Thinking about this - this may be a pattern that;s designed to match something that expands from a string instruction. While the loop he's testing is a useless

Thinking about this - this may be a pattern that;s designed to match something that expands from a string instruction. While the loop he's testing is a useless bit of code that does nothing the optimisation he's discovered may help speed things like scasb/stosb allowing portions of 2 unrolled copies to be processed per clock