for (auto operand : op.getOperands()) {
    auto operand_type = getElementTypeOrSelf(operand);
    if (IsStringType(operand_type)) return true;
  }
  return false;
}

bool HasStringResult(Operation& op) {
  for (auto result : op.getResults()) {
    auto result_type = getElementTypeOrSelf(result);
    if (IsStringType(result_type)) return true;
  }
  return false;
}