fix conv_elemetwise_fuse when elemetwise_bias need broadcast

test=develop

lite/core/mir/fusion/conv_elementwise_fuser.cc

@@ -92,6 +92,27 @@ void ConvElementwiseFuser::InsertNewNode(SSAGraph* graph,
       auto elementwise_add_bias_d =
           elementwise_add_bias_t->mutable_data<float>();
 
+      auto conv_bias_size = conv_bias_t->numel();
+      auto elemetwise_bias_size = elementwise_add_bias_t->numel();
+      // If elements size of `elemwise_bias` and `conv_bias` are not same,
+      // `elemwise_bias` should be broadcast to the same size of `conv_bias`
+      if (conv_bias_size != elemetwise_bias_size && elemetwise_bias_size == 1) {
+        auto data_tmp = elementwise_add_bias_d[0];
+        elementwise_add_bias_t->Resize({conv_bias_size});
+        elementwise_add_bias_d = elementwise_add_bias_t->mutable_data<float>();
+        for (int64_t i = 0; i < conv_bias_size; i++) {
+          elementwise_add_bias_d[i] = data_tmp;
+        }
+      }
+      if (conv_bias_t->numel() != elementwise_add_bias_t->numel()) {
+        LOG(WARNING) << "Elements size of `elemwise_bias` and `conv_bias` "
+                        "should be the same, but get size of `elemwise_bias` "
+                        "is: "
+                     << elementwise_add_bias_t->numel()
+                     << ", size of `conv_bias` is: " << conv_bias_t->numel();
+        return;
+      }
+
       for (unsigned int i = 0; i < conv_bias_t->data_size(); ++i) {
         elementwise_add_bias_d[i] += conv_bias_d[i];
       }