Correct Alignment of a Return-Address-Stack after Call and Return Mispredictions

It is accepted that the alignment of a return-address- stack can be preserved by checkpointing on branches and recovering on branch mispredictions the top-of- stack pointer. However, virtually all published litera- ture, is vague or proposes sub-optimal algorithms on how to repair the alignment of a return-address-stack on call and return mispredictio..