Re: gcc 3.5 integration branch proposal

[Laurent GUERBY <laurent at guerby dot net>]

On Mon, 2004-01-19 at 23:28, Marc Espie wrote:
> On Mon, Jan 19, 2004 at 11:08:15PM +0100, Laurent GUERBY wrote:
> > BTW, people with old machines always have the choice of staying with old
> > software too.
> 
> Not really. Not when you want to compile similar stuff on a wide range
> of machine. It's not as if you have a choice of `small optimizations,
> fast compiler, correct compiler'. Staying with gcc 2.95 comes with the
> price of being completely unable to even compile standard C++ code.

Ok, so you're comparing a not working compiler just able to compile
faster small parts of the code you're interested in with a compiler
able to compile everything but slower? I don't know C++ much, but it
looks like being correct and not horribly inefficient in generated code
in the C++ compiler world is very expensive in terms of CPU cycles.

> Maybe what we're doing with the OpenBSD project is somewhat unusual ?
> but we've found out in the past that each new compiler has its share
> of arch-dependent and arch-independent bug. There comes a point where
> you prefer to have one single compiler, because that way at least,
> you have to cope with just one set of arch-independent bugs.

I must admit I would give a hard try at cross compiling from
fast x86 machines to your targets and then testing
the resulting images on the target machines in various automated ways
(hardware performance allowing of course but if generated code is faster
with newer GCC you should be able to test more in less time :), but I
have no experience in OS building and testing so that might not be
reasonable.

> Right now, we're probably going to end with both gcc 2.95.3 and gcc 3.3.2
> active on different architectures at the same time, and the price in terms
> of maintenance is steep.

That's price of your team time for your users against price of GCC
developpers time for GCC users. Everyone should be able to make
his/her mind while considering the whole free software community.

> Maybe most of you are actually working for companies, and so don't really
> care about the toll in terms of human costs ? I mean, sure, hire a new
> programmer, or buy a new $2000 machine. But real hobbyists ?   We don't
> really have ways to hire new people. And a new $2000 machine means less
> network cards or gfx cards to play with and port drivers to.

At work cost of reasonable developper machines is less than cost of
professional support for GCC for our team and targets paid to ACT
and so used in part to improve GCC too. We have also 30 processors used
for developping our software and more than 500 processors for running
our software. Math is not really hard to do there.

At home, I change machine every two or three years, donate the old
machine to FSF if needed. My current machine is an Athlon 2600 with 512
MB RAM and 120 GB disk I paid less than 500 euros in november last year.
GCC boostrap is less than 30 minutes for c,ada.

Laurent