[Bug target/85590] New: [nvptx, libgomp, openacc] Use cuda runtime fns to determine launch configuration in nvptx plugin

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85590

            Bug ID: 85590
           Summary: [nvptx, libgomp, openacc] Use cuda runtime fns to
                    determine launch configuration in nvptx plugin
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

Choosing runtime dimensions is done in nvptx_exec for openacc.

We could use cuda runtime functions to assist us choosing runtime dimensions,
as indicated in
https://devblogs.nvidia.com/cuda-pro-tip-occupancy-api-simplifies-launch-configuration/
.