diff --git a/lib/symbValue.ml b/lib/symbValue.ml
index e32b53a36a..888c935e98 100644
--- a/lib/symbValue.ml
+++ b/lib/symbValue.ml
@@ -285,6 +285,8 @@ module
     | (Val (Instruction _),Val (Instruction _))
       ->
         Val (Concrete (Cst.Scalar.of_int (compare  v1 v2)))
+    | (Val (Label _),_) | (_,Val (Label _))
+      -> Val (Cst.one)
     (* 0 is sometime used as invalid PTE, no orpat because warning 57
        cannot be disabled in some versions ?  *)
     | (Val (PteVal _),Val cst)