We can execute one less opcode in every iteration (except for the first) of every for-loop by changing from

    GET_ITERtop:    FOR_ITER    [body]    JUMP_BACKWARDS(top)cleanup:end:

to

    GET_ITER    JUMP_FORWARD(bottom)body:    [body]bottom:    FOR_END(body)cleanup:end:

This was suggested by@markshannonhere, but it appears to be similar in spirit toLoop Inversion.

There seems to be a small (on the order of 1%) benefit, but I imagine the benefit will be magnified after any specialization.