[gomp4] OpenACC wait directive

Ilmir Usmanov i.usmanov@samsung.com
Wed Sep 24 07:19:00 GMT 2014

Hi Cesar!

Thank you for the patch!

On 24.09.2014 02:29, Cesar Philippidis wrote:
> This patch adds support for the async clause in the wait directive in
> fortran. It should be pretty straight forward. The fortran FE already
> supports the wait directive, but the async clause was introduced to the
> wait directive in OpenACC 2.0 and that was missing in gomp-4_0-branch.
Yes, I've mostly focused on spec. ver. 1.0.

> Is this OK for gomp-4_0-branch?
No, it isn't. According to the spec and this presentation:
http://www.pgroup.com/lit/presentations/cea-3.pdf (See slide 1-35)
it is possible to write construction like:
!$acc wait(1) async(2)
However, your patch doesn't support this. Also, don't forget to check 
whether a queue waits itself (for example, wait(1) async(1)).
In addition, it breaks current support of the directive (for example, 

> Note that this patch doesn't actually
> implement the async or wait clause in the middle end yet, because that
> requires additional runtime support.
> Thanks,
> Cesar

More information about the Gcc-patches mailing list