diff --git a/stl/inc/__msvc_bit_utils.hpp b/stl/inc/__msvc_bit_utils.hpp
index 94b7cad7fcb..160c37d859f 100644
--- a/stl/inc/__msvc_bit_utils.hpp
+++ b/stl/inc/__msvc_bit_utils.hpp
@@ -352,6 +352,24 @@ constexpr decltype(auto) _Select_countr_zero_impl(_Fn _Callback) {
     return _Callback([](_Ty _Val) _STATIC_LAMBDA { return _Countr_zero_fallback(_Val); });
 }
 
+template <class _Ty>
+_NODISCARD constexpr int _Countl_zero(const _Ty _Val) noexcept {
+    _STL_INTERNAL_STATIC_ASSERT(_Is_standard_unsigned_integer<_Ty>);
+#if _HAS_COUNTL_ZERO_INTRINSICS
+#if (defined(_M_IX86) && !defined(_M_HYBRID_X86_ARM64)) || (defined(_M_X64) && !defined(_M_ARM64EC))
+    if (!_Is_constant_evaluated()) {
+        return _Checked_x86_x64_countl_zero(_Val);
+    }
+#elif defined(_M_ARM64) || defined(_M_ARM64EC) || defined(_M_HYBRID_X86_ARM64)
+    if (!_Is_constant_evaluated()) {
+        return _Checked_arm64_countl_zero(_Val);
+    }
+#endif // defined(_M_ARM64) || defined(_M_ARM64EC) || defined(_M_HYBRID_X86_ARM64)
+#endif // _HAS_COUNTL_ZERO_INTRINSICS
+
+    return _Countl_zero_fallback(_Val);
+}
+
 template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
 _NODISCARD _CONSTEXPR20 int _Popcount(const _Ty _Val) noexcept {
 #if _HAS_POPCNT_INTRINSICS
diff --git a/stl/inc/__msvc_int128.hpp b/stl/inc/__msvc_int128.hpp
index 34f9bc99003..08b0267cafe 100644
--- a/stl/inc/__msvc_int128.hpp
+++ b/stl/inc/__msvc_int128.hpp
@@ -48,24 +48,6 @@ _STD_BEGIN
 #define _STL_128_DIV_INTRINSICS 0
 #endif // ^^^ intrinsics unavailable ^^^
 
-template <class _Ty>
-_NODISCARD constexpr int _Countl_zero_internal(const _Ty _Val) noexcept {
-    _STL_INTERNAL_STATIC_ASSERT(_Is_standard_unsigned_integer<_Ty>);
-#if _HAS_COUNTL_ZERO_INTRINSICS
-#if (defined(_M_IX86) && !defined(_M_HYBRID_X86_ARM64)) || (defined(_M_X64) && !defined(_M_ARM64EC))
-    if (!_Is_constant_evaluated()) {
-        return _Checked_x86_x64_countl_zero(_Val);
-    }
-#elif defined(_M_ARM64) || defined(_M_ARM64EC) || defined(_M_HYBRID_X86_ARM64)
-    if (!_Is_constant_evaluated()) {
-        return _Checked_arm64_countl_zero(_Val);
-    }
-#endif // defined(_M_ARM64) || defined(_M_ARM64EC) || defined(_M_HYBRID_X86_ARM64)
-#endif // _HAS_COUNTL_ZERO_INTRINSICS
-
-    return _Countl_zero_fallback(_Val);
-}
-
 struct alignas(16) _Base128 {
     uint64_t _Word[2];
 
@@ -258,7 +240,7 @@ struct alignas(16) _Base128 {
         }
 #endif // _STL_128_DIV_INTRINSICS
 
