diff --git a/libcxx/benchmarks/CMakeLists.txt b/libcxx/benchmarks/CMakeLists.txt
--- a/libcxx/benchmarks/CMakeLists.txt
+++ b/libcxx/benchmarks/CMakeLists.txt
@@ -176,6 +176,7 @@
     algorithms/stable_sort.bench.cpp
     allocation.bench.cpp
     deque.bench.cpp
+    deque_iterator.bench.cpp
     filesystem.bench.cpp
     format_to_n.bench.cpp
     format_to.bench.cpp
diff --git a/libcxx/benchmarks/deque_iterator.bench.cpp b/libcxx/benchmarks/deque_iterator.bench.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/benchmarks/deque_iterator.bench.cpp
@@ -0,0 +1,232 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include <algorithm>
+#include <deque>
+
+#include "benchmark/benchmark.h"
+
+namespace {
+void run_sizes(auto benchmark) {
+  benchmark->Arg(0)
+      ->Arg(1)
+      ->Arg(2)
+      ->Arg(64)
+      ->Arg(512)
+      ->Arg(1024)
+      ->Arg(4000)
+      ->Arg(4096)
+      ->Arg(5500)
+      ->Arg(64000)
+      ->Arg(65536)
+      ->Arg(70000);
+}
+
+template <class FromContainer, class ToContainer, class Func>
+void benchmark_containers(benchmark::State& state, FromContainer& d, ToContainer& v, Func&& func) {
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(v);
+    benchmark::DoNotOptimize(d);
+    func(d.begin(), d.end(), v.begin());
+  }
+}
+
+template <class Func>
+void benchmark_deque_vector(benchmark::State& state, Func&& func) {
+  auto size = state.range(0);
+  std::deque<int> d;
+  d.resize(size);
+  std::ranges::fill(d, 10);
+  std::vector<int> v;
+  v.resize(size);
+  benchmark_containers(state, d, v, func);
+}
+
+template <class Func>
+void benchmark_deque_deque(benchmark::State& state, Func&& func) {
+  auto size = state.range(0);
+  std::deque<int> d;
+  d.resize(size);
+  std::ranges::fill(d, 10);
+  std::deque<int> v;
+  v.resize(size);
+  benchmark_containers(state, d, v, func);
+}
+
+template <class Func>
+void benchmark_vector_deque(benchmark::State& state, Func&& func) {
+  auto size = state.range(0);
+  std::vector<int> d;
+  d.resize(size);
+  std::ranges::fill(d, 10);
+  std::deque<int> v;
+  v.resize(size);
+  benchmark_containers(state, d, v, func);
+}
+
+template <class FromContainer, class ToContainer, class Func>
+void benchmark_containers_backward(benchmark::State& state, FromContainer& d, ToContainer& v, Func&& func) {
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(v);
+    benchmark::DoNotOptimize(d);
+    func(d.begin(), d.end(), v.end());
+  }
+}
+
+template <class Func>
+void benchmark_deque_vector_backward(benchmark::State& state, Func&& func) {
+  auto size = state.range(0);
+  std::deque<int> d;
+  d.resize(size);
+  std::ranges::fill(d, 10);
+  std::vector<int> v;
+  v.resize(size);
+  benchmark_containers_backward(state, d, v, func);
+}
+
+template <class Func>
+void benchmark_deque_deque_backward(benchmark::State& state, Func&& func) {
+  auto size = state.range(0);
+  std::deque<int> d;
+  d.resize(size);
+  std::ranges::fill(d, 10);
+  std::deque<int> v;
+  v.resize(size);
+  benchmark_containers_backward(state, d, v, func);
+}
+
+template <class Func>
+void benchmark_vector_deque_backward(benchmark::State& state, Func&& func) {
+  auto size = state.range(0);
+  std::vector<int> d;
+  d.resize(size);
+  std::ranges::fill(d, 10);
+  std::deque<int> v;
+  v.resize(size);
+  benchmark_containers_backward(state, d, v, func);
+}
+
+struct CopyFunctor {
+  template <class... Args>
+  auto operator()(Args... args) const {
+    std::copy(std::forward<Args>(args)...);
+  }
+} copy;
+
+struct MoveFunctor {
+  template <class... Args>
+  auto operator()(Args... args) const {
+    std::move(std::forward<Args>(args)...);
+  }
+} move;
+
+struct CopyBackwardFunctor {
+  template <class... Args>
+  auto operator()(Args... args) const {
+    std::copy_backward(std::forward<Args>(args)...);
+  }
+} copy_backward;
+
+struct MoveBackwardFunctor {
+  template <class... Args>
+  auto operator()(Args... args) const {
+    std::move_backward(std::forward<Args>(args)...);
+  }
+} move_backward;
+
+// copy
+void BM_deque_vector_copy(benchmark::State& state) { benchmark_deque_vector(state, copy); }
+BENCHMARK(BM_deque_vector_copy)->Apply(run_sizes);
+
+void BM_deque_vector_ranges_copy(benchmark::State& state) { benchmark_deque_vector(state, std::ranges::copy); }
+BENCHMARK(BM_deque_vector_ranges_copy)->Apply(run_sizes);
+
+void BM_deque_deque_copy(benchmark::State& state) { benchmark_deque_deque(state, copy); }
+BENCHMARK(BM_deque_deque_copy)->Apply(run_sizes);
+
+void BM_deque_deque_ranges_copy(benchmark::State& state) { benchmark_deque_deque(state, std::ranges::copy); }
+BENCHMARK(BM_deque_deque_ranges_copy)->Apply(run_sizes);
+
+void BM_vector_deque_copy(benchmark::State& state) { benchmark_vector_deque(state, copy); }
+BENCHMARK(BM_vector_deque_copy)->Apply(run_sizes);
+
+void BM_vector_deque_ranges_copy(benchmark::State& state) { benchmark_vector_deque(state, std::ranges::copy); }
+BENCHMARK(BM_vector_deque_ranges_copy)->Apply(run_sizes);
+
+// move
+void BM_deque_vector_move(benchmark::State& state) { benchmark_deque_vector(state, move); }
+BENCHMARK(BM_deque_vector_move)->Apply(run_sizes);
+
+void BM_deque_vector_ranges_move(benchmark::State& state) { benchmark_deque_vector(state, std::ranges::move); }
+BENCHMARK(BM_deque_vector_ranges_move)->Apply(run_sizes);
+
+void BM_deque_deque_move(benchmark::State& state) { benchmark_deque_deque(state, move); }
+BENCHMARK(BM_deque_deque_move)->Apply(run_sizes);
+
+void BM_deque_deque_ranges_move(benchmark::State& state) { benchmark_deque_deque(state, std::ranges::move); }
+BENCHMARK(BM_deque_deque_ranges_move)->Apply(run_sizes);
+
+void BM_vector_deque_move(benchmark::State& state) { benchmark_vector_deque(state, move); }
+BENCHMARK(BM_vector_deque_move)->Apply(run_sizes);
+
+void BM_vector_deque_ranges_move(benchmark::State& state) { benchmark_vector_deque(state, std::ranges::move); }
+BENCHMARK(BM_vector_deque_ranges_move)->Apply(run_sizes);
+
+// copy_backward
+void BM_deque_vector_copy_backward(benchmark::State& state) { benchmark_deque_vector_backward(state, copy_backward); }
+BENCHMARK(BM_deque_vector_copy_backward)->Apply(run_sizes);
+
+void BM_deque_vector_ranges_copy_backward(benchmark::State& state) {
+  benchmark_deque_vector_backward(state, std::ranges::copy_backward);
+}
+BENCHMARK(BM_deque_vector_ranges_copy_backward)->Apply(run_sizes);
+
+void BM_deque_deque_copy_backward(benchmark::State& state) { benchmark_deque_deque_backward(state, copy_backward); }
+BENCHMARK(BM_deque_deque_copy_backward)->Apply(run_sizes);
+
+void BM_deque_deque_ranges_copy_backward(benchmark::State& state) {
+  benchmark_deque_deque_backward(state, std::ranges::copy_backward);
+}
+BENCHMARK(BM_deque_deque_ranges_copy_backward)->Apply(run_sizes);
+
+void BM_vector_deque_copy_backward(benchmark::State& state) { benchmark_vector_deque_backward(state, copy_backward); }
+BENCHMARK(BM_vector_deque_copy_backward)->Apply(run_sizes);
+
+void BM_vector_deque_ranges_copy_backward(benchmark::State& state) {
+  benchmark_vector_deque_backward(state, std::ranges::copy_backward);
+}
+BENCHMARK(BM_vector_deque_ranges_copy_backward)->Apply(run_sizes);
+
+// move_backward
+void BM_deque_vector_move_backward(benchmark::State& state) { benchmark_deque_vector_backward(state, move_backward); }
+BENCHMARK(BM_deque_vector_move_backward)->Apply(run_sizes);
+
+void BM_deque_vector_ranges_move_backward(benchmark::State& state) {
+  benchmark_deque_vector_backward(state, std::ranges::move_backward);
+}
+BENCHMARK(BM_deque_vector_ranges_move_backward)->Apply(run_sizes);
+
+void BM_deque_deque_move_backward(benchmark::State& state) { benchmark_deque_deque_backward(state, move_backward); }
+BENCHMARK(BM_deque_deque_move_backward)->Apply(run_sizes);
+
+void BM_deque_deque_ranges_move_backward(benchmark::State& state) {
+  benchmark_deque_deque_backward(state, std::ranges::move_backward);
+}
+BENCHMARK(BM_deque_deque_ranges_move_backward)->Apply(run_sizes);
+
+void BM_vector_deque_move_backward(benchmark::State& state) { benchmark_vector_deque_backward(state, move_backward); }
+BENCHMARK(BM_vector_deque_move_backward)->Apply(run_sizes);
+
+void BM_vector_deque_ranges_move_backward(benchmark::State& state) {
+  benchmark_vector_deque_backward(state, std::ranges::move_backward);
+}
+BENCHMARK(BM_vector_deque_ranges_move_backward)->Apply(run_sizes);
+
+} // namespace
+
+BENCHMARK_MAIN();
diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -47,6 +47,8 @@
 - Declarations of ``std::c8rtomb()`` and ``std::mbrtoc8()`` from P0482R6 are
   now provided when implementations in the global namespace are provided by
   the C library.
+- The ``ranges`` versinos of ``copy``, ``move``, ``copy_backward`` and ``move_backward`` are now also optimized for
+  ``std::deque<>::iterator``.
 
 Deprecations and Removals
 -------------------------
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -9,6 +9,7 @@
   __algorithm/copy.h
   __algorithm/copy_backward.h
   __algorithm/copy_if.h
+  __algorithm/copy_move_common.h
   __algorithm/copy_n.h
   __algorithm/count.h
   __algorithm/count_if.h
@@ -381,6 +382,7 @@
   __iterator/readable_traits.h
   __iterator/reverse_access.h
   __iterator/reverse_iterator.h
+  __iterator/segmented_iterator.h
   __iterator/size.h
   __iterator/sortable.h
   __iterator/unreachable_sentinel.h
diff --git a/libcxx/include/__algorithm/copy.h b/libcxx/include/__algorithm/copy.h
--- a/libcxx/include/__algorithm/copy.h
+++ b/libcxx/include/__algorithm/copy.h
@@ -9,100 +9,116 @@
 #ifndef _LIBCPP___ALGORITHM_COPY_H
 #define _LIBCPP___ALGORITHM_COPY_H
 
-#include <__algorithm/unwrap_iter.h>
-#include <__algorithm/unwrap_range.h>
+#include <__algorithm/copy_move_common.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
 #include <__config>
-#include <__iterator/iterator_traits.h>
-#include <__iterator/reverse_iterator.h>
+#include <__iterator/segmented_iterator.h>
 #include <__utility/move.h>
 #include <__utility/pair.h>
-#include <cstring>
-#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-// copy
+template <class, class _InIter, class _Sent, class _OutIter>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
+
+template <class _AlgPolicy>
+struct __copy_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    while (__first != __last) {
+      *__result = *__first;
+      ++__first;
+      ++__result;
+    }
 
-template <class _InIter, class _Sent, class _OutIter>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-pair<_InIter, _OutIter> __copy_impl(_InIter __first, _Sent __last, _OutIter __result) {
-  while (__first != __last) {
-    *__result = *__first;
-    ++__first;
-    ++__result;
+    return std::make_pair(std::move(__first), std::move(__result));
   }
-  return pair<_InIter, _OutIter>(std::move(__first), std::move(__result));
-}
 
-template <class _InValueT,
-          class _OutValueT,
-          class = __enable_if_t<is_same<__remove_const_t<_InValueT>, _OutValueT>::value
-                             && is_trivially_copy_assignable<_OutValueT>::value> >
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-pair<_InValueT*, _OutValueT*> __copy_impl(_InValueT* __first, _InValueT* __last, _OutValueT* __result) {
-  if (__libcpp_is_constant_evaluated()
-// TODO: Remove this once GCC supports __builtin_memmove during constant evaluation
-#ifndef _LIBCPP_COMPILER_GCC
-      && !is_trivially_copyable<_InValueT>::value
-#endif
-     )
-    return std::__copy_impl<_InValueT*, _InValueT*, _OutValueT*>(__first, __last, __result);
-  const size_t __n = static_cast<size_t>(__last - __first);
-  if (__n > 0)
-    ::__builtin_memmove(__result, __first, __n * sizeof(_OutValueT));
-  return std::make_pair(__first + __n, __result + __n);
-}
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+    auto __sfirst = _Traits::__segment(__first);
+    auto __slast  = _Traits::__segment(__last);
+    if (__sfirst == __slast) {
+      auto __iters = std::__copy<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
+      return std::make_pair(__last, std::move(__iters.second));
+    }
 
-template <class _InIter, class _OutIter,
-          __enable_if_t<is_same<__remove_const_t<__iter_value_type<_InIter> >, __iter_value_type<_OutIter> >::value
-                      && __is_cpp17_contiguous_iterator<typename _InIter::iterator_type>::value
-                      && __is_cpp17_contiguous_iterator<typename _OutIter::iterator_type>::value
-                      && is_trivially_copy_assignable<__iter_value_type<_OutIter> >::value
-                      && __is_reverse_iterator<_InIter>::value
-                      && __is_reverse_iterator<_OutIter>::value, int> = 0>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-pair<_InIter, _OutIter>
-__copy_impl(_InIter __first, _InIter __last, _OutIter __result) {
-  auto __first_base = std::__unwrap_iter(__first.base());
-  auto __last_base = std::__unwrap_iter(__last.base());
-  auto __result_base = std::__unwrap_iter(__result.base());
-  auto __result_first = __result_base - (__first_base - __last_base);
-  std::__copy_impl(__last_base, __first_base, __result_first);
-  return std::make_pair(__last, _OutIter(std::__rewrap_iter(__result.base(), __result_first)));
-}
+    __result = std::__copy<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__sfirst), std::move(__result)).second;
+    ++__sfirst;
+    while (__sfirst != __slast) {
+      __result =
+          std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__end(__sfirst), std::move(__result)).second;
+      ++__sfirst;
+    }
+    __result =
+        std::__copy<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__local(__last), std::move(__result)).second;
+    return std::make_pair(__last, std::move(__result));
+  }
 
