Recently I am looking at PHP8 JIT compiler thing and found a tunable JIT option - jit_hot_side_exit (https://www.php.net/manual/en/opcache.configuration.php#ini.opcache.jit-hot-side-exit). Unfortunately, I have zero knowledge about this terminology and google does not give much useful information only a few control flow graphs.

Anyone can help clarify what 'side exit' is and it is better to have a simple PHP code example which can increase jit_hot_side_exit counter and trigger jit compiler? Thanks in advance.