Re: Faster compilation speed

[Daniel Berlin <dberlin at dberlin dot org>]

On Fri, 9 Aug 2002, Stan Shebs wrote:

> Aldy Hernandez wrote:
> 
> >[...]
> >
> >   So... Don't you think that if we spent more
> >time getting the infrastructure faster, -O0 will improve as well?
> >
> Well sure, it should be part of the plan.
> 
> One of my suspicions is that the massive use of macros in tree
> and RTL is concealing excessive pointer chasing, because they
> don't show up in either profile or coverage numbers

Ding ding, you have another winner.

I actually benched this once, by functionizing some often used macros.

The timings were horrendous.
But what can we do to increase cache locality, or get rid of these 
problems?


> is taking the macros that we function-ized for debugging purposes
> (Ira posted it to gcc-patches some time ago, but nobody wanted it
> because dwarf2 macro debugging was going to be available RSN), and
> will build a (slow) GCC that will do it all through function calls.
> That should yield a much more interesting profile.
> 
> I don't think Mike mentioned it, but speeding up the compiler has
> become our group's top priority, and every idea is on the table
> right now.  The 6x goal sounds extreme, but it helps keep in mind
> that one or two or even a dozen 5% improvements will not be
> sufficient to attain parity with the competition.

I think part of the problem is that the timings gcc itself outputs aren't 
completely accurate, because sometimes we go around the calls that would 
push the timevar.

> Stan
> 
> 
> 
>