fix getinputformat error when input is not a realnode

mindspore/ccsrc/backend/optimizer/gpu/replace_bn_cast_fusion.cc

@@ -49,6 +49,7 @@ const AnfNodePtr ReplaceBNCastFusion::Process(const FuncGraphPtr &graph, const A
   auto manager = graph->manager();
   MS_EXCEPTION_IF_NULL(manager);
   auto outlist = GetRealNodeUsedList(graph, fbn2);
+  bool changed = false;
   for (size_t i = 0; i < outlist->size(); i++) {
     auto index_node = AnfAlgo::GetInputNode(utils::cast<CNodePtr>(outlist->at(i).first), 1);
     auto value_node = index_node->cast<ValueNodePtr>();
@@ -63,8 +64,12 @@ const AnfNodePtr ReplaceBNCastFusion::Process(const FuncGraphPtr &graph, const A
       outputs_type.push_back(kNumberTypeFloat16);
       outputs_shape.push_back(AnfAlgo::GetOutputInferShape(outlist->at(i).first, 0));
       AnfAlgo::SetOutputInferTypeAndShape(outputs_type, outputs_shape, outlist->at(i).first.get());
+      changed = true;
     }
   }
+  if (!changed) {
+    return nullptr;
+  }
   manager->Replace(utils::cast<CNodePtr>(x_after), utils::cast<CNodePtr>(x_before));
   outputs_type.clear();
   outputs_shape.clear();

mindspore/ccsrc/backend/session/anf_runtime_algorithm.cc

@@ -425,7 +425,7 @@ std::string AnfRuntimeAlgorithm::GetInputFormat(const AnfNodePtr &node, size_t i
                       << node->DebugString() << "]";
   }
   if (!IsRealKernel(node)) {
-    GetPrevNodeOutputFormat(node, input_idx);
+    return GetPrevNodeOutputFormat(node, input_idx);
   }
   auto kernel_info = dynamic_cast<device::KernelInfo *>(node->kernel_info());
   MS_EXCEPTION_IF_NULL(kernel_info);