert(!HasFindEndR<ForwardRangeNotSentinelEqualityComparableWith>);
+static_assert(!HasFindEndR<UncheckedRange<int*>, UncheckedRange<int**>>); // not indirectly comparable
+static_assert(!HasFindEndR<UncheckedRange<int*>, ForwardRangeNotDerivedFrom>);
+static_assert(!HasFindEndR<UncheckedRange<int*>, ForwardRangeNotIncrementable>);
+static_assert(!HasFindEndR<UncheckedRange<int*>, ForwardRangeNotSentinelSemiregular>);
+static_assert(!HasFindEndR<UncheckedRange<int*>, ForwardRangeNotSentinelEqualityComparableWith>);
+
+template <class Iter1, class Sent1, class Iter2, class Sent2 = Iter2>
+constexpr void test_iterators() {
+  { // simple test
+    {
+      int a[] = {1, 2, 3, 4, 5, 6};
+      int p[] = {3, 4};
+      std::same_as<std::ranges::subrange<Iter1, Iter1>> decltype(auto) ret =
+          std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 2)));
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 4);
+    }
+    {
+      int a[] = {1, 2, 3, 4, 5, 6};
+      int p[] = {3, 4};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
+      std::same_as<std::ranges::subrange<Iter1, Iter1>> decltype(auto) ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 4);
+    }
+  }
+
+  { // matching part begins at the front
+    {
+      int a[] = {7, 5, 3, 7, 3, 6};
+      int p[] = {7, 5, 3};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 3)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {7, 5, 3, 7, 3, 6};
+      int p[] = {7, 5, 3};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // matching part ends at the back
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {4, 8};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 5)), Iter2(p), Sent2(Iter2(p + 2)));
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {4, 8};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 5)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // pattern does not match
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {1};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 5)), Iter2(p), Sent2(Iter2(p + 1)));
+      assert(base(ret.begin()) == a + 5);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {1};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 5)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 1)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a + 5);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // range and pattern are identical
+    {
+      int a[] = {6, 7, 8, 9};
+      int p[] = {6, 7, 8, 9};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 4)), Iter2(p), Sent2(Iter2(p + 4)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 4);
+    }
+    {
+      int a[] = {6, 7, 8, 9};
+      int p[] = {6, 7, 8, 9};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 4)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 4)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 4);
+    }
+  }
+
+  { // pattern is longer than range
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {6, 7, 8, 9};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 3)), Iter2(p), Sent2(Iter2(p + 4)));
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {6, 7, 8, 9};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 3)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 4)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // pattern has zero length
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 3)), Iter2(p), Sent2(Iter2(p)));
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 3)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // range has zero length
+    {
+      int a[] = {};
+      int p[] = {6, 7, 8};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a)), Iter2(p), Sent2(Iter2(p + 3)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+    {
+      int a[] = {};
+      int p[] = {6, 7, 8};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+  }
+
+  { // check that the first match is returned
+    {
+      int a[] = {6, 7, 8, 6, 7, 8, 6, 7, 8};
+      int p[] = {6, 7, 8};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 9)), Iter2(p), Sent2(Iter2(p + 3)));
+      assert(base(ret.begin()) == a + 6);
+      assert(base(ret.end()) == a + 9);
+    }
+    {
+      int a[] = {6, 7, 8, 6, 7, 8, 6, 7, 8};
+      int p[] = {6, 7, 8};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 9)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::find_end(range1, range2);
+      assert(base(ret.begin()) == a + 6);
+      assert(base(ret.end()) == a + 9);
+    }
+  }
+
+  { // check that the predicate is used
+    {
+      int a[] = {1, 2, 8, 1, 5, 6};
+      int p[] = {7, 0, 4};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 6)),
+                                       Iter2(p), Sent2(Iter2(p + 3)),
+                                       [](int l, int r) { return l > r; });
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {1, 2, 8, 1, 5, 6};
