Index: fwprop.c
===================================================================
--- fwprop.c    (revision 193394)
+++ fwprop.c    (working copy)
@@ -1321,7 +1321,9 @@ forward_propagate_and_simplify (df_ref u
         separately try plugging the definition in the note and simplifying.
         And only install a REQ_EQUAL note when the destination is a REG,
         as the note would be invalid otherwise.  */
-      set_reg_equal = (note == NULL_RTX && REG_P (SET_DEST (use_set)));
+      set_reg_equal = (note == NULL_RTX && REG_P (SET_DEST (use_set))
+                      && ! reg_mentioned_p (SET_DEST (use_set),
+                                            SET_SRC (use_set)));
     }

   if (GET_MODE (*loc) == VOIDmode)