ops_added.call_op = call_op;
  // FuncOutputs refer to the original `Values` in input module which are now
  // invalid after pulling out the defining ops. The values in
  // `call_ops.getResult` refer to the clones of original `Values` which are now
  // returned by the new `FuncOp`. We can replace each in `FuncOutputs` with
  // clone in `call_op` to fix up.
  for (int i = 0; i < subgraph.FuncOutputs().size(); ++i) {

    // `Value`s in MLIR library are implemented as having "value semantics"
    // see "llvm/llvm-project/mlir/include/mlir/IR/Value.h" so copying is fine.
    return func_arguments_;
  }
  const llvm::SmallVector<Value>& FuncOutputs() const { return func_outputs_; }

 private:
  // Compute once at construction and save as field.
  const llvm::SmallVector<Value> func_arguments_;
  const llvm::SmallVector<Value> func_outputs_;
};