+      int p[] = {7, 0, 4};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::find_end(range1, range2, [](int l, int r) { return l > r; });
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // check that the projections are used
+    {
+      int a[] = {1, 3, 5, 1, 5, 6};
+      int p[] = {2, 3, 4};
+      auto ret = std::ranges::find_end(Iter1(a), Sent1(Iter1(a + 6)),
+                                       Iter2(p), Sent2(Iter2(p + 3)),
+                                       {},
+                                       [](int i) { return i + 3; },
+                                       [](int i) { return i * 2; });
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {1, 3, 5, 1, 5, 6};
+      int p[] = {2, 3, 4};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::find_end(range1,
+                                       range2,
+                                       {},
+                                       [](int i) { return i + 3; },
+                                       [](int i) { return i * 2; });
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+}
+
+template <class Iter1, class Sent1 = Iter1>
+constexpr void test_iterators2() {
+  test_iterators<Iter1, Sent1, forward_iterator<int*>>();
+  test_iterators<Iter1, Sent1, forward_iterator<int*>, sized_sentinel<forward_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, bidirectional_iterator<int*>>();
+  test_iterators<Iter1, Sent1, bidirectional_iterator<int*>, sized_sentinel<bidirectional_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, random_access_iterator<int*>>();
+  test_iterators<Iter1, Sent1, random_access_iterator<int*>, sized_sentinel<random_access_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, contiguous_iterator<int*>>();
+  test_iterators<Iter1, Sent1, contiguous_iterator<int*>, sized_sentinel<contiguous_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, int*>();
+}
+
+constexpr bool test() {
+  test_iterators2<forward_iterator<int*>>();
+  test_iterators2<forward_iterator<int*>, sized_sentinel<forward_iterator<int*>>>();
+  test_iterators2<bidirectional_iterator<int*>>();
+  test_iterators2<bidirectional_iterator<int*>, sized_sentinel<bidirectional_iterator<int*>>>();
+  test_iterators2<random_access_iterator<int*>>();
+  test_iterators2<random_access_iterator<int*>, sized_sentinel<random_access_iterator<int*>>>();
+  test_iterators2<contiguous_iterator<int*>>();
+  test_iterators2<contiguous_iterator<int*>, sized_sentinel<contiguous_iterator<int*>>>();
+  test_iterators2<int*>();
+
+  { // check that std::invoke is used
+    struct S {
+      int i;
+
+      constexpr S identity() {
+        return *this;
+      }
+
+      constexpr bool compare(const S& s) {
+        return i == s.i;
+      }
+    };
+    {
+      S a[] = {{1}, {2}, {3}, {4}};
+      S p[] = {{2}, {3}};
+      auto ret = std::ranges::find_end(a, a + 4, p, p + 2, &S::compare, &S::identity, &S::identity);
+      assert(ret.begin() == a + 1);
+      assert(ret.end() == a + 3);
+    }
+    {
+      S a[] = {{1}, {2}, {3}, {4}};
+      S p[] = {{2}, {3}};
+      auto ret = std::ranges::find_end(a, p, &S::compare, &S::identity, &S::identity);
+      assert(ret.begin() == a + 1);
+      assert(ret.end() == a + 3);
+    }
+  }
+
+  { // check that std::ranges::dangling is returned
+    [[maybe_unused]] std::same_as<std::ranges::dangling> decltype(auto) ret =
+        std::ranges::find_end(std::array {1, 2, 3, 4}, std::array {2, 3});
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/ranges.search.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/ranges.search.pass.cpp
@@ -0,0 +1,355 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// template<forward_iterator I1, sentinel_for<I1> S1, forward_iterator I2,
+//          sentinel_for<I2> S2, class Pred = ranges::equal_to,
+//          class Proj1 = identity, class Proj2 = identity>
+//   requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
+//   constexpr subrange<I1>
+//     ranges::search(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
+//                    Proj1 proj1 = {}, Proj2 proj2 = {});
+// template<forward_range R1, forward_range R2, class Pred = ranges::equal_to,
+//          class Proj1 = identity, class Proj2 = identity>
+//   requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
+//   constexpr borrowed_subrange_t<R1>
+//     ranges::search(R1&& r1, R2&& r2, Pred pred = {},
+//                    Proj1 proj1 = {}, Proj2 proj2 = {});
+
+#include <algorithm>
+#include <array>
+#include <ranges>
+
+#include "almost_satisfies_types.h"
+#include "test_iterators.h"
+
+template <class Iter1, class Sent1 = Iter1, class Iter2 = int*, class Sent2 = Iter2>
+concept HasSearchIt = requires (Iter1 first1, Sent1 last1, Iter2 first2, Sent2 last2) {
+  std::ranges::search(first1, last1, first2, last2);
+};
+
+static_assert(HasSearchIt<int*>);
+static_assert(!HasSearchIt<ForwardIteratorNotDerivedFrom>);
+static_assert(!HasSearchIt<ForwardIteratorNotIncrementable>);