-template <class _InIter, class _Sent, class _OutIter,
-          __enable_if_t<!(is_copy_constructible<_InIter>::value
-                       && is_copy_constructible<_Sent>::value
-                       && is_copy_constructible<_OutIter>::value), int> = 0 >
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-pair<_InIter, _OutIter> __copy(_InIter __first, _Sent __last, _OutIter __result) {
-  return std::__copy_impl(std::move(__first), std::move(__last), std::move(__result));
-}
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits = __segmented_iterator_traits<_OutIter>;
+    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter>>::type;
 
-template <class _InIter, class _Sent, class _OutIter,
-          __enable_if_t<is_copy_constructible<_InIter>::value
-                     && is_copy_constructible<_Sent>::value
-                     && is_copy_constructible<_OutIter>::value, int> = 0>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-pair<_InIter, _OutIter> __copy(_InIter __first, _Sent __last, _OutIter __result) {
-  auto __range = std::__unwrap_range(__first, __last);
-  auto __ret   = std::__copy_impl(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__result));
-  return std::make_pair(
-      std::__rewrap_range<_Sent>(__first, __ret.first), std::__rewrap_iter(__result, __ret.second));
+    if (__first == __last)
+      return std::make_pair(std::move(__first), std::move(__result));
+
+    auto __local_first      = _Traits::__local(__result);
+    auto __segment_iterator = _Traits::__segment(__result);
+    while (true) {
+      auto __local_last = _Traits::__end(__segment_iterator);
+      auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iters      = std::__copy<_AlgPolicy>(__first, __first + __size, __local_first);
+      __first           = std::move(__iters.first);
+
+      if (__first == __last)
+        return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
+
+      __local_first = _Traits::__begin(++__segment_iterator);
+    }
+  }
+};
+
+struct __copy_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out, __enable_if_t< is_trivially_assignable<_Out&, _In&>::value, int > = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
+pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+__copy(_InIter __first, _Sent __last, _OutIter __result) {
+  return std::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
 }
 
 template <class _InputIterator, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-_OutputIterator
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
 copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
-  return std::__copy(__first, __last, __result).second;
+  return std::__copy<_ClassicAlgPolicy>(__first, __last, __result).second;
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_COPY_H
diff --git a/libcxx/include/__algorithm/copy_backward.h b/libcxx/include/__algorithm/copy_backward.h
--- a/libcxx/include/__algorithm/copy_backward.h
+++ b/libcxx/include/__algorithm/copy_backward.h
@@ -9,54 +9,132 @@
 #ifndef _LIBCPP___ALGORITHM_COPY_BACKWARD_H
 #define _LIBCPP___ALGORITHM_COPY_BACKWARD_H
 
-#include <__algorithm/copy.h>
+#include <__algorithm/copy_move_common.h>
 #include <__algorithm/iterator_operations.h>
-#include <__algorithm/ranges_copy.h>
-#include <__algorithm/unwrap_iter.h>
-#include <__concepts/same_as.h>
+#include <__algorithm/min.h>
 #include <__config>
-#include <__iterator/iterator_traits.h>
-#include <__iterator/reverse_iterator.h>
-#include <__ranges/subrange.h>
+#include <__iterator/segmented_iterator.h>
 #include <__utility/move.h>
 #include <__utility/pair.h>
-#include <cstring>
-#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _AlgPolicy, class _InputIterator, class _OutputIterator,
-          __enable_if_t<is_same<_AlgPolicy, _ClassicAlgPolicy>::value, int> = 0>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InputIterator, _OutputIterator>
-__copy_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
-  auto __ret = std::__copy(
-      __unconstrained_reverse_iterator<_InputIterator>(__last),
-      __unconstrained_reverse_iterator<_InputIterator>(__first),
-      __unconstrained_reverse_iterator<_OutputIterator>(__result));
-  return pair<_InputIterator, _OutputIterator>(__ret.first.base(), __ret.second.base());
-}
+template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InIter, _OutIter>
+__copy_backward(_InIter __first, _Sent __last, _OutIter __result);
+
+template <class _AlgPolicy>
+struct __copy_backward_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    auto __last_iter          = _IterOps<_AlgPolicy>::next(__first, __last);
+    auto __original_last_iter = __last_iter;
+
+    while (__first != __last_iter) {
+      *--__result = *--__last_iter;
+    }
+
+    return std::make_pair(std::move(__original_last_iter), std::move(__result));
+  }
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+    auto __sfirst = _Traits::__segment(__first);
+    auto __slast  = _Traits::__segment(__last);
+    if (__sfirst == __slast) {
+      auto __iters =
+          std::__copy_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
+      return std::make_pair(__last, __iters.second);
+    }
+
+    __result =
+        std::__copy_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__local(__last), std::move(__result))
+            .second;
+    --__slast;
+    while (__sfirst != __slast) {
+      __result =
+          std::__copy_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__end(__slast), std::move(__result))
+              .second;
+      --__slast;
+    }
+    __result = std::__copy_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__slast), std::move(__result))
+                   .second;
+    return std::make_pair(__last, std::move(__result));
+  }
+
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits           = __segmented_iterator_traits<_OutIter>;
+    auto __orig_last        = __last;
+    auto __segment_iterator = _Traits::__segment(__result);
 
-#if _LIBCPP_STD_VER > 17
-template <class _AlgPolicy, class _Iter1, class _Sent1, class _Iter2,
-          __enable_if_t<is_same<_AlgPolicy, _RangeAlgPolicy>::value, int> = 0>
-_LIBCPP_HIDE_FROM_ABI constexpr pair<_Iter1, _Iter2> __copy_backward(_Iter1 __first, _Sent1 __last, _Iter2 __result) {
-  auto __last_iter     = _IterOps<_AlgPolicy>::next(__first, std::move(__last));
-  auto __reverse_range = std::__reverse_range(std::ranges::subrange(std::move(__first), __last_iter));
-  auto __ret           = ranges::copy(std::move(__reverse_range), std::make_reverse_iterator(__result));
-  return std::make_pair(__last_iter, __ret.out.base());
+    // When the range contains no elements __result might not be a vaid iterator
+    if (__first == __last)
+      return std::make_pair(__first, __result);
+
+    auto __local_last = _Traits::__local(__result);
+    while (true) {
+      using _DiffT = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
+
+      auto __local_first = _Traits::__begin(__segment_iterator);
+      auto __size        = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iter        = std::__copy_backward<_AlgPolicy>(__last - __size, __last, __local_last).second;
+      __last -= __size;
+
+      if (__first == __last)
+        return std::make_pair(std::move(__orig_last), _Traits::__compose(__segment_iterator, std::move(__iter)));
+      --__segment_iterator;
+      __local_last = _Traits::__end(__segment_iterator);
+    }
+  }
+};
+
+struct __copy_backward_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out, __enable_if_t< is_trivially_assignable<_Out&, _In&>::value, int > = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_backward_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
+__copy_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result) {
+  return std::__dispatch_copy_or_move<_AlgPolicy, __copy_backward_loop<_AlgPolicy>, __copy_backward_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
 }
-#endif // _LIBCPP_STD_VER > 17
 
 template <class _BidirectionalIterator1, class _BidirectionalIterator2>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _BidirectionalIterator2
-copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last, _BidirectionalIterator2 __result) {
-  return std::__copy_backward<_ClassicAlgPolicy>(__first, __last, __result).second;
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_BidirectionalIterator2
+copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
+              _BidirectionalIterator2 __result)
+{
+  static_assert(std::is_copy_constructible<_BidirectionalIterator1>::value &&
+                std::is_copy_constructible<_BidirectionalIterator1>::value, "Iterators must be copy constructible.");
+
+  return std::__copy_backward<_ClassicAlgPolicy>(
+      std::move(__first), std::move(__last), std::move(__result)).second;
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_COPY_BACKWARD_H
diff --git a/libcxx/include/__algorithm/copy_move_common.h b/libcxx/include/__algorithm/copy_move_common.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__algorithm/copy_move_common.h
@@ -0,0 +1,124 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_COPY_MOVE_COMMON_H
+#define _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/unwrap_iter.h>
+#include <__algorithm/unwrap_range.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__memory/pointer_traits.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/integral_constant.h>
+#include <__type_traits/is_constant_evaluated.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__type_traits/is_trivially_assignable.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// `memmove` algorithms implementation.
+
+template <class _In, class _Out>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+__copy_trivial_impl(_In* __first, _In* __last, _Out* __result) {
+  const size_t __n = static_cast<size_t>(__last - __first);
+  ::__builtin_memmove(__result, __first, __n * sizeof(_Out));
+
+  return std::make_pair(__last, __result + __n);
+}
+
+template <class _In, class _Out>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+__copy_backward_trivial_impl(_In* __first, _In* __last, _Out* __result) {
+  const size_t __n = static_cast<size_t>(__last - __first);
+  __result -= __n;
+
+  ::__builtin_memmove(__result, __first, __n * sizeof(_Out));
+
+  return std::make_pair(__last, __result);
+}
+
+// Iterator unwrapping and dispatching to the correct overload.
+
+template <class _F1, class _F2>
+struct __overload : _F1, _F2 {
+  using _F1::operator();
+  using _F2::operator();
+};
+
+template <class _InIter, class _Sent, class _OutIter, class = void>
+struct __can_rewrap : false_type {};
+
+template <class _InIter, class _Sent, class _OutIter>
+struct __can_rewrap<_InIter,
+                    _Sent,
+                    _OutIter,
+                    // Note that sentinels are always copy-constructible.
+                    __enable_if_t< is_copy_constructible<_InIter>::value &&
+                                   is_copy_constructible<_OutIter>::value > > : true_type {};
+
+template <class _Algorithm,
+          class _InIter,
+          class _Sent,
+          class _OutIter,
+          __enable_if_t<__can_rewrap<_InIter, _Sent, _OutIter>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
+__unwrap_and_dispatch(_InIter __first, _Sent __last, _OutIter __out_first) {
+  auto __range  = std::__unwrap_range(__first, std::move(__last));
+  auto __result = _Algorithm()(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__out_first));
+  return std::make_pair(std::__rewrap_range<_Sent>(std::move(__first), std::move(__result.first)),
+                                 std::__rewrap_iter(std::move(__out_first), std::move(__result.second)));
+}
+
+template <class _Algorithm,
+          class _InIter,
+          class _Sent,
+          class _OutIter,
+          __enable_if_t<!__can_rewrap<_InIter, _Sent, _OutIter>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
+__unwrap_and_dispatch(_InIter __first, _Sent __last, _OutIter __out_first) {
+  return _Algorithm()(std::move(__first), std::move(__last), std::move(__out_first));
+}
+
+template <class _AlgPolicy,
+          class _NaiveAlgorithm,
+          class _OptimizedAlgorithm,
+          class _InIter,
+          class _Sent,
+          class _OutIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
+__dispatch_copy_or_move(_InIter __first, _Sent __last, _OutIter __out_first) {
+#ifdef _LIBCPP_COMPILER_GCC
+  // GCC doesn't support `__builtin_memmove` during constant evaluation.
+  if (__libcpp_is_constant_evaluated()) {
+    return std::__unwrap_and_dispatch<_NaiveAlgorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+  }
+#else
+  using _InValue = typename _IterOps<_AlgPolicy>::template __value_type<_InIter>;
+  // In Clang, `__builtin_memmove` only supports fully trivially copyable types (just having trivial copy assignment is
+  // insufficient).
+  if (__libcpp_is_constant_evaluated() && !is_trivially_copyable<_InValue>::value) {
+    return std::__unwrap_and_dispatch<_NaiveAlgorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+  }
+#endif // _LIBCPP_COMPILER_GCC
+
+  using _Algorithm = __overload<_NaiveAlgorithm, _OptimizedAlgorithm>;
+  return std::__unwrap_and_dispatch<_Algorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H
diff --git a/libcxx/include/__algorithm/move.h b/libcxx/include/__algorithm/move.h
--- a/libcxx/include/__algorithm/move.h
+++ b/libcxx/include/__algorithm/move.h
@@ -9,111 +9,119 @@
 #ifndef _LIBCPP___ALGORITHM_MOVE_H
 #define _LIBCPP___ALGORITHM_MOVE_H
 
+#include <__algorithm/copy_move_common.h>
 #include <__algorithm/iterator_operations.h>
-#include <__algorithm/unwrap_iter.h>
+#include <__algorithm/min.h>
 #include <__config>
-#include <__iterator/iterator_traits.h>
-#include <__iterator/reverse_iterator.h>
+#include <__iterator/segmented_iterator.h>
 #include <__utility/move.h>
 #include <__utility/pair.h>
-#include <cstring>
-#include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
-_LIBCPP_BEGIN_NAMESPACE_STD
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
 
-// move
+_LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-pair<_InIter, _OutIter> __move_impl(_InIter __first, _Sent __last, _OutIter __result) {
-  while (__first != __last) {
-    *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
-    ++__first;
-    ++__result;
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+__move(_InIter __first, _Sent __last, _OutIter __result);
+
+template <class _AlgPolicy>
+struct __move_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    while (__first != __last) {
+      *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
+      ++__first;
+      ++__result;
+    }
+    return std::make_pair(std::move(__first), std::move(__result));
   }
-  return std::make_pair(std::move(__first), std::move(__result));
-}
-
-template <class _AlgPolicy,
-          class _InType,
-          class _OutType,
-          class = __enable_if_t<is_same<__remove_const_t<_InType>, _OutType>::value
-                             && is_trivially_move_assignable<_OutType>::value> >
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-pair<_InType*, _OutType*> __move_impl(_InType* __first, _InType* __last, _OutType* __result) {
-  if (__libcpp_is_constant_evaluated()
-// TODO: Remove this once GCC supports __builtin_memmove during constant evaluation
-#ifndef _LIBCPP_COMPILER_GCC
-   && !is_trivially_copyable<_InType>::value
-#endif
-     )
-    return std::__move_impl<_AlgPolicy, _InType*, _InType*, _OutType*>(__first, __last, __result);
-  const size_t __n = static_cast<size_t>(__last - __first);
-  ::__builtin_memmove(__result, __first, __n * sizeof(_OutType));
-  return std::make_pair(__first + __n, __result + __n);
-}
 
