How do I obtain the IR of a network written in NNVM for custom IR optimization?
That is, assume I have the following network
net, params = nnvm.testing.resnet.get_workload(num_layers=18, batch_size=batch_size, image_shape=image_shape)
and I would like to obtain the IR for writing custom optimizations as described in the tutorial here 
You can hook nnvm.compiler.lower by calling tvm.register_func with override=True
The lower function is called in
Thanks, but I’m still not clear how to generate a schedule of the network to call the ‘lower’ function.
DoLower calls into GetScheduleArgs https://github.com/dmlc/tvm/blob/bbc78221777a06e3d6b6ee0c07f51f9f37201928/nnvm/src/compiler/compile_engine.cc#L141, which will call TOPI schedule of opperators (the schedules are registered in nnvm/python/nnvm/top)