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

This reverts commit 76a76518507ccc59ccdad5b83f44dc8c3d9593c7.

15 files changed, 155 insertions, 806 deletions

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 05c7c7b6bbcc..5af1f9439301 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -83,7 +83,6 @@ 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
@@ -130,8 +129,6 @@ 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
diff --git a/libcxx/include/__algorithm/find_end.h b/libcxx/include/__algorithm/find_end.h
index 755b643c1180..0220c0939711 100644
--- a/libcxx/include/__algorithm/find_end.h
+++ b/libcxx/include/__algorithm/find_end.h
@@ -11,16 +11,8 @@
 #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
@@ -28,52 +20,35 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <
-    class _IterOps,
-    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) {
+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) {
   // modeled after search algorithm
-  _Iter1 __match_first = _IterOps::next(__first1, __last1); // __last1 is the "default" answer
-  _Iter1 __match_last = __match_first;
+  _ForwardIterator1 __r = __last1; // __last1 is the "default" answer
   if (__first2 == __last2)
-    return pair<_Iter1, _Iter1>(__match_last, __match_last);
+    return __r;
   while (true) {
     while (true) {
-      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)))
+      if (__first1 == __last1) // if source exhausted return last correct answer
+        return __r;            //    (or __last1 if never found)
+      if (__pred(*__first1, *__first2))
         break;
       ++__first1;
     }
     // *__first1 matches *__first2, now match elements after here
-    _Iter1 __m1 = __first1;
-    _Iter2 __m2 = __first2;
+    _ForwardIterator1 __m1 = __first1;
+    _ForwardIterator2 __m2 = __first2;
     while (true) {
       if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one
-        __match_first = __first1;
-        __match_last = ++__m1;
+        __r = __first1;
         ++__first1;
         break;
       }
       if (++__m1 == __last1) // Source exhausted, return last answer
-        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)))
+        return __r;
+      if (!__pred(*__m1, *__m2)) // mismatch, restart with a new __first
       {
         ++__first1;
         break;
@@ -82,52 +57,33 @@ _LIBCPP_HIDE_FROM_ABI inline _LIBCPP_CONSTEXPR_AFTER_CXX11 pair<_Iter1, _Iter1>
   }
 }
 
-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);
+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) {
   // modeled after search algorithm (in reverse)
   if (__first2 == __last2)
     return __last1; // Everything matches an empty sequence
-  _Iter1 __l1 = __last1;
-  _Iter2 __l2 = __last2;
+  _BidirectionalIterator1 __l1 = __last1;
+  _BidirectionalIterator2 __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 (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
+      if (__pred(*--__l1, *__l2))
         break;
     }
     // *__l1 matches *__l2, now match elements before here
-    _Iter1 __m1 = __l1;
-    _Iter2 __m2 = __l2;
+    _BidirectionalIterator1 __m1 = __l1;
+    _BidirectionalIterator2 __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 there is a mismatch, restart with a new __l1
-      if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(__proj2, *--__m2)))
+      if (!__pred(*--__m1, *--__m2)) // if there is a mismatch, restart with a new __l1
       {
         break;
       } // else there is a match, check next elements
@@ -135,53 +91,37 @@ _LIBCPP_CONSTEXPR_AFTER_CXX17 _Iter1 __find_end(
   }
 }
 
-template <
-    class _IterOps,
-    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::next(__first1, __sent1);
-  auto __last2 = _IterOps::next(__first2, __sent2);
+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;
   // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
-  auto __len2 = __last2 - __first2;
+  _D2 __len2 = __last2 - __first2;
   if (__len2 == 0)
     return __last1;
-  auto __len1 = __last1 - __first1;
+  _D1 __len1 = __last1 - __first1;
   if (__len1 < __len2)
     return __last1;
-  const _Iter1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here
-  _Iter1 __l1 = __last1;
-  _Iter2 __l2 = __last2;
+  const _RandomAccessIterator1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here
+  _RandomAccessIterator1 __l1 = __last1;
+  _RandomAccessIterator2 __l2 = __last2;
   --__l2;
   while (true) {
     while (true) {
       if (__s == __l1)
         return __last1;
-      if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
+      if (__pred(*--__l1, *__l2))
         break;
     }
-    _Iter1 __m1 = __l1;
-    _Iter2 __m2 = __l2;
+    _RandomAccessIterator1 __m1 = __l1;
+    _RandomAccessIterator2 __m2 = __l2;
     while (true) {
       if (__m2 == __first2)
         return __m1;
       // no need to check range on __m1 because __s guarantees we have enough source
-      if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(*--__m2))) {
+      if (!__pred(*--__m1, *--__m2)) {
         break;
       }
     }
@@ -189,39 +129,20 @@ _LIBCPP_CONSTEXPR_AFTER_CXX11 _Iter1 __find_end(
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
-_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<_StdIterOps>(
-             __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);
+_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());
 }
 
