openmp, openacc: Fix up handling of data regions [PR98183]

openmp, openacc: Fix up handling of data regions [PR98183]

While the data regions (target data and OpenACC counterparts) aren't
standalone directives, unlike most other OpenMP/OpenACC constructs
we allow (apparently as an extension) exceptions and goto out of
the block. During gimplification we place an *end* call into a finally
block so that it is reached even on exceptions or goto out etc.).
During omplower pass we then add paired #pragma omp return for them,
but due to the exceptions because the region is not SESE we can end up
with #pragma omp return appearing only conditionally in the CFG etc.,
which the ompexp pass can't handle.
For the ompexp pass, we actually don't care about the end part or about
target data nesting, so we can treat it as standalone directive.

2020-12-12  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/98183
	* omp-low.c (lower_omp_target): Don't add OMP_RETURN for
	data regions.
	* omp-expand.c (expand_omp_target): Don't try to remove
	OMP_RETURN for data regions.
	(build_omp_regions_1, omp_make_gimple_edges): Don't expect
	OMP_RETURN for data regions.

	* gcc.dg/gomp/pr98183.c: New test.
	* gcc.dg/goacc/pr98183.c: New test.