diff --git a/include/core/graph.h b/include/core/graph.h
index 4ce8697a..eaa6f4a5 100644
--- a/include/core/graph.h
+++ b/include/core/graph.h
@@ -8,13 +8,10 @@ class GraphObj : public Object {
   protected:
     Runtime runtime;
     TensorVec tensors;
-    // TODO: whether to record input and output tensors
-    // TensorVec inputs;
-    // TensorVec outputs;
     OpVec ops;
 
   public:
-    GraphObj(Runtime runtime) : runtime(runtime){};
+    explicit GraphObj(Runtime runtime) : runtime(runtime){};
     GraphObj(Runtime runtime, OpVec ops_in);
     string toString() const override;
     Runtime getRuntime() const { return runtime; }
@@ -23,10 +20,15 @@ class GraphObj : public Object {
     Tensor addTensor(const Tensor &tensor);
     TensorVec addTensor(const TensorVec &tensors);
     Tensor cloneTensor(const Tensor &tensor) {
-        auto ret = addTensor(tensor->clone(runtime));
-        return ret;
+        return addTensor(tensor->clone(runtime));
     }
 
+    const TensorVec &getTensors() const { return tensors; }
+    const OpVec &getOperators() const { return ops; }
+    OpVec getComputeOps() const;
+
+    void dataMalloc();
+
     /**
      * @brief Add an operator and create its outputs. Output tensor arguments
      * should be empty Refs (e.g., nullptr).
@@ -47,35 +49,33 @@ class GraphObj : public Object {
         return op;
     }
 
-    const TensorVec &getTensors() const { return tensors; }
-    const TensorVec getInputs() const {
+    /**
+     * @brief Gets input tensors of this graph.
+     */
+    inline TensorVec getInputs() const {
         TensorVec ret;
-        for (auto t : tensors)
+        for (const auto &t : tensors)
             if (!t->getOutputOf())
                 ret.emplace_back(t);
         return ret;
     }
-    const TensorVec getOutputs() const {
+
+    /**
+     * @brief Gets output tensors of this graph.
+     */
+    inline TensorVec getOutputs() const {
         TensorVec ret;
-        for (auto t : tensors)
+        for (const auto &t : tensors)
             if (t->getInputOf().empty())
                 ret.emplace_back(t);
         return ret;
     }
-    const OpVec &getOperators() const { return ops; }
-    OpVec getComputeOps() const;
-
-    void dataMalloc();
 
   private:
     /**
      * @brief Add reverse connections and Op relationship in ctor.
      */
     void addOperatorAndConnect(const Operator &op);
-
-    // TODO: move to another class
-    // bool exportOnnx(const char *path);
-    // bool importOnnx(const char *net);
 };
 
 } // namespace infini
diff --git a/src/core/graph.cc b/src/core/graph.cc
index a9edda64..8b2a6bbc 100644
--- a/src/core/graph.cc
+++ b/src/core/graph.cc
@@ -73,15 +73,12 @@ void GraphObj::dataMalloc() {
 }
 
 Tensor GraphObj::addTensor(Shape dim, DataType dtype) {
-    Tensor tensor = make_ref<TensorObj>(dim, dtype, runtime);
-    tensors.emplace_back(tensor);
-    return tensor;
+    return tensors.emplace_back(make_ref<TensorObj>(dim, dtype, runtime));
 }
 
 Tensor GraphObj::addTensor(const Tensor &tensor) {
     IT_ASSERT(tensor->getRuntime() == runtime, "Tensor runtime mismatch");
-    tensors.emplace_back(tensor);
-    return tensor;
+    return tensors.emplace_back(tensor);
 }
 
 TensorVec GraphObj::addTensor(const TensorVec &tensors) {
@@ -98,4 +95,4 @@ OpVec GraphObj::getComputeOps() const {
     return opList;
 };
 
-} // namespace infini
\ No newline at end of file
+} // namespace infini