Your description of optimizing Ruby sounds like it is exactly like optimizing JS. JSC’s main optimizing IR (the DFG) is all about understanding the standard library semantically. We write the standard library in JS+hacks (called “builtins”) or C++ (pick on a per function basis). Some of those functions have opcodes in DFG, or are built out of primitives that have their own specialized opcodes in DFG.
Maybe the reason why Ruby optimization has problems is nobody has done it the JSC way.
Maybe the reason why Ruby optimization has problems is nobody has done it the JSC way.