[Openmp-dev] OpenMP problems with clang 3.7.0

[Christof Söger via Openmp-dev]

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/62c3237d7d312555dad7026f494c6caa6e438181
>>
>> 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
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>