I would expect it depends on where the lookup table enters the picture. If the table lookup is at the end of a dependency chain, it's not going to stall anythin

I would expect it depends on where the lookup table enters the picture. If the table lookup is at the end of a dependency chain, it's not going to stall anything and then you're putting less strain on the branch predictor/reordering machinery. The article is using pext, which is different from a regular table lookup. While it has horrible latency and overhead on older chips, on Zen3 it appears to decode to a single uop with a latency of 3, and on Haswell it also decodes to one uop with a latency of 3. So it's not as bad as a regular table lookup as long as you're on a new enough processor. It's also possible to do vectorized lookup table loads if your lookup table is small enough and you have a modern CPU, see http://0x80.pl/notesen/2016-03-13-simd-lookup-pshufb.html http://0x80.pl/notesen/2016-03-13-simd-lookup-pshufb.html and http://0x80.pl/notesen/2019-02-03-simd-switch-implementation.html http://0x80.pl/notesen/2019-02-03-simd-switch-implementation... (there's a more generalized version of this I can't remember the URL of...)