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Re: [PATCH][2/2] Fix expansion slowness of PR60291
- From: Richard Biener <rguenther at suse dot de>
- To: Richard Sandiford <rdsandiford at googlemail dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Jakub Jelinek <jakub at redhat dot com>, Michael Matz <matz at suse dot de>
- Date: Mon, 24 Feb 2014 18:28:39 +0100 (CET)
- Subject: Re: [PATCH][2/2] Fix expansion slowness of PR60291
- Authentication-results: sourceware.org; auth=none
- References: <alpine dot LSU dot 2 dot 11 dot 1402211102110 dot 27942 at zhemvz dot fhfr dot qr> <alpine dot LSU dot 2 dot 11 dot 1402211120420 dot 27942 at zhemvz dot fhfr dot qr> <alpine dot LSU dot 2 dot 11 dot 1402211223390 dot 27942 at zhemvz dot fhfr dot qr> <alpine dot LSU dot 2 dot 11 dot 1402211302010 dot 27942 at zhemvz dot fhfr dot qr> <87a9dkbpg3 dot fsf at talisman dot default> <alpine dot LSU dot 2 dot 11 dot 1402211408300 dot 27942 at zhemvz dot fhfr dot qr> <alpine dot LSU dot 2 dot 11 dot 1402211420420 dot 27942 at zhemvz dot fhfr dot qr> <alpine dot LSU dot 2 dot 11 dot 1402211515180 dot 27942 at zhemvz dot fhfr dot qr>
On Fri, 21 Feb 2014, Richard Biener wrote:
> On Fri, 21 Feb 2014, Richard Biener wrote:
>
> > On Fri, 21 Feb 2014, Richard Biener wrote:
> >
> > > On Fri, 21 Feb 2014, Richard Sandiford wrote:
> > >
> > > > In a thread a few years ago you talked about the possibility of going
> > > > further and folding the attributes into the MEM itself, so avoiding
> > > > the indirection and separate allocation:
> > > >
> > > > http://thread.gmane.org/gmane.comp.gcc.patches/244464/focus=244538
> > > >
> > > > (and earlier posts in the thread). Would that still be OK?
> > > > I might have a go if so.
> > >
> > > It would work for me. Micha just brought up the easiest incremental
> > > change though, which is
>
> ...
>
> > I am testing the following (and also consider it appropriate as a
> > fix for the regression PR60291).
> >
> > Ok for trunk/branch(es)? Now we have many variants to choose from ;)
>
> Jakub requested statistics for a bootstrap for this one. I get
> for r207939 and a --enable-languages=c x86_64 bootstrap
> 3609924 mem-attrs created overall without the patch and
> 8268976 with the patch (that's a factor of 2.3 and thus "nothing").
One more piece of that statistic, peak number-of-mem-attrs are
121985 without and 298399 with the patch (thats overall number
of GC allocations of a mem-attr for the worst compilation unit
during bootstrap). That's 4.7MB vs. 11.6MB _aggregate_ memory
use (not translatable to the peak number of mem-attrs live, but
it certainly bounds it).
As it seems that nobody is objecting this patch I'll go ahead
and check it in tomorrow.
Thanks,
Richard.