!3802 fix nopnode internal output error

Merge pull request !3802 from kisnwang/fix-ps-task-error

mindspore/ccsrc/backend/session/session_basic.cc

@@ -980,8 +980,9 @@ CNodePtr SessionBasic::ConstructOutput(const AnfNodePtrList &outputs, const std:
       if (context_ptr->execution_mode() == kPynativeMode) {
         return backend_anf;
       }
-      auto front_real_kernel = AnfAlgo::VisitKernel(out, 0);
-      auto backend_real_kernel = AnfAlgo::VisitKernel(backend_anf, 0);
+      auto front_real_kernel_pair = AnfAlgo::VisitKernel(out, 0);
+      auto front_real_kernel = front_real_kernel_pair.first;
+      auto backend_real_kernel_pair = AnfAlgo::VisitKernel(backend_anf, 0);
       MS_EXCEPTION_IF_NULL(out);
       auto out_func_graph = out->func_graph();
       MS_EXCEPTION_IF_NULL(out_func_graph);
@@ -992,26 +993,47 @@ CNodePtr SessionBasic::ConstructOutput(const AnfNodePtrList &outputs, const std:
       auto node_users = out_func_graph_manager->node_users();
       auto users = node_users[out];
       bool internal_output = true;
-      std::string kernel_target = GetCNodeTarget(front_real_kernel.first);
-      for (auto user : users) {
-        auto cnode = user.first->cast<CNodePtr>();
-        if (cnode == nullptr) {
+      std::string kernel_target = GetCNodeTarget(front_real_kernel);
+      if (front_real_kernel != nullptr && front_real_kernel->isa<CNode>()) {
+        auto front_cnode = front_real_kernel->cast<CNodePtr>();
+        if (front_cnode != nullptr) {
+          auto prim = front_cnode->input(kAnfPrimitiveIndex);
+          if (prim == nullptr || !prim->isa<ValueNode>()) {
+            internal_output = false;
+          }
+        } else {
           internal_output = false;
-          break;
         }
-        auto prim = cnode->input(kAnfPrimitiveIndex);
-        if (prim == nullptr || !prim->isa<ValueNode>()) {
+      }
+      if (internal_output && opt::IsNopNode(front_real_kernel)) {
+        auto pre_node_pair = AnfAlgo::GetPrevNodeOutput(front_real_kernel, 0);
+        auto pre_node_target = GetCNodeTarget(pre_node_pair.first);
+        if (pre_node_target != kernel_target) {
           internal_output = false;
-          break;
         }
-        if (!AnfAlgo::IsRealKernel(user.first) || kernel_target != GetCNodeTarget(user.first)) {
-          internal_output = false;
-          break;
+      }
+      if (internal_output) {
+        for (auto user : users) {
+          auto cnode = user.first->cast<CNodePtr>();
+          if (cnode == nullptr) {
+            internal_output = false;
+            break;
+          }
+          auto prim = cnode->input(kAnfPrimitiveIndex);
+          if (prim == nullptr || !prim->isa<ValueNode>()) {
+            internal_output = false;
+            break;
+          }
+          if (!AnfAlgo::IsRealKernel(user.first) || kernel_target != GetCNodeTarget(user.first)) {
+            internal_output = false;
+            break;
+          }
         }
       }
       if (internal_output) {
-        MS_LOG(INFO) << "Internal output1: " << out->DebugString() << "To " << backend_real_kernel.first->DebugString();
-        graph->AddInternalOutput(out, backend_real_kernel.first);
+        MS_LOG(INFO) << "Internal output: " << out->DebugString() << "To "
+                     << backend_real_kernel_pair.first->DebugString();
+        graph->AddInternalOutput(out, backend_real_kernel_pair.first);
       }
       return backend_anf;
     }