Re: Using FDO to speed up compiler?

[Jan Hubicka <jh at suse dot cz>]

> 
> On Wednesday, February 12, 2003, at 02:23  PM, Jan Hubicka wrote:
> 
> >>On Wed, Feb 12, 2003 at 10:17:10PM +0100, Jan Hubicka wrote:
> >>>The number reminds me not-so-related note.  I've also hacked 
> >>>makefiles
> >>>in the past to add profiling into the bootstrap.  I used "make check"
> >>>for train run and measured speedup in between 5-10% on compiling
> >>>on compiling binutils on early rtlopt-branch tree.
> >>
> >>Nice.
> >I will have to re-benchmark the numbers as many things has changed 
> >since
> >that , but hope it won't change in the negative direction :)
> >One of important factors was code placement, as we had extraordinally
> >large insn-attrtab that time.  With DFA this problem has changed a bit.
> 
> This was on x86 right?  FWIW I tried this on ppc a month or so ago and
> it made no significant difference.

I've tried "make profiledbootstrap" on PPC machine and it cuts down the
combine.c compilation time form 28.1 second into 26.7, so it is lower
than what I've seen preivously, but still something.
It is quite interesting, as I would expect PPC to be more sensitive on
code placement than x86 as code is bigger, but it is not, apparently.
Hope it will improve in the future :)
Once new loop unroller is merged in, it would be interesting to re-do
the experiment with loop unrolling and peeling and see if it does
something.

Honza