Hi, Richi I had been using two source trees to speed the bisection and didn't realize that one defaulted to DWARF debugging and the other defaulted to XCOFF debugging, which confused the bisection result. The -f[no-]checking patch is the culprit.
Thanks, David On Sat, Apr 28, 2018 at 4:08 AM Richard Biener <rguent...@suse.de> wrote: > On Sat, 28 Apr 2018, Richard Biener wrote: > > On Fri, 27 Apr 2018, Richard Biener wrote: > > > > > On Fri, 27 Apr 2018, David Edelsohn wrote: > > > > > > > Hi, Richi > > > > > > > > This patches causes a boostrap failure on AIX. Everything miscompares. > > > > The code itself is the same, but the DWARF debug information contains many > > > > differences. > > > > > > Does AIX use bootstrap-debug by default? I don't see how the patch > > > can cause this kind of issue directly but of course it will change > > > CH decisions which may expose latent bugs somewhere. > > > > > > Can you provide more details please, like actual differences? > > > I would have expected the dwarf2out.c change to be a more likely > > > candidate for such symtoms but I trust that you did properly > > > bisect to my patch? > > > > OK, so the x86-64 -O3 bootstrap failure is not caused by this patch, > > reverting it doesn't fix the issue. > > > > The difference w/ the patch reverted is in debug info, all (indirect) > > strings reside at different offsets. If I strip the objects they > > compare identical. > > > > I'm trying reversal of that dwarf2out patch now. > That didn't help. Reverting the bootstrap -f[no-]checking patch did. > Richard.