+static_assert(!HasSearchIt<int*, SentinelForNotSemiregular>);
+static_assert(!HasSearchIt<int*, int*, int**>); // not indirectly comparable
+static_assert(!HasSearchIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
+static_assert(!HasSearchIt<int*, int*, ForwardIteratorNotDerivedFrom>);
+static_assert(!HasSearchIt<int*, int*, ForwardIteratorNotIncrementable>);
+static_assert(!HasSearchIt<int*, int*, int*, SentinelForNotSemiregular>);
+static_assert(!HasSearchIt<int*, int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
+
+template <class Range1, class Range2 = UncheckedRange<int*>>
+concept HasSearchR = requires (Range1 range1, Range2 range2) {
+  std::ranges::search(range1, range2);
+};
+
+static_assert(HasSearchR<UncheckedRange<int*>>);
+static_assert(!HasSearchR<ForwardRangeNotDerivedFrom>);
+static_assert(!HasSearchR<ForwardIteratorNotIncrementable>);
+static_assert(!HasSearchR<ForwardRangeNotSentinelSemiregular>);
+static_assert(!HasSearchR<ForwardRangeNotSentinelEqualityComparableWith>);
+static_assert(!HasSearchR<UncheckedRange<int*>, UncheckedRange<int**>>); // not indirectly comparable
+static_assert(!HasSearchR<UncheckedRange<int*>, ForwardRangeNotDerivedFrom>);
+static_assert(!HasSearchR<UncheckedRange<int*>, ForwardRangeNotIncrementable>);
+static_assert(!HasSearchR<UncheckedRange<int*>, ForwardRangeNotSentinelSemiregular>);
+static_assert(!HasSearchR<UncheckedRange<int*>, ForwardRangeNotSentinelEqualityComparableWith>);
+
+template <class Iter1, class Sent1, class Iter2, class Sent2 = Iter2>
+constexpr void test_iterators() {
+  { // simple test
+    {
+      int a[] = {1, 2, 3, 4, 5, 6};
+      int p[] = {3, 4};
+      std::same_as<std::ranges::subrange<Iter1, Iter1>> decltype(auto) ret =
+          std::ranges::search(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 2)));
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 4);
+    }
+    {
+      int a[] = {1, 2, 3, 4, 5, 6};
+      int p[] = {3, 4};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
+      std::same_as<std::ranges::subrange<Iter1, Iter1>> decltype(auto) ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 4);
+    }
+  }
+
+  { // matching part begins at the front
+    {
+      int a[] = {7, 5, 3, 7, 3, 6};
+      int p[] = {7, 5, 3};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 3)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {7, 5, 3, 7, 3, 6};
+      int p[] = {7, 5, 3};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // matching part ends at the back
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {4, 8};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 5)), Iter2(p), Sent2(Iter2(p + 2)));
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {4, 8};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 5)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // pattern does not match
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {1};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 5)), Iter2(p), Sent2(Iter2(p + 1)));
+      assert(base(ret.begin()) == a + 5);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      int p[] = {1};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 5)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 1)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a + 5);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // range and pattern are identical
+    {
+      int a[] = {6, 7, 8, 9};
+      int p[] = {6, 7, 8, 9};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 4)), Iter2(p), Sent2(Iter2(p + 4)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 4);
+    }
+    {
+      int a[] = {6, 7, 8, 9};
+      int p[] = {6, 7, 8, 9};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 4)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 4)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 4);
+    }
+  }
+
+  { // pattern is longer than range
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {6, 7, 8, 9};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 3)), Iter2(p), Sent2(Iter2(p + 4)));
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {6, 7, 8, 9};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 3)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 4)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // pattern has zero length
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 3)), Iter2(p), Sent2(Iter2(p)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+    {
+      int a[] = {6, 7, 8};
+      int p[] = {};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 3)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+  }
+
+  { // range has zero length
+    {
+      int a[] = {};
+      int p[] = {6, 7, 8};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a)), Iter2(p), Sent2(Iter2(p + 3)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+    {
+      int a[] = {};
