diff --git a/libcxx/include/__numeric/clamp_to_integral.h b/libcxx/include/__numeric/clamp_to_integral.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__numeric/clamp_to_integral.h
@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___NUMERIC_CLAMP_TO_INTEGRAL_H
+#define _LIBCPP___NUMERIC_CLAMP_TO_INTEGRAL_H
+
+#include <__config>
+#include <cmath>
+#include <limits>
+#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 _IntT, class _FloatT,
+    bool _FloatBigger = (numeric_limits<_FloatT>::digits > numeric_limits<_IntT>::digits),
+    int _Bits = (numeric_limits<_IntT>::digits - numeric_limits<_FloatT>::digits)>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR _IntT __max_representable_int_for_float() _NOEXCEPT {
+  static_assert(is_floating_point<_FloatT>::value, "must be a floating point type");
+  static_assert(is_integral<_IntT>::value, "must be an integral type");
+  static_assert(numeric_limits<_FloatT>::radix == 2, "FloatT has incorrect radix");
+  static_assert((_IsSame<_FloatT, float>::value || _IsSame<_FloatT, double>::value
+                 || _IsSame<_FloatT,long double>::value), "unsupported floating point type");
+  return _FloatBigger ? numeric_limits<_IntT>::max() :  (numeric_limits<_IntT>::max() >> _Bits << _Bits);
+}
+
+// Convert a floating point number to the specified integral type after
+// clamping to the integral types representable range.
+//
+// The behavior is undefined if `__r` is NaN.
+template <class _IntT, class _RealT>
+_LIBCPP_INLINE_VISIBILITY
+_IntT __clamp_to_integral(_RealT __r) _NOEXCEPT {
+  using _Lim = numeric_limits<_IntT>;
+  const _IntT _MaxVal = __max_representable_int_for_float<_IntT, _RealT>();
+  if (__r >= ::nextafter(static_cast<_RealT>(_MaxVal), INFINITY)) {
+    return _Lim::max();
+  } else if (__r <= _Lim::lowest()) {
+    return _Lim::min();
+  }
+  return static_cast<_IntT>(__r);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___NUMERIC_CLAMP_TO_INTEGRAL_H
diff --git a/libcxx/include/__random/poisson_distribution.h b/libcxx/include/__random/poisson_distribution.h
--- a/libcxx/include/__random/poisson_distribution.h
+++ b/libcxx/include/__random/poisson_distribution.h
@@ -10,6 +10,7 @@
 #define _LIBCPP___RANDOM_POISSON_DISTRIBUTION_H
 
 #include <__config>
+#include <__numeric/clamp_to_integral.h>
 #include <__random/exponential_distribution.h>
 #include <__random/normal_distribution.h>
 #include <__random/uniform_real_distribution.h>
diff --git a/libcxx/include/cmath b/libcxx/include/cmath
--- a/libcxx/include/cmath
+++ b/libcxx/include/cmath
@@ -638,36 +638,6 @@
 
 #endif // _LIBCPP_STD_VER > 17
 
-template <class _IntT, class _FloatT,
-    bool _FloatBigger = (numeric_limits<_FloatT>::digits > numeric_limits<_IntT>::digits),
-    int _Bits = (numeric_limits<_IntT>::digits - numeric_limits<_FloatT>::digits)>
-_LIBCPP_INLINE_VISIBILITY
-_LIBCPP_CONSTEXPR _IntT __max_representable_int_for_float() _NOEXCEPT {
-  static_assert(is_floating_point<_FloatT>::value, "must be a floating point type");
-  static_assert(is_integral<_IntT>::value, "must be an integral type");
-  static_assert(numeric_limits<_FloatT>::radix == 2, "FloatT has incorrect radix");
-  static_assert((_IsSame<_FloatT, float>::value || _IsSame<_FloatT, double>::value
-                 || _IsSame<_FloatT,long double>::value), "unsupported floating point type");
-  return _FloatBigger ? numeric_limits<_IntT>::max() :  (numeric_limits<_IntT>::max() >> _Bits << _Bits);
-}
-
-// Convert a floating point number to the specified integral type after
-// clamping to the integral types representable range.
-//
-// The behavior is undefined if `__r` is NaN.
-template <class _IntT, class _RealT>
-_LIBCPP_INLINE_VISIBILITY
-_IntT __clamp_to_integral(_RealT __r) _NOEXCEPT {
-  using _Lim = numeric_limits<_IntT>;
-  const _IntT _MaxVal = __max_representable_int_for_float<_IntT, _RealT>();
-  if (__r >= ::nextafter(static_cast<_RealT>(_MaxVal), INFINITY)) {
-    return _Lim::max();
-  } else if (__r <= _Lim::lowest()) {
-    return _Lim::min();
-  }
-  return static_cast<_IntT>(__r);
-}
-
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -667,6 +667,7 @@
     module __numeric {
       module accumulate               { private header "__numeric/accumulate.h" }
       module adjacent_difference      { private header "__numeric/adjacent_difference.h" }
+      module clamp_to_integral        { private header "__numeric/clamp_to_integral.h" }
       module exclusive_scan           { private header "__numeric/exclusive_scan.h" }
       module gcd_lcm                  { private header "__numeric/gcd_lcm.h" }
       module inclusive_scan           { private header "__numeric/inclusive_scan.h" }
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/numeric/clamp_to_integral.module.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/numeric/clamp_to_integral.module.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/numeric/clamp_to_integral.module.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__numeric/clamp_to_integral.h'}}
+#include <__numeric/clamp_to_integral.h>
diff --git a/libcxx/test/libcxx/numerics/clamp_to_integral.pass.cpp b/libcxx/test/libcxx/numerics/clamp_to_integral.pass.cpp
--- a/libcxx/test/libcxx/numerics/clamp_to_integral.pass.cpp
+++ b/libcxx/test/libcxx/numerics/clamp_to_integral.pass.cpp
@@ -12,9 +12,10 @@
 // closest representable value for the specified integer type, or
 // numeric_limits<IntT>::max()/min() if the value isn't representable.
 
-#include <limits>
 #include <cassert>
 #include <cmath>
+#include <limits>
+#include <numeric>
 
 template <class IntT>
 void test() {