in reply to No More Meaningless Benchmarks!
ATLAS is smart about not trusting something like the Benchmark module. I think it measures the results with a wall clock and will not compile if the system is otherwise busy. It takes a while to build.
This type of optimization is probably not a desirable way to mangle your perl source code except for fun, but it might be a great technique for optimizing something important like a regular expression engine. Of course it would not just move code around, the optimizer would explore the space of different buffer sizes, etc.
You can find ATLAS at http://math-atlas.sourceforge.net. I have used ATLAS in my projects and it worked great!