[Openmp-dev] OpenMP problems with clang 3.7.0

[Hahnfeld, Jonas via Openmp-dev]

Hi,

from what my .bash_history says, I then used clang 3.7.0. It is compiled from the tar-balls at llvm.org/releases (including the OpenMP runtime...)

For compilation issues related to clang you should ask on llvm-dev and / or cfe-dev.

Cheers,
Jonas

> -----Original Message-----
> From: Christof Söger [mailto:csoeger at uos.de]
> Sent: Wednesday, September 23, 2015 11:26 AM
> To: Hahnfeld, Jonas
> Cc: LLVM-OpenMP (openmp-dev at lists.llvm.org)
> Subject: Re: [Openmp-dev] OpenMP problems with clang 3.7.0
> 
> I was now able to compile clang and the omp runtime lib from git/svn on
> Linux and the error is gone. For me it seems to be a bug in 3.7.0.
> (@Jonas which llvm version did you use?)
> 
> I have two more questions concerning the compilation of clang /openmp.
> 1) Is it possible to build a static version of libomp?
> 2) I have problems compiling llvm/clang on MacOs X. I tried it with gcc
> 4.8.2 and the standart compiler supplied by apple (based on llvm 3.3svn), but
> with both the compilation fails, do you have a suggestion for a compiler to
> use? Or should I ask this in another place?
> 
> Best,
> Christof
> 
> On 17.09.2015 15:49, Christof Söger wrote:
> > On 07.09.2015 15:10, Hahnfeld, Jonas wrote:
> >> Hi,
> >>
> >> I was able to reproduce the error with v2.12.2 but not with the
> >> current master.
> > Thanks for looking into it! Did you use llvm 3.7.0 or the svn version?
> >> I think this problem got fixed with
> >>
> https://github.com/Normaliz/Normaliz/commit/62c3237d7d312555dad7026f
> 4
> >> 94c6caa6e438181
> >>
> >> The OpenMP standard mentions under restrictions of the critical
> >> construct (ironically in section 2.12.2):
> >>> A throw executed inside a critical region must cause execution to
> >>> resume within the same critical region, and the same thread that
> >>> threw the exception must catch it.
> > This is exactly the point that was fixed in the commit. But it is not
> > the problem I'm having. There should be no exception in this place.
> >
> > I now also tested it on ubuntu 14.04 (with the current master of
> > normaliz), and I get the same problem. Just to clearify it a bit more.
> > If I put asserts right before entering the critical section and inside
> > the critical section like
> >
> >                 assert (Pyramid_key.size()==dim); // works fine
> >                 #pragma omp critical(TRIANG)
> >                 {
> >                 assert (Pyramid_key.size()==dim); // fails
> >
> > then the asserts behave as the comments say.
> >
> > I used the compiled versions of 3.7.0. I will get the svn version and
> > try it with it.
> >
> > Best,
> > Christof
> >> Cheers,
> >> Jonas
> >>
> >>> -----Original Message-----
> >>> From: Openmp-dev [mailto:openmp-dev-bounces at lists.llvm.org] On
> >>> Behalf Of Christof Söger via Openmp-dev
> >>> Sent: Sunday, September 06, 2015 11:26 PM
> >>> To: openmp-dev at lists.llvm.org
> >>> Subject: [Openmp-dev] OpenMP problems with clang 3.7.0
> >>>
> >>> Hi everybody,
> >>>
> >>> I just downloaded the new 3.7 release and also the OpenMP runtime
> >>> for Darwin (compiled versions) and tried to compile our software
> >>> package "Normaliz" with it.
> >>> Without -fopenmp=libomp it compiles and runs fine.
> >>> With the openmp flag it compiles but I ran in problems (even if I
> >>> set the number of threads to 1).
> >>>
> >>> I debugged it a bit and the problem is that at the entering of a
> >>> critical section one std::vector, which is firstprivate in the outer
> >>> parallel loop gets, invalidated.
> >>> As a workaround it works when I copy the vector right before the
> >>> critical, and use that copy inside the critical section.
> >>>
> >>> I don't know under which exact circumstances this happens and was
> >>> not able to create a small example in which it happens. If you are
> >>> interested to check it, you can find the source code on github
> >>> https://github.com/Normaliz/Normaliz. To reproduce the problem
> >>> compile normaliz via cmake and run it with "normaliz -cq -x=1
> example/medium".
> >>> The critical critical is the critical(TRIANG) on line 1113 in
> >>> process_pyramid and the effected vector is Pyramid_key. Right before
> >>> the critical section an
> >>> assert(Pyramid_key.size() == dim);
> >>> succeeds, but in the critical section it fails.
> >>>
> >>> I hope this helps to figure out what happens. If I can any other
> >>> information please let me know.
> >>>
> >>> Best regards,
> >>> Christof
> >>>
> >>> _______________________________________________
> >>> Openmp-dev mailing list
> >>> Openmp-dev at lists.llvm.org
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev
> >

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