+      int p[] = {6, 7, 8};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+  }
+
+  { // check that the first match is returned
+    {
+      int a[] = {6, 7, 8, 6, 7, 8, 6, 7, 8};
+      int p[] = {6, 7, 8};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 9)), Iter2(p), Sent2(Iter2(p + 3)));
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {6, 7, 8, 6, 7, 8, 6, 7, 8};
+      int p[] = {6, 7, 8};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 9)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::search(range1, range2);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // check that the predicate is used
+    {
+      int a[] = {1, 2, 8, 1, 5, 6};
+      int p[] = {7, 0, 4};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 6)),
+                                     Iter2(p), Sent2(Iter2(p + 3)),
+                                     [](int l, int r) { return l > r; });
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {1, 2, 8, 1, 5, 6};
+      int p[] = {7, 0, 4};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::search(range1, range2, [](int l, int r) { return l > r; });
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // check that the projections are used
+    {
+      int a[] = {1, 3, 5, 1, 5, 6};
+      int p[] = {2, 3, 4};
+      auto ret = std::ranges::search(Iter1(a), Sent1(Iter1(a + 6)),
+                                     Iter2(p), Sent2(Iter2(p + 3)),
+                                     {},
+                                     [](int i) { return i + 3; },
+                                     [](int i) { return i * 2; });
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {1, 3, 5, 1, 5, 6};
+      int p[] = {2, 3, 4};
+      auto range1 = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
+      auto range2 = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
+      auto ret = std::ranges::search(range1,
+                                     range2,
+                                     {},
+                                     [](int i) { return i + 3; },
+                                     [](int i) { return i * 2; });
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+}
+
+template <class Iter1, class Sent1 = Iter1>
+constexpr void test_iterators2() {
+  test_iterators<Iter1, Sent1, forward_iterator<int*>>();
+  test_iterators<Iter1, Sent1, forward_iterator<int*>, sized_sentinel<forward_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, bidirectional_iterator<int*>>();
+  test_iterators<Iter1, Sent1, bidirectional_iterator<int*>, sized_sentinel<bidirectional_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, random_access_iterator<int*>>();
+  test_iterators<Iter1, Sent1, random_access_iterator<int*>, sized_sentinel<random_access_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, contiguous_iterator<int*>>();
+  test_iterators<Iter1, Sent1, contiguous_iterator<int*>, sized_sentinel<contiguous_iterator<int*>>>();
+  test_iterators<Iter1, Sent1, int*>();
+}
+
+constexpr bool test() {
+  test_iterators2<forward_iterator<int*>>();
+  test_iterators2<forward_iterator<int*>, sized_sentinel<forward_iterator<int*>>>();
+  test_iterators2<bidirectional_iterator<int*>>();
+  test_iterators2<bidirectional_iterator<int*>, sized_sentinel<bidirectional_iterator<int*>>>();
+  test_iterators2<random_access_iterator<int*>>();
+  test_iterators2<random_access_iterator<int*>, sized_sentinel<random_access_iterator<int*>>>();
+  test_iterators2<contiguous_iterator<int*>>();
+  test_iterators2<contiguous_iterator<int*>, sized_sentinel<contiguous_iterator<int*>>>();
+  test_iterators2<int*>();
+
+  { // check that std::invoke is used
+    struct S {
+      int i;
+
+      constexpr S identity() {
+        return *this;
+      }
+
+      constexpr bool compare(const S& s) {
+        return i == s.i;
+      }
+    };
+    {
+      S a[] = {{1}, {2}, {3}, {4}};
+      S p[] = {{2}, {3}};
+      auto ret = std::ranges::search(a, a + 4, p, p + 2, &S::compare, &S::identity, &S::identity);
+      assert(ret.begin() == a + 1);
+      assert(ret.end() == a + 3);
+    }
+    {
+      S a[] = {{1}, {2}, {3}, {4}};
+      S p[] = {{2}, {3}};
+      auto ret = std::ranges::search(a, p, &S::compare, &S::identity, &S::identity);
+      assert(ret.begin() == a + 1);
+      assert(ret.end() == a + 3);
+    }
+  }
+
+  { // check that std::ranges::dangling is returned
+    [[maybe_unused]] std::same_as<std::ranges::dangling> decltype(auto) ret =
+        std::ranges::search(std::array {1, 2, 3, 4}, std::array {2, 3});
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
--- a/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/ranges.search_n.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.nonmodifying/alg.search/ranges.search_n.pass.cpp
@@ -0,0 +1,298 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// template<forward_iterator I, sentinel_for<I> S, class T,
+//          class Pred = ranges::equal_to, class Proj = identity>
