diff --git a/include/core/common.h b/include/core/common.h
index 0fe7344e..46eb6922 100644
--- a/include/core/common.h
+++ b/include/core/common.h
@@ -16,6 +16,7 @@
 namespace infini {
 using std::list;
 using std::map;
+using std::optional;
 using std::pair;
 using std::set;
 using std::string;
@@ -27,7 +28,7 @@ using std::vector;
 
 // Aliases
 using dtype = float;
-using HashType = size_t; // compatible with std::hash
+using HashType = uint64_t; // compatible with std::hash
 
 // Metaprogramming utilities
 #define _CAT(A, B) A##B
diff --git a/include/core/graph.h b/include/core/graph.h
index 9c87310a..8cb8cea1 100644
--- a/include/core/graph.h
+++ b/include/core/graph.h
@@ -5,7 +5,7 @@
 namespace infini {
 
 // TODO: graph should be attached to a context
-class GraphNode : public Object {
+class GraphObj : public Object {
   protected:
     TensorVec tensors;
     TensorVec inputs;
@@ -16,7 +16,28 @@ class GraphNode : public Object {
     // Graph(OpVec oplist);
     string toString() const override;
 
-    void addOp(Operator op) { ops.push_back(op); };
+    Tensor addTensor(Shape dim, DataType dtype = DataType::Int32);
+
+    /**
+     * @brief Add an operator and create its outputs. Output tensor arguments
+     * should be empty Refs (e.g., nullptr).
+     */
+    template <typename T, typename... Args> Ref<T> addOp(Args &&...args) {
+        Ref<T> op = make_ref<T>(this, std::forward<Args>(args)...);
+        ops.push_back(op);
+        return op;
+    }
+
+    /**
+     * @brief Add an operator with its outputs specified.
+     */
+    template <typename T, typename... Args>
+    Ref<T> addOpWithOutputs(Args &&...args) {
+        Ref<T> op = make_ref<T>(nullptr, std::forward<Args>(args)...);
+        ops.push_back(op);
+        return op;
+    }
+
     const TensorVec &getTensors() const { return tensors; }
     const TensorVec &getInputs() const { return inputs; }
     const TensorVec &getOutputs() const { return outputs; }
@@ -24,12 +45,6 @@ class GraphNode : public Object {
     // TensorVec &getInputs();
     // TensorVec &getOutputs();
 
-    Tensor addTensor(Shape dim, DataType dtype = DataType::Int32) {
-        Tensor tensor = make_ref<TensorNode>(dim, dtype);
-        tensors.emplace_back(tensor);
-        return tensor;
-    }
-
     void dataMalloc();
 
   private:
diff --git a/include/core/hash.h b/include/core/hash.h
new file mode 100644
index 00000000..3963af91
--- /dev/null
+++ b/include/core/hash.h
@@ -0,0 +1,18 @@
+#include "core/common.h"
+
+namespace infini {
+
+inline HashType hashAppend(HashType a, HashType b) {
+    return (a * 10000019 + b * 10000079) % 2147483647;
+}
+
+// inline HashType hashPack(HashType x) { return (x * 10000103) % 2147483647; }
+
+template <typename T> inline HashType hashVector(const vector<T> &vec) {
+    HashType ret = 0;
+    for (auto v : vec)
+        ret = hashAppend(ret, v);
+    return ret;
+}
+
+} // namespace infini
\ No newline at end of file
diff --git a/include/core/operator.h b/include/core/operator.h
index a24f240d..3be1c57f 100644
--- a/include/core/operator.h
+++ b/include/core/operator.h
@@ -127,9 +127,7 @@ struct OpPerfKey {
     }
 };
 
