Hi, This message is probably mainly targeted at Tom, but since we have a mailing list and other people may be interested, I thought I'd send it to everyone. I was looking at compiled bytecode, and I noticed things that might be able to be improved - in rough order of difficulty. I don't think any of these impact on the backend at all, but might make faster code in general. == SLIDE 0 == I noticed some of these, I take it they are a noop? If so, lets peephole them away! Probably one line of code... == JUMP_FALSE -> JUMP_ZERO == If we moved from JUMP_FALSE to JUMP_ZERO (which i take it is the same semantics anyway!) then this could often be used for case statements on two constructors (say lists, for example). Also case on a bool is expanded to a case, if we had JUMP_ZERO this could be collapsed back as a more general transformation. Less code, faster code, happier code. == EVAL; JUMP; RETURN == I noticed a few things that EVAL, then JUMP, then RETURN - of course you could collapse the EVAL to EVAL_RETURN and throw away the jump. Less code, more speed, everyone is happy :) == branch factorisation == I noticed a few cases where two branches both jump to the same place, and execute the same code, but the code before the jump's are the same. These could be factorised into the after the jump bit - less code, same speed, there are possibly more important things before worrying about this... Thanks Neil