message: Reconstruct call graph after running DCE
diff: @@ -2315,6 +2315,7 @@ Status LayoutAssignment::ClearPreviousPassSideEffects(HloModule* module) {
  HloDCE dce;
  TF_RETURN_IF_ERROR(tuple_simplifier.Run(module).status());
  TF_RETURN_IF_ERROR(dce.Run(module).status());
  + call_graph_ = CallGraph::Build(module);
  }
  return Status::OK();
  }
  