-class OperatorNode : public Object {
-    friend class Kernel;
-
+class OperatorObj : public Object {
   protected:
     OpType type;
     TensorVec inputs;
@@ -138,10 +136,24 @@ class OperatorNode : public Object {
     // vector<WRef<Operator>> successors;
 
   public:
-    OperatorNode(OpType opType, TensorVec inputs, TensorVec outputs)
+    OperatorObj(OpType opType, TensorVec inputs, TensorVec outputs)
         : type(opType), inputs(inputs), outputs(outputs) {}
-    virtual vector<Shape> computeShape() const = 0;
-    virtual OpPerfKey getOpPerfKey() const = 0;
+    virtual optional<vector<Shape>>
+    inferShape(const TensorVec &inputs) const = 0;
+    /**
+     * @brief Constructs outputs (if requried) and check whether the operator is
+     * valid.
+     *
+     * @param graph If graph is not nullptr, outputs should be created in this
+     * function.
+     */
+    bool checkValid(GraphObj *graph);
+    OpPerfKey getOpPerfKey() const;
+    /**
+     * @brief Hash operator attributes. Input and output shapes are not
+     * considered.
+     */
+    HashType hash() const;
 
   public: // check Op type
     bool isLinearOp() const;
@@ -167,8 +179,22 @@ class OperatorNode : public Object {
 
     virtual int numInputs() const = 0;
     virtual int numOutputs() const = 0;
-    virtual HashType hash() const { IT_TODO_HALT(); }
-    virtual HashType hashWithShape() const { IT_TODO_HALT(); }
+
+  protected:
+    optional<vector<Shape>> inferShape() const;
+
+  private:
+    /**
+     * @brief The returned vector includes operator attributes, such as paddings
+     * in Conv and transpose in Matmul. However, the input and output shapes are
+     * not taken into consideration.
+     */
+    virtual vector<int> getOpAttrVector() const { IT_TODO_HALT(); }
+    /**
+     * @brief Besides operator attributes, the returned vector includes input
+     * and output shapes.
+     */
+    virtual vector<int> getWorkloadVector() const { IT_TODO_HALT(); }
 };
 
 } // namespace infini
diff --git a/include/core/tensor.h b/include/core/tensor.h
index 67544753..e4bbc6c2 100644
--- a/include/core/tensor.h
+++ b/include/core/tensor.h
@@ -6,13 +6,13 @@ namespace infini {
 // TODO: how to deal with this
 using ShapeElem = int;
 using Shape = vector<ShapeElem>;
-class TensorNode : public TensorBaseNode {
+class TensorObj : public TensorBaseObj {
   private:
     Shape shape;
 
   public:
-    TensorNode(const Shape &shape, DataType dtype);
-    virtual ~TensorNode() {}
+    TensorObj(const Shape &shape, DataType dtype);
+    virtual ~TensorObj() {}
     string toString() const override;
 
     size_t size() const;
@@ -21,7 +21,7 @@ class TensorNode : public TensorBaseNode {
     Shape getDims() const { return shape; }
 
     size_t getOffset(const Shape &ds) const;
-    using TensorBaseNode::getData;
+    using TensorBaseObj::getData;
     VType getData(const Shape &pos) const;
     void copyData(VType *dptr);
     void printData() const;
diff --git a/include/core/tensor_base.h b/include/core/tensor_base.h
index cafea062..eefd300f 100644
--- a/include/core/tensor_base.h
+++ b/include/core/tensor_base.h
@@ -5,15 +5,15 @@
 namespace infini {
 
 // class Tensor;
-class TensorBaseNode;
-class TensorNode;
-class OperatorNode;
-class GraphNode;
+class TensorBaseObj;
+class TensorObj;
+class OperatorObj;
+class GraphObj;
 
-using TensorBase = Ref<TensorBaseNode>;
-using Tensor = Ref<TensorNode>;
-using Operator = Ref<OperatorNode>;
-using Graph = Ref<GraphNode>;
+using TensorBase = Ref<TensorBaseObj>;
+using Tensor = Ref<TensorObj>;
+using Operator = Ref<OperatorObj>;
+using Graph = Ref<GraphObj>;
 
 using TensorVec = vector<Tensor>;
 using OpVec = vector<Operator>;
@@ -25,7 +25,7 @@ enum class DataType {
     Int32,
 };
 
-class TensorBaseNode : public Object {
+class TensorBaseObj : public Object {
   public:
     // enum TensorType {
     //     Input,
@@ -38,8 +38,8 @@ class TensorBaseNode : public Object {
     int dim;
 
