+++ Adhemerval Zanella [2016-04-28 12:07 -0300]:
I do not think this issue is inherent to all JIT implements, but rather to luajit with its NaN-tagging scheme [1] which packs different types of objects in a 8-byte.
Other jits use the same/similar schemes (mozilla's ionmonkey is one AIUI). Not sure how many others do this, or how many JITs do it a different way. BUt it is certainly wider than just luajit.
Wookey