diff --git a/libcxx/include/__utility/cmp.h b/libcxx/include/__utility/cmp.h
index 14dc0c154c040..a3160349c4750 100644
--- a/libcxx/include/__utility/cmp.h
+++ b/libcxx/include/__utility/cmp.h
@@ -26,10 +26,18 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 20
 
+template <__signed_or_unsigned_integer _Tp, __signed_integer _Ip>
+inline _LIBCPP_HIDE_FROM_ABI constexpr bool __comparison_can_promote_to =
+    __signed_integer<_Tp> ? sizeof(_Tp) <= sizeof(_Ip) : sizeof(_Tp) < sizeof(_Ip);
+
 template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
 _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_equal(_Tp __t, _Up __u) noexcept {
   if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
     return __t == __u;
+  else if constexpr (__comparison_can_promote_to<_Tp, int> && __comparison_can_promote_to<_Up, int>)
+    return static_cast<int>(__t) == static_cast<int>(__u);
+  else if constexpr (__comparison_can_promote_to<_Tp, long long> && __comparison_can_promote_to<_Up, long long>)
+    return static_cast<long long>(__t) == static_cast<long long>(__u);
   else if constexpr (is_signed_v<_Tp>)
     return __t < 0 ? false : make_unsigned_t<_Tp>(__t) == __u;
   else
@@ -45,6 +53,10 @@ template <__signed_or_unsigned_integer _Tp, __signed_or_unsigned_integer _Up>
 _LIBCPP_HIDE_FROM_ABI constexpr bool cmp_less(_Tp __t, _Up __u) noexcept {
   if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
     return __t < __u;
+  else if constexpr (__comparison_can_promote_to<_Tp, int> && __comparison_can_promote_to<_Up, int>)
+    return static_cast<int>(__t) < static_cast<int>(__u);
+  else if constexpr (__comparison_can_promote_to<_Tp, long long> && __comparison_can_promote_to<_Up, long long>)
+    return static_cast<long long>(__t) < static_cast<long long>(__u);
   else if constexpr (is_signed_v<_Tp>)
     return __t < 0 ? true : make_unsigned_t<_Tp>(__t) < __u;
   else