-        const auto __d = _Countl_zero_internal(static_cast<uint32_t>(_Div >> 32));
+        const auto __d = _Countl_zero(static_cast<uint32_t>(_Div >> 32));
         if (__d >= 32) { // _Div < 2^32
             auto _Rem    = (_High << 32) | (_Low >> 32);
             auto _Result = _Rem / static_cast<uint32_t>(_Div);
@@ -466,7 +448,7 @@ struct alignas(16) _Base128 {
         // _STL_INTERNAL_CHECK(_Den._Word[1] != 0);
         // _STL_INTERNAL_CHECK(_Num._Word[1] > _Den._Word[1]);
         // Normalize by shifting both left until _Den's high bit is set (So _Den's high digit is >= b / 2)
-        const auto __d = _Countl_zero_internal(_Den._Word[1]);
+        const auto __d = _Countl_zero(_Den._Word[1]);
         _Den <<= __d;
         auto _High_digit = __d == 0 ? 0 : _Num._Word[1] >> (64 - __d); // This creates a third digit for _Num
         _Num <<= __d;
@@ -511,7 +493,7 @@ struct alignas(16) _Base128 {
         }
         return __qhat;
 #else // ^^^ 128-bit intrinsics / no such intrinsics vvv
-        auto __d                   = _Countl_zero_internal(_Den._Word[1]);
+        auto __d                   = _Countl_zero(_Den._Word[1]);
         const bool _Three_word_den = __d >= 32;
         __d &= 31;
         uint32_t __u[5]{
@@ -591,7 +573,7 @@ struct alignas(16) _Base128 {
         // _STL_INTERNAL_CHECK(_Den._Word[1] != 0);
         // _STL_INTERNAL_CHECK(_Num._Word[1] > _Den._Word[1]);
         // Normalize by shifting both left until _Den's high bit is set (So _Den's high digit is >= b / 2)
-        const auto __d = _Countl_zero_internal(_Den._Word[1]);
+        const auto __d = _Countl_zero(_Den._Word[1]);
         _Den <<= __d;
         auto _High_digit = __d == 0 ? 0 : _Num._Word[1] >> (64 - __d); // This creates a third digit for _Num
         _Num <<= __d;
@@ -638,7 +620,7 @@ struct alignas(16) _Base128 {
             (void) _AddCarry64(_Carry, _Num._Word[1], _Den._Word[1], _Num._Word[1]);
         }
 #else // ^^^ 128-bit intrinsics / no such intrinsics vvv
-        auto __d                   = _Countl_zero_internal(_Den._Word[1]);
+        auto __d                   = _Countl_zero(_Den._Word[1]);
         const bool _Three_word_den = __d >= 32;
         __d &= 31;
         uint32_t __u[5]{
@@ -748,7 +730,7 @@ struct alignas(16) _Base128 {
         // _STL_INTERNAL_CHECK(_Den._Word[1] != 0);
         // _STL_INTERNAL_CHECK(_Num._Word[1] > _Den._Word[1]);
         // Normalize by shifting both left until _Den's high bit is set (So _Den's high digit is >= b / 2)
-        const auto __d = _STD _Countl_zero_internal(_Den._Word[1]);
+        const auto __d = _STD _Countl_zero(_Den._Word[1]);
         _Den <<= __d;
         auto _High_digit = __d == 0 ? 0 : _Num._Word[1] >> (64 - __d); // This creates a third digit for _Num
         _Num <<= __d;
@@ -795,7 +777,7 @@ struct alignas(16) _Base128 {
         }
         _Result = __qhat;
 #else // ^^^ 128-bit intrinsics / no such intrinsics vvv
-        auto __d                   = _Countl_zero_internal(_Den._Word[1]);
+        auto __d                   = _Countl_zero(_Den._Word[1]);
         const bool _Three_word_den = __d >= 32;
         __d &= 31;
         uint32_t __u[5]{
diff --git a/stl/inc/bit b/stl/inc/bit
index 2b6d9195930..94a5cedd990 100644
--- a/stl/inc/bit
+++ b/stl/inc/bit
@@ -198,24 +198,12 @@ _NODISCARD constexpr _Ty rotr(const _Ty _Val, const int _Rotation) noexcept {
 
 _EXPORT_STD template <_Standard_unsigned_integral _Ty>
 _NODISCARD constexpr int countl_zero(const _Ty _Val) noexcept {
-#if _HAS_COUNTL_ZERO_INTRINSICS
-#if (defined(_M_IX86) && !defined(_M_HYBRID_X86_ARM64)) || (defined(_M_X64) && !defined(_M_ARM64EC))
-    if (!_STD is_constant_evaluated()) {
-        return _Checked_x86_x64_countl_zero(_Val);
-    }
-#elif defined(_M_ARM64) || defined(_M_ARM64EC) || defined(_M_HYBRID_X86_ARM64)
-    if (!_STD is_constant_evaluated()) {
-        return _Checked_arm64_countl_zero(_Val);
-    }
-#endif // defined(_M_ARM64) || defined(_M_ARM64EC) || defined(_M_HYBRID_X86_ARM64)
-#endif // _HAS_COUNTL_ZERO_INTRINSICS
-
-    return _Countl_zero_fallback(_Val);
+    return _Countl_zero(_Val);
 }
 
 _EXPORT_STD template <_Standard_unsigned_integral _Ty>
 _NODISCARD constexpr int countl_one(const _Ty _Val) noexcept {
-    return _STD countl_zero(static_cast<_Ty>(~_Val));
+    return _Countl_zero(static_cast<_Ty>(~_Val));
 }
 
 _EXPORT_STD template <_Standard_unsigned_integral _Ty>
diff --git a/stl/inc/random b/stl/inc/random
index 90ae36415a5..a275ca4e7f0 100644
--- a/stl/inc/random
+++ b/stl/inc/random
@@ -2583,7 +2583,7 @@ _NODISCARD _Flt _Float_upper_bound(_Ty _Val) noexcept {
         constexpr auto _Mask = static_cast<_Ty>(-1) << (_Ty_digits - _Flt_digits);
 #ifdef _M_CEE_PURE
         constexpr auto _Ty_32or64_digits = numeric_limits<_Ty_32or64>::digits;
-        const auto _Log_plus1 = _Ty_32or64_digits - _Countl_zero_internal(static_cast<_Ty_32or64>(_Val | _Ty{1}));
+        const auto _Log_plus1            = _Ty_32or64_digits - _Countl_zero(static_cast<_Ty_32or64>(_Val | _Ty{1}));
 #else // ^^^ defined(_M_CEE_PURE) / !defined(_M_CEE_PURE) vvv
         const auto _Log_plus1 = _Bit_scan_reverse(static_cast<_Ty_32or64>(_Val | _Ty{1}));
 #endif // ^^^ !defined(_M_CEE_PURE) ^^^