It's well known that it's possible to change a program that uses GOTOs into one that uses loops and conditionals if you're allowed to duplicate code or add more variables. One very easy way is just to change the program into a state machine, with one state for each label and a big loop around the whole thing. But under what conditions can you eliminate GOTOs if you can't do either?
The "Multiple break" example in the "More keywords" blog post is a piece of code that can't be de-GOTOized in C. I'm wondering if there are any examples of pieces of code that can't be de-GOTOized without multiple break, extra variables or code duplication. If I understand the abstract of Peterson 1973 correctly I think there aren't - that multiple break is enough to make GOTO redundant (but I can't find a non-paywalled copy of that article to check, and I don't care enough to spend $15 to find out).