Re: cgraph based inlining heuristics

[Richard Guenther <rguenth at tat dot physik dot uni-tuebingen dot de>]

On Wed, 2 Jul 2003, Jan Hubicka wrote:

> > Ok, here they go. I tested four different setups:
> >
> > (0) gcc3.4
> > (1) gcc3.4 with __attribute__((leafify)) patch
> > (2) gcc3.4 with your patch
> > (3) gcc3.4 with your patch and -funit-at-a-time
> > (4) gcc3.4 with your patch and -funit-at-a-time --param max-inline-insns-auto=200 --param max-inline-insns-single=200 --param inline-unit-growth=1000 --param large-function-growth=1000
> >
> > flags otherwise used are
> > -O2 -g -march=athlon -fno-math-errno -fno-trapping-math -ffinite-math-only
> > -funroll-loops
> >
> >                       (0)         (1)        (2)       (3)       (4)
> > binary size        10166017    10681144    8405237   8405237   9874056
> > compile time      2m57.503s   3m40.638s  1m19.553s 1m20.742s 2m55.031s
> > runtime performance   3.97s       1.66s      2.65s     2.64s     1.74s
> >
> > timings are seconds per iteration. The new heuristics are a huge
> > improvement, both in compile and runtime! I suspect from the numbers,
> > that -funit-at-a-time is enabled at -O2 already? Also we probably get
>
> I do it in my tree, so I more likely hit the bugs during bootstraps, but
> it is not the case in the mainline.  I would like to see it enabled at
> -O2 in the future assuming that it makes average compilation faster.

So it was enabled in the patch you sent? I doubt it would make zero effect
on both binary size and compile time else, see numbers for (2) and (3).

Also I rarely use -O3 as it usually makes compilation and code slower.

Richard.