Compilation performance comparison of GCC 3.4.2 and GCC 4.0.0 (041024) on MICO sources

[Jan Hubicka]

> 
> 
> On Mon, 25 Oct 2004, Jan Hubicka wrote:
> 
> >>>My bet: GC allocating lots and lots of bitmaps :-/
> >>
> >>Probably.
> >>
> >>Here's the interesting question:
> >>If these bitmaps live over compilation, and we know exactly when they die
> >>(cgraph_reset_static_var_maps), why the heck are they gc allocated?
> >Ineed ;)
> >
> >Also the current usage of these bitsmaps is disabled and Kenny already
> >has patch that reduce good amount of them when inlining takes place.
> >We probably need to decide what to do about mainline - either disable
> >collecting the information too or try harder to fix it.
> 
> If his patch to fix this stuff up for the mainline (which was submitted 
> and is awaiting review from you and diego, i believe, since it touches 
> cgraph and tree-ssa) isn't accepted, we should probably disable it until 
> 4.1

We apparently went here into trouble with lack of maintainer
understanding both areas.  I already told Kenneth that the cgraph
changes are good but obvioiusly never did format approval, sorry for
that.

The cgraph bits are OK with the cgraph-* file renamed to ipa-* file 
(the cgraph prefix for ipa optimizers is bit confusing and we already
have both with ipcp code).  Thinking about it we probably want cgraph
prefix only for the cgraph itself use ip/ipa/ipo prefix for the
optimizers and analysis and ipa is already taken.

But my understanding is that it (except for Diego's approval) still need
fixing in the global variable initializers area, right?  I plan to at
least apply the patch into tree-profiling branch once we sort out the
inliner issues so we can make progress there.

Honza
> 
>  > > Honza
> >