[petsc-dev] CI error

[Mark Adams]

It did seem to be non-deterministic. (how is that possible?).
I got this error, sent my message.
Tried Barry's idea and initialized them all (5) by hand.
It worked!
I tried initializing just one.
It worked.
I tried initializing none (yes, back to where I started)
And it worked :o

I guess this error is another try-it-again CI error.

On Sun, Apr 11, 2021 at 8:06 PM <jacob.fai at gmail.com> wrote:

> I ran into a similar problem months ago and the long and short of it is
> that any compilers uninitialized variable detection is incredibly dependent
> on optimization level, which the higher you go becomes non-deterministic.
>
>
>
> That being said, gcc is pretty terrible at getting this particular warning
> right :)
> https://gcc.gnu.org/bugzilla/buglist.cgi?quicksearch=may%20be%20uninitialized
>
>
>
> Best regards,
>
>
>
> Jacob Faibussowitsch
>
> (Jacob Fai - booss - oh - vitch)
>
> Cell: (312) 694-3391
>
>
>
> *From:* petsc-dev <petsc-dev-bounces at mcs.anl.gov> *On Behalf Of *Barry
> Smith
> *Sent:* Sunday, April 11, 2021 17:51
> *To:* Mark Adams <mfadams at lbl.gov>
> *Cc:* For users of the development version of PETSc <petsc-dev at mcs.anl.gov
> >
> *Subject:* Re: [petsc-dev] CI error
>
>
>
>
>
>   You might be able to do:
>
>
>
> col_scale[LANDAU_MAX_Q_FACE = {0};
>
>
>
> but then the compiler may complain about not initializing enough values.
> Googling this type of initialization might help, something C initialize
> arrays "may be used uninitialized"
>
>
>
>
>
>
>
> On Apr 11, 2021, at 2:05 PM, Mark Adams <mfadams at lbl.gov> wrote:
>
>
>
> This warning went away. i don't know why.
>
>
>
> On Sun, Apr 11, 2021 at 2:10 PM Mark Adams <mfadams at lbl.gov> wrote:
>
> I get this error in CI with complex float:
> https://gitlab.com/petsc/petsc/-/jobs/1170144554
>
>
>
> I put in code earlier to fix this warning about uninitialized vars, but
> now it does not seem to work:
>
>
>
> /home/glci/builds-stage1/AbTGp5-t/0/petsc/petsc/src/ts/utils/dmplexlandau/plexland.c:414:94:
> error: ‘col_scale[4]’ may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
>
> 2251 <https://gitlab.com/petsc/petsc/-/jobs/1170144554#L2251> PetscScalar
> vals[LANDAU_MAX_Q_FACE*LANDAU_MAX_Q_FACE],row_scale[LANDAU_MAX_Q_FACE],col_scale[LANDAU_MAX_Q_FACE];
>
>
> Yet I have code to initialize col_scale:
>
>
>
>         for (q = 0; q < LANDAU_MAX_Q_FACE; q++) col_scale[q] = 0.0; //
> suppress warnings
>
>
>
> I get a similar error with an integer array.
>
>
>
> Any suggestions?
>
>
>
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