-template <class>
-struct __is_trivially_move_assignable_unwrapped_impl : false_type {};
-
-template <class _Type>
-struct __is_trivially_move_assignable_unwrapped_impl<_Type*> : is_trivially_move_assignable<_Type> {};
-
-template <class _Iter>
-struct __is_trivially_move_assignable_unwrapped
-    : __is_trivially_move_assignable_unwrapped_impl<decltype(std::__unwrap_iter<_Iter>(std::declval<_Iter>()))> {};
-
-template <class _AlgPolicy,
-          class _InIter,
-          class _OutIter,
-          __enable_if_t<is_same<__remove_const_t<typename iterator_traits<_InIter>::value_type>,
-                                typename iterator_traits<_OutIter>::value_type>::value
-                     && __is_cpp17_contiguous_iterator<_InIter>::value
-                     && __is_cpp17_contiguous_iterator<_OutIter>::value
-                     && is_trivially_move_assignable<__iter_value_type<_OutIter> >::value, int> = 0>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17
-pair<reverse_iterator<_InIter>, reverse_iterator<_OutIter> >
-__move_impl(reverse_iterator<_InIter> __first,
-            reverse_iterator<_InIter> __last,
-            reverse_iterator<_OutIter> __result) {
-  auto __first_base = std::__unwrap_iter(__first.base());
-  auto __last_base = std::__unwrap_iter(__last.base());
-  auto __result_base = std::__unwrap_iter(__result.base());
-  auto __result_first = __result_base - (__first_base - __last_base);
-  std::__move_impl<_AlgPolicy>(__last_base, __first_base, __result_first);
-  return std::make_pair(__last, reverse_iterator<_OutIter>(std::__rewrap_iter(__result.base(), __result_first)));
-}
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+    auto __sfirst = _Traits::__segment(__first);
+    auto __slast  = _Traits::__segment(__last);
+    if (__sfirst == __slast) {
+      auto __iters = std::__move<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
+      return std::make_pair(__last, std::move(__iters.second));
+    }
+
+    __result = std::__move<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__sfirst), std::move(__result)).second;
+    ++__sfirst;
+    while (__sfirst != __slast) {
+      __result =
+          std::__move<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__end(__sfirst), std::move(__result)).second;
+      ++__sfirst;
+    }
+    __result =
+        std::__move<_AlgPolicy>(_Traits::__begin(__sfirst), _Traits::__local(__last), std::move(__result)).second;
+    return std::make_pair(__last, std::move(__result));
+  }
 
-template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-__enable_if_t<is_copy_constructible<_InIter>::value
-           && is_copy_constructible<_Sent>::value
-           && is_copy_constructible<_OutIter>::value, pair<_InIter, _OutIter> >
-__move(_InIter __first, _Sent __last, _OutIter __result) {
-  auto __ret = std::__move_impl<_AlgPolicy>(
-      std::__unwrap_iter(__first), std::__unwrap_iter(__last), std::__unwrap_iter(__result));
-  return std::make_pair(std::__rewrap_iter(__first, __ret.first), std::__rewrap_iter(__result, __ret.second));
-}
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits = __segmented_iterator_traits<_OutIter>;
+    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter>>::type;
+
+    if (__first == __last)
+      return std::make_pair(std::move(__first), std::move(__result));
+
+    auto __local_first      = _Traits::__local(__result);
+    auto __segment_iterator = _Traits::__segment(__result);
+    while (true) {
+      auto __local_last = _Traits::__end(__segment_iterator);
+      auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iters      = std::__move<_AlgPolicy>(__first, __first + __size, __local_first);
+      __first           = std::move(__iters.first);
+
+      if (__first == __last)
+        return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
+
+      __local_first = _Traits::__begin(++__segment_iterator);
+    }
+  }
+};
+
+struct __move_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out, __enable_if_t< is_trivially_assignable<_Out&, _In&&>::value, int > = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_trivial_impl(__first, __last, __result);
+  }
+};
 
 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
-__enable_if_t<!is_copy_constructible<_InIter>::value
-           || !is_copy_constructible<_Sent>::value
-           || !is_copy_constructible<_OutIter>::value, pair<_InIter, _OutIter> >
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
 __move(_InIter __first, _Sent __last, _OutIter __result) {
-  return std::__move_impl<_AlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
+  return std::__dispatch_copy_or_move<_AlgPolicy, __move_loop<_AlgPolicy>, __move_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
 }
 
 template <class _InputIterator, class _OutputIterator>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
-_OutputIterator move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
-  return std::__move<_ClassicAlgPolicy>(__first, __last, __result).second;
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
+  static_assert(is_copy_constructible<_InputIterator>::value, "Iterators has to be copy constructible.");
+  static_assert(is_copy_constructible<_OutputIterator>::value, "The output iterator has to be copy constructible.");
+
+  return std::__move<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_MOVE_H
diff --git a/libcxx/include/__algorithm/move_backward.h b/libcxx/include/__algorithm/move_backward.h
--- a/libcxx/include/__algorithm/move_backward.h
+++ b/libcxx/include/__algorithm/move_backward.h
@@ -9,81 +9,128 @@
 #ifndef _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
 #define _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
 
+#include <__algorithm/copy_move_common.h>
 #include <__algorithm/iterator_operations.h>
-#include <__algorithm/unwrap_iter.h>
+#include <__algorithm/min.h>
 #include <__config>
+#include <__iterator/segmented_iterator.h>
 #include <__utility/move.h>
-#include <cstring>
-#include <type_traits>
+#include <__utility/pair.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _AlgPolicy, class _InputIterator, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-_OutputIterator
-__move_backward_constexpr(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
-{
-    while (__first != __last)
-        *--__result = _IterOps<_AlgPolicy>::__iter_move(--__last);
-    return __result;
-}
+template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
+__move_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result);
 
-template <class _AlgPolicy, class _InputIterator, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-_OutputIterator
-__move_backward_impl(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
-{
-    return _VSTD::__move_backward_constexpr<_AlgPolicy>(__first, __last, __result);
-}
+template <class _AlgPolicy>
+struct __move_backward_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    auto __last_iter          = _IterOps<_AlgPolicy>::next(__first, __last);
+    auto __original_last_iter = __last_iter;
 
-template <class _AlgPolicy, class _Tp, class _Up>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
-typename enable_if
-<
-    is_same<__remove_const_t<_Tp>, _Up>::value &&
-    is_trivially_move_assignable<_Up>::value,
-    _Up*
->::type
-__move_backward_impl(_Tp* __first, _Tp* __last, _Up* __result)
-{
-    const size_t __n = static_cast<size_t>(__last - __first);
-    if (__n > 0)
-    {
-        __result -= __n;
-        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    while (__first != __last_iter) {
+      *--__result = _IterOps<_AlgPolicy>::__iter_move(--__last_iter);
     }
-    return __result;
-}
 
-template <class _AlgPolicy, class _BidirectionalIterator1, class _BidirectionalIterator2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-_BidirectionalIterator2
-__move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
-                _BidirectionalIterator2 __result)
-{
-    if (__libcpp_is_constant_evaluated()) {
-        return _VSTD::__move_backward_constexpr<_AlgPolicy>(__first, __last, __result);
-    } else {
-        return _VSTD::__rewrap_iter(__result,
-            _VSTD::__move_backward_impl<_AlgPolicy>(_VSTD::__unwrap_iter(__first),
-                                                    _VSTD::__unwrap_iter(__last),
-                                                    _VSTD::__unwrap_iter(__result)));
+    return std::make_pair(std::move(__original_last_iter), std::move(__result));
+  }
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+    auto __sfirst = _Traits::__segment(__first);
+    auto __slast  = _Traits::__segment(__last);
+    if (__sfirst == __slast) {
+      auto __iters =
+          std::__move_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
+      return std::make_pair(__last, __iters.second);
+    }
+
+    __result =
+        std::__move_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__local(__last), std::move(__result))
+            .second;
+    --__slast;
+    while (__sfirst != __slast) {
+      __result =
+          std::__move_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__end(__slast), std::move(__result))
+              .second;
+      --__slast;
+    }
+    __result = std::__move_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__slast), std::move(__result))
+                   .second;
+    return std::make_pair(__last, std::move(__result));
+  }
+
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__is_cpp17_random_access_iterator<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits = __segmented_iterator_traits<_OutIter>;
+    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
+
+    // When the range contains no elements __result might not be a vaid iterator
+    if (__first == __last)
+      return std::make_pair(__first, __result);
+
+    auto __orig_last = __last;
+
+    auto __local_last       = _Traits::__local(__result);
+    auto __segment_iterator = _Traits::__segment(__result);
+    while (true) {
+      auto __local_first = _Traits::__begin(__segment_iterator);
+      auto __size        = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iter        = std::__move_backward<_AlgPolicy>(__last - __size, __last, __local_last).second;
+      __last -= __size;
+
+      if (__first == __last)
+        return std::make_pair(std::move(__orig_last), _Traits::__compose(__segment_iterator, std::move(__iter)));
+
+      __local_last = _Traits::__end(--__segment_iterator);
     }
+  }
+};
+
+struct __move_backward_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out, __enable_if_t< is_trivially_assignable<_Out&, _In&&>::value, int > = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_backward_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
+__move_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result) {
+  static_assert(std::is_copy_constructible<_BidirectionalIterator1>::value &&
+                std::is_copy_constructible<_BidirectionalIterator1>::value, "Iterators must be copy constructible.");
+
+  return std::__dispatch_copy_or_move<_AlgPolicy, __move_backward_loop<_AlgPolicy>, __move_backward_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
 }
 
 template <class _BidirectionalIterator1, class _BidirectionalIterator2>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-_BidirectionalIterator2
-move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
-              _BidirectionalIterator2 __result)
-{
-  return std::__move_backward<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _BidirectionalIterator2
+move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last, _BidirectionalIterator2 __result) {
+  return std::__move_backward<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
 }
 
 _LIBCPP_END_NAMESPACE_STD
 
+_LIBCPP_POP_MACROS
+
 #endif // _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
diff --git a/libcxx/include/__algorithm/ranges_copy.h b/libcxx/include/__algorithm/ranges_copy.h
--- a/libcxx/include/__algorithm/ranges_copy.h
+++ b/libcxx/include/__algorithm/ranges_copy.h
@@ -11,6 +11,7 @@
 
 #include <__algorithm/copy.h>
 #include <__algorithm/in_out_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__functional/identity.h>
 #include <__iterator/concepts.h>
@@ -40,7 +41,7 @@
     requires indirectly_copyable<_InIter, _OutIter>
   _LIBCPP_HIDE_FROM_ABI constexpr
   copy_result<_InIter, _OutIter> operator()(_InIter __first, _Sent __last, _OutIter __result) const {
-    auto __ret = std::__copy(std::move(__first), std::move(__last), std::move(__result));
+    auto __ret = std::__copy<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
     return {std::move(__ret.first), std::move(__ret.second)};
   }
 
@@ -48,7 +49,7 @@
     requires indirectly_copyable<iterator_t<_Range>, _OutIter>
   _LIBCPP_HIDE_FROM_ABI constexpr
   copy_result<borrowed_iterator_t<_Range>, _OutIter> operator()(_Range&& __r, _OutIter __result) const {
-    auto __ret = std::__copy(ranges::begin(__r), ranges::end(__r), std::move(__result));
+    auto __ret = std::__copy<_RangeAlgPolicy>(ranges::begin(__r), ranges::end(__r), std::move(__result));
     return {std::move(__ret.first), std::move(__ret.second)};
   }
 };
diff --git a/libcxx/include/__algorithm/ranges_copy_backward.h b/libcxx/include/__algorithm/ranges_copy_backward.h
--- a/libcxx/include/__algorithm/ranges_copy_backward.h
+++ b/libcxx/include/__algorithm/ranges_copy_backward.h
@@ -14,7 +14,6 @@
 #include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__iterator/concepts.h>
-#include <__iterator/reverse_iterator.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
 #include <__ranges/dangling.h>
diff --git a/libcxx/include/__algorithm/ranges_copy_n.h b/libcxx/include/__algorithm/ranges_copy_n.h
--- a/libcxx/include/__algorithm/ranges_copy_n.h
+++ b/libcxx/include/__algorithm/ranges_copy_n.h
@@ -11,6 +11,7 @@
 
 #include <__algorithm/copy.h>
 #include <__algorithm/in_out_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__algorithm/ranges_copy.h>
 #include <__config>
 #include <__functional/identity.h>
@@ -51,7 +52,7 @@
   template <random_access_iterator _InIter, class _DiffType, random_access_iterator _OutIter>
   _LIBCPP_HIDE_FROM_ABI constexpr static
   copy_n_result<_InIter, _OutIter> __go(_InIter __first, _DiffType __n, _OutIter __result) {
-    auto __ret = std::__copy(__first, __first + __n, __result);
+    auto __ret = std::__copy<_RangeAlgPolicy>(__first, __first + __n, __result);
     return {__ret.first, __ret.second};
   }
 
diff --git a/libcxx/include/__algorithm/ranges_move.h b/libcxx/include/__algorithm/ranges_move.h
--- a/libcxx/include/__algorithm/ranges_move.h
+++ b/libcxx/include/__algorithm/ranges_move.h
@@ -14,7 +14,6 @@
 #include <__algorithm/move.h>
 #include <__config>
 #include <__iterator/concepts.h>
-#include <__iterator/iter_move.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
 #include <__ranges/dangling.h>
diff --git a/libcxx/include/__algorithm/ranges_move_backward.h b/libcxx/include/__algorithm/ranges_move_backward.h
--- a/libcxx/include/__algorithm/ranges_move_backward.h
+++ b/libcxx/include/__algorithm/ranges_move_backward.h
@@ -10,12 +10,12 @@
 #define _LIBCPP___ALGORITHM_RANGES_MOVE_BACKWARD_H
 
 #include <__algorithm/in_out_result.h>
-#include <__algorithm/ranges_move.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/move_backward.h>
 #include <__config>
 #include <__iterator/concepts.h>
 #include <__iterator/iter_move.h>
 #include <__iterator/next.h>
-#include <__iterator/reverse_iterator.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
 #include <__ranges/dangling.h>
@@ -40,11 +40,8 @@
   template <class _InIter, class _Sent, class _OutIter>
   _LIBCPP_HIDE_FROM_ABI constexpr static
   move_backward_result<_InIter, _OutIter> __move_backward_impl(_InIter __first, _Sent __last, _OutIter __result) {
-    auto __last_iter = ranges::next(__first, std::move(__last));
-    auto __ret = ranges::move(std::make_reverse_iterator(__last_iter),
-                              std::make_reverse_iterator(__first),
-                              std::make_reverse_iterator(__result));
-    return {std::move(__last_iter), std::move(__ret.out.base())};
+    auto __ret = std::__move_backward<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
+    return {std::move(__ret.first), std::move(__ret.second)};
   }
 
   template <bidirectional_iterator _InIter, sentinel_for<_InIter> _Sent, bidirectional_iterator _OutIter>
diff --git a/libcxx/include/__algorithm/ranges_set_difference.h b/libcxx/include/__algorithm/ranges_set_difference.h
--- a/libcxx/include/__algorithm/ranges_set_difference.h
+++ b/libcxx/include/__algorithm/ranges_set_difference.h
@@ -10,6 +10,7 @@
 #define _LIBCPP___ALGORITHM_RANGES_SET_DIFFERENCE_H
 
 #include <__algorithm/in_out_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__algorithm/make_projected.h>
 #include <__algorithm/set_difference.h>
 #include <__config>
@@ -60,7 +61,7 @@
       _Comp __comp   = {},
       _Proj1 __proj1 = {},
       _Proj2 __proj2 = {}) const {
-    auto __ret = std::__set_difference(
+    auto __ret = std::__set_difference<_RangeAlgPolicy>(
         __first1, __last1, __first2, __last2, __result, ranges::__make_projected_comp(__comp, __proj1, __proj2));
     return {std::move(__ret.first), std::move(__ret.second)};
   }
@@ -81,7 +82,7 @@
         _Comp __comp   = {},
         _Proj1 __proj1 = {},
         _Proj2 __proj2 = {}) const {
-    auto __ret = std::__set_difference(
+    auto __ret = std::__set_difference<_RangeAlgPolicy>(
         ranges::begin(__range1),
         ranges::end(__range1),
         ranges::begin(__range2),
diff --git a/libcxx/include/__algorithm/ranges_set_symmetric_difference.h b/libcxx/include/__algorithm/ranges_set_symmetric_difference.h
--- a/libcxx/include/__algorithm/ranges_set_symmetric_difference.h
+++ b/libcxx/include/__algorithm/ranges_set_symmetric_difference.h
@@ -10,6 +10,7 @@
 #define _LIBCPP___ALGORITHM_RANGES_SET_SYMMETRIC_DIFFERENCE_H
 
