Re: dejagnu version update?

[Jonathan Wakely]

On Wed, 13 May 2020 at 18:19, Mike Stump via Gcc <address@hidden> 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 <address@hidden> 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.


> > 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.