Technically speaking, break / continue / early return are unstructured by the classical definition. The algorithm you are likely thinking of can easily be exten

Technically speaking, break / continue / early return are unstructured by the classical definition. The algorithm you are likely thinking of can easily be extended to handle arbitrary control-flow: https://pp.info.uni-karlsruhe.de/uploads/publikationen/braun13cc.pdf https://pp.info.uni-karlsruhe.de/uploads/publikationen/braun... In the case of irreducible control-flow it may produce redundant cyclic phis, but those can be eliminated with a pretty simple post-pass.