openmp: Add support for OpenMP 5.1 masked construct

openmp: Add support for OpenMP 5.1 masked construct

This construct has been introduced as a replacement for master
construct, but unlike that construct is slightly more general,
has an optional clause which allows to choose which thread
will be the one running the region, it can be some other thread
than the master (primary) thread with number 0, or it could be no
threads or multiple threads (then of course one needs to be careful
about data races).

It is way too early to deprecate the master construct though, we don't
even have OpenMP 5.0 fully implemented, it has been deprecated in 5.1,
will be also in 5.2 and removed in 6.0.  But even then it will likely
be a good idea to just -Wdeprecated warn about it and still accept it.

The patch also contains something I should have done much earlier,
for clauses that accept some integral expression where we only care
about the value, forces during gimplification that value into
either a min invariant (as before), SSA_NAME or a fresh temporary,
but never e.g. a user VAR_DECL, so that for those clauses we don't
need to worry about adjusting it.

2021-08-12  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* tree.def (OMP_MASKED): New tree code.
	* tree-core.h (enum omp_clause_code): Add OMP_CLAUSE_FILTER.
	* tree.h (OMP_MASKED_BODY, OMP_MASKED_CLAUSES, OMP_MASKED_COMBINED,
	OMP_CLAUSE_FILTER_EXPR): Define.
	* tree.c (omp_clause_num_ops): Add OMP_CLAUSE_FILTER entry.
	(omp_clause_code_name): Likewise.
	(walk_tree_1): Handle OMP_CLAUSE_FILTER.
	* tree-nested.c (convert_nonlocal_omp_clauses,
	convert_local_omp_clauses): Handle OMP_CLAUSE_FILTER.
	(convert_nonlocal_reference_stmt, convert_local_reference_stmt,
	convert_gimple_call): Handle GIMPLE_OMP_MASTER.
	* tree-pretty-print.c (dump_omp_clause): Handle OMP_CLAUSE_FILTER.
	(dump_generic_node): Handle OMP_MASTER.
	* gimple.def (GIMPLE_OMP_MASKED): New gimple code.
	* gimple.c (gimple_build_omp_masked): New function.
	(gimple_copy): Handle GIMPLE_OMP_MASKED.
	* gimple.h (gimple_build_omp_masked): Declare.
	(gimple_has_substatements): Handle GIMPLE_OMP_MASKED.
	(gimple_omp_masked_clauses, gimple_omp_masked_clauses_ptr,
	gimple_omp_masked_set_clauses): New inline functions.
	(CASE_GIMPLE_OMP): Add GIMPLE_OMP_MASKED.
	* gimple-pretty-print.c (dump_gimple_omp_masked): New function.
	(pp_gimple_stmt_1): Handle GIMPLE_OMP_MASKED.
	* gimple-walk.c (walk_gimple_stmt): Likewise.
	* gimple-low.c (lower_stmt): Likewise.
	* gimplify.c (is_gimple_stmt): Handle OMP_MASTER.
	(gimplify_scan_omp_clauses): Handle OMP_CLAUSE_FILTER.  For clauses
	that take one expression rather than decl or constant, force
	gimplification of that into a SSA_NAME or temporary unless min
	invariant.
	(gimplify_adjust_omp_clauses): Handle OMP_CLAUSE_FILTER.
	(gimplify_expr): Handle OMP_MASKED.
	* tree-inline.c (remap_gimple_stmt): Handle GIMPLE_OMP_MASKED.
	(estimate_num_insns): Likewise.
	* omp-low.c (scan_sharing_clauses): Handle OMP_CLAUSE_FILTER.
	(check_omp_nesting_restrictions): Handle GIMPLE_OMP_MASKED.  Adjust
	diagnostics for existence of masked construct.
	(scan_omp_1_stmt, lower_omp_master, lower_omp_1, diagnose_sb_1,
	diagnose_sb_2): Handle GIMPLE_OMP_MASKED.
	* omp-expand.c (expand_omp_synch, expand_omp, omp_make_gimple_edges):
	Likewise.
gcc/c-family/
	* c-pragma.h (enum pragma_kind): Add PRAGMA_OMP_MASKED.
	(enum pragma_omp_clause): Add PRAGMA_OMP_CLAUSE_FILTER.
	* c-pragma.c (omp_pragmas_simd): Add masked construct.
	* c-common.h (enum c_omp_clause_split): Add C_OMP_CLAUSE_SPLIT_MASKED
	enumerator.
	(c_finish_omp_masked): Declare.
	* c-omp.c (c_finish_omp_masked): New function.
	(c_omp_split_clauses): Handle combined masked constructs.
gcc/c/
	* c-parser.c (c_parser_omp_clause_name): Parse filter clause name.
	(c_parser_omp_clause_filter): New function.
	(c_parser_omp_all_clauses): Handle PRAGMA_OMP_CLAUSE_FILTER.
	(OMP_MASKED_CLAUSE_MASK): Define.
	(c_parser_omp_masked): New function.
	(c_parser_omp_parallel): Handle parallel masked.
	(c_parser_omp_construct): Handle PRAGMA_OMP_MASKED.
	* c-typeck.c (c_finish_omp_clauses): Handle OMP_CLAUSE_FILTER.
gcc/cp/
	* parser.c (cp_parser_omp_clause_name): Parse filter clause name.
	(cp_parser_omp_clause_filter): New function.
	(cp_parser_omp_all_clauses): Handle PRAGMA_OMP_CLAUSE_FILTER.
	(OMP_MASKED_CLAUSE_MASK): Define.
	(cp_parser_omp_masked): New function.
	(cp_parser_omp_parallel): Handle parallel masked.
	(cp_parser_omp_construct, cp_parser_pragma): Handle PRAGMA_OMP_MASKED.
	* semantics.c (finish_omp_clauses): Handle OMP_CLAUSE_FILTER.
	* pt.c (tsubst_omp_clauses): Likewise.
	(tsubst_expr): Handle OMP_MASKED.
gcc/testsuite/
	* c-c++-common/gomp/clauses-1.c (bar): Add tests for combined masked
	constructs with clauses.
	* c-c++-common/gomp/clauses-5.c (foo): Add testcase for filter clause.
	* c-c++-common/gomp/clause-dups-1.c (f1): Likewise.
	* c-c++-common/gomp/masked-1.c: New test.
	* c-c++-common/gomp/masked-2.c: New test.
	* c-c++-common/gomp/masked-combined-1.c: New test.
	* c-c++-common/gomp/masked-combined-2.c: New test.
	* c-c++-common/goacc/uninit-if-clause.c: Remove xfails.
	* g++.dg/gomp/block-11.C: New test.
	* g++.dg/gomp/tpl-masked-1.C: New test.
	* g++.dg/gomp/attrs-1.C (bar): Add tests for masked construct and
	combined masked constructs with clauses in attribute syntax.
	* g++.dg/gomp/attrs-2.C (bar): Likewise.
	* gcc.dg/gomp/nesting-1.c (f1, f2): Add tests for masked construct
	nesting.
	* gfortran.dg/goacc/host_data-tree.f95: Allow also SSA_NAMEs in if
	clause.
	* gfortran.dg/goacc/kernels-tree.f95: Likewise.
libgomp/
	* testsuite/libgomp.c-c++-common/masked-1.c: New test.