Seems reasonable. Does this implicitly rely on the zjit instructions a) being contiguous and b) being reliably ordered after all the other instructions?

Thanks! I was a bit worried about making the interpreter loop function overly big for non users too.

Does this implicitly rely on the zjit instructions a) being contiguous and b) being reliably ordered after all the other instructions?

Yes, it does. I added tests for the assumption d67294e.

I initially printed #if 1 or #if USE_ZJIT for every instruction, but it made the source code in the distributed package harder to read. Also the offset calculation would be much harder to implement if we didn't rely on it.

Ah, can you toss in a --disable-zjit build in .github/workflows/compilers.yml for good measure?

done 932f29c