[X86] Enhance fc_fuse_pass to enable fusing relu to fc_op (#2701)

* Enhance fc_fuse_pass to enable fusing relu to fc_op
test=develop

* restrict fusing relu in x86
test=develop

lite/core/mir/fusion/fc_fuse_pass.cc

@@ -23,8 +23,13 @@ namespace lite {
 namespace mir {
 
 void FcFusePass::Apply(const std::unique_ptr<SSAGraph>& graph) {
-  fusion::FcFuser fuser;
+#ifdef LITE_WITH_X86
+  fusion::FcFuser fuser(true);
   fuser(graph.get());
+#endif
+
+  fusion::FcFuser fuser2(false);
+  fuser2(graph.get());
 }
 
 }  // namespace mir

lite/core/mir/fusion/fc_fuse_pass_test.cc

@@ -88,6 +88,7 @@ USE_LITE_OP(mul);
 USE_LITE_OP(elementwise_add);
 USE_LITE_OP(elementwise_sub);
 USE_LITE_OP(fc);
+USE_LITE_OP(relu);
 USE_LITE_OP(feed);
 USE_LITE_OP(fetch);
 USE_LITE_OP(io_copy);

lite/core/mir/fusion/fc_fuser.cc

@@ -35,12 +35,23 @@ void FcFuser::BuildPattern() {
   std::vector<PMNode*> mul_inputs{W, x};
   std::vector<PMNode*> add_inputs{mul_out, b};
   mul_inputs >> *mul >> *mul_out;
-  add_inputs >> *add >> *Out;
 
   // Some op specialities.
   mul_out->AsIntermediate();
   mul->AsIntermediate();
   add->AsIntermediate();
+
+  if (with_relu_) {
+    auto* add_out = VarNode("add_out");
+    auto* relu = OpNode("relu", "relu");
+    std::vector<PMNode*> relu_inputs{add_out};
+    add_inputs >> *add >> *add_out;
+    relu_inputs >> *relu >> *Out;
+    add_out->AsIntermediate();
+    relu->AsIntermediate();
+  } else {
+    add_inputs >> *add >> *Out;
+  }
 }
 
 void FcFuser::InsertNewNode(SSAGraph* graph, const key2nodes_t& matched) {
@@ -71,6 +82,9 @@ cpp::OpDesc FcFuser::GenOpDesc(const key2nodes_t& matched) {
   op_desc.SetAttr(
       "in_num_col_dims",
       matched.at("mul")->stmt()->op_info()->GetAttr<int>("x_num_col_dims"));
+  if (with_relu_) {
+    op_desc.SetAttr("activation_type", std::string{"relu"});
+  }
   return op_desc;
 }
 

lite/core/mir/fusion/fc_fuser.h

@@ -25,11 +25,13 @@ namespace fusion {
 
 class FcFuser : public FuseBase {
  public:
+  explicit FcFuser(bool with_relu) : with_relu_(with_relu) {}
   void BuildPattern() override;
   void InsertNewNode(SSAGraph* graph, const key2nodes_t& matched) override;
 
  private:
   cpp::OpDesc GenOpDesc(const key2nodes_t& matched) override;
+  bool with_relu_;
 };
 
 }  // namespace fusion