diff --git a/libcxx/benchmarks/CMakeLists.txt b/libcxx/benchmarks/CMakeLists.txt
--- a/libcxx/benchmarks/CMakeLists.txt
+++ b/libcxx/benchmarks/CMakeLists.txt
@@ -153,6 +153,7 @@
 #==============================================================================
 set(BENCHMARK_TESTS
     algorithms.partition_point.bench.cpp
+    algorithms/count.bench.cpp
     algorithms/equal.bench.cpp
     algorithms/find.bench.cpp
     algorithms/lower_bound.bench.cpp
diff --git a/libcxx/benchmarks/algorithms/count.bench.cpp b/libcxx/benchmarks/algorithms/count.bench.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/benchmarks/algorithms/count.bench.cpp
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 <benchmark/benchmark.h>
+#include <cstring>
+#include <random>
+#include <vector>
+
+static void bm_vector_bool_count(benchmark::State& state) {
+  std::vector<bool> vec1(state.range(), false);
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(vec1);
+    benchmark::DoNotOptimize(std::count(vec1.begin(), vec1.end(), true));
+  }
+}
+BENCHMARK(bm_vector_bool_count)->DenseRange(1, 8)->Range(16, 1 << 20);
+
+static void bm_vector_bool_ranges_count(benchmark::State& state) {
+  std::vector<bool> vec1(state.range(), false);
+
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(vec1);
+    benchmark::DoNotOptimize(std::ranges::count(vec1.begin(), vec1.end(), true));
+  }
+}
+BENCHMARK(bm_vector_bool_ranges_count)->DenseRange(1, 8)->Range(16, 1 << 20);
+
+BENCHMARK_MAIN();
diff --git a/libcxx/include/__algorithm/count.h b/libcxx/include/__algorithm/count.h
--- a/libcxx/include/__algorithm/count.h
+++ b/libcxx/include/__algorithm/count.h
@@ -10,7 +10,13 @@
 #ifndef _LIBCPP___ALGORITHM_COUNT_H
 #define _LIBCPP___ALGORITHM_COUNT_H
 
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
+#include <__bit/invert_if.h>
+#include <__bit/popcount.h>
 #include <__config>
+#include <__functional/identity.h>
+#include <__fwd/bit_reference.h>
 #include <__iterator/iterator_traits.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -19,17 +25,63 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _InputIterator, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
-    typename iterator_traits<_InputIterator>::difference_type
-    count(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
-  typename iterator_traits<_InputIterator>::difference_type __r(0);
+// generic implementation
+template <class _AlgPolicy, class _Iter, class _Sent, class _Tp, class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __policy_diff_t<_AlgPolicy, _Iter>
+__count_impl(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) {
+  __policy_diff_t<_AlgPolicy, _Iter> __r(0);
   for (; __first != __last; ++__first)
-    if (*__first == __value)
+    if (std::__invoke(__proj, *__first) == __value)
       ++__r;
   return __r;
 }
 
+// __bit_iterator implementation
+
+template <bool _ToCount, class _Cp, bool _IsConst>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 typename __bit_iterator<_Cp, _IsConst>::difference_type
+__count_bool(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n) {
+  using _It             = __bit_iterator<_Cp, _IsConst>;
+  using __storage_type  = typename _It::__storage_type;
+  using difference_type = typename _It::difference_type;
+
+  const int __bits_per_word = _It::__bits_per_word;
+  difference_type __r       = 0;
+  // do first partial word
+  if (__first.__ctz_ != 0) {
+    __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+    __storage_type __dn    = std::min(__clz_f, __n);
+    __storage_type __m     = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+    __r                    = std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m);
+    __n -= __dn;
+    ++__first.__seg_;
+  }
+  // do middle whole words
+  for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
+    __r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_));
+  // do last partial word
+  if (__n > 0) {
+    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+    __r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m);
+  }
+  return __r;
+}
+
+template <class, class _Cp, bool _IsConst, class _Tp, class _Proj, __enable_if_t<__is_identity<_Proj>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 __iter_diff_t<__bit_iterator<_Cp, _IsConst> >
+__count_impl(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value, _Proj&) {
+  if (__value)
+    return std::__count_bool<true>(__first, static_cast<typename _Cp::size_type>(__last - __first));
+  return std::__count_bool<false>(__first, static_cast<typename _Cp::size_type>(__last - __first));
+}
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<_InputIterator>
+count(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
+  __identity __proj;
+  return std::__count_impl<_ClassicAlgPolicy>(__first, __last, __value, __proj);
+}
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_COUNT_H
diff --git a/libcxx/include/__algorithm/iterator_operations.h b/libcxx/include/__algorithm/iterator_operations.h
--- a/libcxx/include/__algorithm/iterator_operations.h
+++ b/libcxx/include/__algorithm/iterator_operations.h
@@ -173,6 +173,9 @@
   }
 };
 