 #include <__algorithm/in_in_out_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__algorithm/make_projected.h>
 #include <__algorithm/set_symmetric_difference.h>
 #include <__config>
@@ -58,7 +59,7 @@
       _Comp __comp   = {},
       _Proj1 __proj1 = {},
       _Proj2 __proj2 = {}) const {
-    auto __ret = std::__set_symmetric_difference(
+    auto __ret = std::__set_symmetric_difference<_RangeAlgPolicy>(
         std::move(__first1),
         std::move(__last1),
         std::move(__first2),
@@ -92,7 +93,7 @@
         _Comp __comp   = {},
         _Proj1 __proj1 = {},
         _Proj2 __proj2 = {}) const {
-    auto __ret = std::__set_symmetric_difference(
+    auto __ret = std::__set_symmetric_difference<_RangeAlgPolicy>(
         ranges::begin(__range1),
         ranges::end(__range1),
         ranges::begin(__range2),
diff --git a/libcxx/include/__algorithm/ranges_set_union.h b/libcxx/include/__algorithm/ranges_set_union.h
--- a/libcxx/include/__algorithm/ranges_set_union.h
+++ b/libcxx/include/__algorithm/ranges_set_union.h
@@ -10,6 +10,7 @@
 #define _LIBCPP___ALGORITHM_RANGES_SET_UNION_H
 
 #include <__algorithm/in_in_out_result.h>
+#include <__algorithm/iterator_operations.h>
 #include <__algorithm/make_projected.h>
 #include <__algorithm/set_union.h>
 #include <__config>
@@ -61,7 +62,7 @@
       _Comp __comp   = {},
       _Proj1 __proj1 = {},
       _Proj2 __proj2 = {}) const {
-    auto __ret = std::__set_union(
+    auto __ret = std::__set_union<_RangeAlgPolicy>(
         std::move(__first1),
         std::move(__last1),
         std::move(__first2),
@@ -95,7 +96,7 @@
         _Comp __comp   = {},
         _Proj1 __proj1 = {},
         _Proj2 __proj2 = {}) const {
-    auto __ret = std::__set_union(
+    auto __ret = std::__set_union<_RangeAlgPolicy>(
         ranges::begin(__range1),
         ranges::end(__range1),
         ranges::begin(__range2),
diff --git a/libcxx/include/__algorithm/rotate.h b/libcxx/include/__algorithm/rotate.h
--- a/libcxx/include/__algorithm/rotate.h
+++ b/libcxx/include/__algorithm/rotate.h
@@ -48,7 +48,7 @@
 
     _BidirectionalIterator __lm1 = _Ops::prev(__last);
     value_type __tmp = _Ops::__iter_move(__lm1);
-    _BidirectionalIterator __fp1 = std::__move_backward<_AlgPolicy>(__first, __lm1, std::move(__last));
+    _BidirectionalIterator __fp1 = std::__move_backward<_AlgPolicy>(__first, __lm1, std::move(__last)).second;
     *__first = _VSTD::move(__tmp);
     return __fp1;
 }
diff --git a/libcxx/include/__algorithm/set_difference.h b/libcxx/include/__algorithm/set_difference.h
--- a/libcxx/include/__algorithm/set_difference.h
+++ b/libcxx/include/__algorithm/set_difference.h
@@ -12,6 +12,7 @@
 #include <__algorithm/comp.h>
 #include <__algorithm/comp_ref_type.h>
 #include <__algorithm/copy.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__functional/identity.h>
 #include <__functional/invoke.h>
@@ -26,7 +27,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template < class _Comp, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
+template <class _AlgPolicy, class _Comp, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<__remove_cvref_t<_InIter1>, __remove_cvref_t<_OutIter> >
 __set_difference(
     _InIter1&& __first1, _Sent1&& __last1, _InIter2&& __first2, _Sent2&& __last2, _OutIter&& __result, _Comp&& __comp) {
@@ -42,7 +43,7 @@
       ++__first2;
     }
   }
-  return std::__copy(std::move(__first1), std::move(__last1), std::move(__result));
+  return std::__copy<_AlgPolicy>(std::move(__first1), std::move(__last1), std::move(__result));
 }
 
 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
@@ -54,7 +55,8 @@
     _OutputIterator __result,
     _Compare __comp) {
   typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp).second;
+  return std::__set_difference<_ClassicAlgPolicy, _Comp_ref>(
+      __first1, __last1, __first2, __last2, __result, __comp).second;
 }
 
 template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
@@ -64,7 +66,7 @@
     _InputIterator2 __first2,
     _InputIterator2 __last2,
     _OutputIterator __result) {
-  return std::__set_difference(
+  return std::__set_difference<_ClassicAlgPolicy>(
       __first1,
       __last1,
       __first2,
diff --git a/libcxx/include/__algorithm/set_symmetric_difference.h b/libcxx/include/__algorithm/set_symmetric_difference.h
--- a/libcxx/include/__algorithm/set_symmetric_difference.h
+++ b/libcxx/include/__algorithm/set_symmetric_difference.h
@@ -12,6 +12,7 @@
 #include <__algorithm/comp.h>
 #include <__algorithm/comp_ref_type.h>
 #include <__algorithm/copy.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__iterator/iterator_traits.h>
 #include <__utility/move.h>
@@ -35,13 +36,13 @@
       : __in1_(std::move(__in_iter1)), __in2_(std::move(__in_iter2)), __out_(std::move(__out_iter)) {}
 };
 
-template <class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
+template <class _AlgPolicy, class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __set_symmetric_difference_result<_InIter1, _InIter2, _OutIter>
 __set_symmetric_difference(
     _InIter1 __first1, _Sent1 __last1, _InIter2 __first2, _Sent2 __last2, _OutIter __result, _Compare&& __comp) {
   while (__first1 != __last1) {
     if (__first2 == __last2) {
-      auto __ret1 = std::__copy_impl(std::move(__first1), std::move(__last1), std::move(__result));
+      auto __ret1 = std::__copy<_AlgPolicy>(std::move(__first1), std::move(__last1), std::move(__result));
       return __set_symmetric_difference_result<_InIter1, _InIter2, _OutIter>(
           std::move(__ret1.first), std::move(__first2), std::move((__ret1.second)));
     }
@@ -59,7 +60,7 @@
       ++__first2;
     }
   }
-  auto __ret2 = std::__copy_impl(std::move(__first2), std::move(__last2), std::move(__result));
+  auto __ret2 = std::__copy<_AlgPolicy>(std::move(__first2), std::move(__last2), std::move(__result));
   return __set_symmetric_difference_result<_InIter1, _InIter2, _OutIter>(
       std::move(__first1), std::move(__ret2.first), std::move((__ret2.second)));
 }
@@ -73,7 +74,7 @@
     _OutputIterator __result,
     _Compare __comp) {
   typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_symmetric_difference<_Comp_ref>(
+  return std::__set_symmetric_difference<_ClassicAlgPolicy, _Comp_ref>(
              std::move(__first1),
              std::move(__last1),
              std::move(__first2),
diff --git a/libcxx/include/__algorithm/set_union.h b/libcxx/include/__algorithm/set_union.h
--- a/libcxx/include/__algorithm/set_union.h
+++ b/libcxx/include/__algorithm/set_union.h
@@ -12,6 +12,7 @@
 #include <__algorithm/comp.h>
 #include <__algorithm/comp_ref_type.h>
 #include <__algorithm/copy.h>
+#include <__algorithm/iterator_operations.h>
 #include <__config>
 #include <__iterator/iterator_traits.h>
 #include <__utility/move.h>
@@ -35,12 +36,12 @@
       : __in1_(std::move(__in_iter1)), __in2_(std::move(__in_iter2)), __out_(std::move(__out_iter)) {}
 };
 
-template <class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
+template <class _AlgPolicy, class _Compare, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __set_union_result<_InIter1, _InIter2, _OutIter> __set_union(
     _InIter1 __first1, _Sent1 __last1, _InIter2 __first2, _Sent2 __last2, _OutIter __result, _Compare&& __comp) {
   for (; __first1 != __last1; ++__result) {
     if (__first2 == __last2) {
-      auto __ret1 = std::__copy_impl(std::move(__first1), std::move(__last1), std::move(__result));
+      auto __ret1 = std::__copy<_AlgPolicy>(std::move(__first1), std::move(__last1), std::move(__result));
       return __set_union_result<_InIter1, _InIter2, _OutIter>(
           std::move(__ret1.first), std::move(__first2), std::move((__ret1.second)));
     }
@@ -55,7 +56,7 @@
       ++__first1;
     }
   }
-  auto __ret2 = std::__copy_impl(std::move(__first2), std::move(__last2), std::move(__result));
+  auto __ret2 = std::__copy<_AlgPolicy>(std::move(__first2), std::move(__last2), std::move(__result));
   return __set_union_result<_InIter1, _InIter2, _OutIter>(
       std::move(__first1), std::move(__ret2.first), std::move((__ret2.second)));
 }
@@ -69,7 +70,7 @@
     _OutputIterator __result,
     _Compare __comp) {
   typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
-  return std::__set_union<_Comp_ref>(
+  return std::__set_union<_ClassicAlgPolicy, _Comp_ref>(
              std::move(__first1),
              std::move(__last1),
              std::move(__first2),
diff --git a/libcxx/include/__iterator/reverse_iterator.h b/libcxx/include/__iterator/reverse_iterator.h
--- a/libcxx/include/__iterator/reverse_iterator.h
+++ b/libcxx/include/__iterator/reverse_iterator.h
@@ -25,6 +25,7 @@
 #include <__iterator/next.h>
 #include <__iterator/prev.h>
 #include <__iterator/readable_traits.h>
+#include <__iterator/segmented_iterator.h>
 #include <__memory/addressof.h>
 #include <__ranges/access.h>
 #include <__ranges/concepts.h>
@@ -195,12 +196,6 @@
 #endif // _LIBCPP_STD_VER > 17
 };
 
-template <class _Iter>
-struct __is_reverse_iterator : false_type {};
-
-template <class _Iter>
-struct __is_reverse_iterator<reverse_iterator<_Iter> > : true_type {};
-
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX17
 bool
@@ -478,9 +473,6 @@
   }
 };
 
-template <class _Iter>
-struct __is_reverse_iterator<__unconstrained_reverse_iterator<_Iter>> : true_type {};
-
 #endif // _LIBCPP_STD_VER <= 17
 
 template <template <class> class _RevIter1, template <class> class _RevIter2, class _Iter>
diff --git a/libcxx/include/__iterator/segmented_iterator.h b/libcxx/include/__iterator/segmented_iterator.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__iterator/segmented_iterator.h
@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___SEGMENTED_ITERATOR_H
+#define _LIBCPP___SEGMENTED_ITERATOR_H
+
+// Segmented iterators are iterators over (not necessarily contiguous) sub-ranges.
+//
+// For example, std::deque stores its data into multiple blocks of contiguous memory,
+// which are not stored contiguously themselves. The concept of segmented iterators
+// allows algorithms to operate over these multi-level iterators natively, opening the
+// door to various optimizations. See http://lafstern.org/matt/segmented.pdf for details.
+//
+// Given Traits = __segmented_iterator_traits<It>, if Traits::__is_segmented_iterator::value
+// is true, the following functions and associated types must be provided:
+// - Traits::__local_iterator
+//   The type of iterators used to iterate inside a segment.
+//
+// - Traits::__segment_iterator
+//   The type of iterators used to iterate over segments.
+//   Segment iterators can be forward iterators or bidirectional iterators, depending on the
+//   underlying data structure.
+//
+// - static __segment_iterator Traits::__segment(It __it)
+//   Returns an iterator to the segment that the provided iterator is in.
+//
+// - static __local_iterator Traits::__local(It __it)
+//   Returns the local iterator pointing to the element that the provided iterator points to.
+//
+// - static __local_iterator Traits::__begin(__segment_iterator __it)
+//   Returns the local iterator to the beginning of the segment that the provided iterator is pointing into.
+//
+// - static __local_iterator Traits::__end(__segment_iterator __it)
+//   Returns the one-past-the-end local iterator to the segment that the provided iterator is pointing into.
+//
+// - static It Traits::__compose(__segment_iterator, __local_iterator)
+//   Returns the iterator composed of the segment iterator and local iterator.
+
+#include <__config>
+#include <__type_traits/integral_constant.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iterator>
+struct __segmented_iterator_traits {
+  using __is_segmented_iterator = false_type;
+  using __segment_iterator      = void*;
+  using __local_iterator        = void*;
+
+  static __segment_iterator __segment(_Iterator)                   = delete;
+  static __local_iterator __local(_Iterator)                       = delete;
+  static __local_iterator __begin(__segment_iterator)              = delete;
+  static __local_iterator __end(__segment_iterator)                = delete;
+  static _Iterator __compose(__segment_iterator, __local_iterator) = delete;
+};
+
+template <class _Iterator>
+using __is_segmented_iterator = typename __segmented_iterator_traits<_Iterator>::__is_segmented_iterator;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___SEGMENTED_ITERATOR_H
diff --git a/libcxx/include/deque b/libcxx/include/deque
--- a/libcxx/include/deque
+++ b/libcxx/include/deque
@@ -176,6 +176,7 @@
 #include <__iterator/next.h>
 #include <__iterator/prev.h>
 #include <__iterator/reverse_iterator.h>
+#include <__iterator/segmented_iterator.h>
 #include <__memory/pointer_traits.h>
 #include <__memory/temp_value.h>
 #include <__memory/unique_ptr.h>
@@ -214,98 +215,6 @@
 
 template <class _Tp, class _Allocator = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS deque;
 
-template <class _ValueType, class _Pointer, class _Reference, class _MapPointer,
-          class _DiffType, _DiffType _BlockSize>
-class _LIBCPP_TEMPLATE_VIS __deque_iterator;
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy(_RAIter __f,
-     _RAIter __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     _OutputIterator __r);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy_backward(_RAIter __f,
-              _RAIter __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              _OutputIterator __r);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move(_RAIter __f,
-     _RAIter __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     _OutputIterator __r);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move_backward(_RAIter __f,
-              _RAIter __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              _OutputIterator __r);
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
 template <class _ValueType, class _DiffType>
 struct __deque_block_size {
   static const _DiffType value = sizeof(_ValueType) < 256 ? 4096 / sizeof(_ValueType) : 16;
@@ -476,105 +385,32 @@
     template <class _Vp, class _Pp, class _Rp, class _MP, class _Dp, _Dp>
         friend class _LIBCPP_TEMPLATE_VIS __deque_iterator;
 
