diff --git a/libcxx/include/typeinfo b/libcxx/include/typeinfo
--- a/libcxx/include/typeinfo
+++ b/libcxx/include/typeinfo
@@ -174,8 +174,8 @@
 // we pick a default implementation based on the platform here.
 #ifndef _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION
 
-  // Windows binaries can't merge typeinfos, so use the NonUnique implementation.
-# ifdef _LIBCPP_OBJECT_FORMAT_COFF
+  // Windows and AIX binaries can't merge typeinfos, so use the NonUnique implementation.
+# if defined(_LIBCPP_OBJECT_FORMAT_COFF) || defined(_LIBCPP_OBJECT_FORMAT_XCOFF)
 #   define _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION 2
 
   // On arm64 on Apple platforms, use the special NonUniqueARMRTTIBit implementation.