diff --git a/src/common/depCore.h b/src/common/depCore.h
index 3d7948cc835e9c4f1ac4670c6bd600028f2f48c1..d9873a3896d1ac83cfc45e0666ca8491a645ed8e 100644
--- a/src/common/depCore.h
+++ b/src/common/depCore.h
@@ -28,14 +28,6 @@ class depCore {
       const std::vector<std::shared_ptr<framework::OperatorBase<Dtype>>>& ops) {
     std::unordered_map<std::string, int> vars;
     size_t nop = ops.size();
-    for (size_t i = 0; i < nop; i++) {
-      const auto& op = ops[i];
-      for (const auto& kv : op->Outputs()) {
-        for (const auto& v : kv.second) {
-          vars[v] = i;
-        }
-      }
-    }
     deps.resize(nop);
     next.resize(nop);
     for (size_t i = 0; i < nop; i++) {
@@ -56,6 +48,11 @@ class depCore {
           next[di].push_back(i);
         }
       }
+      for (const auto& kv : op->Outputs()) {
+        for (const auto& v : kv.second) {
+          vars[v] = i;
+        }
+      }
     }
   }
   const std::vector<int>& getNext(int i) { return next[i]; }