I'm glad you mentioned optimizing. I already though about a method.. If you make az abstarct representation of the semantics of the code (as I wrote in the first part of my previous post) then you can even transform it back to asm. Since you can describe asm with this language, you can create many representations back and choose the one that is most optimal for you. You just have to be sure that you transformed everything.
I'm not sure I can describe my idea well... so the algorithm could be like:
describe the asm instructions with these abstract statements (there could be more than one representation, of course). Then you look for these sequences in the abstract representation (doestn't have to be strictly a sequence, there canm be holes that will be represented by other instructions). Then, you will have many-many asm representations that do exactly the same. So you can make a function that computes you an optimality value, and choose the best.

I didn't know whether there is research in this direction, maybe I didn't find anything new

kp