[pypy-dev] Loop invaraints

[Maciej Fijalkowski]

On Tue, Aug 31, 2010 at 9:20 AM, Hakan Ardo <hakan at debian.org> wrote:
> On Sun, Aug 29, 2010 at 1:04 PM, Armin Rigo <arigo at tunes.org> wrote:
>>
>> I'm not saying that loop-invariant code motion could also have a
>> negative effect on large loops; I think it's a pure win, so it's
>> probably worth a try.  I'm just giving a warning: it may not help much
>> in the case of a "general Python program doing lots of stuff", but only
>> in the case of small numerical computation loops.
>
> Right. I write a lot of numerical computation loops these days, both
> small and somewhat bigger, and I am typically force to write them in C
> to get decent performance. So the motivation here would rater be to
> broaden the usability of python than to improve performance of
> exciting python programs.
>
> Another motivation might be to help pypy developers focus on the
> important instruction while staring at traces, ie by hiding the
> instructions that will be inserted only once :)
>

I second hakan here - small loops are not uninteresting, since it
broadens areas where you can use python, not limiting yourself to
existing python programs.