Hi Tobias,

Thanks for your review.

Here is a revised patch resulting from your comments.

The only issue that I could not easily fix is the following code 
triggering an ICE:

```
    !$OMP begin metadirective &
    !$OMP   when ( user = { condition ( UseDevice ) } &
    !$OMP     : nothing ) &
    !$OMP   default ( parallel )
    block
       call foo()
    end block
    call bar()	<--- ICE
    !$omp end metadirective
```

I filed a PR on Bugzilla: 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107067

Is it OK for you?
-- 
PA