+22,11 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 // A type is trivially relocatable if a move construct + destroy of the original object is equivalent to
 // `memcpy(dst, src, sizeof(T))`.
-
-#if __has_builtin(__is_trivially_relocatable)
+//
+// Note that we don't use the __is_trivially_relocatable Clang builtin right now because it does not
+// implement the semantics of any current or future trivial relocation proposal and it can lead to
+// incorrect optimizations on some platforms (Windows) and supported compilers (AppleClang).
+#if __has_builtin(__is_trivially_relocatable) && 0
 template <class _Tp, class = void>
 struct __libcpp_is_trivially_relocatable : integral_constant<bool, __is_trivially_relocatable(_Tp)> {};
 #else