[pypy-dev] [pypy-commit] pypy default: Unroll list.count() when the list is virtual or very small and constant lenght

[Alex Gaynor]

Fixing the code is fine with me, does someone want to help get that patch
upstream into CPython so we don't have to worry about losing our
modifications when we upgrade the stdlib?

Alex


On Fri, Aug 30, 2013 at 9:47 AM, Carl Friedrich Bolz <cfbolz at gmx.de> wrote:

> On 30/08/13 15:09, Alex Gaynor wrote:
> > Hi Carl,
> >
> > I wonder if there's some sub-set of cases we can still unroll in. The
> > particular code this was for is:
> >
> https://bitbucket.org/pypy/pypy/src/default/lib-python/2.7/uuid.py#cl-130.
>
> This is a completely indirect and way too clever way to express what is
> meant. I have absolutely no pity for this code being slow. Let's
> rewrite it to simply be more explicit, even if it's a few lines longer.
>
> > I wonder if there are cases where the list is both virtual *and* we
> > aren't able to constant fold some of the space.eq_w()?
>
> Yes, there can be, it's easy to write. Even the uuid case has the
> combinatorial problem, it's just that we expect people to not pass in
> random combinations of arguments.
>
> Cheers,
>
> Carl Friedrich
>



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