Merge pull request #305 from Xyzhao1999/dev/fix_empty_initializer

fix: Preserve empty initializer inputs

onnxsim/onnxsim.cpp

@@ -243,6 +243,14 @@ std::vector<onnx::TensorProto> RunOp(onnx::ModelProto& model,
                                      const onnx::NodeProto& op) {
   std::vector<std::string> input_names;
   std::vector<onnx::TensorProto> input_tps;
+  std::set<std::string> initializer_names;
+
+  onnx::ModelProto op_model;
+  op_model.set_ir_version(model.ir_version());
+  for (const auto& x : model.opset_import()) {
+    *op_model.add_opset_import() = x;
+  }
+  *op_model.mutable_graph()->add_node() = op;
 
   for (const auto& input : op.input()) {
     if (std::find(input_names.begin(), input_names.end(), input) !=
@@ -253,16 +261,19 @@ std::vector<onnx::TensorProto> RunOp(onnx::ModelProto& model,
     if (input.empty()) {
       continue;
     }
-    input_names.push_back(input);
+    if (initializer_names.find(input) != initializer_names.end()) {
+      continue;
+    }
     auto in_tp = FindInitializerByName(model, input);
+    if (in_tp.dims().size() == 1 && in_tp.dims()[0] == 0) {
+      initializer_names.insert(input);
+      *op_model.mutable_graph()->add_initializer() = in_tp;
+      continue;
+    }
+    input_names.push_back(input);
     input_tps.push_back(in_tp);
   }
-  onnx::ModelProto op_model;
-  op_model.set_ir_version(model.ir_version());
-  for (const auto& x : model.opset_import()) {
-    *op_model.add_opset_import() = x;
-  }
-  *op_model.mutable_graph()->add_node() = op;
+
   for (const auto& x : input_names) {
     // skip "" which represents the unset optional input
     if (x.empty()) {