 template <class _ForwardIterator1, class _ForwardIterator2>
-_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_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_END_NAMESPACE_STD
diff --git a/libcxx/include/__algorithm/iterator_operations.h b/libcxx/include/__algorithm/iterator_operations.h
index 4c4f406efe81..bccac368f302 100644
--- a/libcxx/include/__algorithm/iterator_operations.h
+++ b/libcxx/include/__algorithm/iterator_operations.h
@@ -39,7 +39,6 @@ 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
 
diff --git a/libcxx/include/__algorithm/ranges_find_end.h b/libcxx/include/__algorithm/ranges_find_end.h
deleted file mode 100644
index 5c301b35abbd..000000000000
--- a/libcxx/include/__algorithm/ranges_find_end.h
+++ /dev/null
@@ -1,113 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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<_RangesIterOps>(
-        __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<_RangesIterOps>(
-        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
diff --git a/libcxx/include/__algorithm/ranges_search.h b/libcxx/include/__algorithm/ranges_search.h
deleted file mode 100644
index a7b7695d280f..000000000000
--- a/libcxx/include/__algorithm/ranges_search.h
+++ /dev/null
@@ -1,134 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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<_RangesIterOps>(
-              __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
-          return {__ret.first, __ret.second};
-        }
-      }
-    }
-
-    auto __ret =
-        std::__search_forward_impl<_RangesIterOps>(__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
diff --git a/libcxx/include/__algorithm/ranges_search_n.h b/libcxx/include/__algorithm/ranges_search_n.h
deleted file mode 100644
index d7178ca415b1..000000000000
--- a/libcxx/include/__algorithm/ranges_search_n.h
+++ /dev/null
@@ -1,120 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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<_RangesIterOps>(__first, __last,
-                                                                   __count,
-                                                                   __value,
-                                                                   __pred,
-                                                                   __proj,
-                                                                   __size);
-        return {std::move(__ret.first), std::move(__ret.second)};
-      }
-    }
-
-    auto __ret = std::__search_n_forward_impl<_RangesIterOps>(__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
diff --git a/libcxx/include/__algorithm/search.h b/libcxx/include/__algorithm/search.h
index b5c4820e5daa..d89ec2b1c5bc 100644
--- a/libcxx/include/__algorithm/search.h
+++ b/libcxx/include/__algorithm/search.h
@@ -11,15 +11,9 @@
 #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
@@ -27,43 +21,31 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _IterOps,
-          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) {
+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) {
   if (__first2 == __last2)
-    return std::make_pair(__first1, __first1); // Everything matches an empty sequence
+    return _VSTD::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
-        _IterOps::__advance_to(__first1, __last1);
-        return std::make_pair(__first1, __first1);
-      }
-      if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+      if (__first1 == __last1) // return __last1 if no element matches *__first2
+        return _VSTD::make_pair(__last1, __last1);
+      if (__pred(*__first1, *__first2))
         break;
       ++__first1;
     }
     // *__first1 matches *__first2, now match elements after here
-    _Iter1 __m1 = __first1;
-    _Iter2 __m2 = __first2;
+    _ForwardIterator1 __m1 = __first1;
+    _ForwardIterator2 __m2 = __first2;
     while (true) {
       if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
-        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)))
+        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
       {
         ++__first1;
         break;
@@ -72,42 +54,38 @@ pair<_Iter1, _Iter1> __search_forward_impl(_Iter1 __first1, _Sent1 __last1,
   }
 }
 
