MKLDNN residual connections fuse pass: counting statistics added to the pass

paddle/fluid/framework/ir/conv_elementwise_add_mkldnn_fuse_pass.h

@@ -21,11 +21,45 @@
 #include "paddle/fluid/framework/ir/graph.h"
 #include "paddle/fluid/framework/ir/graph_pattern_detector.h"
 
+#include <boost/optional.hpp>
+
 namespace paddle {
 namespace framework {
 namespace ir {
 
+// poor replacement for C++17 std::optional and Boost.Optional
+struct InPlace {};
+InPlace in_place;
+
+template <typename T>
+class Maybe {
+ private:
+  typename std::aligned_storage<sizeof(T), alignof(T)>::type data;
+  bool is_initialized{false};
+
+ public:
+  template <typename... Args>
+  explicit Maybe(InPlace, Args&&... args) {
+    new (&data) T(std::forward<Args>(args)...);
+    is_initialized = true;
+  }
+
+  Maybe() {}
+
+  operator bool() { return is_initialized; }
+
+  T& value() { return *reinterpret_cast<T*>(&data); }
+
+  ~Maybe() { reinterpret_cast<T*>(&data)->~T(); }
+};
+
+template <typename T, typename... Args>
+Maybe<T> MakeMaybe(Args&&... args) {
+  return Maybe<T>(in_place, std::forward<Args>(args)...);
+}
+
 using graph_ptr = std::unique_ptr<ir::Graph>;
+using GraphWithStats = std::pair<ir::Graph*, Maybe<int>>;
 
 void CorrectGraphEdges(Graph* graph, Node* from, Node* to);
 bool IsReachable(ir::Graph* graph, Node* from, Node* to);
@@ -33,8 +67,10 @@ std::pair<bool, Node*> HasBias(const Node& op, const std::string& bias_name);
 
 class ResidualConnectionMKLDNNFusePass : public FusePassBase {
  private:
-  graph_ptr FuseConvAsX(const std::string& name_scope_, graph_ptr graph) const;
-  graph_ptr FuseConvAsY(const std::string& name_scope_, graph_ptr graph) const;
+  GraphWithStats FuseConvAsX(const std::string& name_scope,
+                             const GraphWithStats& graph_with_stats) const;
+  GraphWithStats FuseConvAsY(const std::string& name_scope,
+                             const GraphWithStats& graph_with_stats) const;
 
   template <typename RetType>
   using GetNodeFunc =
@@ -48,12 +84,15 @@ class ResidualConnectionMKLDNNFusePass : public FusePassBase {
                 const ElementwiseAddFunc& get_node_from_elementwise_add_op,
                 const CanFuseFunc& can_fuse_func);
 
+    void operator()(const GraphPatternDetector::subgraph_t& subgraph,
+                    Graph* graph);
+    int get_stats() const { return *fusion_stats; }
+
+   private:
+    std::shared_ptr<int> fusion_stats;
     ConvFunc get_node_from_conv_op;
     ElementwiseAddFunc get_node_from_elementwise_add_op;
     CanFuseFunc can_fuse_func;
-
-    void operator()(const GraphPatternDetector::subgraph_t& subgraph,
-                    Graph* graph);
   };
 
  public: