In your example you've written more code to make the machine do less, which fits the spirit of the advice just fine. Memory-access optimizations are just another way of making the hardware do less in some cases.
you've written more code to make the machine do less
Not really: if you're improving the program's memory access behavior, the machine really is "doing more": by removing a memory stall, you're replacing a situation in which the processor was idling with a situation in which the processor is doing useful work. Prefetching and speculative execution are other examples of the "do more work, spend less time idling" theme.
