You do loop unrolling on purpose? I think loop unrolling is one of the disadvantages we have in real life.

I already made my bed, now can't you do it for me for d in days? It's the same every time! What's with all this premature optimization?

Oh sure I do, especially in cooking. Rather than just repeat the same procedure with cleanup and all, I do all of them then clean up, i.e. chopping peppers, shredding cheese, frying sausage, etc.