Fix a bug in Tensor::equals()

1. Check if data_ is null before compare it;
2. Always allocate an array for data_ even if size is zero.

mindspore/core/ir/tensor.cc

@@ -176,13 +176,8 @@ class TensorDataImpl : public TensorData {
   ssize_t ndim() const override { return static_cast<ssize_t>(ndim_); }
 
   void *data() override {
-    static T empty_data = static_cast<T>(0);
-    if (data_size_ == 0) {
-      // Prevent null pointer for empty shape.
-      return &empty_data;
-    }
-    // Lazy allocation.
     if (data_ == nullptr) {
+      // Lazy allocation.
       data_ = std::make_unique<T[]>(data_size_);
     }
     return data_.get();
@@ -193,8 +188,14 @@ class TensorDataImpl : public TensorData {
     if (ptr == nullptr) {
       return false;
     }
-    return (ptr == this) || ((ndim_ == ptr->ndim_) && (data_size_ == ptr->data_size_) &&
-                             (std::equal(data_.get(), data_.get() + data_size_, ptr->data_.get())));
+    if (ptr == this) {
+      return true;
+    }
+    if (data_ == nullptr || ptr->data_ == nullptr) {
+      return false;
+    }
+    return (ndim_ == ptr->ndim_) && (data_size_ == ptr->data_size_) &&
+           std::equal(data_.get(), data_.get() + data_size_, ptr->data_.get());
   }
 
   std::string ToString(const TypeId type, const std::vector<int> &shape) const override {

tests/ut/cpp/ir/meta_tensor_test.cc

@@ -225,6 +225,27 @@ TEST_F(TestTensor, EqualTest) {
   ASSERT_EQ(TypeId::kNumberTypeFloat64, tensor_float64->data_type_c());
 }
 
+TEST_F(TestTensor, ValueEqualTest) {
+  py::tuple tuple = py::make_tuple(1, 2, 3, 4, 5, 6);
+  TensorPtr t1 = TensorPy::MakeTensor(py::array(tuple), kInt32);
+  TensorPtr t2 = TensorPy::MakeTensor(py::array(tuple), kInt32);
+  ASSERT_TRUE(t1->ValueEqual(*t1));
+  ASSERT_TRUE(t1->ValueEqual(*t2));
+
+  std::vector<int> shape = {6};
+  TensorPtr t3 = std::make_shared<Tensor>(kInt32->type_id(), shape);
+  TensorPtr t4 = std::make_shared<Tensor>(kInt32->type_id(), shape);
+  ASSERT_TRUE(t3->ValueEqual(*t3));
+  ASSERT_FALSE(t3->ValueEqual(*t4));
+  ASSERT_FALSE(t3->ValueEqual(*t1));
+  ASSERT_FALSE(t1->ValueEqual(*t3));
+
+  memcpy_s(t3->data_c(), t3->data().nbytes(), t1->data_c(), t1->data().nbytes());
+  ASSERT_TRUE(t1->ValueEqual(*t3));
+  ASSERT_FALSE(t3->ValueEqual(*t4));
+  ASSERT_FALSE(t4->ValueEqual(*t3));
+}
+
 TEST_F(TestTensor, PyArrayTest) {
   py::array_t<float, py::array::c_style> input({2, 3});
   auto array = input.mutable_unchecked();