[Python-Dev] lnotab and the AST optimizer

Thomas Lee tom at vector-seven.com
Thu Jul 24 17:59:54 CEST 2008


Antoine Pitrou wrote:
> Antoine Pitrou <solipsis <at> pitrou.net> writes:
>   
>> In http://bugs.python.org/issue2459 ("speedup for / while / if with better
>> bytecode") I had the same problem and decided to change the lnotab format so
>> that line number increments are signed bytes rather than unsigned.
>>     
>
> By the way, the same change could be done for relative jump offsets in the
> bytecode (change them from unsigned shorts to signed shorts). Taken together,
> both modifications would release a lot of constraints on the ordering of code
> blocks.
>
>
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>   
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, though, and if 
that's the case then I want to try and deal with it at the AST level.

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

Cheers,
T


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