CVS-175447-[OVEP] Add a check for type mismatches in QDQ stripping (#834)

* [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.

* Expand type transform

* Limit output types to f32/f16, add const_cast

* Apply null check suggestion

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: MayureshV1 <47039074+MayureshV1@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: 3 people

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

@@ -463,11 +463,35 @@ 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 = {const_cast<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_str = dq_node_ref.OutputDefs()[0]->Type();
+          ORT_ENFORCE(type_str != nullptr, "Type string is null in QDQ scales fix.");
+          auto type_cast = type_str->find("tensor(float)") != std::string::npos ? onnx::TensorProto_DataType_FLOAT : onnx::TensorProto_DataType_FLOAT16;
+          ORT_ENFORCE((type_cast == onnx::TensorProto_DataType_FLOAT) || (type_str->find("tensor(float16)") != std::string::npos),
+              "QDQ type misalignment, expected float32 or float16 output");
+          cast_node.AddAttribute("to", static_cast<int64_t>(type_cast));
           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));
+          }
         }
       }
     }