By the way I checked the old threads and I think the examples that were given at the time to argue against the gas savings of EIP 2315 may have actually been inaccurately based on an old draft of the EIP. The latest gas values in the EIP are 5 gas for JUMPSUB and 3 gas for RETURNSUB – exactly the same as CALLF and RETF. So I don’t think it makes sense to use the arguments based on “gas benefit” or “compiler benefit” against EIP-2315, since they apply equally if not more to EOF. EOF not only has the same gas costs, it is also structurally more restrictive, blocking optimizations that are conversely available via EIP-2315, and requiring substantially more complexity on the compiler side.
For reference, our POC for EOF in Vyper took nearly 1k lines of code to be EOF-compliant. And I’m not that familiar with the Solidity codebase, but it looks like the EOF POC was 14,000 lines (Implementation of EOF in Solidity [DO NOT MERGE] by rodiazet · Pull Request #15294 · ethereum/solidity · GitHub). Whereas for EIP-2315, I can’t speak for Solidity but at least on the Vyper side, EIP-2315 is a 10-20 line change.