compiling very large functions.

[Daniel Berlin]

On 11/5/06, Eric Botcazou <ebotcazou@adacore.com> wrote:
> > > Tree alias analysis can partially disable itself though:
> >
> > No, it can't.  Tree alias representation can :)
>
> I presume you're thinking of the pass that performs the analysis, while I was
> more thinking of the global machinery; my understanding is that the machinery
> will not be able to disambiguate memory accesses it would have been able to,
> if the limit were not reached.

Depends on what you mean by "the machinery".  There is no standard API
to using the results of the analysis without using the representation
we provide, but some passes do it anyway through hackery, so yes and
no :)

>
> > it is also not really partially disabling. It's really fully disabling
> > in 99% of
>
> Partially because it only affects call-clobbered variables IIUC.

It affects all variables that escape or are non-local, which is
roughly all variables that have interesting aliasing properties (IE
those that cannot be ascertained trivially).

Anyway, I would certainly not hold up what we do in alias
representation as a good example of proper throttling in the case of
large functions.