-    template <class _RAIter,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    copy(_RAIter __f,
-         _RAIter __l,
-         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-         typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _OutputIterator>
-    friend
-    _OutputIterator
-    copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-         _OutputIterator __r);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
-    template <class _RAIter,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    copy_backward(_RAIter __f,
-                  _RAIter __l,
-                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-                  typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _OutputIterator>
-    friend
-    _OutputIterator
-    copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-                  _OutputIterator __r);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
-    template <class _RAIter,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    move(_RAIter __f,
-         _RAIter __l,
-         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-         typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _OutputIterator>
-    friend
-    _OutputIterator
-    move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-         _OutputIterator __r);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
-
-    template <class _RAIter,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    move_backward(_RAIter __f,
-                  _RAIter __l,
-                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-                  typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _OutputIterator>
-    friend
-    _OutputIterator
-    move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-                  _OutputIterator __r);
-
-    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-    friend
-    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-    move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+    template <class>
+    friend struct __segmented_iterator_traits;
+};
+
+template <class _ValueType, class _Pointer, class _Reference, class _MapPointer, class _DiffType, _DiffType _BlockSize>
+struct __segmented_iterator_traits<
+    __deque_iterator<_ValueType, _Pointer, _Reference, _MapPointer, _DiffType, _BlockSize> > {
+private:
+  using _Iterator = __deque_iterator<_ValueType, _Pointer, _Reference, _MapPointer, _DiffType, _BlockSize>;
+
+public:
+  using __is_segmented_iterator = true_type;
+  using __segment_iterator = _MapPointer;
+  using __local_iterator = _Pointer;
+
+  static _LIBCPP_HIDE_FROM_ABI __segment_iterator __segment(_Iterator __iter) { return __iter.__m_iter_; }
+  static _LIBCPP_HIDE_FROM_ABI __local_iterator __local(_Iterator __iter) { return __iter.__ptr_; }
+  static _LIBCPP_HIDE_FROM_ABI __local_iterator __begin(__segment_iterator __iter) { return *__iter; }
+  static _LIBCPP_HIDE_FROM_ABI __local_iterator __end(__segment_iterator __iter) { return *__iter + _BlockSize; }
+  static _LIBCPP_HIDE_FROM_ABI _Iterator __compose(__segment_iterator __segment, __local_iterator __local) {
+    if (__local == __end(__segment)) {
+      ++__segment;
+      return _Iterator(__segment, *__segment);
+    }
+    return _Iterator(__segment, __local);
+  }
 };
 
 template <class _ValueType, class _Pointer, class _Reference, class _MapPointer,
@@ -583,358 +419,6 @@
                                  _DiffType, _BlockSize>::__block_size =
     __deque_block_size<_ValueType, _DiffType>::value;
 
-// copy
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy(_RAIter __f,
-     _RAIter __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
-{
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
-    const difference_type __block_size = __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::__block_size;
-    while (__f != __l)
-    {
-        pointer __rb = __r.__ptr_;
-        pointer __re = *__r.__m_iter_ + __block_size;
-        difference_type __bs = __re - __rb;
-        difference_type __n = __l - __f;
-        _RAIter __m = __l;
-        if (__n > __bs)
-        {
-            __n = __bs;
-            __m = __f + __n;
-        }
-        _VSTD::copy(__f, __m, __rb);
-        __f = __m;
-        __r += __n;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     _OutputIterator __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        pointer __fb = __f.__ptr_;
-        pointer __fe = *__f.__m_iter_ + __block_size;
-        difference_type __bs = __fe - __fb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __fe = __fb + __bs;
-        }
-        __r = _VSTD::copy(__fb, __fe, __r);
-        __n -= __bs;
-        __f += __bs;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        pointer __fb = __f.__ptr_;
-        pointer __fe = *__f.__m_iter_ + __block_size;
-        difference_type __bs = __fe - __fb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __fe = __fb + __bs;
-        }
-        __r = _VSTD::copy(__fb, __fe, __r);
-        __n -= __bs;
-        __f += __bs;
-    }
-    return __r;
-}
-
-// copy_backward
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy_backward(_RAIter __f,
-              _RAIter __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
-{
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
-    while (__f != __l)
-    {
-        __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __rp = _VSTD::prev(__r);
-        pointer __rb = *__rp.__m_iter_;
-        pointer __re = __rp.__ptr_ + 1;
-        difference_type __bs = __re - __rb;
-        difference_type __n = __l - __f;
-        _RAIter __m = __f;
-        if (__n > __bs)
-        {
-            __n = __bs;
-            __m = __l - __n;
-        }
-        _VSTD::copy_backward(__m, __l, __re);
-        __l = __m;
-        __r -= __n;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              _OutputIterator __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        --__l;
-        pointer __lb = *__l.__m_iter_;
-        pointer __le = __l.__ptr_ + 1;
-        difference_type __bs = __le - __lb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __lb = __le - __bs;
-        }
-        __r = _VSTD::copy_backward(__lb, __le, __r);
-        __n -= __bs;
-        __l -= __bs - 1;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        --__l;
-        pointer __lb = *__l.__m_iter_;
-        pointer __le = __l.__ptr_ + 1;
-        difference_type __bs = __le - __lb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __lb = __le - __bs;
-        }
-        __r = _VSTD::copy_backward(__lb, __le, __r);
-        __n -= __bs;
-        __l -= __bs - 1;
-    }
-    return __r;
-}
-
-// move
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move(_RAIter __f,
-     _RAIter __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
-{
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
-    const difference_type __block_size = __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::__block_size;
-    while (__f != __l)
-    {
-        pointer __rb = __r.__ptr_;
-        pointer __re = *__r.__m_iter_ + __block_size;
-        difference_type __bs = __re - __rb;
-        difference_type __n = __l - __f;
-        _RAIter __m = __l;
-        if (__n > __bs)
-        {
-            __n = __bs;
-            __m = __f + __n;
-        }
-        _VSTD::move(__f, __m, __rb);
-        __f = __m;
-        __r += __n;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     _OutputIterator __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        pointer __fb = __f.__ptr_;
-        pointer __fe = *__f.__m_iter_ + __block_size;
-        difference_type __bs = __fe - __fb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __fe = __fb + __bs;
-        }
-        __r = _VSTD::move(__fb, __fe, __r);
-        __n -= __bs;
-        __f += __bs;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        pointer __fb = __f.__ptr_;
-        pointer __fe = *__f.__m_iter_ + __block_size;
-        difference_type __bs = __fe - __fb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __fe = __fb + __bs;
-        }
-        __r = _VSTD::move(__fb, __fe, __r);
-        __n -= __bs;
-        __f += __bs;
-    }
-    return __r;
-}
-
-// move_backward
-
-template <class _RAIter,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move_backward(_RAIter __f,
-              _RAIter __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
-              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
-{
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
-    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
-    while (__f != __l)
-    {
-        __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __rp = _VSTD::prev(__r);
-        pointer __rb = *__rp.__m_iter_;
-        pointer __re = __rp.__ptr_ + 1;
-        difference_type __bs = __re - __rb;
-        difference_type __n = __l - __f;
-        _RAIter __m = __f;
-        if (__n > __bs)
-        {
-            __n = __bs;
-            __m = __l - __n;
-        }
-        _VSTD::move_backward(__m, __l, __re);
-        __l = __m;
-        __r -= __n;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _OutputIterator>
-_LIBCPP_HIDE_FROM_ABI _OutputIterator
-move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              _OutputIterator __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        --__l;
-        pointer __lb = *__l.__m_iter_;
-        pointer __le = __l.__ptr_ + 1;
-        difference_type __bs = __le - __lb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __lb = __le - __bs;
-        }
-        __r = _VSTD::move_backward(__lb, __le, __r);
-        __n -= __bs;
-        __l -= __bs - 1;
-    }
-    return __r;
-}
-
-template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
-          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
-_LIBCPP_HIDE_FROM_ABI __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
-move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
-              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
-              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
-{
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
-    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
-    difference_type __n = __l - __f;
-    while (__n > 0)
-    {
-        --__l;
-        pointer __lb = *__l.__m_iter_;
-        pointer __le = __l.__ptr_ + 1;
-        difference_type __bs = __le - __lb;
-        if (__bs > __n)
-        {
-            __bs = __n;
-            __lb = __le - __bs;
-        }
-        __r = _VSTD::move_backward(__lb, __le, __r);
-        __n -= __bs;
-        __l -= __bs - 1;
-    }
-    return __r;
-}
-
 template <class _Tp, class _Allocator /*= allocator<_Tp>*/>
 class _LIBCPP_TEMPLATE_VIS deque
 {
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -251,6 +251,7 @@
       module copy                            { private header "__algorithm/copy.h" }
       module copy_backward                   { private header "__algorithm/copy_backward.h" }
       module copy_if                         { private header "__algorithm/copy_if.h" }
+      module copy_move_common                { private header "__algorithm/copy_move_common.h" }
       module copy_n                          { private header "__algorithm/copy_n.h" }
       module count                           { private header "__algorithm/count.h" }
       module count_if                        { private header "__algorithm/count_if.h" }
diff --git a/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp
deleted file mode 100644
--- a/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy.pass.cpp
+++ /dev/null
@@ -1,179 +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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14, c++17
-
-// When the debug mode is enabled, we don't unwrap iterators in std::copy
-// so we don't get this optimization.
-// UNSUPPORTED: libcpp-has-debug-mode
-
-// <algorithm>
-
-// This test checks that std::copy forwards to memmove when appropriate.
-
-#include <algorithm>
-#include <cassert>
-#include <iterator>
-#include <ranges>
-#include <type_traits>
-
-struct S {
-  int i;
-  constexpr S(int i_) : i(i_) {}
-  S(const S&) = default;
-  S(S&&) = delete;
-  constexpr S& operator=(const S&) = default;
-  S& operator=(S&&) = delete;
-  constexpr bool operator==(const S&) const = default;
-};
-
-static_assert(std::is_trivially_copyable_v<S>);
-
-template <class T>
-struct NotIncrementableIt {
-  T* i;
-  using iterator_category = std::contiguous_iterator_tag;
-  using iterator_concept = std::contiguous_iterator_tag;
-  using value_type = T;
-  using difference_type = ptrdiff_t;
-  using pointer = T*;
-  using reference = T&;
-
-  constexpr NotIncrementableIt() = default;
-  constexpr NotIncrementableIt(T* i_) : i(i_) {}
-
-  friend constexpr bool operator==(const NotIncrementableIt& lhs, const NotIncrementableIt& rhs) {
-    return lhs.i == rhs.i;
-  }
-
-  constexpr T& operator*() { return *i; }
-  constexpr T& operator*() const { return *i; }
-  constexpr T* operator->() { return i; }
-  constexpr T* operator->() const { return i; }
-
-  constexpr NotIncrementableIt& operator++() {
-    assert(false);
-    return *this;
-  }
-
-  constexpr NotIncrementableIt& operator++(int) {
-    assert(false);
-    return *this;
-  }
-
-  constexpr NotIncrementableIt& operator--() {
-    assert(false);
-    return *this;
-  }
-
-  friend constexpr NotIncrementableIt operator+(const NotIncrementableIt& it, difference_type size) { return it.i + size; }
-  friend constexpr difference_type operator-(const NotIncrementableIt& x, const NotIncrementableIt& y) { return x.i - y.i; }
-  friend constexpr NotIncrementableIt operator-(const NotIncrementableIt& x, difference_type size) { return NotIncrementableIt(x.i - size); }
-};
-
-static_assert(std::__is_cpp17_contiguous_iterator<NotIncrementableIt<S>>::value);
-
-template <size_t N, class Iter, std::enable_if_t<N == 0>* = nullptr>
-constexpr auto wrap_n_times(Iter i) {
-  return i;
-}
-
-template <size_t N, class Iter, std::enable_if_t<N != 0>* = nullptr>
-constexpr auto wrap_n_times(Iter i) {
-  return std::make_reverse_iterator(wrap_n_times<N - 1>(i));
-}
-
-static_assert(std::is_same_v<decltype(wrap_n_times<2>(std::declval<int*>())),
-                             std::reverse_iterator<std::reverse_iterator<int*>>>);
-
-template <size_t InCount, size_t OutCount, class Iter>
-constexpr void test_normal() {
-  {
-    S a[] = {1, 2, 3, 4};
-    S b[] = {0, 0, 0, 0};
-    std::copy(wrap_n_times<InCount>(Iter(a)), wrap_n_times<InCount>(Iter(a + 4)), wrap_n_times<OutCount>(Iter(b)));
-    assert(std::equal(a, a + 4, b));
-  }
-  {
-    S a[] = {1, 2, 3, 4};
-    S b[] = {0, 0, 0, 0};
-    std::ranges::copy(wrap_n_times<InCount>(Iter(a)),
-                      wrap_n_times<InCount>(Iter(a + 4)),
-                      wrap_n_times<OutCount>(Iter(b)));
-    assert(std::equal(a, a + 4, b));
-  }
-  {
-    S a[] = {1, 2, 3, 4};
-    S b[] = {0, 0, 0, 0};
-    auto range = std::ranges::subrange(wrap_n_times<InCount>(Iter(a)), wrap_n_times<InCount>(Iter(a + 4)));
-    std::ranges::copy(range, Iter(b));
-    assert(std::equal(a, a + 4, b));
-  }
-}
-
-template <size_t InCount, size_t OutCount, class Iter>
-constexpr void test_reverse() {
-  {
-    S a[] = {1, 2, 3, 4};
-    S b[] = {0, 0, 0, 0};
-    std::copy(std::make_reverse_iterator(wrap_n_times<InCount>(Iter(a + 4))),
-              std::make_reverse_iterator(wrap_n_times<InCount>(Iter(a))),
-              std::make_reverse_iterator(wrap_n_times<OutCount>(Iter(b + 4))));
-    assert(std::equal(a, a + 4, b));
-  }
-  {
-    S a[] = {1, 2, 3, 4};
-    S b[] = {0, 0, 0, 0};
-    std::ranges::copy(std::make_reverse_iterator(wrap_n_times<InCount>(Iter(a + 4))),
-                      std::make_reverse_iterator(wrap_n_times<InCount>(Iter(a))),
-                      std::make_reverse_iterator(wrap_n_times<OutCount>(Iter(b + 4))));
-    assert(std::equal(a, a + 4, b));
-  }
-  {
-    S a[] = {1, 2, 3, 4};
-    S b[] = {0, 0, 0, 0};
-    auto range = std::ranges::subrange(wrap_n_times<InCount>(std::make_reverse_iterator(Iter(a + 4))),
-                                       wrap_n_times<InCount>(std::make_reverse_iterator(Iter(a))));
-    std::ranges::copy(range, std::make_reverse_iterator(wrap_n_times<OutCount>(Iter(b + 4))));
-    assert(std::equal(a, a + 4, b));
-  }
-}
-
-template <size_t InCount, size_t OutCount>
-constexpr void test_normal_reverse() {
-  test_normal<InCount, OutCount, S*>();
-  test_normal<InCount, OutCount, NotIncrementableIt<S>>();
-  test_reverse<InCount, OutCount, S*>();
-  test_reverse<InCount, OutCount, NotIncrementableIt<S>>();
-}
-
-template <size_t InCount>
-constexpr void test_out_count() {
-  test_normal_reverse<InCount, 0>();
-  test_normal_reverse<InCount, 2>();
-  test_normal_reverse<InCount, 4>();
-  test_normal_reverse<InCount, 6>();
-  test_normal_reverse<InCount, 8>();
-}
-
-constexpr bool test() {
-  test_out_count<0>();
-  test_out_count<2>();
-  test_out_count<4>();
-  test_out_count<6>();
-  test_out_count<8>();
-
-  return true;
-}
-
-int main(int, char**) {
-  test();
-  static_assert(test());
-
-  return 0;
-}
diff --git a/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy_move_nontrivial.pass.cpp b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy_move_nontrivial.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy_move_nontrivial.pass.cpp
@@ -0,0 +1,250 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <algorithm>
+
+// These tests checks that `std::copy` and `std::move` (including their variations like `copy_n`) don't forward to
+// `std::memmove` when doing so would be observable.
+
+#include <algorithm>
+#include <cassert>
+#include <iterator>
+#include <ranges>
+#include <type_traits>
+
+#include "test_iterators.h"
+#include "test_macros.h"
+
+template <size_t N, class Iter>
+requires (N == 0)
+constexpr auto wrap_n_times(Iter i) {
+  return i;
+}
+
+template <size_t N, class Iter>
+requires (N != 0)
+constexpr auto wrap_n_times(Iter i) {
+  return std::make_reverse_iterator(wrap_n_times<N - 1>(i));
+}
+
+static_assert(std::is_same_v<decltype(wrap_n_times<2>(std::declval<int*>())),
+                             std::reverse_iterator<std::reverse_iterator<int*>>>);
+
+struct NonTrivialMoveAssignment {
+  int i;
+
+  constexpr NonTrivialMoveAssignment() = default;
+  constexpr NonTrivialMoveAssignment(int set_i) : i(set_i) {}
+
+  constexpr NonTrivialMoveAssignment(NonTrivialMoveAssignment&& rhs) = default;
+  constexpr NonTrivialMoveAssignment& operator=(NonTrivialMoveAssignment&& rhs) noexcept {
+    i = rhs.i;
+    return *this;
+  }
+
+  constexpr friend bool operator==(const NonTrivialMoveAssignment&, const NonTrivialMoveAssignment&) = default;
+};
+
+static_assert(!std::is_trivially_move_assignable_v<NonTrivialMoveAssignment>);
+
+struct NonTrivialMoveCtr {
+  int i;
+
+  constexpr NonTrivialMoveCtr() = default;
+  constexpr NonTrivialMoveCtr(int set_i) : i(set_i) {}
+
+  constexpr NonTrivialMoveCtr(NonTrivialMoveCtr&& rhs) noexcept : i(rhs.i) {}
+  constexpr NonTrivialMoveCtr& operator=(NonTrivialMoveCtr&& rhs) = default;
+
+  constexpr friend bool operator==(const NonTrivialMoveCtr&, const NonTrivialMoveCtr&) = default;
+};
+
+static_assert(std::is_trivially_move_assignable_v<NonTrivialMoveCtr>);
+static_assert(!std::is_trivially_copyable_v<NonTrivialMoveCtr>);
+
+struct NonTrivialCopyAssignment {
+  int i;
+
+  constexpr NonTrivialCopyAssignment() = default;
+  constexpr NonTrivialCopyAssignment(int set_i) : i(set_i) {}
+
+  constexpr NonTrivialCopyAssignment(const NonTrivialCopyAssignment& rhs) = default;
+  constexpr NonTrivialCopyAssignment& operator=(const NonTrivialCopyAssignment& rhs) {
+    i = rhs.i;
+    return *this;
+  }
+
+  constexpr friend bool operator==(const NonTrivialCopyAssignment&, const NonTrivialCopyAssignment&) = default;
+};
+
+static_assert(!std::is_trivially_copy_assignable_v<NonTrivialCopyAssignment>);
+
+struct NonTrivialCopyCtr {
+  int i;
+
+  constexpr NonTrivialCopyCtr() = default;
+  constexpr NonTrivialCopyCtr(int set_i) : i(set_i) {}
+
+  constexpr NonTrivialCopyCtr(const NonTrivialCopyCtr& rhs) : i(rhs.i) {}
+  constexpr NonTrivialCopyCtr& operator=(const NonTrivialCopyCtr& rhs) = default;
+
+  constexpr friend bool operator==(const NonTrivialCopyCtr&, const NonTrivialCopyCtr&) = default;
+};
+
+static_assert(std::is_trivially_copy_assignable_v<NonTrivialCopyCtr>);
+static_assert(!std::is_trivially_copyable_v<NonTrivialCopyCtr>);
+
+// Unwrapping the iterator inside `std::copy` and similar algorithms relies on `to_address`. If the `memmove`
+// optimization is used, the result of the call to `to_address` will be passed to `memmove`. This test deliberately
+// specializes `to_address` for `contiguous_iterator` to return a type that doesn't implicitly convert to `void*`, so
+// that a call to `memmove` would fail to compile.
+template <>
+struct std::pointer_traits<::contiguous_iterator<NonTrivialCopyAssignment*>> {
+  static constexpr ::contiguous_iterator<NonTrivialCopyAssignment*>
+  to_address(const ::contiguous_iterator<NonTrivialCopyAssignment*>& iter) {
+    return iter;
+  }
+};
+template <>
+struct std::pointer_traits<::contiguous_iterator<NonTrivialMoveAssignment*>> {
+  static constexpr ::contiguous_iterator<NonTrivialMoveAssignment*>
+  to_address(const ::contiguous_iterator<NonTrivialMoveAssignment*>& iter) {
+    return iter;
+  }
+};
+
+template <class InIter, template <class> class SentWrapper, class OutIter, size_t W1, size_t W2, class Func>
+constexpr void test_one(Func func) {
+  using Value = typename std::iterator_traits<InIter>::value_type;
+
+  {
+    const size_t N = 4;
+
+    Value input[N] = {Value{1}, {2}, {3}, {4}};
+    Value output[N];
+
+    auto in     = wrap_n_times<W1>(InIter(input));
+    auto in_end = wrap_n_times<W1>(InIter(input + N));
+    auto sent   = SentWrapper<decltype(in_end)>(in_end);
+    auto out    = wrap_n_times<W2>(OutIter(output));
+
+    func(in, sent, out, N);
+    assert(std::equal(input, input + N, output));
+  }
+
+  {
+    const size_t N = 0;
+
+    Value input[1]  = {1};
+    Value output[1] = {2};
+
+    auto in     = wrap_n_times<W1>(InIter(input));
+    auto in_end = wrap_n_times<W1>(InIter(input + N));
+    auto sent   = SentWrapper<decltype(in_end)>(in_end);
+    auto out    = wrap_n_times<W2>(OutIter(output));
+
+    func(in, sent, out, N);
+    assert(output[0] == Value(2));
+  }
+}
+
+template <class InIter, template <class> class SentWrapper, class OutIter, size_t W1, size_t W2>
+constexpr void test_copy() {
+  // Classic.
+  if constexpr (std::same_as<InIter, SentWrapper<InIter>>) {
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+      std::copy(first, last, out);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+      std::copy_backward(first, last, out + n);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto, auto out, size_t n) {
+      std::copy_n(first, n, out);
+    });
+  }
+
+  // Ranges.
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+    std::ranges::copy(first, last, out);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+    std::ranges::copy_backward(first, last, out + n);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto, auto out, size_t n) {
+    std::ranges::copy_n(first, n, out);
+  });
+}
+
+template <class InIter, template <class> class SentWrapper, class OutIter, size_t W1, size_t W2>
+constexpr void test_move() {
+  if constexpr (std::same_as<InIter, SentWrapper<InIter>>) {
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+      std::move(first, last, out);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+      std::move_backward(first, last, out + n);
+    });
+  }
+
+  // Ranges.
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+    std::ranges::move(first, last, out);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+    std::ranges::move_backward(first, last, out + n);
+  });
+}
+
+template <class T, size_t W1, size_t W2>
+constexpr void test_copy_with_type() {
+  using CopyIter = contiguous_iterator<T*>;
+
+  test_copy<CopyIter, std::type_identity_t, CopyIter, W1, W2>();
+  test_copy<CopyIter, sized_sentinel, CopyIter, W1, W2>();
+  test_copy<CopyIter, std::type_identity_t, T*, W1, W2>();
+  test_copy<T*, std::type_identity_t, CopyIter, W1, W2>();
+}
+
+template <class T, size_t W1, size_t W2>
+constexpr void test_move_with_type() {
+  using MoveIter = contiguous_iterator<T*>;
+
+  test_move<MoveIter, std::type_identity_t, MoveIter, W1, W2>();
+  test_move<MoveIter, sized_sentinel, MoveIter, W1, W2>();
+  test_move<MoveIter, std::type_identity_t, T*, W1, W2>();
+  test_move<T*, std::type_identity_t, MoveIter, W1, W2>();
+}
+
+template <size_t W1, size_t W2>
+constexpr void test_copy_and_move() {
+  test_copy_with_type<NonTrivialCopyAssignment, W1, W2>();
+  test_copy_with_type<NonTrivialCopyCtr, W1, W2>();
+
+  test_move_with_type<NonTrivialMoveAssignment, W1, W2>();
+  test_move_with_type<NonTrivialMoveCtr, W1, W2>();
+}
+
+constexpr bool test() {
+  test_copy_and_move<0, 0>();
+  test_copy_and_move<0, 2>();
+  test_copy_and_move<2, 0>();
+  test_copy_and_move<2, 2>();
+  test_copy_and_move<2, 4>();
+  test_copy_and_move<4, 4>();
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+
+  return 0;
+}
diff --git a/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy_move_trivial.pass.cpp b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy_move_trivial.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/algorithms/alg.modifying.operations/copy_move_trivial.pass.cpp
@@ -0,0 +1,178 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// When the debug mode is enabled, we don't unwrap iterators in `std::copy` and similar algorithms so we don't get this
+// optimization.
+// UNSUPPORTED: libcpp-has-debug-mode
+// In the modules build, adding another overload of `memmove` doesn't work.
+// UNSUPPORTED: modules-build
+
+// <algorithm>
+
+// These tests checks that `std::copy` and `std::move` (including their variations like `copy_n`) forward to
+// `memmove` when possible.
+
+#include <cstddef>
+#include <type_traits>
+
+struct Foo {
+  int i = 0;
+
+  Foo() = default;
+  Foo(int set_i) : i(set_i) {}
+
+  friend bool operator==(const Foo&, const Foo&) = default;
+};
+static_assert(std::is_trivially_copyable_v<Foo>);
+
+static bool memmove_called = false;
+
+// This overload is a better match than the actual `builtin_memmove`, so it should hijack the call inside `std::copy`
+// and similar algorithms.
+void* __builtin_memmove(Foo* dst, Foo* src, size_t count) {
+  memmove_called = true;
+  return __builtin_memmove(static_cast<void*>(dst), static_cast<void*>(src), count);
+}
+
+#include <algorithm>
+#include <cassert>
+#include <iterator>
+#include <ranges>
+
+#include "test_iterators.h"
+
+template <size_t N, class Iter>
+requires (N == 0)
+constexpr auto wrap_n_times(Iter i) {
+  return i;
+}
+
+template <size_t N, class Iter>
+requires (N != 0)
+constexpr auto wrap_n_times(Iter i) {
+  return std::make_reverse_iterator(wrap_n_times<N - 1>(i));
+}
+
+static_assert(std::is_same_v<decltype(wrap_n_times<2>(std::declval<int*>())),
+                             std::reverse_iterator<std::reverse_iterator<int*>>>);
+
+template <class InIter, template <class> class SentWrapper, class OutIter, size_t W1, size_t W2, class Func>
+void test_one(Func func) {
+  {
+    const size_t N = 4;
+
+    Foo input[N] = {{1}, {2}, {3}, {4}};
+    Foo output[N];
+
+    auto in     = wrap_n_times<W1>(InIter(input));
+    auto in_end = wrap_n_times<W1>(InIter(input + N));
+    auto sent   = SentWrapper<decltype(in_end)>(in_end);
+    auto out    = wrap_n_times<W2>(OutIter(output));
+
+    assert(!memmove_called);
+    func(in, sent, out, N);
+
+    assert(std::equal(input, input + N, output));
+    assert(memmove_called);
+    memmove_called = false;
+  }
+
+  {
+    const size_t N = 0;
+
+    Foo input[1]  = {1};
+    Foo output[1] = {2};
+
+    auto in     = wrap_n_times<W1>(InIter(input));
+    auto in_end = wrap_n_times<W1>(InIter(input + N));
+    auto sent   = SentWrapper<decltype(in_end)>(in_end);
+    auto out    = wrap_n_times<W2>(OutIter(output));
+
+    assert(!memmove_called);
+    func(in, sent, out, N);
+
+    assert(output[0] == 2);
+    assert(memmove_called);
+    memmove_called = false;
+  }
+}
+
+template <class InIter, template <class> class SentWrapper, class OutIter, size_t W1, size_t W2>
+void test_copy_and_move() {
+  // Classic.
+  if constexpr (std::same_as<InIter, SentWrapper<InIter>>) {
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+      std::copy(first, last, out);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+      std::copy_backward(first, last, out + n);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto, auto out, size_t n) {
+      std::copy_n(first, n, out);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+      std::move(first, last, out);
+    });
+    test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+      std::move_backward(first, last, out + n);
+    });
+  }
+
+  // Ranges.
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+    std::ranges::copy(first, last, out);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+    std::ranges::copy_backward(first, last, out + n);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto, auto out, size_t n) {
+    std::ranges::copy_n(first, n, out);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t) {
+    std::ranges::move(first, last, out);
+  });
+  test_one<InIter, SentWrapper, OutIter, W1, W2>([](auto first, auto last, auto out, size_t n) {
+    std::ranges::move_backward(first, last, out + n);
+  });
+}
+
+template <class InIter, template <class> class SentWrapper, class OutIter>
+void test_all_permutations_with_initer_sent_outiter() {
+  test_copy_and_move<InIter, SentWrapper, OutIter, 0, 0>();
+  test_copy_and_move<InIter, SentWrapper, OutIter, 0, 2>();
+  test_copy_and_move<InIter, SentWrapper, OutIter, 2, 0>();
+  test_copy_and_move<InIter, SentWrapper, OutIter, 2, 2>();
+  test_copy_and_move<InIter, SentWrapper, OutIter, 2, 4>();
+  test_copy_and_move<InIter, SentWrapper, OutIter, 4, 4>();
+}
+
+template <class InIter, template <class> class SentWrapper>
+void test_all_permutations_with_initer_sent() {
+  test_all_permutations_with_initer_sent_outiter<InIter, SentWrapper, Foo*>();
+  test_all_permutations_with_initer_sent_outiter<InIter, SentWrapper, contiguous_iterator<Foo*>>();
+}
+
+template <class InIter>
+void test_all_permutations_with_initer() {
+  test_all_permutations_with_initer_sent<InIter, std::type_identity_t>();
+  test_all_permutations_with_initer_sent<InIter, sized_sentinel>();
+}
+
+void test() {
+  test_all_permutations_with_initer<Foo*>();
+  test_all_permutations_with_initer<contiguous_iterator<Foo*>>();
+}
+
+int main(int, char**) {
+  test();
+  // The test relies on a global variable, so it cannot be made `constexpr`; the `memmove` optimization is not used in
+  // `constexpr` mode anyway.
+
+  return 0;
+}
diff --git a/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_iterator.compile.pass.cpp b/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_iterator.compile.pass.cpp
--- a/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_iterator.compile.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_iterator.compile.pass.cpp
@@ -15,19 +15,9 @@
 
