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diff --git a/libcxx/include/__algorithm/ranges_is_partitioned.h b/libcxx/include/__algorithm/ranges_is_partitioned.h
new file mode 100644
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+++ b/libcxx/include/__algorithm/ranges_is_partitioned.h
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+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_IS_PARTITIONED_H
+#define _LIBCPP___ALGORITHM_RANGES_IS_PARTITIONED_H
+
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/indirectly_comparable.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __is_partitioned {
+struct __fn {
+
+  template <class _Iter, class _Sent, class _Proj, class _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  bool __is_parititioned_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
+    for (; __first != __last; ++__first) {
+      if (!std::invoke(__pred, std::invoke(__proj, *__first)))
+        break;
+    }
+
+    if (__first == __last)
+      return true;
+    ++__first;
+
+    for (; __first != __last; ++__first) {
+      if (std::invoke(__pred, std::invoke(__proj, *__first)))
+        return false;
+    }
+
+    return true;
+  }
+
+  template <input_iterator _Iter, sentinel_for<_Iter> _Sent,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
+    return __is_parititioned_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+
+  template <input_range _Range,
+            class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
+    return __is_parititioned_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
+  }
+};
+} // namespace __is_partitioned
+
+inline namespace __cpo {
+  inline constexpr auto is_partitioned = __is_partitioned::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP___ALGORITHM_RANGES_IS_PARTITIONED_H