add reference. test=develop

paddle/fluid/framework/details/memory_optimize_pass.cc

@@ -46,7 +46,6 @@ namespace details {
 std::unique_ptr<ir::Graph> MemoryOptimizePass::ApplyImpl(
     std::unique_ptr<ir::Graph> graph) const {
   auto nodes = graph->Nodes();
-  ClearControlDepVars(graph.get());
   CollectSkipVarsSet(nodes);
 
   cfg_.reset(new details::ControlFlowGraph(*graph));
@@ -79,7 +78,7 @@ std::unique_ptr<ir::Graph> MemoryOptimizePass::ApplyImpl(
         ir::Node* cache = pool_.FindBestFitNode(var);
         while (cache != nullptr && var->Name() == cache->Name()) {
           VLOG(3) << "The same cache variable is cascade reused. "
-                  << var->Name() << " is re-filled to the pool after"
+                  << cache->Name() << " is re-filled to the pool after "
                   << "the reused op is finished. Current op can not "
                   << "replace it again. Skip this candidate.";
           cache = pool_.FindNextBestFitNode(var, cache);
@@ -325,32 +324,6 @@ void MemoryOptimizePass::RenameVarInGraphNode(const std::string& var,
   }
 }
 
-void MemoryOptimizePass::ClearControlDepVars(ir::Graph* graph) const {
-  for (auto& op : graph->Nodes()) {
-    if (!op->IsOp()) continue;
-    {
-      auto& nodes = op->inputs;
-      nodes.erase(
-          std::remove_if(nodes.begin(), nodes.end(),
-                         [&](ir::Node* var) { return var->IsCtrlVar(); }),
-          nodes.end());
-    }
-    {
-      auto& nodes = op->outputs;
-      nodes.erase(
-          std::remove_if(nodes.begin(), nodes.end(),
-                         [&](ir::Node* var) { return var->IsCtrlVar(); }),
-          nodes.end());
-    }
-  }
-
-  for (auto& node : graph->Nodes()) {
-    if (node->IsCtrlVar()) {
-      graph->RemoveNode(node);
-    }
-  }
-}
-
 }  // namespace details
 }  // namespace framework
 }  // namespace paddle

paddle/fluid/framework/details/memory_optimize_pass.h

@@ -48,7 +48,6 @@ class MemoryOptimizePass : public ir::Pass {
   void RenameVarInGraphNode(const std::string& var,
                             const std::string& cache_var, size_t idx,
                             ir::Graph* graph) const;
-  void ClearControlDepVars(ir::Graph* graph) const;
 
   void SubGraphOptimize(OpDesc* op_desc) const;
   // 1. scan op with subblock and collect the output/input vars.