add func graph cache avoid repeat func graphs

mindspore/core/ir/func_graph.h

@@ -34,6 +34,7 @@
 #include "utils/ordered_map.h"
 #include "base/base_ref.h"
 #include "ir/func_graph_cloner.h"
+#include "abstract/abstract_value.h"
 
 namespace mindspore {
 using BaseRefCounterMap = OrderedMap<BaseRef, int, BaseRefHash>;
@@ -417,6 +418,9 @@ class FuncGraph : public FuncGraphBase {
   // Design switch_layer_input as a ptr to
   // share between derived backpropagator and cloned graphs
   std::shared_ptr<bool> switch_layer_input_;
+  std::unordered_map<AbstractBasePtrList, FuncGraphPtr, abstract::AbstractBasePtrListHasher,
+                     abstract::AbstractBasePtrListEqual>
+    func_graph_cache_;
 };
 
 inline CNodePtr NewCNode(const std::vector<AnfNodePtr> &inputs, const FuncGraphPtr &fg) {

mindspore/core/ir/func_graph_extends.cc

@@ -245,6 +245,10 @@ FuncGraphPtr FuncGraph::GenerateGraph(const AbstractBasePtrList &args_spec_list)
   if (!NeedGenerate(kwarg_list)) {
     return shared_from_base<FuncGraph>();
   }
+  auto iter = func_graph_cache_.find(args_spec_list);
+  if (iter != func_graph_cache_.end()) {
+    return iter->second;
+  }
   FuncGraphPtr specialized_graph = BasicClone(shared_from_base<FuncGraph>());
   size_t kwarg_count = kwarg_list.size();
   int pos_args_input_count = SizeToInt(arguments_count - kwarg_count - hyper_param_count_);
@@ -290,6 +294,7 @@ FuncGraphPtr FuncGraph::GenerateGraph(const AbstractBasePtrList &args_spec_list)
   specialized_graph->set_kwonlyargs_count(0);
   specialized_graph->ClearDefaultValues();
   specialized_graph->set_is_generate(true);
+  func_graph_cache_[args_spec_list] = specialized_graph;
   return specialized_graph;
 }