llvm dev - Apr 2018 - GCC toolchain versioning policy? (D43779)

Hi.

As per[1], gcc-4.8 is the oldest supported *major* gcc version.
But what about minor/patch versions?

When https://reviews.llvm.org/D43779 was initially committed,
a few[2][3] buildbots failed. As i have now looked into the issue:
* but it is *REPRODUCIBLE* with gcc-4.8.4 and gcc-4.9.2 from debian
oldstable (Jessie).
* it is *NOT* reproducible with gcc-4.8.5 and gcc-4.9.3 from ubuntu 16.04,
So it looks like it was a gcc problem, and it is resolved in latest
minor/patch versions.

So is there some more specific guideline on minor/patch version requirements?
Do we want LLVM to be buildable with all gcc 4.8/4.9 versions?
Or is it okay to only build with the latest point versions, that
contain the fix?

(Regardless, it would be good to have the answer in [1])

Roman.

[1]
http://llvm.org/docs/GettingStarted.html#host-c-toolchain-both-compiler-and-standard-library
[2] http://lab.llvm.org:8011/buildslaves/atom1-buildbot
[3] http://lab.llvm.org:8011/buildslaves/ps4-buildslave1a

Hmm, i guess i should have mailed cfe-dev too. Doing that now.

On Sun, Apr 8, 2018 at 9:38 PM, Roman Lebedev <lebedev.ri at gmail.com>
wrote:
> Hi.
>
> As per[1], gcc-4.8 is the oldest supported *major* gcc version.
> But what about minor/patch versions?
>
> When https://reviews.llvm.org/D43779 was initially committed,
> a few[2][3] buildbots failed. As i have now looked into the issue:
> * but it is *REPRODUCIBLE* with gcc-4.8.4 and gcc-4.9.2 from debian
> oldstable (Jessie).
> * it is *NOT* reproducible with gcc-4.8.5 and gcc-4.9.3 from ubuntu 16.04,
> So it looks like it was a gcc problem, and it is resolved in latest
> minor/patch versions.
>
> So is there some more specific guideline on minor/patch version
requirements?
> Do we want LLVM to be buildable with all gcc 4.8/4.9 versions?
> Or is it okay to only build with the latest point versions, that
> contain the fix?
>
> (Regardless, it would be good to have the answer in [1])
>
> Roman.
>
> [1]
http://llvm.org/docs/GettingStarted.html#host-c-toolchain-both-compiler-and-standard-library
> [2] http://lab.llvm.org:8011/buildslaves/atom1-buildbot
> [3] http://lab.llvm.org:8011/buildslaves/ps4-buildslave1a

+ Denis and Galina who should know about the affected buildbots and whether
it's fine to upgrade them or whether their configurations reflect some
important use cases. Sylvestre should know if the release process for LLVM
on Ubuntu/Debian relies on the older GCC toolchains somehow.

On Mon, Apr 9, 2018 at 1:51 PM Roman Lebedev via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hmm, i guess i should have mailed cfe-dev too. Doing that now.
>
> On Sun, Apr 8, 2018 at 9:38 PM, Roman Lebedev <lebedev.ri at
gmail.com>
> wrote:
> > Hi.
> >
> > As per[1], gcc-4.8 is the oldest supported *major* gcc version.
> > But what about minor/patch versions?
> >
> > When https://reviews.llvm.org/D43779 was initially committed,
> > a few[2][3] buildbots failed. As i have now looked into the issue:
> > * but it is *REPRODUCIBLE* with gcc-4.8.4 and gcc-4.9.2 from debian
> > oldstable (Jessie).
> > * it is *NOT* reproducible with gcc-4.8.5 and gcc-4.9.3 from ubuntu
> 16.04,
> > So it looks like it was a gcc problem, and it is resolved in latest
> > minor/patch versions.
> >
> > So is there some more specific guideline on minor/patch version
> requirements?
> > Do we want LLVM to be buildable with all gcc 4.8/4.9 versions?
> > Or is it okay to only build with the latest point versions, that
> > contain the fix?
> >
> > (Regardless, it would be good to have the answer in [1])
> >
> > Roman.
> >
> > [1]
>
http://llvm.org/docs/GettingStarted.html#host-c-toolchain-both-compiler-and-standard-library
> > [2] http://lab.llvm.org:8011/buildslaves/atom1-buildbot
> > [3] http://lab.llvm.org:8011/buildslaves/ps4-buildslave1a
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
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>
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