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

DISCUSSION David Daney 4 participants 5 messages Nov 19, 2003 – Nov 20, 2003 MIPS

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#0 lore raw

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.

#1 lore raw
Quoted 16 lines · David Daney

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?

Quoted 8 lines

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.

We haven't had problems here.

Signature · 2 lines
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer
#2 lore raw
In reply to David Daney
Quoted 11 lines · David Daney

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).

Quoted 4 lines

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?

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

Ralf

#3 lore raw
Quoted 8 lines · Ralf Baechle
Quoted 4 lines · David Daney

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

Quoted 6 lines

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

Ralf

That's the whole point of my question.

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

David Daney.

#4 lore raw

On Wed, 2003-11-19 16:29:43 -0800, David Daney <[email protected]> wrote in message <[email protected]>:

Quoted 4 lines
Quoted 1 line · Ralf Baechle

On Tue, Nov 18, 2003 at 05:40:31PM -0800, David Daney wrote:

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

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