The byte code for the virtual machine of this years ICFP specified a language with single assignment per simulation step. Interestingly most memory locations get overwritten each simulation step before they are read. That means, those locations don't have to be remember between steps. Also locations that never get overwritten (e.g. location associated with Noops), are constant. Thus the variables state of the simulation is orders of magnitude smaller than the naive 2^16 * 32 bit + 1 bit. I wrote a small program that analyses the dataflow of a byte code program (and initial memory setup) for the VM. After analyzing my program emits Haskell code to run the given byte code. If anyboby is interested, I can document my program and put it online somewhere. I also made pretty graphs of the dataflow with graphviz.