fix subgraph bugs

onnxslim/onnx_graphsurgeon/ir/graph.py

@@ -1287,7 +1287,7 @@ def fold_subgraphs():
             while index < len(self.nodes):
                 node = self.nodes[index]
                 if node.op == "If" and isinstance(node.inputs[0], Constant):
-                    G_LOGGER.debug("Flattening conditional: {:}".format(node))
+                    G_LOGGER.debug("Flattening conditional: {:}".format(node.name))
                     cond = get_scalar_value(node.inputs[0])
                     subgraph = node.attrs["then_branch"] if cond else node.attrs["else_branch"]
                     # Need to add a suffix to subgraph tensors so they don't collide with outer graph tensors
@@ -1297,7 +1297,8 @@ def fold_subgraphs():
                     # The subgraph outputs correspond to the If node outputs. Only the latter are visible
                     # in the parent graph, so we rebind the producer nodes of the subgraph outputs to point
                     # to the output tensors of the If instead.
-                    for node_out, subgraph_out in zip(node.outputs, subgraph.outputs):
+                    node_outputs = list(node.outputs)
+                    for node_out, subgraph_out in zip(node_outputs, subgraph.outputs):
                         node_out.inputs.clear()
                         for producer in subgraph_out.inputs:
                             for tensor_idx, out_tensor in enumerate(producer.outputs):