message: Avoid removing constant
diff: @@ -185,8 +185,10 @@ impl SSAStorage {
  fn remove_node(&mut self, exi: NodeIndex) {
  radeco_trace!(logger::Event::SSARemoveNode(&exi));
  // Remove the current association.
  + if self.get_const(&exi).is_none() {
  self.g.remove_node(exi);
  }
  + }
  fn replace_node(&mut self, i: NodeIndex, j: NodeIndex) {
  radeco_trace!(logger::Event::SSAReplaceNode(&i, &j));
  