There's currently no robust predicate to determine whether an oacc offload
function is for a kernels region (as opposed to a parallel region). The test in
tree-ssa-loop.c uses the heuristic of seeing if all the dimensions are defaulted
(which can easily be true for parallel offloads at that point).
This patch marks TREE_PUBLIC on the offload attribute values, to note kernels
regions, and adds a predicate to check that. I also broke out the function
level determination from oacc_validate_dims, as there it was only laziness on my
part to have not done that earlier.
Using these predicates improves the dump output of the openacc device lowering
pass too.
ok?