     DataType dtype;
-    vector<WRef<TensorBaseNode>> inputOf;
-    WRef<TensorBaseNode> outputOf;
+    vector<WRef<TensorBaseObj>> inputOf;
+    WRef<TensorBaseObj> outputOf;
     // TODO: Ref<void> -> Ref<Blob>
     Ref<VType[]> data;
     // ComputeState computed;
@@ -47,8 +47,8 @@ class TensorBaseNode : public Object {
     // static bool random_inited;
 
   public:
-    TensorBaseNode(int dim, DataType dtype);
-    virtual ~TensorBaseNode() {}
+    TensorBaseObj(int dim, DataType dtype);
+    virtual ~TensorBaseObj() {}
 
     Ref<VType[]> getDataPtr() const { return data; }
     VType getData(size_t offset) const;
diff --git a/include/operators/matmul.h b/include/operators/matmul.h
index b94dabe0..328756b0 100644
--- a/include/operators/matmul.h
+++ b/include/operators/matmul.h
@@ -3,26 +3,37 @@
 
 namespace infini {
 
-class MatmulNode : public OperatorNode {
+class MatmulObj : public OperatorObj {
   private:
-    // InfiniTensor assume a row-major tensor layout. transA=false means default
-    // dims, true means A should be transposed before matmul. This is in
-    // oppsite to column-major BLAS.
+    // InfiniTensor assumes a row-major tensor layout. `transA`=false means
+    // default dims, true means A should be transposed before matmul. This is in
+    // oppsite to the column-major BLAS.
     bool transA, transB;
     ActType act;
 
-    // Auxiliary attributes
+    // Auxiliary attributes which are not a part of operator attributes.
     int b, m, n, k;
 
   public:
-    MatmulNode(Tensor A, Tensor B, Tensor C, bool transA = false,
-               bool transB = false, Tensor bias = nullptr,
-               ActType act = ActType::None);
+    /**
+     * @brief This comments show how operators is defined in InfiniTensor. The
+     * constructor can create output tensors for the operator or not, which
+     * depends on `graph`.
+     *
+     * @param graph If graph is not empty, create outputs in the constructor.
+     * Otherwise, check the provided shape with the results of `inferShape` in
+     * `checkValid`.
+     * @param C C is the output of Matmul. If outputs are going to be created in
+     * the constructor, C should be an empty Ref.
+     */
+    MatmulObj(GraphObj *graph, Tensor A, Tensor B, Tensor C,
+              bool transA = false, bool transB = false, Tensor bias = nullptr,
+              ActType act = ActType::None);
 
     std::string toString() const override;
-    vector<Shape> computeShape() const override;
+    optional<vector<Shape>> inferShape(const TensorVec &inputs) const override;
 
-    int numInputs() const override { return 2; }
+    int numInputs() const override { return 3; }
     int numOutputs() const override { return 1; }
 
     Tensor getBias() const { return inputs[2]; }
@@ -34,14 +45,9 @@ class MatmulNode : public OperatorNode {
     int getN() const { return n; }
     int getK() const { return k; }
 
-    HashType hashWithShape() const override;
-    OpPerfKey getOpPerfKey() const override;
-
   private:
-    // Q: whether to check the output? Since we can build an Op first and then
-    // assure output.
-    // Fix 1: make shape inference a static method. But OpPerfKey are required.
-    bool checkValid(const TensorVec &inputs) const;
+    vector<int> getWorkloadVector() const override;
+    vector<int> getOpAttrVector() const override;
 };
 
 } // namespace infini
diff --git a/src/core/graph.cc b/src/core/graph.cc
index 0f6fb180..f8d85122 100644
--- a/src/core/graph.cc
+++ b/src/core/graph.cc
@@ -2,19 +2,25 @@
 
 namespace infini {
 
-void GraphNode::updateConnection() { IT_TODO_HALT(); }
+void GraphObj::updateConnection() { IT_TODO_HALT(); }
 
-string GraphNode::toString() const {
+string GraphObj::toString() const {
     std::ostringstream oss;
-    oss << "GraphNode operators:\n";
+    oss << "Graph operators:\n";
     for (const auto &op : ops)
         oss << op << "\n";
     return oss.str();
 }
 
-void GraphNode::dataMalloc() {
+void GraphObj::dataMalloc() {
     for (auto &tensor : tensors)
         tensor->dataMalloc();
 }
 
