[Bug libgomp/80394] Empty OpenMP task is wrongly removed when optimizing

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80394

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 41174
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41174&action=edit
gcc7-pr80394.patch

Untested fix.