What algorithm will solve IK?

I modified my rig to replace the constraints along the IK chain with drivers and it seems to be working. I set up my rig so that both shoulders have three bones: ShoulderDriver, ShoulderManual, and just Shoulder. I have a constraint on Shoulder to add the rotation of ShoulderDriver and ShoulderManual. UpArm is a child of Shoulder, and Shoulder has a driver that depends on UpArm. I think this would be a dependency cycle but Blender is not warning me about a dependency cycle. Are dependency cycles involving drivers not an issue?