Re: GCC tickling obscure hardware bug or...?

> On Fri, 2003-09-12 at 12:56, culverk_at_yumyumyum.org wrote:
> > Quoting Scott Reese <sreese_at_codysbooks.com>:
> > 
> > > Hello all, I'm rephrasing my previous question to reflect new findings
> > > in my situation in the hopes that someone may have an idea of what's
> > > going on here (see thread "Internal compiler error in
> > > reload_cse_simplify_operands" from earlier this week).
> > >
> > > In a nutshell, I have upgraded my machine to a PIV 2.4 GHz processor on
> > > a VIA P4B 400 motherboard with 512 MB Samsung 2700 DDRAM.  I have a 300
> > > Watt power supply with a ball-bearing fan and a Seagate 40 GB HD.  The
> > > problem I'm having that I did not see with my PIII is that I'm getting
> > > intermittent internal compiler errors when attempting to compile
> > > anything (again, see previous thread for an example).  I even did a
> > > fresh install of the system yesterday in order to rule out something
> > > random getting hosed causing problems with my compiler.  Through
> > > experimentation, I've found that toggling the CFLAGS from -O to -O2 or
> > > vice-versa works around the problem (actually, I've had greater success
> > > leaving my CFLAGS set to -O2 -pipe and occasionally bringing them back
> > > to -O -pipe when I run into an ICE and then setting them back again).
> > > My hunch is that some hardware bug is being tickled by gcc somehow.  I
> > > don't think it's the standard "broken hardware" thing because I've not
> > > received any signal 11/7/4 errors at all and the system runs
> > > wonderfully.  So far it's been up for over 24 hours, compiling ports and
> > > running without a hitch.  The only strangeness is the compiler's
> > > behavior.  Also, I should mention that I added
> > >
> > > options DISABLE_PSE
> > > options DISABLE_PG_G
> > >
> > > to my kernel config but the ICE's still persist, though they seem to be
> > > less frequent now.
> > >
> > > Attached is my dmesg, please let me know if anyone would like any more
> > > information about this or if you have any idea what might be going on
> > > here.
> > >
> > > Thank you,
> > > Scott
> > >
> > 
> > Whenever I've had problems like this, it's been either bad memory, or bad memory
> > settings in bios. I'd check both of those things.
> 
> Sonofagun...I just tweaked the RAM settings yet another time and turned
> the speed down to 133 (recommended 166 in the mobo manual) and that
> seems to be working so far.
> 
> Sorry for the noise, folks.

These are known problems in 5.1-RELEASE but have been dealt with in -current,
I'm waiting for 5.2 too in order to remove both the options DISABLE_PSE and
DISABLE_PG_G.

Furthermore GCC have been also improved and should more correctly support P4
with optimization levels higher than -O.

Please check this mailing-list archives for more information.

Anthony.