diff --git a/stl/inc/limits b/stl/inc/limits
index 9421c6d3088..bd7225aa540 100644
--- a/stl/inc/limits
+++ b/stl/inc/limits
@@ -1051,9 +1051,20 @@ _NODISCARD constexpr int _Popcount_fallback(_Ty _Val) noexcept {
     return static_cast<int>(_Val >> (_Digits - 8));
 }
 
-#if defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
+#if (defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))) && !defined(_M_CEE_PURE) && !defined(__CUDACC__) \
+    && !defined(__INTEL_COMPILER)
+#define _HAS_TZCNT_BSF_INTRINSICS 1
+#else // ^^^ intrinsics available ^^^ / vvv intrinsics unavailable vvv
+#define _HAS_TZCNT_BSF_INTRINSICS 0
+#endif // ^^^ intrinsics unavailable ^^^
+
+#if _HAS_TZCNT_BSF_INTRINSICS
 extern "C" {
 extern int __isa_available;
+}
+
+#if _HAS_CXX20
+
 #ifdef __clang__
 #define _TZCNT_U32 __builtin_ia32_tzcnt_u32
 #define _TZCNT_U64 __builtin_ia32_tzcnt_u64
@@ -1061,7 +1072,6 @@ extern int __isa_available;
 #define _TZCNT_U32 _tzcnt_u32
 #define _TZCNT_U64 _tzcnt_u64
 #endif // __clang__
-}
 
 template <class _Ty>
 _NODISCARD int _Countr_zero_tzcnt(const _Ty _Val) noexcept {
@@ -1088,6 +1098,9 @@ _NODISCARD int _Countr_zero_tzcnt(const _Ty _Val) noexcept {
     }
 }
 
+#undef _TZCNT_U32
+#undef _TZCNT_U64
+
 template <class _Ty>
 _NODISCARD int _Countr_zero_bsf(const _Ty _Val) noexcept {
     constexpr int _Digits = numeric_limits<_Ty>::digits;
@@ -1137,9 +1150,9 @@ _NODISCARD int _Checked_x86_x64_countr_zero(const _Ty _Val) noexcept {
 #endif // __AVX2__
 }
 
-#undef _TZCNT_U32
-#undef _TZCNT_U64
-#endif // defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
+#endif // _HAS_CXX20
+
+#endif // _HAS_TZCNT_BSF_INTRINSICS
 
 #if (defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))) && !defined(_M_CEE_PURE) && !defined(__CUDACC__) \
     && !defined(__INTEL_COMPILER)
@@ -1190,13 +1203,11 @@ constexpr bool _Is_standard_unsigned_integer =
 
 template <class _Ty, enable_if_t<_Is_standard_unsigned_integer<_Ty>, int> = 0>
 _NODISCARD constexpr int _Countr_zero(const _Ty _Val) noexcept {
-#if defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
-#if _HAS_CXX20
+#if _HAS_CXX20 && _HAS_TZCNT_BSF_INTRINSICS
     if (!_STD is_constant_evaluated()) {
         return _Checked_x86_x64_countr_zero(_Val);
     }
-#endif // _HAS_CXX20
-#endif // defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
+#endif // _HAS_CXX20 && _HAS_TZCNT_BSF_INTRINSICS
     // C++17 constexpr gcd() calls this function, so it should be constexpr unless we detect runtime evaluation.
     return _Countr_zero_fallback(_Val);
 }
@@ -1243,6 +1254,7 @@ _CONSTEXPR20 decltype(auto) _Select_popcount_impl(_Fn _Callback) {
 }
 
 #undef _HAS_POPCNT_INTRINSICS
+#undef _HAS_TZCNT_BSF_INTRINSICS
 #undef _HAS_NEON_INTRINSICS
 
 _STD_END
diff --git a/tests/std/tests/GH_001103_countl_zero_correctness/test.cpp b/tests/std/tests/GH_001103_countl_zero_correctness/test.cpp
index f9b389658e6..b2465871e13 100644
--- a/tests/std/tests/GH_001103_countl_zero_correctness/test.cpp
+++ b/tests/std/tests/GH_001103_countl_zero_correctness/test.cpp
@@ -3,13 +3,11 @@
 
 #include <bit>
 #include <cassert>
+#include <limits>
 
-// Indirectly test countl_zero on old x86/x64 processors by testing a private helper,
+// Indirectly test countl_zero/countr_zero on old x86/x64 processors by testing a private helper,
 // which is different from the usual branch.
 
-// Currently need this test only in C++20 mode;
-// may update to older C++ if the helper is used internally too, for example in <bitset>.
-
 using namespace std;
 
 int main() {
@@ -42,26 +40,31 @@ int main() {
 
     assert(_Countr_zero_bsf(static_cast<unsigned char>(0x00)) == 8);
     assert(_Countr_zero_bsf(static_cast<unsigned char>(0x13)) == 0);
+    assert(_Countr_zero_bsf(static_cast<unsigned char>(0x82)) == 1);
     assert(_Countr_zero_bsf(static_cast<unsigned char>(0x80)) == 7);
     assert(_Countr_zero_bsf(static_cast<unsigned char>(0xF8)) == 3);
 
     assert(_Countr_zero_bsf(static_cast<unsigned short>(0x0000)) == 16);
     assert(_Countr_zero_bsf(static_cast<unsigned short>(0x0013)) == 0);
+    assert(_Countr_zero_bsf(static_cast<unsigned short>(0x8002)) == 1);
     assert(_Countr_zero_bsf(static_cast<unsigned short>(0x8000)) == 15);
     assert(_Countr_zero_bsf(static_cast<unsigned short>(0xF008)) == 3);
 
     assert(_Countr_zero_bsf(static_cast<unsigned int>(0x0000'0000)) == 32);
     assert(_Countr_zero_bsf(static_cast<unsigned int>(0x0000'0013)) == 0);
+    assert(_Countr_zero_bsf(static_cast<unsigned int>(0x8000'0002)) == 1);
     assert(_Countr_zero_bsf(static_cast<unsigned int>(0x8000'0000)) == 31);
     assert(_Countr_zero_bsf(static_cast<unsigned int>(0xF000'0008)) == 3);
 
     assert(_Countr_zero_bsf(static_cast<unsigned long>(0x0000'0000)) == 32);
     assert(_Countr_zero_bsf(static_cast<unsigned long>(0x0000'0013)) == 0);
+    assert(_Countr_zero_bsf(static_cast<unsigned long>(0x8000'0002)) == 1);
     assert(_Countr_zero_bsf(static_cast<unsigned long>(0x8000'0000)) == 31);
     assert(_Countr_zero_bsf(static_cast<unsigned long>(0xF000'0008)) == 3);
 
     assert(_Countr_zero_bsf(static_cast<unsigned long long>(0x0000'0000'0000'0000)) == 64);
     assert(_Countr_zero_bsf(static_cast<unsigned long long>(0x0000'0000'0000'0013)) == 0);
+    assert(_Countr_zero_bsf(static_cast<unsigned long long>(0x8000'0000'0000'0002)) == 1);
     assert(_Countr_zero_bsf(static_cast<unsigned long long>(0x8000'0000'0000'0000)) == 63);
     assert(_Countr_zero_bsf(static_cast<unsigned long long>(0xF000'0000'0000'0008)) == 3);
 #endif // ^^^ defined(_M_IX86) || defined(_M_X64) ^^^