>>>>> Dirk Eddelbuettel writes:

> On 29 April 2019 at 15:03, Kurt Hornik wrote:
> | >>>>> Johannes Ranke writes:
> | 
> | > Am Montag, 29. April 2019, 13:44:03 CEST schrieb Kurt Hornik:
> | >> >>>>> Johannes Ranke writes:
> | >> Thanks.  You may have seen that with current gfortran in
> | >> testing/unstable, there are problems with the R BLAS/LAPACK API entries
> | >> using a Fortran interface (and hence in particular when using the BLAS
> | >> and LAPACK sources that ship with R).
> | 
> | > No, I wasn't aware of this. Is there a bug report where this is
> | > discussed?
> | 
> | Not really, as the issue seems to complicated to condense into a bug
> | report.  From discussions with Thomas Koenig from the GCC team, it seems
> | that f2c, g77 and now gfortran have always added additional character
> | length arguments for each character argument, where the R
> | F77_NAME/F77_CALL mechanism has always called with the arguments of the
> | Fortran subroutine but without the additional length arguments.  A
> | change in gcc trunk also ported to gcc-8-branch apparently changed what
> | happened in such case, to the effect that we're now seeing about 25
> | CRAN packages fail their run time checks with segfaults or run time
> | errors ...
> | 
> | But things are actually hard to pin down for us, and no obvious "fix"
> | is in sight.  It would be great if at least for the gfortran-8 that
> | Debian will release we would get the old behavior back ...

> From what I saw, the change is triggered by 'lto' -- link-time
> optimisation.  A genuinely desirable feature (which can lead to
> improved performance from 'whole program' view) which however appears
> to have a side effect with older Fortran code and its calling
> convention.

> Note, however, that Debian unstable still has the 8.3.* branch. As
> such I would find that it is a little early to ring alarm bells at
> full tilt. CCing Martyn who use the R Foundation twitter handle for
> one such alarm.  Without commensurate discussion on r-devel or
> r-package-devel this may not help much.

Dirk: Martyn has a first tweet coming up shortly.

The change is actually not triggered by lto, but illustrated.  From what
we learned, calling Fortran from C without the additional character
length arguments for character arguments (as done in the R API) now
works differently as before, breaking at least about 25 CRAN packages,
half of which with segfaults.  And that compiler change is in the trunk
since several months but was ported to gcc-8-branch about a month ago,
and more or less immediately picked up in the gfortran-8 package in
testing/unstable ...

-k

> Dirk

> | 
> | Best
> | -k
> | 
> | > Johannes
> | 
> | >> It seems I can avoid these using
> | >> OpenBLAS (but then this really only works find for me provided I setenv
> | >> OPENBLAS_NUM_THREADS=1).
> | >> 
> | >> -k
> | >> 
> | >> > Dear all,
> | >> > Now that the upcoming Debian release "buster" is frozen, I have started
> | >> > supplying backports for it. Pending mirror synchronisations, R 3.6.0 is
> | >> > now
> | >> > available for Debian buster on i386 and amd64 architectures. Please 
> refer
> | >> > to> 
> | >> >   https://cran.r-project.org/bin/linux/debian/
> | >> > 
> | >> > for details. At the moment I am not providing binaries for the arm
> | >> > architecture for buster, as the SD card in my raspberry 3 has died and 
> I
> | >> > do
> | >> > not use these binaries any more anyways. Let me know if this is a 
> problem.
> | >> > 
> | >> > Kind regards,
> | >> > 
> | >> > Johannes
> | >> > 
> | >> > _______________________________________________
> | >> > R-SIG-Debian mailing list
> | >> > R-SIG-Debian@r-project.org
> | >> > https://stat.ethz.ch/mailman/listinfo/r-sig-debian
> | 
> | _______________________________________________
> | R-SIG-Debian mailing list
> | R-SIG-Debian@r-project.org
> | https://stat.ethz.ch/mailman/listinfo/r-sig-debian

> -- 
> http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org

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