A couple of bug fixes (#1945)

Fixes a couple of bugs that show up in GPT2 optimization.

onnxscript/optimizer/_inliner.py

@@ -236,9 +236,9 @@ def _instantiate_call(self, node: ir.Node, call_site_id: CallSiteId) -> NodeRepl
 
         # Identify call-stack for node, used to generate unique names.
         call_stack = self.node_context.get(node, [])
-        call_stack.append(call_site_id)
+        new_call_stack = [*call_stack, call_site_id]
 
-        cloner = _CopyReplace(self, attributes, value_map, node.metadata_props, call_stack)
+        cloner = _CopyReplace(self, attributes, value_map, node.metadata_props, new_call_stack)
 
         # iterate over the nodes in the function, creating a copy of each node
         # and replacing inputs with the corresponding values in the value map.

onnxscript/rewriter/collapse_slices.py

@@ -28,6 +28,10 @@ def _check_if_redundant_slice(
     axes_const = axes.const_value
     steps_const = steps.const_value
 
+    if starts_const is None or ends_const is None or axes_const is None or steps_const is None:
+        logger.info("The value 'start', 'end', 'axis', 'step' is not statically known.")
+        return False
+
     # Check if the values are scalar
     if starts_const.numpy().size != 1:  # type: ignore[union-attr]
         logger.info("The value 'start' is not a scalar.")
@@ -42,9 +46,6 @@ def _check_if_redundant_slice(
         logger.info("The value 'step' is not a scalar.")
         return False
 
-    if starts_const is None or ends_const is None or axes_const is None or steps_const is None:
-        logger.info("The value 'start', 'end', 'axis', 'step' is not statically known.")
-        return False
     if steps_const.numpy().item() != 1:
         logger.info("The value 'step' is not 1.")
         return False