!14942 clean code

From: @hwjiaorui
Reviewed-by: @jjfeing,@zhoufeng54
Signed-off-by: @zhoufeng54

mindspore/ccsrc/runtime/device/launch_mul.cc

@@ -28,10 +28,10 @@ std::shared_ptr<session::KernelGraph> LaunchMul::ObtainMulKernelGraph() {
   std::vector<TypeId> output_dtypes = {dtype_};
   // obtain input & output shapes
   size_t dtype_size = abstract::TypeIdSize(dtype_);
-  int64_t shape = total_size_ / dtype_size;
   if (dtype_size == 0) {
     MS_LOG(EXCEPTION) << "Divide by zero.";
   }
+  int64_t shape = total_size_ / dtype_size;
   std::vector<std::vector<int64_t>> input_shapes = {{shape}, {1}};
   std::vector<std::vector<size_t>> output_shapes = {{static_cast<size_t>(shape)}};
   auto mul_graph = session::SingleKernelGraph::ConstructKernelGraphBasedOnSingleOp(