search for: r158310

We don't currently have a way of writing unit tests for code in lib/CodeGen, and we do have some code that could benefit from having tests. (See r158310). The problem is that you can't just create a MachineFunction test instance and start poking at it. You need to give it a target first, and certain helper classes like MachineRegisterInfo are also expected to be present. I am looking for a volunteer to build the scaffolding required in unitte...