+Tensor GraphObj::addTensor(Shape dim, DataType dtype) {
+    Tensor tensor = make_ref<TensorObj>(dim, dtype);
+    tensors.emplace_back(tensor);
+    return tensor;
+}
+
 } // namespace infini
\ No newline at end of file
diff --git a/src/core/operator.cc b/src/core/operator.cc
index b215cb8a..e81c004b 100644
--- a/src/core/operator.cc
+++ b/src/core/operator.cc
@@ -1,32 +1,77 @@
 #include "core/operator.h"
+#include "core/graph.h"
+#include "core/hash.h"
 
 namespace infini {
 
-bool OperatorNode::isLinearOp() const {
+bool OperatorObj::isLinearOp() const {
     return enum_to_underlying(type) >= 100 && enum_to_underlying(type) < 200;
 }
 
-bool OperatorNode::isElementWiseOp() const {
+bool OperatorObj::isElementWiseOp() const {
     return enum_to_underlying(type) >= 200 && enum_to_underlying(type) < 300;
 }
 
-bool OperatorNode::isSplitOp() const { return type == OpType::Split; }
+bool OperatorObj::isSplitOp() const { return type == OpType::Split; }
 
-bool OperatorNode::isConcatOp() const { return type == OpType::Concat; }
+bool OperatorObj::isConcatOp() const { return type == OpType::Concat; }
 
-bool OperatorNode::isComputeOp() const {
+bool OperatorObj::isComputeOp() const {
     return type == OpType::Conv || type == OpType::Matmul ||
            type == OpType::ConvTrans || type == OpType::G2BMM ||
            type == OpType::GBMML;
 }
 
-bool OperatorNode::isTransposeOp() const { return type == OpType::Transpose; }
+bool OperatorObj::isTransposeOp() const { return type == OpType::Transpose; }
 
-bool OperatorNode::isReshapeOp() const { return type == OpType::Reshape; }
+bool OperatorObj::isReshapeOp() const { return type == OpType::Reshape; }
 
-bool OperatorNode::isMemBoundOp() const {
+bool OperatorObj::isMemBoundOp() const {
     return type == OpType::MemBound || type == OpType::Activation ||
            type == OpType::Transpose;
 }
 
+OpPerfKey OperatorObj::getOpPerfKey() const {
+    auto workloadVector = getWorkloadVector();
+    // Calculate hash of workload, i.e. hash with shape. This is different from
+    // Operator::hash, which hashes operator attributes and ignores tensor
+    // shapes.
+    HashType hash = 0;
+    hash = hashAppend(hash, enum_to_underlying(type));
+    hash = hashAppend(hash, hashVector(workloadVector));
+    return OpPerfKey(hash, type, workloadVector);
+}
+
+HashType OperatorObj::hash() const {
+    HashType hash = 0;
+    hash = hashAppend(hash, enum_to_underlying(type));
+    hash = hashAppend(hash, hashVector(getOpAttrVector()));
+    return hash;
+}
+
+bool OperatorObj::checkValid(GraphObj *graph) {
+    auto optShapes = inferShape();
+    if (!optShapes) // shape inference failed
+        return false;
+    const vector<Shape> &shapes = *optShapes;
+    if (shapes.size() != outputs.size())
+        return false;
+    if (graph) { // if graph != nullptr, outputs should be created
+        for (size_t i = 0; i < outputs.size(); i++) {
+            IT_ASSERT(!outputs[i]);
+            outputs[i] = graph->addTensor(shapes[i]);
+        }
+    } else { // if graph is not empty, check outputs match inferred shapes
+        for (size_t i = 0; i < shapes.size(); ++i) {
+            if (shapes[i] != outputs[i]->getDims())
+                return false;
+        }
+    }
+    return true;
+}
+
+optional<vector<Shape>> OperatorObj::inferShape() const {
+    return inferShape(inputs);
+}
+
 } // namespace infini
\ No newline at end of file
diff --git a/src/core/tensor.cc b/src/core/tensor.cc
index 18460986..41aa0aac 100644
--- a/src/core/tensor.cc
+++ b/src/core/tensor.cc
@@ -1,24 +1,22 @@
 #include <core/tensor.h>
 namespace infini {
 
