[Python-Dev] lnotab and the AST optimizer

[Antoine Pitrou]

Thomas Lee <tom <at> vector-seven.com> writes:
> By the way, you were right about JUMP_IF_TRUE/JUMP_IF_FALSE. It's far 
> too late. Apologies.
> 
> I'm still pretty sure this is the peepholer's doing,

Yes indeed.

> Which is what's being achieved with the AST optimization I originally 
> proposed, right?

Well, not exactly, your optimization eliminates the UNARY_NOT by swapping the
if/else blocks, while the peepholer eliminates the UNARY_NOT by fusing it with
the subsequent jump opcode. In this case it doesn't make much of a difference,
but if there is only an "if" without an "else", the peepholer's optimization is
still possible while yours is not.

(bottom line: the peepholer is not dead!)

cheers,

Antoine.