follow comment. test=develop

paddle/fluid/framework/details/inplace_op_pass.cc

@@ -401,7 +401,7 @@ void GraphView::Build(ir::Graph* g) {
   }
 }
 
-const& std::vector<ir::Node*> GraphView::AllOps() { return ops_; }
+const std::vector<ir::Node*>& GraphView::AllOps() { return ops_; }
 
 bool GraphView::ReusedInPythonMemOpt(const std::string& var) const {
   return dup_nodes_.count(var);

paddle/fluid/framework/details/inplace_op_pass.h

@@ -33,7 +33,7 @@ class GraphView {
 
   void Build(ir::Graph* g);
 
-  const& std::vector<ir::Node*> AllOps();
+  const std::vector<ir::Node*>& AllOps();
 
   ir::Node* GetNodeByName(const std::string& name,
                           const std::vector<ir::Node*>& nodes) const;