[icodestuff]

There are a number of considerations there. Size is only one of them. Speed and internal processor state effects are two others. For instance, a larger, slower instruction might prevent a pipeline stall in a particular function or might enable loop unrolling or might allow a shorter loop unrolling, while in a similar function that doesn’t pipeline the same way, the compiler will choose a faster instruction.

[anitil]

You're right I completely overlooked pipelining. I guess I'm out of my depth here