Fixed combo by fixing an old artefact from the older libFirm Cmp nodes.

In older libFirm version, Cmp computes top, true or bottom.
Now Cmp computes true or false, so the monotony fix must be upgraded.

This fixes opt/combo_paper.c

ir/opt/combo.c

@@ -2258,11 +2258,11 @@ static void compute_Cmp(node_t *node)
 	} else if (r->part == l->part && !mode_is_float(get_irn_mode(l->node))) {
 		tv = relation & ir_relation_equal ? tarval_b_true : tarval_b_false;
 
-		/* if the node was ONCE evaluated by all constants, but now
+		/* if the node was ONCE evaluated to a constant, but now
 		   this breaks AND we get from the argument partitions a different
-		   result, switch to bottom.
+		   result, ensure monotony by fall to bottom.
 		   This happens because initially all nodes are in the same partition ... */
-		if (node->type.tv != tv)
+		if (node->type.tv != tv && is_constant_type(node->type))
 			tv = tarval_bottom;
 		node->type.tv = tv;
 	} else {