OpenACC 2.7: Implement self clause for compute constructs

This patch implements the 'self' clause for compute constructs: parallel,
kernels, and serial. This clause conditionally uses the local device
(the host mult-core CPU) as the executing device of the compute region.

The actual implementation of the "local device" device type inside libgomp
(presumably using pthreads) is still not yet completed, so the libgomp
side is still implemented the exact same as host-fallback mode. (so as of now,
it essentially behaves like the 'if' clause with the condition inverted)

gcc/c/ChangeLog:

	* c-parser.cc (c_parser_oacc_compute_clause_self): New function.
	(c_parser_oacc_all_clauses): Add new 'bool compute_p = false'
	parameter, add parsing of self clause when compute_p is true.
	(OACC_KERNELS_CLAUSE_MASK): Add PRAGMA_OACC_CLAUSE_SELF.
	(OACC_PARALLEL_CLAUSE_MASK): Likewise,
	(OACC_SERIAL_CLAUSE_MASK): Likewise.
	(c_parser_oacc_compute): Adjust call to c_parser_oacc_all_clauses to
	set compute_p argument to true.
	* c-typeck.cc (c_finish_omp_clauses): Add OMP_CLAUSE_SELF case.

gcc/cp/ChangeLog:

	* parser.cc (cp_parser_oacc_compute_clause_self): New function.
	(cp_parser_oacc_all_clauses): Add new 'bool compute_p = false'
	parameter, add parsing of self clause when compute_p is true.
	(OACC_KERNELS_CLAUSE_MASK): Add PRAGMA_OACC_CLAUSE_SELF.
	(OACC_PARALLEL_CLAUSE_MASK): Likewise,
	(OACC_SERIAL_CLAUSE_MASK): Likewise.
	(cp_parser_oacc_compute): Adjust call to c_parser_oacc_all_clauses to
	set compute_p argument to true.
	* pt.cc (tsubst_omp_clauses): Add OMP_CLAUSE_SELF case.
	* semantics.cc (c_finish_omp_clauses): Add OMP_CLAUSE_SELF case, merged
	with OMP_CLAUSE_IF case.

gcc/fortran/ChangeLog:

	* gfortran.h (typedef struct gfc_omp_clauses): Add self_expr field.
	* openmp.cc (enum omp_mask2): Add OMP_CLAUSE_SELF.
	(gfc_match_omp_clauses): Add handling for OMP_CLAUSE_SELF.
	(OACC_PARALLEL_CLAUSES): Add OMP_CLAUSE_SELF.
	(OACC_KERNELS_CLAUSES): Likewise.
	(OACC_SERIAL_CLAUSES): Likewise.
	(resolve_omp_clauses): Add handling for omp_clauses->self_expr.
	* trans-openmp.cc (gfc_trans_omp_clauses): Add handling of
	clauses->self_expr and building of OMP_CLAUSE_SELF tree clause.
	(gfc_split_omp_clauses): Add handling of self_expr field copy.

gcc/ChangeLog:

	* gimplify.cc (gimplify_scan_omp_clauses): Add OMP_CLAUSE_SELF case.
	(gimplify_adjust_omp_clauses): Likewise.
	* omp-expand.cc (expand_omp_target): Add OMP_CLAUSE_SELF expansion code,
	* omp-low.cc (scan_sharing_clauses): Add OMP_CLAUSE_SELF case.
	* tree-core.h (enum omp_clause_code): Add OMP_CLAUSE_SELF enum.
	* tree-nested.cc (convert_nonlocal_omp_clauses): Add OMP_CLAUSE_SELF
	case.
	(convert_local_omp_clauses): Likewise.
	* tree-pretty-print.cc (dump_omp_clause): Add OMP_CLAUSE_SELF case.
	* tree.cc (omp_clause_num_ops): Add OMP_CLAUSE_SELF entry.
	(omp_clause_code_name): Likewise.
	* tree.h (OMP_CLAUSE_SELF_EXPR): New macro.

gcc/testsuite/ChangeLog:

	* c-c++-common/goacc/self-clause-1.c: New test.
	* c-c++-common/goacc/self-clause-2.c: New test.
	* gfortran.dg/goacc/self.f95: New test.

include/ChangeLog:

	* gomp-constants.h (GOACC_FLAG_LOCAL_DEVICE): New flag bit value.

libgomp/ChangeLog:

	* oacc-parallel.c (GOACC_parallel_keyed): Add code to handle
	GOACC_FLAG_LOCAL_DEVICE case.
	* testsuite/libgomp.oacc-c-c++-common/self-1.c: New test.