-TensorNode::TensorNode(const Shape &shape, DataType dtype)
-    : TensorBaseNode(shape.size(), dtype), shape(shape) {}
+TensorObj::TensorObj(const Shape &shape, DataType dtype)
+    : TensorBaseObj(shape.size(), dtype), shape(shape) {}
 
-void TensorNode::dataMalloc() {
+void TensorObj::dataMalloc() {
     IT_ASSERT(data == nullptr);
     // initialized to zero
     data.reset(reinterpret_cast<VType *>(calloc(size(), sizeof(VType))));
 }
 
-VType TensorNode::getData(const Shape &pos) const {
+VType TensorObj::getData(const Shape &pos) const {
     return getData(getOffset(pos));
 }
 
-string TensorNode::toString() const {
-    return "TensorNode " + std::to_string(guid);
-}
+string TensorObj::toString() const { return "Tensor " + std::to_string(guid); }
 
-size_t TensorNode::getOffset(const Shape &pos) const {
+size_t TensorObj::getOffset(const Shape &pos) const {
     auto nDim = pos.size();
     IT_ASSERT(shape.size() == nDim);
     if (pos.empty())
@@ -32,14 +30,14 @@ size_t TensorNode::getOffset(const Shape &pos) const {
     return idx;
 }
 
-size_t TensorNode::size() const {
+size_t TensorObj::size() const {
     size_t ret = 1;
     for (const auto &d : shape)
         ret *= d;
     return ret;
 }
 
-void TensorNode::copyData(VType *dptr) {
+void TensorObj::copyData(VType *dptr) {
     IT_ASSERT(data != nullptr);
     size_t sz = size();
 #pragma omp parallel for
@@ -48,7 +46,7 @@ void TensorNode::copyData(VType *dptr) {
     }
 }
 
-void TensorNode::printData() const {
+void TensorObj::printData() const {
     IT_ASSERT(data != nullptr);
     std::cout << "Tensor: " << guid << std::endl;
     auto numDims = shape.size();
@@ -75,7 +73,7 @@ void TensorNode::printData() const {
     }
 }
 
-bool TensorNode::equalData(const Tensor &rhs) const {
+bool TensorObj::equalData(const Tensor &rhs) const {
     IT_ASSERT(data != nullptr);
     IT_ASSERT(rhs->data != nullptr);
     if (shape != rhs->getDims())
diff --git a/src/core/tensor_base.cc b/src/core/tensor_base.cc
index 72297ce0..84cad959 100644
--- a/src/core/tensor_base.cc
+++ b/src/core/tensor_base.cc
@@ -1,9 +1,9 @@
 #include <core/tensor_base.h>
 namespace infini {
 
-TensorBaseNode::TensorBaseNode(int dim, DataType dtype)
+TensorBaseObj::TensorBaseObj(int dim, DataType dtype)
     : dim(dim), dtype(dtype) {}
 
-VType TensorBaseNode::getData(size_t offset) const { return data[offset]; }
+VType TensorBaseObj::getData(size_t offset) const { return data[offset]; }
 
 }; // namespace infini
\ No newline at end of file
diff --git a/src/kerels/cpu/matmul.cc b/src/kerels/cpu/matmul.cc
index 84fa53a3..527fd66c 100644
--- a/src/kerels/cpu/matmul.cc
+++ b/src/kerels/cpu/matmul.cc
@@ -5,7 +5,7 @@ namespace infini {
 
 template <typename T> class NaiveMatmul : public Kernel {
     void compute(const Operator &_op, const PerfRecord &record) const override {
-        auto op = as<MatmulNode>(_op);
+        auto op = as<MatmulObj>(_op);
         T *A = reinterpret_cast<T *>(op->getInputs(0)->getDataPtr().get());
         T *B = reinterpret_cast<T *>(op->getInputs(1)->getDataPtr().get());
         T *C = reinterpret_cast<T *>(op->getOutput()->getDataPtr().get());
diff --git a/src/operators/matmul.cc b/src/operators/matmul.cc
index 9f15bc5c..20f60914 100644
--- a/src/operators/matmul.cc
+++ b/src/operators/matmul.cc
@@ -2,19 +2,17 @@
 
