fix unneeded call to typecast op for string

mindspore/ccsrc/dataset/kernels/data/data_utils.cc

@@ -113,22 +113,27 @@ Status OneHotEncoding(std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *ou
 }
 
 Status Fill(const std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *output, std::shared_ptr<Tensor> fill_value) {
-  CHECK_FAIL_RETURN_UNEXPECTED(!((fill_value->type() == DataType::DE_STRING) && (input->type() != DataType::DE_STRING)),
+  const DataType &fill_type = fill_value->type();
+  const DataType &input_type = input->type();
+  const TensorShape &input_shape = input->shape();
+
+  CHECK_FAIL_RETURN_UNEXPECTED(!((fill_type == DataType::DE_STRING) && (input_type != DataType::DE_STRING)),
                                "Types do not match");
 
   CHECK_FAIL_RETURN_UNEXPECTED(fill_value->shape() == TensorShape({}), "fill_value is not a scalar");
 
-  std::shared_ptr<Tensor> out;
-
-  const DataType &to = input->type();
-  std::unique_ptr<TypeCastOp> op(new TypeCastOp(to));
+  std::shared_ptr<Tensor> out, fill_output;
 
-  std::shared_ptr<Tensor> fill_output;
-  RETURN_IF_NOT_OK(op->Compute(fill_value, &fill_output));
+  if (input_type != DataType::DE_STRING && fill_type != DataType::DE_STRING && input_type != fill_type) {
+    std::unique_ptr<TypeCastOp> op(new TypeCastOp(input_type));
+    RETURN_IF_NOT_OK(op->Compute(fill_value, &fill_output));
+  } else {
+    fill_output = fill_value;
+  }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, TensorImpl::kFlexible, input->shape(), input->type()));
+  RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, TensorImpl::kFlexible, input_shape, input_type));
 
-  switch (input->type().value()) {
+  switch (input_type.value()) {
     case DataType::DE_BOOL: {
       bool value = 0;
       RETURN_IF_NOT_OK(fill_output->GetItemAt(&value, {}));
@@ -206,10 +211,10 @@ Status Fill(const std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *output
       std::string_view fill_string_view;
       RETURN_IF_NOT_OK(fill_value->GetItemAt(&fill_string_view, {}));
       std::string fill_string = std::string(fill_string_view);
-      for (int i = 0; i < input->shape().NumOfElements(); i++) {
+      for (int i = 0; i < input_shape.NumOfElements(); i++) {
         strings.emplace_back(fill_string);
       }
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, strings, input->shape()));
+      RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, strings, input_shape));
       break;
     }
     case DataType::DE_UNKNOWN: {