Python supports arithmetic on mixed numeric types, so it makes sense that floats and ints should have a hash function that behaves somewhat consistently. I don't write a lot of python, but having used other scripting languages it wouldn't surprise me if numeric types get mixed up by accident often enough. You probably want int(2) and float(2) to be considered the same key in a dictionary to avoid surprises.
Yeah, I expect the real advantage of a JIT is that you can perform proper register allocation and avoid a lot of stack and/or virtual register manipulation.
I wrote a toy copy-patch JIT before and I don't remember being impressed with the performance, even compared to a naive dispatch loop, even on my ~11 year old processor.
See: https://docs.python.org/3/library/stdtypes.html#hashing-of-n...