llvm dev - Oct 2015 - What is the purpose of itineraries and stages in tablegen?

As far as I understand itineraries instruction stages and instruction
itinerary data  classes are used to describe how instruction is moving
through the pipeline. The LLVM for OR1K (
https://github.com/openrisc/llvm-or1k) does not have these kind of
descriptions. What am I missing? How come it doesn't have it? Is there
another way to provide this information?

Any help is appreciated.
Thanks
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