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Author: ldionne

libcxx/include/__type_traits/is_trivially_relocatable.h

@@ -22,8 +22,17 @@ _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))`.
+//
+// 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
 template <class _Tp, class = void>
 struct __libcpp_is_trivially_relocatable : is_trivially_copyable<_Tp> {};
+#endif
 
 template <class _Tp>
 struct __libcpp_is_trivially_relocatable<_Tp,