[Bug middle-end/54146] Very slow compile with attribute((flatten))

[rguenther at suse dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54146

--- Comment #51 from rguenther at suse dot de <rguenther at suse dot de> 2012-08-16 14:06:06 UTC ---
On Thu, 16 Aug 2012, stevenb.gcc at gmail dot com wrote:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54146
> 
> --- Comment #50 from stevenb.gcc at gmail dot com <stevenb.gcc at gmail dot com> 2012-08-16 13:55:40 UTC ---
> On Thu, Aug 16, 2012 at 2:10 PM, rguenth at gcc dot gnu.org
> <gcc-bugzilla@gcc.gnu.org> wrote:
> > bitmap stats are confusing because they show leaks for bitmaps we free
> > by releasing their obstack.  DF and PTA bitmaps are largest.
> 
> The bitmap obstack stats are not very reliable anyway, I think. I've
> been using my own stats for this (with a size_t version of
> obstack_memory_used:
> 
> +static size_t
> +obstack_memory_used2 (struct obstack *h)
> +{
> +  struct _obstack_chunk* lp;
> +  size_t nbytes = 0;
> +
> +  for (lp = h->chunk; lp != 0; lp = lp->prev)
> +    {
> +      nbytes += (size_t) (lp->limit - (char *) lp);
> +    }
> +  return nbytes;
> +}
> +
> 
> so that also the "freed" bitmap elements are counted). With that, you
> can show that the reg_obstack and bitmap_default_obstack grow up to
> several GB that isn't released between passes. An added problem is

Hum, I thought we release those obstacks after each pass ...