&symbol_table_collection_));
  return IsPureFunction(func_op);
}

bool OpSideEffectCollector::IsPureFunction(func::FuncOp func_op) const {
  auto it = is_pure_function_.find(func_op);
  if (it == is_pure_function_.end()) {
    bool is_pure = true;
    is_pure_function_[func_op] = is_pure;  // prevent infinite recursion
    func_op->walk([&](Operation* op) {
      if (op == func_op) {
        return WalkResult::advance();
      }