fix momentum-cast fusion

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

@@ -39,10 +39,14 @@ const AnfNodePtr ReplaceMomentumCastFusion::Process(const FuncGraphPtr &graph, c
   MS_EXCEPTION_IF_NULL(equiv);
 
   auto grad_cast = AnfAlgo::GetInputNode(utils::cast<CNodePtr>(node), 3);
-  auto grad = AnfAlgo::GetInputNode(utils::cast<CNodePtr>(grad_cast), 0);
   MS_EXCEPTION_IF_NULL(grad_cast);
+  auto src = AnfAlgo::GetPrevNodeOutputInferDataType(grad_cast, 0);
+  // momentum only support fp32/fp16 by now, do nothing if not.
+  if (src != kNumberTypeFloat16 || src != kNumberTypeFloat32) {
+    return nullptr;
+  }
+  auto grad = AnfAlgo::GetInputNode(utils::cast<CNodePtr>(grad_cast), 0);
   MS_EXCEPTION_IF_NULL(grad);
-
   auto manager = graph->manager();
   MS_EXCEPTION_IF_NULL(manager);
   manager->Replace(utils::cast<CNodePtr>(grad_cast), utils::cast<CNodePtr>(grad));