Problem with testing libstdc++ parallel headers?

[Paolo Carlini]

Hi,
> I was looking into why parallel tests like 
> 25_algorithms/headers/algorithm/algorithm_parallel_mode.cc
> were failing on IA64 HP-UX and I found lines like:
>
>  #pragma message: slow fetch_and_add_64
>  #pragma message: slow compare_and_swap_64
>
> OK, I looked at compatibility.h and basically understood why I get
> these messages
Ok. I think your issue may be a special case of libstdc++/34106.
>  but then I went to IA64 Linux where I didn't see
> these messages in order to see how the test passes there and I see:
>
> UNSUPPORTED: 25_algorithms/headers/algorithm/algorithm_parallel_mode.cc
>
> along with lines like:
>
> parallel_mode31631.cc:1:17: error: omp.h: No such file or directory
>
> This seems odd ot me since I am building libgomp with my compiler.
>   
Yes. I think it's simply because the relevant search path is missing 
when the dg-require run. We should fix this indeed, affects a few basic 
headers/ tests.
> And when I saw the same messages in my x86_64 build, then I got
> really suspicious.
>
> Is there a known problem on Linux where we aren't testing the parallel
> algorithms that we should be testing because check_v3_target_parallel_mode
> is saying that we don't support a parallel mode?
>   
... however, to be sure, let's not mistake the handful tests at issue, 
with proper testing of the parallel algorithms, which is done via make 
check-parallel, see:

  http://gcc.gnu.org/onlinedocs/libstdc++/manual/parallel_mode.html

for further details.

Paolo.