 namespace infini {
 
-vector<Shape> MatmulNode::computeShape() const { return {{b, m, n}}; }
-
-MatmulNode::MatmulNode(Tensor A, Tensor B, Tensor C, bool transA, bool transB,
-                       Tensor bias, ActType act)
-    : OperatorNode(OpType::Matmul, {A, B, bias}, {C}), transA(transA),
+MatmulObj::MatmulObj(GraphObj *graph, Tensor A, Tensor B, Tensor C, bool transA,
+                     bool transB, Tensor bias, ActType act)
+    : OperatorObj(OpType::Matmul, {A, B, bias}, {C}), transA(transA),
       transB(transB), act(act), b(A->getDims()[0]),
       m(transA ? A->getDims()[2] : A->getDims()[1]),
       n(transB ? B->getDims()[1] : B->getDims()[2]),
       k(transA ? A->getDims()[1] : A->getDims()[2]) {
-    IT_ASSERT(checkValid(inputs));
+    IT_ASSERT(checkValid(graph));
 }
 
-string MatmulNode::toString() const {
+string MatmulObj::toString() const {
     std::ostringstream os;
     os << "Matmul([" << (transA ? "A^T" : "A") << "," << (transB ? "B^T" : "B")
        << ",act=" << enum_to_underlying(act) << "],A=" << inputs[0]->getGuid()
@@ -23,34 +21,29 @@ string MatmulNode::toString() const {
     return os.str();
 }
 
-bool MatmulNode::checkValid(const TensorVec &inputs) const {
+optional<vector<Shape>> MatmulObj::inferShape(const TensorVec &inputs) const {
     auto A = inputs[0], B = inputs[1];
     // if (A->getType() == Tensor::Weight && B->getType() == Tensor::Weight)
     //     return false;
-    IT_ASSERT(A->getDims().size() == 3 && B->getDims().size() == 3);
-    IT_ASSERT(A->getDims()[0] == B->getDims()[0]);
-    IT_ASSERT((transA ? A->getDims()[1] : A->getDims()[2]) ==
-              (transB ? B->getDims()[2] : B->getDims()[1]));
-    // if (A->getDims().size() != 3 || B->getDims().size() != 3) {
-    //     return false;
-    // }
-    // if (A->getDims()[0] != B->getDims()[0]) {
-    //     return false;
-    // }
-    // if ((args.transA ? A->getDims()[1] : A->getDims()[2]) !=
-    //     (args.transB ? B->getDims()[2] : B->getDims()[1])) {
-    //     return false;
-    // }
-    return true;
+    if (!(A->getDims().size() == 3 && B->getDims().size() == 3))
+        return {};
+    if (!(A->getDims()[0] == B->getDims()[0]))
+        return {};
+    if (!((transA ? A->getDims()[1] : A->getDims()[2]) ==
+          (transB ? B->getDims()[2] : B->getDims()[1])))
+        return {};
+    int b(A->getDims()[0]), m(transA ? A->getDims()[2] : A->getDims()[1]),
+        n(transB ? B->getDims()[1] : B->getDims()[2]);
+    return {{{b, m, n}}};
 }
 
-HashType MatmulNode::hashWithShape() const {
-    // TODO: use a real hash
-    return b + m + n + k + transA + transB + enum_to_underlying(act);
+vector<int> MatmulObj::getWorkloadVector() const {
+    return {enum_to_underlying(type), b, m, n, k, transA, transB,
+            enum_to_underlying(act)};
 }
 
-OpPerfKey MatmulNode::getOpPerfKey() const {
-    return OpPerfKey(hashWithShape(), type,
-                     {b, m, n, k, transA, transB, enum_to_underlying(act)});
+vector<int> MatmulObj::getOpAttrVector() const {
+    return {enum_to_underlying(type), transA, transB, enum_to_underlying(act)};
 }
+
 } // namespace infini
\ No newline at end of file
diff --git a/test/core/test_graph.cc b/test/core/test_graph.cc
index b8a12333..21db982b 100644
--- a/test/core/test_graph.cc
+++ b/test/core/test_graph.cc
@@ -6,41 +6,41 @@
 namespace infini {
 
