set ir based on opset

Author: guschmue

tf2onnx/constants.py

@@ -37,3 +37,9 @@
 
 # Environment variables
 ENV_TF2ONNX_DEBUG_MODE = "TF2ONNX_DEBUG_MODE"
+
+# Mapping opset to IR version.
+# When adding here, make sure that the IR changes don't impact that we do.
+OPSET_TO_IR_VERSION = {
+    1: 3, 2:3, 3: 3, 4: 4, 5: 3, 6:3, 7:3, 8:3, 9:4, 10:5, 11:6, 12:7
+}

tf2onnx/graph.py

@@ -1039,6 +1039,9 @@ def make_model(self, graph_doc, optimize=False, graph_name="tf2onnx", **kwargs):
             kwargs["opset_imports"] = opsets
         model_proto = helper.make_model(graph, **kwargs)
 
+        # set the IR version based on opset
+        model_proto.ir_version = constants.OPSET_TO_IR_VERSION.get(self.opset, model_proto.ir_version)
+
         # optimize the model proto.
         # TODO: this is disabled by default because of bugs in fuse_consecutive_transposes
         if optimize: