Re: gcc 3.5 integration branch proposal

[Jan Hubicka <hubicka at ucw dot cz>]

> On Sun, Jan 18, 2004 at 10:49:30PM -0500, David Edelsohn wrote:
> 
> > 	Did you build head configured with --disable-checking?
> 
> Rebuilt with --disable-checking, and double-checked the options. There
> was a bug that meant I was not -O2 in both cases.
> 
> Now, the actual options are 
> -Wall -Wstrict-prototypes -Wmissing-prototypes
> -Wno-uninitialized -Wno-format -Wno-main  -fno-builtin-printf
> -fno-builtin-log -fno-builtin-malloc -O2 -fno-strict-aliasing
> in both cases.
> 
> And it's still a bit slower:
> 
> gcc 3.3.2:
>   527.98s real   421.02s user    30.36s system
> 
> gcc -head  with --disable-checking:
>   544.91s real   439.52s user    30.27s system
> 
> 
> Okay, the slow-down is not as marked as with --enable-checking, but it
> still does exist: 4% is something.
> 
> Basically, the code there is just an OpenBSD kernel. It won't fly as a
> testcase unless you have an OpenBSD system available.
> 
> It's just plain old C.  Nothing really fancy about it.
> 
> So, the compiler is not getting faster.
> 
> To give you some scope, again. A similar bulk of code used to compile in
> 3 hours on a 68040.  This 4% translates to an extra 7 minutes.

Since you apparently do have access to 68040 machine easilly, would be
possible for you to post some comparsion of the speed relative to gcc
2.95?
One of major changes of post 3.0 GCCs is the new x86 backend that has
many advantages for modern CPUs (support for scheduling, SSE, x86-64)
but is whole a lot more complex and memory houngry than the old has
been.  I would be very curious how the numbers look like on the machine
where backend didn't changed much.
The profiles would be very welcome too!
I do have one 68040 myself, but it is 120Km away right now :)

Honza
> 
> A make build on such a machine takes about two days. This 4% translates to
> 2 hours more.
> 
> I'll try doing some profiling in the near future...