On 5/6/21 3:12 PM, Tom de Vries wrote:
> On 5/6/21 12:30 PM, Jakub Jelinek wrote:
>> On Thu, May 06, 2021 at 12:17:03PM +0200, Tobias Burnus wrote:
>>> OpenMP: Fix SIMT for complex/float reduction with && and ||
>>>
>>> gcc/ChangeLog:
>>>
>>> * omp-low.c (lower_rec_input_clauses): Also handle SIMT part
>>> for complex/float recution with && and ||.
>>>
>>> libgomp/ChangeLog:
>>>
>>> * testsuite/libgomp.c-c++-common/reduction-5.c: New test, testing
>>> complex/floating-point || + && recduction with 'omp target'.
>>
>> As the float/complex ||/&& reductions are IMHO just conformance issues, not
>> something anyone would actually use in meaningful code - floats or complex
>> aren't the most obvious or efficient holders of boolean values - I think
>> punting SIMT on those isn't a workaround, but the right solution.
>>
>
> Ack.
>
> WIP patch below tries that approach and fixes the ICE, but this simple
> example still doesn't work:
> ...
> int
> main ()
> {
> float andf = 1;
>
> #pragma omp target parallel reduction(&&: andf)
> for (int i=0; i < 1024; ++i)
> andf = andf && 0.0;
>
> if ((int)andf != 0)
> __builtin_abort ();
>
> return 0;
> }
> ...
Hm, after rewriting things like this:
...
#pragma omp target map (tofrom: andf)
#pragma omp parallel reduction(&&: andf)
for (int i=0; i < 1024; ++i)
andf = andf && 0.0;
...
it does work.
My limited openmp knowledge is not enough to decide whether the fail of
the first variant is a test-case issue, or a gcc issue.
Thanks,
- Tom
