On Wed, 13 May 2020 at 19:44, Jonathan Wakely via Gcc <gcc@gcc.gnu.org> wrote:
>
> On Wed, 13 May 2020 at 18:19, Mike Stump via Gcc <gcc@gcc.gnu.org> wrote:
> >
> > I've changed the subject to match the 2015, 2017 and 2018 email threads.
> >
> > On May 13, 2020, at 3:26 AM, Thomas Schwinge <tho...@codesourcery.com>
> > wrote:
> > >
> > > Comparing DejaGnu/GCC testsuite '*.sum' files between two systems ("old"
> > > vs. "new") that ought to return identical results, I found that they
> > > didn't:
> >
> > > I have not found any evidence in DejaGnu master branch that this not
> > > working would've been a "recent" DejaGnu regression (and then fixed for
> > > DejaGnu 1.6) -- so do we have to assume that this never worked as
> > > intended back then?
> >
> > Likely not.
> >
> > > Per our "Prerequisites for GCC" installation documentation, we currently
> > > require DejaGnu 1.4.4. Advancing that to 1.6 is probably out of
> > > question, given that it has "just" been released (four years ago).
> >
> > :-) A user that wants full coverage should use 1.6, apparently.
>
> As documented at
> https://gcc.gnu.org/onlinedocs/libstdc++/manual/test.html#test.run.permutations
> anything older than 1.5.3 causes problems for libstdc++ (and probably
> the rest of GCC) because the options in --target_board get placed
> after the options in dg-options. If the test depends on the options in
> dg-options to work properly it might fail. For example, a test that
> has { dg-options "-O2" } and fails without optimisation would FAIL if
> you use --target_board=unix/-O0 with dejagnu 1.5.
>
I think that was commit:
http://git.savannah.gnu.org/gitweb/?p=dejagnu.git;a=commitdiff;h=5256bd82343000c76bc0e48139003f90b6184347
which for sure was a major change (though I don't see it documented in
dejagnu/NEWS file)
>
> > > As the failure mode with old DejaGnu is "benign" (only causes missing
> > > execution testing), we could simply move on, and accept non-reproducible
> > > results between different DejaGnu versions? Kind of lame... ;-|
> >
> > An ugly wart to be sure.
> >
> > So, now that ubuntu 20.04 is out and RHEL 8 is out, and they both contain
> > 6, and SLES has 6 and since we've been sitting at 1.4.4 for so long, anyone
> > want to not update dejagnu to require 1.6?
>
> There are still lots of older systems in use for GCC dev, like all the
> POWER servers in the compile farm (but I've put a recent dejagnu in
> /opt/cfarm on some of them).
>
> > I had previously approved the update to 1.5.3, but no one really wanted it
> > as no one updated the requirement. Let's have the 1.6 discussion. I'm not
> > only inclined to up to 1.6, but to actually edit it in this time.
>
> Would the tests actually refuse to run with an older version?
>
> > Anyone strongly against? Why?
>
> I'm in favour of requiring 1.5.3 or later, so 1.6 would be OK for me.