+//   requires indirectly_comparable<I, const T*, Pred, Proj>
+//   constexpr subrange<I>
+//     ranges::search_n(I first, S last, iter_difference_t<I> count,
+//                      const T& value, Pred pred = {}, Proj proj = {});
+// template<forward_range R, class T, class Pred = ranges::equal_to,
+//          class Proj = identity>
+//   requires indirectly_comparable<iterator_t<R>, const T*, Pred, Proj>
+//   constexpr borrowed_subrange_t<R>
+//     ranges::search_n(R&& r, range_difference_t<R> count,
+//                      const T& value, Pred pred = {}, Proj proj = {});
+
+#include <algorithm>
+#include <array>
+#include <ranges>
+
+#include "almost_satisfies_types.h"
+#include "test_iterators.h"
+
+template <class Iter1, class Sent1 = Iter1>
+concept HasSearchNIt = requires (Iter1 first1, Sent1 last1) {
+  std::ranges::search_n(first1, last1, 0, 0);
+};
+
+static_assert(HasSearchNIt<int*>);
+static_assert(!HasSearchNIt<ForwardIteratorNotDerivedFrom>);
+static_assert(!HasSearchNIt<ForwardIteratorNotIncrementable>);
+static_assert(!HasSearchNIt<int*, SentinelForNotSemiregular>);
+static_assert(!HasSearchNIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
+static_assert(!HasSearchNIt<int**, int**>); // not indirectly comparable
+
+template <class Range1, class Range2 = UncheckedRange<int*>>
+concept HasSearchNR = requires (Range1 range) {
+  std::ranges::search_n(range, 0, 0);
+};
+
+static_assert(HasSearchNR<UncheckedRange<int*>>);
+static_assert(!HasSearchNR<ForwardRangeNotDerivedFrom>);
+static_assert(!HasSearchNR<ForwardIteratorNotIncrementable>);
+static_assert(!HasSearchNR<ForwardRangeNotSentinelSemiregular>);
+static_assert(!HasSearchNR<ForwardRangeNotSentinelEqualityComparableWith>);
+static_assert(!HasSearchNR<UncheckedRange<int**>>); // not indirectly comparable
+
+template <class Iter, class Sent = Iter>
+constexpr void test_iterators() {
+  { // simple test
+    {
+      int a[] = {1, 2, 3, 4, 5, 6};
+      std::same_as<std::ranges::subrange<Iter, Iter>> decltype(auto) ret =
+          std::ranges::search_n(Iter(a), Sent(Iter(a + 6)), 1, 3);
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {1, 2, 3, 4, 5, 6};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 6)));
+      std::same_as<std::ranges::subrange<Iter, Iter>> decltype(auto) ret = std::ranges::search_n(range, 1, 3);
+      assert(base(ret.begin()) == a + 2);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // matching part begins at the front
+    {
+      int a[] = {7, 7, 3, 7, 3, 6};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 6)), 2, 7);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 2);
+    }
+    {
+      int a[] = {7, 7, 3, 7, 3, 6};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 6)));
+      auto ret = std::ranges::search_n(range, 2, 7);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 2);
+    }
+  }
+
+  { // matching part ends at the back
+    {
+      int a[] = {9, 3, 6, 4, 4};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 5)), 2, 4);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {9, 3, 6, 4, 4};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 5)));
+      auto ret = std::ranges::search_n(range, 2, 4);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // pattern does not match
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 5)), 1, 1);
+      assert(base(ret.begin()) == a + 5);
+      assert(base(ret.end()) == a + 5);
+    }
+    {
+      int a[] = {9, 3, 6, 4, 8};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 5)));
+      auto ret = std::ranges::search_n(range, 1, 1);
+      assert(base(ret.begin()) == a + 5);
+      assert(base(ret.end()) == a + 5);
+    }
+  }
+
+  { // range and pattern are identical
+    {
+      int a[] = {1, 1, 1, 1};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 4)), 4, 1);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 4);
+    }
+    {
+      int a[] = {1, 1, 1, 1};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 4)));
+      auto ret = std::ranges::search_n(range, 4, 1);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 4);
+    }
+  }
+
+  { // pattern is longer than range
+    {
+      int a[] = {3, 3, 3};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 3)), 4, 3);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {3, 3, 3};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 3)));
+      auto ret = std::ranges::search_n(range, 4, 3);
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // pattern has zero length
+    {
+      int a[] = {6, 7, 8};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 3)), 0, 7);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+    {
+      int a[] = {6, 7, 8};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 3)));
+      auto ret = std::ranges::search_n(range, 0, 7);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+  }
+
+  { // range has zero length
+    {
