Graph tuning error from PyTorch Inception V3 model

I encountered the following error when trying to graph tune the Inception V3 from torchvision:

Traceback (most recent call last):
  File "run_pytorch_inception_v3.py", line 28, in <module>
    executor.benchmark_layout_transform(min_exec_num=2000)
  File "/home/ubuntu/cody-tvm/python/tvm/autotvm/graph_tuner/base_graph_tuner.py", line 434, in benchmark_layout_transform
    self._iterate_layout_transform(_fetch_args_callback)
  File "/home/ubuntu/cody-tvm/python/tvm/autotvm/graph_tuner/base_graph_tuner.py", line 272, in _iterate_layout_transform
    i_topi_op = in_node_entry["topi_op"][0]
KeyError: 'topi_op'

I also tried the Inception V3 model from Gluon CV model zoo as well as other torchvision models but didn’t encounter this issue. I guess it might be due to the torchvision Inception V3 architecture.

You can use the following two files to repeoduce the problem. Note that it may take a while to convert PyTorch Inception V3 to the Relay module.

https://gist.githubusercontent.com/comaniac/b689010eaf0467105248efccffa13352/raw/046324129f42bd02f9516cd027f47c4b56cbd988/run_pytorch_inception_v3.py

https://gist.githubusercontent.com/comaniac/922bdcbecd4cfb6c36bd8add5977b7ec/raw/7f727366cd8530ba61cb00ff6b7f9681febf7f23/inception_v3.json

cc @kevinthesun @alexwong