Generate sequential loop for OpenACC loop directive inside kernels

Generate sequential loop for OpenACC loop directive inside kernels

2019-09-20  Chung-Lin Tang <cltang@codesourcery.com>
	    Cesar Philippidis  <cesar@codesourcery.com>

	gcc/
	* omp-expand.cc (struct omp_region): Add inside_kernels_p field.
	(expand_omp_for_generic): Adjust to generate a 'sequential' loop
	when GOMP builtin arguments are BUILT_IN_NONE.
	(expand_omp_for): Use expand_omp_for_generic to generate a
	non-parallelized loop for OMP_FORs inside OpenACC kernels regions.
	(expand_omp): Mark inside_kernels_p field true for regions
	nested inside OpenACC kernels constructs.
	gcc/testsuite/
	* c-c++-common/goacc/kernels-loop-acc-loop.c: New test.
	* c-c++-common/goacc/kernels-loop-2-acc-loop.c: New test.
	* c-c++-common/goacc/kernels-loop-3-acc-loop.c: New test.
	* c-c++-common/goacc/kernels-loop-n-acc-loop.c: New test.
	* c-c++-common/goacc/kernels-acc-loop-reduction.c: New test.
	* c-c++-common/goacc/kernels-acc-loop-smaller-equal.c: New test.