+      int a[] = {};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a)), 1, 1);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+    {
+      int a[] = {};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a)));
+      auto ret = std::ranges::search_n(range, 1, 1);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a);
+    }
+  }
+
+  { // check that the first match is returned
+    {
+      int a[] = {6, 6, 8, 6, 6, 8, 6, 6, 8};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 9)), 2, 6);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 2);
+    }
+    {
+      int a[] = {6, 6, 8, 6, 6, 8, 6, 6, 8};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 9)));
+      auto ret = std::ranges::search_n(range, 2, 6);
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 2);
+    }
+  }
+
+  { // check that the predicate is used
+    {
+      int a[] = {1, 4, 4, 3, 6, 1};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 6)),
+                                       3,
+                                       4,
+                                       [](int l, int r) { return l == r || l == 1; });
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+    {
+      int a[] = {1, 4, 4, 3, 6, 1};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 6)));
+      auto ret = std::ranges::search_n(range, 3, 4, [](int l, int r) { return l == r || l == 1; });
+      assert(base(ret.begin()) == a);
+      assert(base(ret.end()) == a + 3);
+    }
+  }
+
+  { // check that the projections are used
+    {
+      int a[] = {1, 3, 1, 6, 5, 6};
+      auto ret = std::ranges::search_n(Iter(a), Sent(Iter(a + 6)),
+                                       3,
+                                       6,
+                                       {},
+                                       [](int i) { return i % 2 == 0 ? i : i + 1; });
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 6);
+    }
+    {
+      int a[] = {1, 3, 1, 6, 5, 6};
+      auto range = std::ranges::subrange(Iter(a), Sent(Iter(a + 6)));
+      auto ret = std::ranges::search_n(range,
+                                       3,
+                                       6,
+                                       {},
+                                       [](int i) { return i % 2 == 0 ? i : i + 1; });
+      assert(base(ret.begin()) == a + 3);
+      assert(base(ret.end()) == a + 6);
+    }
+  }
+}
+constexpr bool test() {
+  test_iterators<forward_iterator<int*>>();
+  test_iterators<forward_iterator<int*>, sized_sentinel<forward_iterator<int*>>>();
+  test_iterators<bidirectional_iterator<int*>>();
+  test_iterators<bidirectional_iterator<int*>, sized_sentinel<bidirectional_iterator<int*>>>();
+  test_iterators<random_access_iterator<int*>>();
+  test_iterators<random_access_iterator<int*>, sized_sentinel<random_access_iterator<int*>>>();
+  test_iterators<contiguous_iterator<int*>>();
+  test_iterators<contiguous_iterator<int*>, sized_sentinel<contiguous_iterator<int*>>>();
+  test_iterators<int*>();
+
+  { // check that std::invoke is used
+    struct S {
+      int i;
+
+      constexpr S identity() {
+        return *this;
+      }
+
+      constexpr bool compare(int o) {
+        return i == o;
+      }
+    };
+    {
+      S a[] = {{1}, {2}, {3}, {4}};
+      auto ret = std::ranges::search_n(a, a + 4, 1, 2, &S::compare, &S::identity);
+      assert(ret.begin() == a + 1);
+      assert(ret.end() == a + 2);
+    }
+    {
+      S a[] = {{1}, {2}, {3}, {4}};
+      auto ret = std::ranges::search_n(a, 1, 2, &S::compare, &S::identity);
+      assert(ret.begin() == a + 1);
+      assert(ret.end() == a + 2);
+    }
+  }
+
+  { // check that std::ranges::dangling is returned
+    [[maybe_unused]] std::same_as<std::ranges::dangling> decltype(auto) ret =
+        std::ranges::search_n(std::array {1, 2, 3, 4}, 1, 0);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
--- 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
@@ -78,7 +78,7 @@ static_assert(test(std::ranges::equal, a, a));
 static_assert(test(std::ranges::fill, a, 42));
 static_assert(test(std::ranges::fill_n, a, 10, 42));
 static_assert(test(std::ranges::find, a, 42));
-//static_assert(test(std::ranges::find_end, a, a));
+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));
@@ -131,8 +131,8 @@ static_assert(test(std::ranges::reverse_copy, a, a));
 //static_assert(test(std::ranges::rotate, a, a+5));
 static_assert(test(std::ranges::rotate_copy, a, a+5, a));
 //static_assert(test(std::ranges::sample, a, a, 5));
-//static_assert(test(std::ranges::search, a, a));
-//static_assert(test(std::ranges::search_n, a, 10, 42));
+static_assert(test(std::ranges::search, a, a));
+static_assert(test(std::ranges::search_n, a, 10, 42));
 static_assert(test(std::ranges::set_difference, a, a, a));
 static_assert(test(std::ranges::set_intersection, a, a, a));
 //static_assert(test(std::ranges::set_symmetric_difference, a, a, a));