Smarter optimizer

[Idorobots]

Instead of merely looping optimizations around the optimizer should be smarter about selecting different optimizations to run.
For instance, it could run a gradient descent-like search in the space of optimized programs. Then the compiler optimizations can be guided with a specially crafted score function - either to minimize code size, or maximize performance.

[Idorobots]

Some things still to try:

• Add a third "complexity" measure so that it prefers less complex code.
• Add a fourth "further optimization potential" measure.
• Run optimizations lazily and incrementally, so that there's no need to inline functions in a branch that is dead.
• Perform a better reachabillity and escape analysis for better treatment of recursive functions.
• Maintain free variable & usage counts incrementally, instead of recomputing them all the time.