title: What are you favorite low level code optimization tricks?
body: <p>I know that you should only optimize things when it is deemed necessary. But, if it is deemed necessary, what are your favorite low level (as opposed to algorithmic level) optimization tricks.</p>
  
  <p>For example: <a href="http://en.wikipedia.org/wiki/Loop_unwinding" rel="noreferrer">loop unrolling</a>.</p>