Subject: How reliable is GCC-3.3.1 wrt building mipsel-linux kernel?

From: David Daney <[email-masked]>
Date: Tue, 18 Nov 2003 17:40:31 -0800

The subject line kind of says it all.

We are running linux 2.4.18 on a mips4Kc core (ATI Xilleon 225) and find 
it to be quite stable when compiled with gcc 2.96/binutils 2.11.92.0.10

When the kernel is compiled with gcc 3.3.1/binutils 2.14.90.0.5 it also 
seems to be quite stable, except for when one certian driver is used 
(basically an mpeg decoder driver).  Under certian conditions the system 
seems to "freeze" (no messages printed anywhere and only a hard reset 
will recover).

Yeah that is a good bug report...

But my main question is this:  Have other people experienced 
miscompilation (ie bad code generation) with gcc 3.3.1?

One thing I am aware of is that if -fno-common is not used, bad code is 
generated for accessing some large structures.  But I we use -fno-common 
for all compilation.

I am trying to figrue out if I should be looking more at bugs in the 
driver, or if I should give up on gcc 3.3.1 and be done with it.

Thanks in advance for any insight.

David Daney.

---

From: Daniel Jacobowitz <[email-masked]>
Date: Tue, 18 Nov 2003 20:49:29 -0500

> Thanks in advance for any insight.

We haven't had problems here.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

---

From: Ralf Baechle <[email-masked]>
Date: Thu, 20 Nov 2003 00:30:23 +0100

> miscompilation (ie bad code generation) with gcc 3.3.1?

Quite frequently using a new, possibly more agressive compiler triggers
bugs in the kernel code ...

  Ralf

---

From: David Daney <[email-masked]>
Date: Wed, 19 Nov 2003 16:29:43 -0800

Ralf Baechle wrote:

>><...>
That's the whole point of my question.

Which options have other people used with gcc 3.3.1 with good results?

David Daney.

---

From: Jan-Benedict Glaw <[email-masked]>
Date: Thu, 20 Nov 2003 10:25:43 +0100

On Wed, 2003-11-19 16:29:43 -0800, David Daney <[email-masked]>

> Which options have other people used with gcc 3.3.1 with good results?

It's a question of what you call "good results". If there are bugs in
the kernel sources which only show up with a really aggressive HEAD
compiler, then IMHO it's a good result to see the compiled kernel crash,
just because there actually *is* a bug.

Companies however tend to accept a slower/more bloated/whatever software
(produced by an older compiler) in order not to start hunting down the
remaining (and possibly hard to find) bugs...

MfG, JBG

-- 
   Jan-Benedict Glaw       [email-masked]    . +49-172-7608481
   "Eine Freie Meinung in  einem Freien Kopf    | Gegen Zensur | Gegen Krieg
    fuer einen Freien Staat voll Freier Bürger" | im Internet! |   im Irak!
   ret = do_actions((curr | FREE_SPEECH) & ~(NEW_COPYRIGHT_LAW | DRM | TCPA));