[Bug libgomp/87835] nvptx offloading: libgomp.oacc-c-c++-common/asyncwait-1.c execution test intermittently fails at -O2

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87835

--- Comment #1 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Thomas Schwinge from comment #0)
> After r264397 "[nvptx] Remove use of CUDA unified memory in libgomp", I'm
> seeing (intermittently only, and only on some systems):
> 

I see the failure reproduced consistently with a Quadro M1200.

> I have not yet analyzed what's causing this, but I have some ideas about
> pending patches that might cure it.

OK, let's see if those make it. If not, we may want to investigate and decide
if we want to revert the patch.