On Sat, Feb 06, 2016 at 12:42:49PM -0700, Jeff Law wrote: > On 02/06/2016 12:08 PM, David Edelsohn wrote: > > >>Normally I'd say that if it was approved before, then it's still good to go > >>since there haven't been major conceptual changes in this code since the > >>patch was originally written and now. > >> > >>However, in this instance the patch had been reported to cause problems on > >>AIX, problems that we can't reproduce now -- which makes me want to be more > >>cautious. Was it a problem with the patch, or some other latent issue -- we > >>don't know at this point. > >> > >>So I think the way to go is to apply this patch on top of r219827 where it > >>caused the AIX failure. Then bootstrap on aix and determine the root cause > >>of of the AIX bootstrap failure. If it's this patch, then update the patch > >>as needed. If the patch is just exposing a latent bug elsewhere, we should > >>evaluate whether or not that latent but has been fixed or not before > >>applying this fix to the trunk. > >> > >>It's considerably more work, but ISTM it's the right thing to do. > > > >I'm on the fence about this patch. I definitely don't think that it > >should be merged for GCC 6. > > > >If the patch were to be proposed during Stage 1 for GCC 7 and had not > >caused bootstrap problems for AIX, no one would have any question. > > > >The problem is we don't know if the patch exposed a latent bug that > >independently was fixed after the patch was reverted or if the patch > >still contains a bug that has been rendered latent by another change. > > > >Another approach to track down the cause would be to bisect which > >patch fixed the bootstrap failure if the patch had not been reverted. > Yes, that would be a good approach as well. The concern here would be that > without doing the root cause analysis, bisection may just find a patch which > made the issue go latent. To be sure we still have to do some root cause > analysis. > > Given this fixes a regression, I'm still open to incorporating the patch, > but we've got to know what went wrong when the patch was previously applied > and that whatever that problem was got fixed. > Jeff > Hi, Your concern is pretty clear for me, thanks.
I'll try to root cause that bootstrap issue. Let it be some kind of entertainment for a weekend. Hope to notify you this Monday. Regards, Alexander
