diff --git a/paddle/fluid/framework/inplace_op_inference.h b/paddle/fluid/framework/inplace_op_inference.h
index 40026eaca9a92e6acdb60e03578ad41f137e8502..225c8e26b24e5f083d8a2737b3bffcb3de048ead 100644
--- a/paddle/fluid/framework/inplace_op_inference.h
+++ b/paddle/fluid/framework/inplace_op_inference.h
@@ -43,13 +43,11 @@ class SingleOpInplaceInToOut : public InplaceOpInference {
  public:
   std::unordered_map<std::string, std::string> operator()(
       const OpDesc& op_desc, bool use_cuda) const override {
-    PADDLE_ENFORCE_EQ(op_desc.InputNames().size(), 1,
-                      "Op inputs must be unique");
-    PADDLE_ENFORCE_EQ(op_desc.OutputNames().size(), 1,
-                      "Op outputs must be unique");
-    auto x_name = op_desc.InputNames().at(0);
-    auto out_name = op_desc.OutputNames().at(0);
-    return std::unordered_map<std::string, std::string>{{x_name, out_name}};
+    auto inputs = op_desc.InputNames();
+    auto outputs = op_desc.OutputNames();
+    PADDLE_ENFORCE_EQ(inputs.size(), 1, "Op inputs must be unique");
+    PADDLE_ENFORCE_EQ(outputs.size(), 1, "Op outputs must be unique");
+    return {{inputs[0], outputs[0]}};
   }
 };
 
diff --git a/paddle/fluid/operators/activation_op.h b/paddle/fluid/operators/activation_op.h
index ea19dcd3ab08d64e5ee6806df4d70f8be64a9905..8c70c9abccd43dcbf23a73de823144f700388de7 100644
--- a/paddle/fluid/operators/activation_op.h
+++ b/paddle/fluid/operators/activation_op.h
@@ -210,14 +210,6 @@ struct BaseActivationFunctor {
   using AttrPair = std::vector<std::pair<const char*, float*>>;
 
   AttrPair GetAttrs() { return AttrPair(); }
-
-  /* NOTE(*): Output reuse X memory if X is not dependented by its Gradient.
-     For example, sigmoid op's gradient didn't involve x, so its output can
-     reuse
-     input memory. But abs op's gradient use x, it can not be inplaced.
-     gradient did use x.
-   */
-  bool Inplace() const { return false; }
 };
 
 // sigmoid(x) = 1 / (1 + exp(-x))