 TEST(Graph, build_and_run) {
-    Graph g = make_ref<GraphNode>();
+    Graph g = make_ref<GraphObj>();
     Tensor i0 = g->addTensor({1, 2, 3}, DataType::Int32);
     Tensor w0 = g->addTensor({1, 3, 4}, DataType::Int32);
     Tensor o0 = g->addTensor({1, 2, 4}, DataType::Int32);
     g->dataMalloc();
     i0->copyData(vector<VType>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}.data());
     w0->copyData(vector<VType>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}.data());
-    g->addOp(make_ref<MatmulNode>(i0, w0, o0));
+    g->addOpWithOutputs<MatmulObj>(i0, w0, o0);
     RunEngine(Device::CPU).run(g);
     // check answer
-    auto ans = make_ref<TensorNode>(Shape{1, 2, 4}, DataType::Int32);
+    auto ans = make_ref<TensorObj>(Shape{1, 2, 4}, DataType::Int32);
     ans->dataMalloc();
     ans->copyData(vector<VType>{38, 44, 50, 56, 83, 98, 113, 128}.data());
     EXPECT_TRUE(o0->equalData(ans));
 }
 
 TEST(Graph, perf_engine) {
-    Graph g = make_ref<GraphNode>();
+    Graph g = make_ref<GraphObj>();
     Tensor i0 = g->addTensor({1, 2, 3}, DataType::Int32);
     Tensor w0 = g->addTensor({1, 3, 4}, DataType::Int32);
-    Tensor o0 = g->addTensor({1, 2, 4}, DataType::Int32);
+    auto matmul = g->addOp<MatmulObj>(i0, w0, nullptr);
+
     g->dataMalloc();
     i0->copyData(vector<VType>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}.data());
     w0->copyData(vector<VType>{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}.data());
-    g->addOp(make_ref<MatmulNode>(i0, w0, o0));
     RunEngine(Device::CPU).run(g, true, true);
     double perfTime = RunEngine(Device::CPU).getPerfTime(g);
     // The example matmul takes 0.0036ms with one core
     EXPECT_GT(perfTime, 0);
     EXPECT_LT(perfTime, 0.01);
     // check answer
-    auto ans = make_ref<TensorNode>(Shape{1, 2, 4}, DataType::Int32);
+    auto ans = make_ref<TensorObj>(Shape{1, 2, 4}, DataType::Int32);
     ans->dataMalloc();
     ans->copyData(vector<VType>{38, 44, 50, 56, 83, 98, 113, 128}.data());
-    EXPECT_TRUE(o0->equalData(ans));
+    EXPECT_TRUE(matmul->getOutput()->equalData(ans));
 }
 
 } // namespace infini
\ No newline at end of file
diff --git a/test/core/test_hash.cc b/test/core/test_hash.cc
new file mode 100644
index 00000000..22955ec0
--- /dev/null
+++ b/test/core/test_hash.cc
@@ -0,0 +1,31 @@
+#include "core/graph.h"
+#include "core/run_enigne.h"
+#include "operators/matmul.h"
+#include "test.h"
+
+namespace infini {
+
+TEST(Hash, OperatorHash) {
+    OpPerfKey key1(0, OpType::Unknown), key2(0, OpType::Unknown);
+    { // build with addOpWithOutputs
+        Graph g = make_ref<GraphObj>();
+        Tensor i0 = g->addTensor({1, 2, 3}, DataType::Int32);
+        Tensor w0 = g->addTensor({1, 3, 4}, DataType::Int32);
+        Tensor o0 = g->addTensor({1, 2, 4}, DataType::Int32);
+        auto matmul = g->addOpWithOutputs<MatmulObj>(i0, w0, o0);
+        key1 = matmul->getOpPerfKey();
+        EXPECT_NE(key1.hash, 0);
+        EXPECT_GT(key1.attrs.size(), 5);
+    }
+    { // build with addOp
+        Graph g = make_ref<GraphObj>();
+        Tensor i0 = g->addTensor({2, 2, 3}, DataType::Int32);
+        Tensor w0 = g->addTensor({2, 3, 4}, DataType::Int32);
+        auto matmul = g->addOp<MatmulObj>(i0, w0, nullptr);
+        key2 = matmul->getOpPerfKey();
+        EXPECT_NE(key2.hash, 0);
+    }
+    EXPECT_NE(key1.hash, key2.hash);
+}
+
+} // namespace infini
\ No newline at end of file