 #include "test_iterators.h"
 
-struct ForwardProxyIterator {
-  using value_type = int;
-  using difference_type = int;
-  ForwardProxyIterator& operator++();
-  ForwardProxyIterator operator++(int);
-  bool operator==(const ForwardProxyIterator&) const;
-
-  int operator*() const;
-};
-
 static_assert(std::ranges::__nothrow_forward_iterator<forward_iterator<int*>>);
-static_assert(std::forward_iterator<ForwardProxyIterator>);
-static_assert(!std::ranges::__nothrow_forward_iterator<ForwardProxyIterator>);
+static_assert(std::forward_iterator<ForwardProxyIterator<int*>>);
+static_assert(!std::ranges::__nothrow_forward_iterator<ForwardProxyIterator<int*>>);
 
 constexpr bool forward_subsumes_input(std::ranges::__nothrow_forward_iterator auto) {
   return true;
diff --git a/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_range.compile.pass.cpp b/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_range.compile.pass.cpp
--- a/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_range.compile.pass.cpp
+++ b/libcxx/test/libcxx/algorithms/specialized.algorithms/special.mem.concepts/nothrow_forward_range.compile.pass.cpp
@@ -16,18 +16,6 @@
 #include "test_iterators.h"
 #include "test_range.h"
 
-// Has to be a template to work with `test_range`.
-template <typename>
-struct ForwardProxyIterator {
-  using value_type = int;
-  using difference_type = int;
-  ForwardProxyIterator& operator++();
-  ForwardProxyIterator operator++(int);
-  bool operator==(const ForwardProxyIterator&) const;
-
-  int operator*() const;
-};
-
 static_assert(std::ranges::__nothrow_forward_range<test_range<forward_iterator>>);
 static_assert(!std::ranges::__nothrow_forward_range<test_range<cpp20_input_iterator>>);
 static_assert(std::ranges::forward_range<test_range<ForwardProxyIterator>>);
diff --git a/libcxx/test/libcxx/private_headers.verify.cpp b/libcxx/test/libcxx/private_headers.verify.cpp
--- a/libcxx/test/libcxx/private_headers.verify.cpp
+++ b/libcxx/test/libcxx/private_headers.verify.cpp
@@ -46,6 +46,7 @@
 #include <__algorithm/copy.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/copy.h'}}
 #include <__algorithm/copy_backward.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/copy_backward.h'}}
 #include <__algorithm/copy_if.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/copy_if.h'}}
+#include <__algorithm/copy_move_common.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/copy_move_common.h'}}
 #include <__algorithm/copy_n.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/copy_n.h'}}
 #include <__algorithm/count.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/count.h'}}
 #include <__algorithm/count_if.h> // expected-error@*:* {{use of private header from outside its module: '__algorithm/count_if.h'}}
@@ -412,6 +413,7 @@
 #include <__iterator/readable_traits.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/readable_traits.h'}}
 #include <__iterator/reverse_access.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/reverse_access.h'}}
 #include <__iterator/reverse_iterator.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/reverse_iterator.h'}}
+#include <__iterator/segmented_iterator.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/segmented_iterator.h'}}
 #include <__iterator/size.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/size.h'}}
 #include <__iterator/sortable.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/sortable.h'}}
 #include <__iterator/unreachable_sentinel.h> // expected-error@*:* {{use of private header from outside its module: '__iterator/unreachable_sentinel.h'}}
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy.pass.cpp
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy.pass.cpp
@@ -20,7 +20,9 @@
 #include <algorithm>
 #include <array>
 #include <cassert>
+#include <deque>
 #include <ranges>
+#include <vector>
 
 #include "almost_satisfies_types.h"
 #include "test_iterators.h"
@@ -52,20 +54,21 @@
 
 static_assert(std::is_same_v<std::ranges::copy_result<int, long>, std::ranges::in_out_result<int, long>>);
 
+// clang-format off
 template <class In, class Out, class Sent = In>
 constexpr void test_iterators() {
   { // simple test
     {
-      std::array in {1, 2, 3, 4};
+      std::array in{1, 2, 3, 4};
       std::array<int, 4> out;
       std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
-        std::ranges::copy(In(in.data()), Sent(In(in.data() + in.size())), Out(out.data()));
+          std::ranges::copy(In(in.data()), Sent(In(in.data() + in.size())), Out(out.data()));
       assert(in == out);
       assert(base(ret.in) == in.data() + in.size());
       assert(base(ret.out) == out.data() + out.size());
     }
     {
-      std::array in {1, 2, 3, 4};
+      std::array in{1, 2, 3, 4};
       std::array<int, 4> out;
       auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
       std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::copy(range, Out(out.data()));
@@ -87,32 +90,80 @@
       std::array<int, 0> in;
       std::array<int, 0> out;
       auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
-      auto ret = std::ranges::copy(range, Out(out.data()));
+      auto ret   = std::ranges::copy(range, Out(out.data()));
       assert(base(ret.in) == in.data());
       assert(base(ret.out) == out.data());
     }
   }
 }
+// clang-format on
 
-template <class In, class Out>
+template <class InContainer, class OutContainer, class In, class Out, class Sent = In>
+constexpr void test_containers() {
+  {
+    InContainer in{1, 2, 3, 4};
+    OutContainer out(4);
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
+        std::ranges::copy(In(in.begin()), Sent(In(in.end())), Out(out.begin()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.end());
+  }
+  {
+    InContainer in{1, 2, 3, 4};
+    OutContainer out(4);
+    auto range = std::ranges::subrange(In(in.begin()), Sent(In(in.end())));
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::copy(range, Out(out.begin()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.end());
+  }
+}
+
+template <template <class> class In, template <class> class Out>
 constexpr void test_sentinels() {
-  test_iterators<In, Out>();
-  test_iterators<In, Out, sized_sentinel<In>>();
-  test_iterators<In, Out, sentinel_wrapper<In>>();
+  test_iterators<In<int*>, Out<int*>>();
+  test_iterators<In<int*>, Out<int*>, sized_sentinel<In<int*>>>();
+  test_iterators<In<int*>, Out<int*>, sentinel_wrapper<In<int*>>>();
+
+  if (!std::is_constant_evaluated()) {
+    if constexpr (!std::is_same_v<In<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<Out<int*>, contiguous_iterator<int*>>) {
+      test_containers<std::deque<int>,
+                      std::deque<int>,
+                      In<std::deque<int>::iterator>,
+                      Out<std::deque<int>::iterator>>();
+      test_containers<std::deque<int>,
+                      std::vector<int>,
+                      In<std::deque<int>::iterator>,
+                      Out<std::vector<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::deque<int>,
+                      In<std::vector<int>::iterator>,
+                      Out<std::deque<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::vector<int>,
+                      In<std::vector<int>::iterator>,
+                      Out<std::vector<int>::iterator>>();
+    }
+  }
 }
 
-template <class Out>
+template <template <class> class Out>
 constexpr void test_in_iterators() {
-  test_iterators<cpp20_input_iterator<int*>, Out, sentinel_wrapper<cpp20_input_iterator<int*>>>();
-  test_sentinels<forward_iterator<int*>, Out>();
-  test_sentinels<bidirectional_iterator<int*>, Out>();
-  test_sentinels<random_access_iterator<int*>, Out>();
-  test_sentinels<contiguous_iterator<int*>, Out>();
+  test_iterators<cpp20_input_iterator<int*>, Out<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
+  test_sentinels<forward_iterator, Out>();
+  test_sentinels<bidirectional_iterator, Out>();
+  test_sentinels<random_access_iterator, Out>();
+  test_sentinels<contiguous_iterator, Out>();
+  test_sentinels<std::type_identity_t, Out>();
 }
 
 template <class Out>
 constexpr void test_proxy_in_iterators() {
-  test_iterators<ProxyIterator<cpp20_input_iterator<int*>>, Out, sentinel_wrapper<ProxyIterator<cpp20_input_iterator<int*>>>>();
+  test_iterators<ProxyIterator<cpp20_input_iterator<int*>>,
+                 Out,
+                 sentinel_wrapper<ProxyIterator<cpp20_input_iterator<int*>>>>();
   test_iterators<ProxyIterator<forward_iterator<int*>>, Out>();
   test_iterators<ProxyIterator<bidirectional_iterator<int*>>, Out>();
   test_iterators<ProxyIterator<random_access_iterator<int*>>, Out>();
@@ -120,11 +171,12 @@
 }
 
 constexpr bool test() {
-  test_in_iterators<cpp20_input_iterator<int*>>();
-  test_in_iterators<forward_iterator<int*>>();
-  test_in_iterators<bidirectional_iterator<int*>>();
-  test_in_iterators<random_access_iterator<int*>>();
-  test_in_iterators<contiguous_iterator<int*>>();
+  test_in_iterators<cpp20_input_iterator>();
+  test_in_iterators<forward_iterator>();
+  test_in_iterators<bidirectional_iterator>();
+  test_in_iterators<random_access_iterator>();
+  test_in_iterators<contiguous_iterator>();
+  test_in_iterators<std::type_identity_t>();
 
   test_proxy_in_iterators<ProxyIterator<cpp20_input_iterator<int*>>>();
   test_proxy_in_iterators<ProxyIterator<forward_iterator<int*>>>();
@@ -135,13 +187,13 @@
   { // check that ranges::dangling is returned
     std::array<int, 4> out;
     std::same_as<std::ranges::in_out_result<std::ranges::dangling, int*>> auto ret =
-      std::ranges::copy(std::array {1, 2, 3, 4}, out.data());
+        std::ranges::copy(std::array{1, 2, 3, 4}, out.data());
     assert(ret.out == out.data() + 4);
     assert((out == std::array{1, 2, 3, 4}));
   }
 
   { // check that an iterator is returned with a borrowing range
-    std::array in {1, 2, 3, 4};
+    std::array in{1, 2, 3, 4};
     std::array<int, 4> out;
     std::same_as<std::ranges::in_out_result<int*, int*>> auto ret = std::ranges::copy(std::views::all(in), out.data());
     assert(ret.in == in.data() + 4);
@@ -151,8 +203,8 @@
 
   { // check that every element is copied exactly once
     struct CopyOnce {
-      bool copied = false;
-      constexpr CopyOnce() = default;
+      bool copied                               = false;
+      constexpr CopyOnce()                      = default;
       constexpr CopyOnce(const CopyOnce& other) = delete;
       constexpr CopyOnce& operator=(const CopyOnce& other) {
         assert(!other.copied);
@@ -161,16 +213,16 @@
       }
     };
     {
-      std::array<CopyOnce, 4> in {};
-      std::array<CopyOnce, 4> out {};
+      std::array<CopyOnce, 4> in{};
+      std::array<CopyOnce, 4> out{};
       auto ret = std::ranges::copy(in.begin(), in.end(), out.begin());
       assert(ret.in == in.end());
       assert(ret.out == out.end());
       assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
     }
     {
-      std::array<CopyOnce, 4> in {};
-      std::array<CopyOnce, 4> out {};
+      std::array<CopyOnce, 4> in{};
+      std::array<CopyOnce, 4> out{};
       auto ret = std::ranges::copy(in, out.begin());
       assert(ret.in == in.end());
       assert(ret.out == out.end());
@@ -181,8 +233,8 @@
   { // check that the range is copied forwards
     struct OnlyForwardsCopyable {
       OnlyForwardsCopyable* next = nullptr;
-      bool canCopy = false;
-      OnlyForwardsCopyable() = default;
+      bool canCopy               = false;
+      OnlyForwardsCopyable()     = default;
       constexpr OnlyForwardsCopyable& operator=(const OnlyForwardsCopyable&) {
         assert(canCopy);
         if (next != nullptr)
@@ -191,12 +243,12 @@
       }
     };
     {
-      std::array<OnlyForwardsCopyable, 3> in {};
-      std::array<OnlyForwardsCopyable, 3> out {};
-      out[0].next = &out[1];
-      out[1].next = &out[2];
+      std::array<OnlyForwardsCopyable, 3> in{};
+      std::array<OnlyForwardsCopyable, 3> out{};
+      out[0].next    = &out[1];
+      out[1].next    = &out[2];
       out[0].canCopy = true;
-      auto ret = std::ranges::copy(in.begin(), in.end(), out.begin());
+      auto ret       = std::ranges::copy(in.begin(), in.end(), out.begin());
       assert(ret.in == in.end());
       assert(ret.out == out.end());
       assert(out[0].canCopy);
@@ -204,12 +256,12 @@
       assert(out[2].canCopy);
     }
     {
-      std::array<OnlyForwardsCopyable, 3> in {};
-      std::array<OnlyForwardsCopyable, 3> out {};
-      out[0].next = &out[1];
-      out[1].next = &out[2];
+      std::array<OnlyForwardsCopyable, 3> in{};
+      std::array<OnlyForwardsCopyable, 3> out{};
+      out[0].next    = &out[1];
+      out[1].next    = &out[2];
       out[0].canCopy = true;
-      auto ret = std::ranges::copy(in, out.begin());
+      auto ret       = std::ranges::copy(in, out.begin());
       assert(ret.in == in.end());
       assert(ret.out == out.end());
       assert(out[0].canCopy);
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy_backward.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy_backward.pass.cpp
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy_backward.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.copy/ranges.copy_backward.pass.cpp
@@ -23,7 +23,9 @@
 #include <algorithm>
 #include <array>
 #include <cassert>
+#include <deque>
 #include <ranges>
+#include <vector>
 
 #include "almost_satisfies_types.h"
 #include "test_iterators.h"
@@ -99,35 +101,84 @@
   }
 }
 
-template <class InIter, class OutIter>
+template <class InContainer, class OutContainer, class In, class Out, class Sent = In>
+constexpr void test_containers() {
+  {
+    InContainer in {1, 2, 3, 4};
+    OutContainer out(4);
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
+      std::ranges::copy_backward(In(in.begin()), Sent(In(in.end())), Out(out.end()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.begin());
+  }
+  {
+    InContainer in {1, 2, 3, 4};
+    OutContainer out(4);
+    auto range = std::ranges::subrange(In(in.begin()), Sent(In(in.end())));
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::copy_backward(range, Out(out.end()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.begin());
+  }
+}
+
+template <template <class> class InIter, template <class> class OutIter>
 constexpr void test_sentinels() {
-  test_iterators<InIter, OutIter, InIter>();
-  test_iterators<InIter, OutIter, sentinel_wrapper<InIter>>();
-  test_iterators<InIter, OutIter, sized_sentinel<InIter>>();
+  test_iterators<InIter<int*>, OutIter<int*>, InIter<int*>>();
+  test_iterators<InIter<int*>, OutIter<int*>, sentinel_wrapper<InIter<int*>>>();
+  test_iterators<InIter<int*>, OutIter<int*>, sized_sentinel<InIter<int*>>>();
+
+  if (!std::is_constant_evaluated()) {
+    if constexpr (!std::is_same_v<InIter<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<OutIter<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<InIter<int*>, ContiguousProxyIterator<int*>> &&
+                  !std::is_same_v<OutIter<int*>, ContiguousProxyIterator<int*>>) {
+      test_containers<std::deque<int>,
+                      std::deque<int>,
+                      InIter<std::deque<int>::iterator>,
+                      OutIter<std::deque<int>::iterator>>();
+      test_containers<std::deque<int>,
+                      std::vector<int>,
+                      InIter<std::deque<int>::iterator>,
+                      OutIter<std::vector<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::deque<int>,
+                      InIter<std::vector<int>::iterator>,
+                      OutIter<std::deque<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::vector<int>,
+                      InIter<std::vector<int>::iterator>,
+                      OutIter<std::vector<int>::iterator>>();
+    }
+  }
 }
 
