[shub]

Thank you (seriously) for the detailed explantion.

JITs already do this, to my mind. What else are you going to call it when HotSpot sees bytecode for a loop initializing an array and replaces it with a call to memset? Special-casing instruction patterns is applicable whether or not you're doing native codegen. The big difference is that you have these VMs which have decided not to JIT so they need to fix their perf problems somewhere else, because (and Nock is especially bad about this) a naive interpreter is unacceptably slow.