return op->emitError()
             << "Cannot find function " << sym.getRootReference();
    }
    callees.push_back(callee);
  }
  return success();
}

bool HasSingleBlock(func::FuncOp func) {
  return func->getNumRegions() == 1 && func.getBody().hasOneBlock();
}

      }
      return WalkResult::advance();
    });
    if (result.wasInterrupted()) return failure();
  }
  return success();
}

// Check if a function has one region and one block only.
bool HasSingleBlock(func::FuncOp func);

}  // namespace mlir