[jcranmer]

Graph rewriting turns out to be a rather difficult problem, and many optimizations are better recast in other frameworks. For example, instruction scheduling (on superscalar processors) is pretty much a textbook example of the job scheduling problem. Loop optimizations can be most easily expressed in the polyhedral loop optimization model. Decisions like inlining can be framed as high-dimension, highly non-linear, multi-goal optimization (in the mathematics sense) problems.