openmp: Add C/C++ support for "omp unroll" directive

openmp: Add C/C++ support for "omp unroll" directive

This commit implements the C and the C++ front end changes to support
the "omp unroll" directive.  The execution of the loop transformation
relies on the pass that has been added as a part of the earlier
Fortran patch.

gcc/c-family/ChangeLog:

	* c-gimplify.cc (c_genericize_control_stmt): Handle OMP_UNROLL.
	* c-omp.cc: Add "unroll" to omp_directives[].
	* c-pragma.cc: Add "unroll" to omp_pragmas_simd[].
	* c-pragma.h (enum pragma_kind): Add PRAGMA_OMP_UNROLL to
	pragma_kind and adjust PRAGMA_OMP__LAST_.
	(enum pragma_omp_clause): Add PRAGMA_OMP_CLAUSE_FULL and
	PRAGMA_OMP_CLAUSE_PARTIAL.

gcc/c/ChangeLog:

	* c-parser.cc (c_parser_omp_clause_name): Handle "full" and
	"partial" clauses.
	(check_no_duplicate_clause): Change return type to bool and
	return check result.
	(c_parser_omp_clause_unroll_full): New function for parsing
	the "unroll clause".
	(c_parser_omp_clause_unroll_partial): New function for
	parsing the "partial" clause.
	(c_parser_omp_all_clauses): Handle PRAGMA_OMP_CLAUSE_FULL
	and PRAGMA_OMP_CLAUSE_PARTIAL.
	(c_parser_nested_omp_unroll_clauses): New function for parsing
	"omp unroll" directives following another directive.
	(OMP_UNROLL_CLAUSE_MASK): New definition.
	(c_parser_omp_unroll): New function for parsing "omp unroll"
	loops that are not associated with another directive.
	(c_parser_omp_construct): Handle PRAGMA_OMP_UNROLL.
	* c-typeck.cc (c_finish_omp_clauses): Handle
	OMP_CLAUSE_UNROLL_FULL, OMP_CLAUSE_UNROLL_PARTIAL,
	and OMP_CLAUSE_UNROLL_NONE.

gcc/cp/ChangeLog:

	* cp-gimplify.cc (cp_gimplify_expr): Handle OMP_UNROLL.
	(cp_fold_r): Likewise.
	(cp_genericize_r): Likewise.
	* parser.cc (cp_parser_omp_clause_name): Handle "full" clause.
	(check_no_duplicate_clause): Change return type to bool and
	return check result.
	(cp_parser_omp_clause_unroll_full): New function for parsing
	the "unroll clause".
	(cp_parser_omp_clause_unroll_partial): New function for
	parsing the "partial" clause.
	(cp_parser_omp_all_clauses): Handle OMP_CLAUSE_UNROLL and
	OMP_CLAUSE_FULL.
	(cp_parser_nested_omp_unroll_clauses): New function for parsing
	"omp unroll" directives following another directive.
	(cp_parser_omp_for_loop): Handle "omp unroll" directives
	between directive and loop.
	(OMP_UNROLL_CLAUSE_MASK): New definition.
	(cp_parser_omp_unroll): New function for parsing "omp unroll"
	loops that are not associated with another directive.

	(cp_parser_omp_construct): Handle PRAGMA_OMP_UNROLL.
	(cp_parser_pragma): Handle PRAGMA_OMP_UNROLL.
	* pt.cc (tsubst_omp_clauses): Handle
	OMP_CLAUSE_UNROLL_PARTIAL, OMP_CLAUSE_UNROLL_FULL, and
	OMP_CLAUSE_UNROLL_NONE.
	(tsubst_expr): Handle OMP_UNROLL.
	* semantics.cc (finish_omp_clauses): Handle
	OMP_CLAUSE_UNROLL_FULL, OMP_CLAUSE_UNROLL_PARTIAL,
	and OMP_CLAUSE_UNROLL_NONE.

libgomp/ChangeLog:

	* testsuite/libgomp.c++/loop-transforms/unroll-1.C: New test.
	* testsuite/libgomp.c++/loop-transforms/unroll-2.C: New test.
	* testsuite/libgomp.c-c++-common/loop-transforms/unroll-1.c: New test.

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/loop-transforms/unroll-1.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-2.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-3.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-4.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-5.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-6.c: New test.
	* g++.dg/gomp/loop-transforms/unroll-1.C: New test.
	* g++.dg/gomp/loop-transforms/unroll-2.C: New test.
	* g++.dg/gomp/loop-transforms/unroll-3.C: New test.