message: Ignore control edges as inputs
diff: @@ -443,7 +443,9 @@ class Converter {
  * 2) Control dependency inputs contain caret at the beginning and we
  * remove this and annotate the edge as a control dependency.
  ************************************************************************/
  - string name = input_name[0] == '^' ? input_name.substr(1) : input_name;
  + // skip control nodes
  + if (input_name[0] == '^' ) continue;
  + string name = input_name;
  auto first = name.find_first_of(':');
  if (first != string::npos && first + 2 == name.size() &&
  name[first + 1] == '0')
  