Interpreter Optimizations

[rob.kinyon]

Do any of the browsers do automatic optimizations? For example,
- constant folding
- branch folding
- optree pruning
- inlining of subroutines (under any conditions)

I've been googling and cannot find anything on the topic. Also, if
there are variations between the interpreters, is there a list of which
interpreters do which optimizations?

Thanks,
Rob