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Re: 200.sixtrack is miscomparing on x86_64 and i686 (-O2) since Mar 19th
On Thu, 22 Mar 2007, Richard Guenther wrote:
> On Wed, 21 Mar 2007, Jerry DeLisle wrote:
>
> > Richard Guenther wrote:
> > > The regression was introduced between rev 123033 and 123047. The likely
> > > offender is
> > >
> > > Index: libgfortran/ChangeLog
> > > ===================================================================
> > > --- libgfortran/ChangeLog (revision 123033)
> > > +++ libgfortran/ChangeLog (revision 123047)
> > > @@ -1,3 +1,15 @@
> > > +2007-03-18 Jerry DeLisle <jvdelisle@gcc.gnu.org>
> > > +
> > > + PR libgfortran/31052
> > > + * io/file_position (st_rewind): Fix comments. Remove use of
> > > + test_endfile. Don't seek if already at 0 position. Use new
> >
> > Richard,
> >
> > Can you confirm that this occurs only with -O2 ?
>
> No, it occurs also with -O3 (but -O2 is the lowest level I have checked).
>
> > Can you revert the patch on a local tree and confirm this is it?
>
> I'll do so later today.
I can confirm reverting the patch fixes the problem. (Just exchanging
the libgfortran runtime library to a one with the patch reverted fixes
the problem)
> > Would you be willing to help me debug this, the patch is not that complicated?
> >
> > If not is there anyone with SPEC that I can work with?
> >
> > Also, I do work out of my home and a Non-Disclosure Agreement is no problem to
> > me.
>
> I don't think a NDA will help here. I'll see if there's something
> obvious.
An strace difference shows (diff from good to bad)
@@ -80532,6096 +80531,28 @@
write(1, " Alignment errors read"..., 54) = 54
write(1, "\n", 1) = 1
write(1, "\n", 1) = 1
-write(1, " From file fort.8 : "..., 56) = 56
+read(6, "", 8192) = 0
+read(6, "", 8192) = 0
write(1, "\n", 1) = 1
write(1, "\n", 1) = 1
-lseek(8, 0, SEEK_SET) = 0
-lseek(8, 0, SEEK_SET) = 0
-ftruncate(8, 0) = 0
-write(8, "\'QF9.R1\' 63.279998 "..., 161) = 161
...
Richard.
--
Richard Guenther <rguenther@suse.de>
Novell / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746 - GF: Markus Rex