r22832 - gnucash/trunk/src/libqof/qof - Compile md5.c with "-fno-strict-aliasing".

[Geert Janssens]

On Sunday 24 March 2013 13:58:42 Mike Alexander wrote:
> --On March 24, 2013 2:50:53 PM +0100 Geert Janssens
> 
> <janssens-geert at telenet.be> wrote:
> > On Saturday 23 March 2013 20:03:55 Mike Alexander wrote:
> >> Author: mta
> >> Date: 2013-03-23 20:03:54 -0400 (Sat, 23 Mar 2013)
> >> New Revision: 22832
> >> Trac: http://svn.gnucash.org/trac/changeset/22832
> >> 
> >> Modified:
> >>    gnucash/trunk/src/libqof/qof/Makefile.am
> >> 
> >> Log:
> >> Compile md5.c with "-fno-strict-aliasing".
> >> The function md5_finish_ctx dereferences type-punned pointers which
> >> breaks strict aliasing rules.
> > 
> > I haven't looked at the code so this may be totally wrong: I wonder
> > if it  would be possible to remove the warning by fixing the code
> > instead of ignoring  it ?
> 
> I'm not ignoring the warning, I'm telling the compiler to turn off the
> optimization that is causing it.  Ignoring the warning is a real bad
> idea since the code generated may not do anything like what you think
> it should do.  There is a discussion of this at
> <http://blog.qt.digia.com/blog/2011/06/10/type-punning-and-strict-aliasing/>
> . Changing the code to avoid the problem (without turning off the
> optimization) is difficult.  You would probably have to change type
> definitions quite a way back up the call chain.
> 
>          Mike

Ok, thanks for the clarification.

Geert