-template <class _IterOps,
-          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
+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
 
   while (true) {
     while (true) {
-      if (__first1 == __s) {
-        _IterOps::__advance_to(__first1, __last1);
-        return std::make_pair(__first1, __first1);
-      }
-      if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+      if (__first1 == __s)
+        return _VSTD::make_pair(__last1, __last1);
+      if (__pred(*__first1, *__first2))
         break;
       ++__first1;
     }
 
-    _Iter1 __m1 = __first1;
-    _Iter2 __m2 = __first2;
+    _RandomAccessIterator1 __m1 = __first1;
+    _RandomAccessIterator2 __m2 = __first2;
     while (true) {
       if (++__m2 == __last2)
-        return std::make_pair(__first1, __first1 + _DiffT1(__size2));
+        return _VSTD::make_pair(__first1, __first1 + _D1(__len2));
       ++__m1; // no need to check range on __m1 because __s guarantees we have enough source
-      if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
+      if (!__pred(*__m1, *__m2)) {
         ++__first1;
         break;
       }
@@ -115,78 +93,22 @@ pair<_Iter1, _Iter1> __search_random_access_impl(_Iter1 __first1, _Sent1 __last1
   }
 }
 
-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<_StdIterOps>(__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<_StdIterOps>(__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) {
-  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;
+_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;
 }
 
 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) {
-  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>());
+_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>());
 }
 
 #if _LIBCPP_STD_VER > 14
diff --git a/libcxx/include/__algorithm/search_n.h b/libcxx/include/__algorithm/search_n.h
index 2a9285f4efe5..c51701415bdc 100644
--- a/libcxx/include/__algorithm/search_n.h
+++ b/libcxx/include/__algorithm/search_n.h
@@ -11,15 +11,8 @@
 #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)
@@ -28,39 +21,30 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _IterOps, 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) {
+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) {
   if (__count <= 0)
-    return std::make_pair(__first, __first);
+    return __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
-        _IterOps::__advance_to(__first, __last);
-        return std::make_pair(__first, __first);
-      }
-      if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value))
+      if (__first == __last) // return __last if no element matches __value_
+        return __last;
+      if (__pred(*__first, __value))
         break;
       ++__first;
     }
-    // *__first matches __value, now match elements after here
-    _Iter __m = __first;
-    _SizeT __c(0);
+    // *__first matches __value_, now match elements after here
+    _ForwardIterator __m = __first;
+    _Size __c(0);
     while (true) {
       if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
-        return std::make_pair(__first, ++__m);
-      if (++__m == __last) { // Otherwise if source exhaused, pattern not found
-        _IterOps::__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))
+        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
       {
         __first = __m;
         ++__first;
@@ -70,44 +54,35 @@ pair<_Iter, _Iter> __search_n_forward_impl(_Iter __first, _Sent __last,
   }
 }
 
-template <class _IterOps, 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::__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
+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
   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
-        _IterOps::__advance_to(__first, __last);
-        return std::make_pair(__first, __first);
-      }
-      if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value))
+      if (__first >= __s) // return __last if no element matches __value_
+        return __last;
+      if (__pred(*__first, __value))
         break;
       ++__first;
     }
     // *__first matches __value_, now match elements after here
-    auto __m = __first;
-    _SizeT __c(0);
+    _RandomAccessIterator __m = __first;
+    _Size __c(0);
     while (true) {
       if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
-        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))
+        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
       {
         __first = __m;
         ++__first;
@@ -117,63 +92,19 @@ std::pair<_Iter, _Iter> __search_n_random_access_impl(_Iter __first, _Sent __las
   }
 }
 
-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<_StdIterOps>(__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<_StdIterOps>(__first, __last,
-                                                   __count,
-                                                   __value,
-                                                   __pred,
-                                                   __proj);
-}
-
 template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
-_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;
+_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());
 }
 
 template <class _ForwardIterator, class _Size, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
-_ForwardIterator search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value) {
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _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 std::search_n(__first, __last, std::__convert_to_integral(__count), __value, __equal_to<__v, _Tp>());
+  return _VSTD::search_n(__first, __last, _VSTD::__convert_to_integral(__count), __value, __equal_to<__v, _Tp>());
 }
 