-template <class Out>
+template <template <class> class Out>
 constexpr void test_in_iterators() {
-  test_sentinels<bidirectional_iterator<int*>, Out>();
-  test_sentinels<random_access_iterator<int*>, Out>();
-  test_sentinels<contiguous_iterator<int*>, Out>();
+  test_sentinels<bidirectional_iterator, Out>();
+  test_sentinels<random_access_iterator, Out>();
+  test_sentinels<contiguous_iterator, Out>();
+  test_sentinels<std::type_identity_t, Out>();
 }
 
-template <class Out>
+template <template <class> class Out>
 constexpr void test_proxy_in_iterators() {
-  test_sentinels<ProxyIterator<bidirectional_iterator<int*>>, Out>();
-  test_sentinels<ProxyIterator<random_access_iterator<int*>>, Out>();
-  test_sentinels<ProxyIterator<contiguous_iterator<int*>>, Out>();
+  test_sentinels<BidirectionalProxyIterator, Out>();
+  test_sentinels<RandomAccessProxyIterator, Out>();
+  test_sentinels<ContiguousProxyIterator, Out>();
+  test_sentinels<ProxyIterator, Out>();
 }
 
 constexpr bool test() {
-  test_in_iterators<bidirectional_iterator<int*>>();
-  test_in_iterators<random_access_iterator<int*>>();
-  test_in_iterators<contiguous_iterator<int*>>();
+  test_in_iterators<bidirectional_iterator>();
+  test_in_iterators<random_access_iterator>();
+  test_in_iterators<contiguous_iterator>();
+  test_in_iterators<std::type_identity_t>();
 
-  test_proxy_in_iterators<ProxyIterator<bidirectional_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<random_access_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<contiguous_iterator<int*>>>();
+  test_proxy_in_iterators<BidirectionalProxyIterator>();
+  test_proxy_in_iterators<RandomAccessProxyIterator>();
+  test_proxy_in_iterators<ContiguousProxyIterator>();
 
   { // check that ranges::dangling is returned
     std::array<int, 4> out;
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move.pass.cpp
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move.pass.cpp
@@ -22,7 +22,9 @@
 #include <algorithm>
 #include <array>
 #include <cassert>
+#include <deque>
 #include <ranges>
+#include <vector>
 
 #include "almost_satisfies_types.h"
 #include "MoveOnly.h"
@@ -77,6 +79,28 @@
   }
 }
 
+template <class InContainer, class OutContainer, class In, class Out, class Sent = In>
+constexpr void test_containers() {
+  {
+    InContainer in {1, 2, 3, 4};
+    OutContainer out(4);
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
+      std::ranges::move(In(in.begin()), Sent(In(in.end())), Out(out.begin()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.end());
+  }
+  {
+    InContainer in {1, 2, 3, 4};
+    OutContainer out(4);
+    auto range = std::ranges::subrange(In(in.begin()), Sent(In(in.end())));
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::move(range, Out(out.begin()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.end());
+  }
+}
+
 template <class In, class Out, class Sent = In>
 constexpr void test_iterators() {
   // simple test
@@ -85,22 +109,57 @@
   test<In, Out, Sent, 0>({});
 }
 
-template <class Out>
+template <template <class> class In, template <class> class Out>
+constexpr void test_sentinels() {
+  test_iterators<In<int*>, Out<int*>>();
+  test_iterators<In<int*>, Out<int*>, sized_sentinel<In<int*>>>();
+  test_iterators<In<int*>, Out<int*>, sentinel_wrapper<In<int*>>>();
+
+  if (!std::is_constant_evaluated()) {
+    if constexpr (!std::is_same_v<In<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<Out<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<In<int*>, ContiguousProxyIterator<int*>> &&
+                  !std::is_same_v<Out<int*>, ContiguousProxyIterator<int*>>) {
+      test_containers<std::deque<int>,
+                      std::deque<int>,
+                      In<std::deque<int>::iterator>,
+                      Out<std::deque<int>::iterator>>();
+      test_containers<std::deque<int>,
+                      std::vector<int>,
+                      In<std::deque<int>::iterator>,
+                      Out<std::vector<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::deque<int>,
+                      In<std::vector<int>::iterator>,
+                      Out<std::deque<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::vector<int>,
+                      In<std::vector<int>::iterator>,
+                      Out<std::vector<int>::iterator>>();
+    }
+  }
+}
+
+template <template <class> class Out>
 constexpr void test_in_iterators() {
-  test_iterators<cpp20_input_iterator<int*>, Out, sentinel_wrapper<cpp20_input_iterator<int*>>>();
-  test_iterators<forward_iterator<int*>, Out>();
-  test_iterators<bidirectional_iterator<int*>, Out>();
-  test_iterators<random_access_iterator<int*>, Out>();
-  test_iterators<contiguous_iterator<int*>, Out>();
+  test_iterators<cpp20_input_iterator<int*>, Out<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
+  test_sentinels<forward_iterator, Out>();
+  test_sentinels<bidirectional_iterator, Out>();
+  test_sentinels<random_access_iterator, Out>();
+  test_sentinels<contiguous_iterator, Out>();
+  test_sentinels<std::type_identity_t, Out>();
 }
 
-template <class Out>
+template <template <class> class Out>
 constexpr void test_proxy_in_iterators() {
-  test_iterators<ProxyIterator<cpp20_input_iterator<int*>>, Out, sentinel_wrapper<ProxyIterator<cpp20_input_iterator<int*>>>>();
-  test_iterators<ProxyIterator<forward_iterator<int*>>, Out>();
-  test_iterators<ProxyIterator<bidirectional_iterator<int*>>, Out>();
-  test_iterators<ProxyIterator<random_access_iterator<int*>>, Out>();
-  test_iterators<ProxyIterator<contiguous_iterator<int*>>, Out>();
+  test_iterators<ProxyIterator<cpp20_input_iterator<int*>>,
+                 Out<int*>,
+                 sentinel_wrapper<ProxyIterator<cpp20_input_iterator<int*>>>>();
+  test_sentinels<ForwardProxyIterator, Out>();
+  test_sentinels<BidirectionalProxyIterator, Out>();
+  test_sentinels<RandomAccessProxyIterator, Out>();
+  test_sentinels<ContiguousProxyIterator, Out>();
+  test_sentinels<ProxyIterator, Out>();
 }
 
 struct IteratorWithMoveIter {
@@ -120,21 +179,27 @@
   constexpr bool operator==(const IteratorWithMoveIter& other) const = default;
 };
 
+// cpp17_intput_iterator has a defaulted template argument
+template <class Iter>
+using Cpp17InIter = cpp17_input_iterator<Iter>;
+
 constexpr bool test() {
-  test_in_iterators<cpp17_output_iterator<int*>>();
-  test_in_iterators<cpp20_output_iterator<int*>>();
-  test_in_iterators<cpp17_input_iterator<int*>>();
-  test_in_iterators<cpp20_input_iterator<int*>>();
-  test_in_iterators<forward_iterator<int*>>();
-  test_in_iterators<bidirectional_iterator<int*>>();
-  test_in_iterators<random_access_iterator<int*>>();
-  test_in_iterators<contiguous_iterator<int*>>();
-
-  test_proxy_in_iterators<ProxyIterator<cpp20_input_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<forward_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<bidirectional_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<random_access_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<contiguous_iterator<int*>>>();
+  test_in_iterators<cpp17_output_iterator>();
+  test_in_iterators<cpp20_output_iterator>();
+  test_in_iterators<Cpp17InIter>();
+  test_in_iterators<cpp20_input_iterator>();
+  test_in_iterators<forward_iterator>();
+  test_in_iterators<bidirectional_iterator>();
+  test_in_iterators<random_access_iterator>();
+  test_in_iterators<contiguous_iterator>();
+  test_in_iterators<std::type_identity_t>();
+
+  test_proxy_in_iterators<Cpp20InputProxyIterator>();
+  test_proxy_in_iterators<ForwardProxyIterator>();
+  test_proxy_in_iterators<BidirectionalProxyIterator>();
+  test_proxy_in_iterators<RandomAccessProxyIterator>();
+  test_proxy_in_iterators<ContiguousProxyIterator>();
+  test_proxy_in_iterators<ProxyIterator>();
 
   { // check that a move-only type works
     {
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move_backward.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move_backward.pass.cpp
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move_backward.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.move/ranges.move_backward.pass.cpp
@@ -22,7 +22,9 @@
 #include <algorithm>
 #include <array>
 #include <cassert>
+#include <deque>
 #include <ranges>
+#include <vector>
 
 #include "almost_satisfies_types.h"
 #include "MoveOnly.h"
@@ -85,20 +87,73 @@
   test<In, Out, Sent, 0>({});
 }
 
-template <class Out>
+template <class InContainer, class OutContainer, class In, class Out, class Sent = In>
+constexpr void test_containers() {
+  {
+    InContainer in {1, 2, 3, 4};
+    OutContainer out(4);
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
+      std::ranges::move_backward(In(in.begin()), Sent(In(in.end())), Out(out.end()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.begin());
+  }
+  {
+    InContainer in {1, 2, 3, 4};
+    OutContainer out(4);
+    auto range = std::ranges::subrange(In(in.begin()), Sent(In(in.end())));
+    std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::move_backward(range, Out(out.end()));
+    assert(std::ranges::equal(in, out));
+    assert(base(ret.in) == in.end());
+    assert(base(ret.out) == out.begin());
+  }
+}
+
+template <template <class> class InIter, template <class> class OutIter>
+constexpr void test_sentinels() {
+  test_iterators<InIter<int*>, OutIter<int*>, InIter<int*>>();
+  test_iterators<InIter<int*>, OutIter<int*>, sentinel_wrapper<InIter<int*>>>();
+  test_iterators<InIter<int*>, OutIter<int*>, sized_sentinel<InIter<int*>>>();
+
+  if (!std::is_constant_evaluated()) {
+    if constexpr (!std::is_same_v<InIter<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<OutIter<int*>, contiguous_iterator<int*>> &&
+                  !std::is_same_v<InIter<int*>, ContiguousProxyIterator<int*>> &&
+                  !std::is_same_v<OutIter<int*>, ContiguousProxyIterator<int*>>) {
+      test_containers<std::deque<int>,
+                      std::deque<int>,
+                      InIter<std::deque<int>::iterator>,
+                      OutIter<std::deque<int>::iterator>>();
+      test_containers<std::deque<int>,
+                      std::vector<int>,
+                      InIter<std::deque<int>::iterator>,
+                      OutIter<std::vector<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::deque<int>,
+                      InIter<std::vector<int>::iterator>,
+                      OutIter<std::deque<int>::iterator>>();
+      test_containers<std::vector<int>,
+                      std::vector<int>,
+                      InIter<std::vector<int>::iterator>,
+                      OutIter<std::vector<int>::iterator>>();
+    }
+  }
+}
+
+template <template <class> class Out>
 constexpr void test_in_iterators() {
-  test_iterators<bidirectional_iterator<int*>, Out, sentinel_wrapper<bidirectional_iterator<int*>>>();
-  test_iterators<bidirectional_iterator<int*>, Out>();
-  test_iterators<random_access_iterator<int*>, Out>();
-  test_iterators<contiguous_iterator<int*>, Out>();
+  test_sentinels<bidirectional_iterator, Out>();
+  test_sentinels<random_access_iterator, Out>();
+  test_sentinels<contiguous_iterator, Out>();
+  test_sentinels<std::type_identity_t, Out>();
 }
 
-template <class Out>
+template <template <class> class Out>
 constexpr void test_proxy_in_iterators() {
-  test_iterators<ProxyIterator<bidirectional_iterator<int*>>, Out, sentinel_wrapper<ProxyIterator<bidirectional_iterator<int*>>>>();
-  test_iterators<ProxyIterator<bidirectional_iterator<int*>>, Out>();
-  test_iterators<ProxyIterator<random_access_iterator<int*>>, Out>();
-  test_iterators<ProxyIterator<contiguous_iterator<int*>>, Out>();
+  test_sentinels<BidirectionalProxyIterator, Out>();
+  test_sentinels<RandomAccessProxyIterator, Out>();
+  test_sentinels<ContiguousProxyIterator, Out>();
+  test_sentinels<ProxyIterator, Out>();
 }
 
 struct IteratorWithMoveIter {
@@ -122,13 +177,15 @@
 };
 
 constexpr bool test() {
-  test_in_iterators<bidirectional_iterator<int*>>();
-  test_in_iterators<random_access_iterator<int*>>();
-  test_in_iterators<contiguous_iterator<int*>>();
-
-  test_proxy_in_iterators<ProxyIterator<bidirectional_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<random_access_iterator<int*>>>();
-  test_proxy_in_iterators<ProxyIterator<contiguous_iterator<int*>>>();
+  test_in_iterators<bidirectional_iterator>();
+  test_in_iterators<random_access_iterator>();
+  test_in_iterators<contiguous_iterator>();
+  test_in_iterators<std::type_identity_t>();
+
+  test_proxy_in_iterators<BidirectionalProxyIterator>();
+  test_proxy_in_iterators<RandomAccessProxyIterator>();
+  test_proxy_in_iterators<ContiguousProxyIterator>();
+  test_proxy_in_iterators<ProxyIterator>();
 
   { // check that a move-only type works
     {
diff --git a/libcxx/test/support/test_iterators.h b/libcxx/test/support/test_iterators.h
--- a/libcxx/test/support/test_iterators.h
+++ b/libcxx/test/support/test_iterators.h
@@ -1216,6 +1216,21 @@
 static_assert(std::indirectly_writable<ProxyIterator<int*>, Proxy<int>>);
 static_assert(std::indirectly_writable<ProxyIterator<int*>, Proxy<int&>>);
 
+template <class Iter>
+using Cpp20InputProxyIterator = ProxyIterator<cpp20_input_iterator<Iter>>;
+
+template <class Iter>
+using ForwardProxyIterator = ProxyIterator<forward_iterator<Iter>>;
+
+template <class Iter>
+using BidirectionalProxyIterator = ProxyIterator<bidirectional_iterator<Iter>>;
+
+template <class Iter>
+using RandomAccessProxyIterator = ProxyIterator<random_access_iterator<Iter>>;
+
+template <class Iter>
+using ContiguousProxyIterator = ProxyIterator<contiguous_iterator<Iter>>;
+
 template <class BaseSent>
 struct ProxySentinel {
   BaseSent base_;