[pizlonator]

> The main thing we're doing differently in SM is that all of our ICs are generated using a simple linear IR (CacheIR)

JSC calls this PolymorphicAccess. It’s a mini IR with a JIT that tries to emit optimal code based on this IR. Register allocation and everything, just for a very restricted IR.

It’s been there since I don’t remember when. I wrote it ages ago and then it has evolved into a beast.

[IainIreland]

Taking a quick look at the JSC code, the main difference is that CacheIR is more pervasive and load-bearing. Even monomorphic cases go through CacheIR.

The main justification for CacheIR isn't that it enables us to do optimizations that can't be done in other ways. It's just a convenient unifying framework.