// collect the call arguments post lookup through cast Op's
    extern_values.push_back(first);
    return true;
  };

  const TrivialTransformInfo tti(IsSingleCallRegion(if_region.getThenBranch()),
                                 IsSingleCallRegion(if_region.getElseBranch()),
                                 if_arg_matcher);

  std::string then_name, else_name;

  if (tti.can_transform) {