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/__algorithm/set_intersection.h b/libcxx/include/__algorithm/set_intersection.h
index e0f5bd140be7..650705703219 100644
--- a/libcxx/include/__algorithm/set_intersection.h
+++ b/libcxx/include/__algorithm/set_intersection.h
@@ -14,7 +14,6 @@
 #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)
diff --git a/libcxx/include/__functional/default_searcher.h b/libcxx/include/__functional/default_searcher.h
index 8e37082b6bed..05fb23d7c3c4 100644
--- a/libcxx/include/__functional/default_searcher.h
+++ b/libcxx/include/__functional/default_searcher.h
@@ -12,7 +12,6 @@
 
 #include <__algorithm/search.h>
 #include <__config>
-#include <__functional/identity.h>
 #include <__functional/operations.h>
 #include <__iterator/iterator_traits.h>
 #include <__utility/pair.h>
@@ -39,15 +38,16 @@ public:
     pair<_ForwardIterator2, _ForwardIterator2>
     operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
     {
-        auto __proj = __identity();
-        return std::__search_impl(__f, __l, __first_, __last_, __pred_, __proj, __proj);
+        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
+            typename iterator_traits<_ForwardIterator>::iterator_category(),
+            typename iterator_traits<_ForwardIterator2>::iterator_category());
     }
 
 private:
     _ForwardIterator __first_;
     _ForwardIterator __last_;
     _BinaryPredicate __pred_;
-};
+    };
 
 #endif // _LIBCPP_STD_VER > 14
 
diff --git a/libcxx/include/__iterator/iterator_traits.h b/libcxx/include/__iterator/iterator_traits.h
index 63525e230add..1fbdc955d148 100644
--- a/libcxx/include/__iterator/iterator_traits.h
+++ b/libcxx/include/__iterator/iterator_traits.h
@@ -481,12 +481,6 @@ 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;
 
diff --git a/libcxx/include/__string/char_traits.h b/libcxx/include/__string/char_traits.h
index 18ad67b28e16..457a771b94cf 100644
--- a/libcxx/include/__string/char_traits.h
+++ b/libcxx/include/__string/char_traits.h
@@ -802,7 +802,9 @@ __str_rfind(const _CharT *__p, _SizeT __sz,
         __pos += __n;
     else
         __pos = __sz;
-    const _CharT* __r = std::__find_end_classic(__p, __p + __pos, __s, __s + __n, _Traits::eq);
+    const _CharT* __r = _VSTD::__find_end(
+                  __p, __p + __pos, __s, __s + __n, _Traits::eq,
+                        random_access_iterator_tag(), random_access_iterator_tag());
     if (__n > 0 && __r == __p + __pos)
         return __npos;
     return static_cast<_SizeT>(__r - __p);
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 18d8ef3805e5..387aebe78e6c 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -649,49 +649,6 @@ 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
@@ -1435,7 +1392,6 @@ 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>
@@ -1468,8 +1424,6 @@ 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>
diff --git a/libcxx/include/experimental/functional b/libcxx/include/experimental/functional
index 12440744ca50..04f195d3cf24 100644
--- a/libcxx/include/experimental/functional
+++ b/libcxx/include/experimental/functional
@@ -62,7 +62,6 @@ 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>
@@ -105,8 +104,9 @@ public:
     pair<_ForwardIterator2, _ForwardIterator2>
     operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
     {
-        auto __proj = __identity();
-        return std::__search_impl(__f, __l, __first_, __last_, __pred_, __proj, __proj);
+        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
+            typename iterator_traits<_ForwardIterator>::iterator_category(),
+            typename iterator_traits<_ForwardIterator2>::iterator_category());
     }
 
 private:
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index c0ecfac991fd..8efeb1fc4926 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -322,7 +322,6 @@ 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" }
@@ -369,8 +368,6 @@ 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" }