[OVEP] Add a check for type mismatches in QDQ stripping

When rewiring the graph after eliminating QDQ pairs, the runtime now checks
whether the type matches before and after the eliminated nodes and inserts a
Cast node if there is a mismatch.

Author: mdvoretc-intel

onnxruntime/core/providers/openvino/qdq_transformations/qdq_scales_fix.cpp

@@ -463,11 +463,32 @@ struct CustomGraph {
       }
 
       if (!is_prev_input) {
-        for (const auto& edge : output_edges) {
+        if (prev.node_ptr->OutputDefs()[0]->Type() != dq_node_ref.OutputDefs()[0]->Type()) {
+          NodeArg& output = original_graph.GetOrCreateNodeArg(prev.node_name + "_cast_0", dq_node_ref.OutputDefs()[0]->TypeAsProto());
+          std::string cast_node_name = prev.node_ptr->OutputDefs()[0]->Name() + "_cast";
+          InlinedVector<NodeArg*> input_args = {(NodeArg*)(prev.node_ptr->OutputDefs()[0])};
+          InlinedVector<NodeArg*> output_args = {&output};
+          Node& cast_node = original_graph.AddNode(cast_node_name, "Cast", "", input_args, output_args, nullptr, "");
+          auto type_dummy = dq_node_ref.OutputDefs()[0]->Type();
+          auto type_final = type_dummy->find("tensor(float)") != std::string::npos ? onnx::TensorProto_DataType_FLOAT : onnx::TensorProto_DataType_FLOAT16;
+          cast_node.AddAttribute("to", int64_t(type_final));
           original_graph.AddEdge(prev.node_ptr->Index(),
-                                 std::get<0>(edge),
+                                 cast_node.Index(),
                                  prev_output_index,
-                                 std::get<2>(edge));
+                                 0);
+          for (const auto& edge : output_edges) {
+            original_graph.AddEdge(cast_node.Index(),
+                                   std::get<0>(edge),
+                                   0,
+                                   std::get<2>(edge));
+          }
+        } else {
+          for (const auto& edge : output_edges) {
+            original_graph.AddEdge(prev.node_ptr->Index(),
+                                   std::get<0>(edge),
+                                   prev_output_index,
+                                   std::get<2>(edge));
+          }
         }
       }
     }