> This idea can be implemented without opcode cache. I will try it.
I'd actually encourage trying to use the opcode cache because this way the optimization will be more generic. E.g. `decimal + decimal` would also be specialized via the cache, because you'd cache a pointer to the specific `+` operator implementation. I'm really not sure that adding specialized byte code is a good idea.
> * PHP uses scalar type for float and int
While at it, maybe we push the number of bits per int digit to 60?
While at it, I'd also increase the digit size