+template <class _AlgPolicy, class _Iter>
+using __policy_diff_t = typename _IterOps<_AlgPolicy>::template __difference_type<_Iter>;
+
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
diff --git a/libcxx/include/__algorithm/ranges_count.h b/libcxx/include/__algorithm/ranges_count.h
--- a/libcxx/include/__algorithm/ranges_count.h
+++ b/libcxx/include/__algorithm/ranges_count.h
@@ -9,7 +9,7 @@
 #ifndef _LIBCPP___ALGORITHM_RANGES_COUNT_H
 #define _LIBCPP___ALGORITHM_RANGES_COUNT_H
 
-#include <__algorithm/ranges_count_if.h>
+#include <__algorithm/count.h>
 #include <__config>
 #include <__functional/identity.h>
 #include <__functional/ranges_operations.h>
@@ -36,16 +36,14 @@
     requires indirect_binary_predicate<ranges::equal_to, projected<_Iter, _Proj>, const _Type*>
   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
   operator()(_Iter __first, _Sent __last, const _Type& __value, _Proj __proj = {}) const {
-    auto __pred = [&](auto&& __e) { return __e == __value; };
-    return ranges::__count_if_impl(std::move(__first), std::move(__last), __pred, __proj);
+    return std::__count_impl<_RangeAlgPolicy>(std::move(__first), std::move(__last), __value, __proj);
   }
 
   template <input_range _Range, class _Type, class _Proj = identity>
     requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<_Range>, _Proj>, const _Type*>
   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr range_difference_t<_Range>
   operator()(_Range&& __r, const _Type& __value, _Proj __proj = {}) const {
-    auto __pred = [&](auto&& __e) { return __e == __value; };
-    return ranges::__count_if_impl(ranges::begin(__r), ranges::end(__r), __pred, __proj);
+    return std::__count_impl<_RangeAlgPolicy>(ranges::begin(__r), ranges::end(__r), __value, __proj);
   }
 };
 } // namespace __count
diff --git a/libcxx/include/__bit_reference b/libcxx/include/__bit_reference
--- a/libcxx/include/__bit_reference
+++ b/libcxx/include/__bit_reference
@@ -171,45 +171,6 @@
   __bit_const_reference& operator=(const __bit_const_reference&) = delete;
 };
 
-// count
-
-template <bool _ToCount, class _Cp, bool _IsConst>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 typename __bit_iterator<_Cp, _IsConst>::difference_type
-__count_bool(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n) {
-  using _It             = __bit_iterator<_Cp, _IsConst>;
-  using __storage_type  = typename _It::__storage_type;
-  using difference_type = typename _It::difference_type;
-
-  const int __bits_per_word = _It::__bits_per_word;
-  difference_type __r       = 0;
-  // do first partial word
-  if (__first.__ctz_ != 0) {
-    __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
-    __storage_type __dn    = std::min(__clz_f, __n);
-    __storage_type __m     = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
-    __r                    = std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m);
-    __n -= __dn;
-    ++__first.__seg_;
-  }
-  // do middle whole words
-  for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
-    __r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_));
-  // do last partial word
-  if (__n > 0) {
-    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
-    __r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m);
-  }
-  return __r;
-}
-
-template <class _Cp, bool _IsConst, class _Tp>
-inline _LIBCPP_HIDE_FROM_ABI typename __bit_iterator<_Cp, _IsConst>::difference_type
-count(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value) {
-  if (static_cast<bool>(__value))
-    return std::__count_bool<true>(__first, static_cast<typename _Cp::size_type>(__last - __first));
-  return std::__count_bool<false>(__first, static_cast<typename _Cp::size_type>(__last - __first));
-}
-
 // fill_n
 
 template <bool _FillValue, class _Cp>
diff --git a/libcxx/include/bitset b/libcxx/include/bitset
--- a/libcxx/include/bitset
+++ b/libcxx/include/bitset
@@ -112,6 +112,7 @@
 
 */
 
+#include <__algorithm/count.h>
 #include <__algorithm/fill.h>
 #include <__algorithm/find.h>
 #include <__assert> // all public C++ headers provide the assertion handler
@@ -1013,7 +1014,7 @@
 size_t
 bitset<_Size>::count() const _NOEXCEPT
 {
-    return static_cast<size_t>(_VSTD::__count_bool<true>(base::__make_iter(0), _Size));
+    return static_cast<size_t>(std::count(base::__make_iter(0), base::__make_iter(_Size), true));
 }
 
 template <size_t _Size>