[Patch] Fortran/openmp: Fix '!$omp end'

[Jakub Jelinek]

On Thu, Nov 11, 2021 at 06:11:23PM +0100, Tobias Burnus wrote:
> --- a/gcc/fortran/parse.c
> +++ b/gcc/fortran/parse.c
> @@ -915,15 +915,16 @@ decode_omp_directive (void)
>        matcho ("error", gfc_match_omp_error, ST_OMP_ERROR);
>        matcho ("end atomic", gfc_match_omp_eos_error, ST_OMP_END_ATOMIC);
>        matcho ("end critical", gfc_match_omp_end_critical, ST_OMP_END_CRITICAL);
> -      matchs ("end distribute parallel do simd", gfc_match_omp_eos_error,
> +      matchs ("end distribute parallel do simd", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_DISTRIBUTE_PARALLEL_DO_SIMD);
> -      matcho ("end distribute parallel do", gfc_match_omp_eos_error,
> +      matcho ("end distribute parallel do", gfc_match_omp_end_nowait,

I think the above two changes are incorrect.
At least looking at 5.1 which is clearer than 5.2, 5.1 [221:17-23] says
for C/C++ that while nowait is allowed on worksharing-loop, it is not
allowed on combined parallel worksharing-loop, and Fortran has that
restriction through the syntax (no [nowait] on !$omp end parallel do).

> @@ -936,9 +937,12 @@ decode_omp_directive (void)
>  	      ST_OMP_END_MASTER_TASKLOOP);
>        matcho ("end master", gfc_match_omp_eos_error, ST_OMP_END_MASTER);
>        matchs ("end ordered", gfc_match_omp_eos_error, ST_OMP_END_ORDERED);
> -      matchs ("end parallel do simd", gfc_match_omp_eos_error,
> +      matchs ("end parallel do simd", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_PARALLEL_DO_SIMD);
> -      matcho ("end parallel do", gfc_match_omp_eos_error, ST_OMP_END_PARALLEL_DO);
> +      matcho ("end parallel do", gfc_match_omp_end_nowait,
> +	      ST_OMP_END_PARALLEL_DO);

Likewise for the above two.

> @@ -951,46 +955,53 @@ decode_omp_directive (void)
>  	      ST_OMP_END_PARALLEL_MASTER_TASKLOOP);
>        matcho ("end parallel master", gfc_match_omp_eos_error,
>  	      ST_OMP_END_PARALLEL_MASTER);
> -      matcho ("end parallel sections", gfc_match_omp_eos_error,
> +      matcho ("end parallel sections", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_PARALLEL_SECTIONS);
> -      matcho ("end parallel workshare", gfc_match_omp_eos_error,
> +      matcho ("end parallel workshare", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_PARALLEL_WORKSHARE);

Ditto for the above two.

>        matcho ("end parallel", gfc_match_omp_eos_error, ST_OMP_END_PARALLEL);
>        matcho ("end scope", gfc_match_omp_end_nowait, ST_OMP_END_SCOPE);
>        matcho ("end sections", gfc_match_omp_end_nowait, ST_OMP_END_SECTIONS);
>        matcho ("end single", gfc_match_omp_end_single, ST_OMP_END_SINGLE);
>        matcho ("end target data", gfc_match_omp_eos_error, ST_OMP_END_TARGET_DATA);
> -      matchs ("end target parallel do simd", gfc_match_omp_eos_error,
> +      matchs ("end target parallel do simd", gfc_match_omp_end_nowait,

The above seems like a bug in 5.1 standard, haven't checked 5.2.
!$omp end target parallel do simd nowait
should be IMO valid, but [241:16] mistakenly doesn't list it.

>  	      ST_OMP_END_TARGET_PARALLEL_DO_SIMD);
> -      matcho ("end target parallel do", gfc_match_omp_eos_error,
> +      matcho ("end target parallel do", gfc_match_omp_end_nowait,

Similarly.

>  	      ST_OMP_END_TARGET_PARALLEL_DO);
> -      matcho ("end target parallel", gfc_match_omp_eos_error,
> +      matcho ("end target parallel loop", gfc_match_omp_end_nowait,
> +	      ST_OMP_END_TARGET_PARALLEL_LOOP);

Similarly.

> +      matcho ("end target parallel", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_TARGET_PARALLEL);

Similarly.

> -      matchs ("end target simd", gfc_match_omp_eos_error, ST_OMP_END_TARGET_SIMD);
> +      matchs ("end target simd", gfc_match_omp_end_nowait, ST_OMP_END_TARGET_SIMD);

Similarly.

>        matchs ("end target teams distribute parallel do simd",
> -	      gfc_match_omp_eos_error,
> +	      gfc_match_omp_end_nowait,
>  	      ST_OMP_END_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD);
> -      matcho ("end target teams distribute parallel do", gfc_match_omp_eos_error,
> +      matcho ("end target teams distribute parallel do",
> +	      gfc_match_omp_end_nowait,
>  	      ST_OMP_END_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO);
> -      matchs ("end target teams distribute simd", gfc_match_omp_eos_error,
> +      matchs ("end target teams distribute simd", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_TARGET_TEAMS_DISTRIBUTE_SIMD);
> -      matcho ("end target teams distribute", gfc_match_omp_eos_error,
> +      matcho ("end target teams distribute", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_TARGET_TEAMS_DISTRIBUTE);
> -      matcho ("end target teams", gfc_match_omp_eos_error, ST_OMP_END_TARGET_TEAMS);
> -      matcho ("end target", gfc_match_omp_eos_error, ST_OMP_END_TARGET);
> +      matcho ("end target teams loop", gfc_match_omp_end_nowait,
> +	      ST_OMP_END_TARGET_TEAMS_LOOP);
> +      matcho ("end target teams", gfc_match_omp_end_nowait,
> +	      ST_OMP_END_TARGET_TEAMS);
> +      matcho ("end target", gfc_match_omp_end_nowait, ST_OMP_END_TARGET);

Similarly all the above.  !$omp end target
followed by anything should accept nowait.

>        matcho ("end taskgroup", gfc_match_omp_eos_error, ST_OMP_END_TASKGROUP);
>        matchs ("end taskloop simd", gfc_match_omp_eos_error,
>  	      ST_OMP_END_TASKLOOP_SIMD);
>        matcho ("end taskloop", gfc_match_omp_eos_error, ST_OMP_END_TASKLOOP);
>        matcho ("end task", gfc_match_omp_eos_error, ST_OMP_END_TASK);
> -      matchs ("end teams distribute parallel do simd", gfc_match_omp_eos_error,
> +      matchs ("end teams distribute parallel do simd", gfc_match_omp_end_nowait,
>  	      ST_OMP_END_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD);
> -      matcho ("end teams distribute parallel do", gfc_match_omp_eos_error,
> +      matcho ("end teams distribute parallel do", gfc_match_omp_end_nowait,

These again shouldn't allow nowait, the outermost leaf construct
that accepts nowait is do and when do is combined with parallel, nowait
shouldn't be specified.

	Jakub