diff --git a/Include/pyport.h b/Include/pyport.h
index 63d3b81de5d..bdbd0c942f6 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -829,10 +829,10 @@ extern _invalid_parameter_handler _Py_silent_invalid_parameter_handler;
 #endif
 
 /* Mark a function which cannot return. Example:
+   PyAPI_FUNC(void) _Py_NO_RETURN PyThread_exit_thread(void);
 
-   PyAPI_FUNC(void) _Py_NO_RETURN PyThread_exit_thread(void); */
+   XLC support is intentionally omitted due to bpo-40244 */
 #if defined(__clang__) || \
-    defined(__xlc__) || \
     (defined(__GNUC__) && \
      ((__GNUC__ >= 3) || \
       (__GNUC__ == 2) && (__GNUC_MINOR__ >= 5)))