[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: arm gcc 4.1.3 -O2 dead code removal breaks configure test
From: |
Ralf Wildenhues |
Subject: |
Re: arm gcc 4.1.3 -O2 dead code removal breaks configure test |
Date: |
Wed, 30 Mar 2011 07:08:04 +0200 |
User-agent: |
Mutt/1.5.20 (2010-08-04) |
Hello Andrew,
* Andrew W. Nosenko wrote on Wed, Mar 30, 2011 at 02:01:45AM CEST:
> On Tue, Mar 29, 2011 at 20:18, Ralf Wildenhues wrote:
> >
> > In order to be absolutely sure that the compiler can't optimize away the
> > reference, I'd say you need to modify external state depending on it.
> > Typically, you can do that by printing its contents, or, if those aren't
> > well-defined (so the compiler might warn about that), its address (with
> > %lu and cast to unsigned long, for portability). Of course this means
> > the test needs to include AC_INCLUDES_DEFAULT in the test header, for
> > stdio.h. The latter means you can then drop including sys/types another
> > time.
>
> IMHO, better would to be just disable a compiler to do optimization
> dances around 'in6' variable (i.e. mark 'in6' as 'volatile'):
Ah yes, that sounds simpler.
I've been too preoccupied with Fortran again lately, it seems.
Thanks,
Ralf