!9412 Never inline middle after block for control flow.

From: @zh_qh
Reviewed-by: 
Signed-off-by:

mindspore/ccsrc/frontend/optimizer/irpass/inline.h

@@ -134,12 +134,24 @@ class InlinerBase : public AnfVisitor {
 
     std::vector<AnfNodePtr> args;
     (void)std::copy(inputs.begin() + 1, inputs.end(), std::back_inserter(args));
-    // compare size to avoid the case that the function has default value after grad.
+    // Compare size to avoid the case that the function has default value after grad.
     // for which after renormalize, the function default value will be an input
     if (fg->parameters().size() != args.size()) {
       return nullptr;
     }
+
     if (IsUniqueUse(nullptr, fg, nullptr)) {
+      // The other branch calling the last after block.
+      if (fg->has_flag(FUNC_GRAPH_FLAG_AFTER_BLOCK)) {
+        // Check if parameters' changed.
+        auto param_simplified_caller = SimplifyAfterParameter(fg, node, args);
+        if (param_simplified_caller != nullptr) {
+          return param_simplified_caller;
+        }
+      }
+
+      // For the single used fg, including non-after and after not matched above,
+      // we move the whole fg nodes.
       if (use_move_) {
         auto mng = fg->manager();
         MS_EXCEPTION_IF_NULL(mng);
@@ -148,10 +160,20 @@ class InlinerBase : public AnfVisitor {
         mng->MoveAllCNodeDropGraph(fg, node->func_graph(), inputs[0]->scope());
         return out_node;
       }
-    } else if (fg->has_flag(FUNC_GRAPH_FLAG_AFTER_BLOCK) && GraphHasBranch(fg)) {
-      // Not to inline after block if it has switch call inside, to avoid switch expansion.
-      return TransformBranchCall(fg, node, args);
+    } else {
+      // We don't expand the middle multiple used after block, except the last one.
+      if (GraphHasBranch(fg)) {
+        return nullptr;
+      }
+      // Check if parameters' changed for the first met branch calling.
+      if (fg->has_flag(FUNC_GRAPH_FLAG_AFTER_BLOCK)) {
+        auto param_simplified_caller = SimplifyAfterParameter(fg, node, args);
+        if (param_simplified_caller != nullptr) {
+          return param_simplified_caller;
+        }
+      }
     }
+    // Or, just make a clone for not single used fg.
     return InlineClone(fg, node->func_graph(), args, inputs[0]->scope());
   }
 
@@ -183,37 +205,34 @@ class InlinerBase : public AnfVisitor {
 
   // For after block which contains branch call, delete the parameters which is not used.
   // In most cases, it may be a `Module` or other constant input.
-  AnfNodePtr TransformBranchCall(const FuncGraphPtr &fg, const AnfNodePtr &node, const std::vector<AnfNodePtr> &args) {
+  AnfNodePtr SimplifyAfterParameter(const FuncGraphPtr &fg, const AnfNodePtr &node,
+                                    const std::vector<AnfNodePtr> &args) {
     auto &fg_params = fg->parameters();
     std::vector<int64_t> used_param_index;
     auto mng = fg->manager();
+    bool should_simplify = false;
     for (size_t i = 0; i < fg_params.size(); i++) {
       if (mng->node_users()[fg_params[i]].size() != 0) {
         used_param_index.emplace_back(i);
+      } else {
+        MS_LOG(DEBUG) << "Not used parameter " << fg_params[i]->DebugString() << " for calling " << fg->ToString();
+        should_simplify = true;
       }
     }
-    // If all parameters are used by cnodes
-    if (used_param_index.size() == fg_params.size()) {
+    if (!should_simplify) {
       return nullptr;
     }
-    if (transformed_branch_chache_.find(fg) == transformed_branch_chache_.end()) {
-      MS_LOG(DEBUG) << "Parameter not used found for graph :" << fg->ToString();
-      // clone a new graph and ignore the not used parameters
-      FuncGraphPtr new_fg = TransformableClone(fg);
-      auto &new_fg_params = new_fg->parameters();
-      std::vector<AnfNodePtr> new_params;
-      std::transform(used_param_index.begin(), used_param_index.end(), std::back_inserter(new_params),
-                     [&new_fg_params](size_t i) { return new_fg_params[i]; });
-      new_fg->set_parameters(new_params);
-      // New func graph must set FUNC_GRAPH_FLAG_AFTER_BLOCK flag otherwise the new graph will be inlined.
-      new_fg->set_flag(FUNC_GRAPH_FLAG_AFTER_BLOCK, true);
-      // Add new graph to the cache to improve perfomance when call HasBranchCall.
-      graph_branch_cache_[new_fg] = true;
-      // If a graph be called at two or more locations, it should not be cloned once again, so add it to the cache.
-      transformed_branch_chache_[fg] = new_fg;
-    }
+    MS_LOG(DEBUG) << "Parameter not used found for graph :" << fg->ToString();
+    // Clone a new graph and ignore the not used parameters
+    auto new_fg = TransformableClone(fg);
+    auto &new_fg_params = new_fg->parameters();
+    std::vector<AnfNodePtr> new_params;
+    std::transform(used_param_index.begin(), used_param_index.end(), std::back_inserter(new_params),
+                   [&new_fg_params](size_t i) { return new_fg_params[i]; });
+    new_fg->set_parameters(new_params);
+
     std::vector<AnfNodePtr> node_inputs;
-    node_inputs.push_back(NewValueNode(transformed_branch_chache_[fg]));
+    node_inputs.push_back(NewValueNode(new_fg));
     std::transform(used_param_index.begin(), used_param_index.end(), std::back_inserter(node_inputs),
                    [&args](size_t i) { return args[i]; });
     return node->func_graph()->NewCNode(node_inputs);
@@ -273,8 +292,6 @@ class InlinerBase : public AnfVisitor {
   bool use_move_;
   std::vector<std::vector<CriterionFuncType>> criterions_;
   std::unordered_map<FuncGraphPtr, bool> graph_branch_cache_;
-  // Key is the old func graph, and the value is the new func_graph
-  std::unordered_map<FuncGraphPtr, FuncGraphPtr> transformed_branch_chache_;
 };
 
 bool IsUniqueUse(InlinerBase *, const FuncGraphPtr &fg, const AnfNodePtr &) {