Add support for device-modifiers for 'omp target device'.

'device_num' and 'ancestor' are now parsed on target device constructs for C,
C++, and Fortran (see OpenMP specification 5.0, p. 170). When 'ancestor' is
 used, then 'sorry, not supported' is output. Moreover, the restrictions for
'ancestor' are implemented (see OpenMP specification 5.0, p. 174f).

gcc/c/ChangeLog:

	* c-parser.c (c_parser_omp_clause_device): Parse device-modifiers 'device_num'
	and 'ancestor' in 'target device' clauses.

gcc/cp/ChangeLog:

	* parser.c (cp_parser_omp_clause_device): Parse device-modifiers 'device_num'
	and 'ancestor' in 'target device' clauses.
	* semantics.c (finish_omp_clauses): Error handling. Constant device ids must
	evaluate to '1' if 'ancestor' is used.

gcc/fortran/ChangeLog:

	* gfortran.h: Add variable for 'ancestor' in struct gfc_omp_clauses.
	* openmp.c (gfc_match_omp_clauses): Parse device-modifiers 'device_num'
	and 'ancestor' in 'target device' clauses.
	* trans-openmp.c (gfc_trans_omp_clauses): Set OMP_CLAUSE_DEVICE_ANCESTOR.

gcc/ChangeLog:

	* gimplify.c (gimplify_scan_omp_clauses): Error handling. 'ancestor' only
	allowed on target constructs and only with particular other clauses.
	* omp-expand.c (expand_omp_target): Output of 'sorry, not supported' if
	'ancestor' is used.
	* omp-low.c (check_omp_nesting_restrictions): Error handling. No nested OpenMP
	structs when 'ancestor' is used.
	(scan_omp_1_stmt): No usage of OpenMP runtime routines in a target region when
	'ancestor' is used.
	* tree-pretty-print.c (dump_omp_clause): Append 'ancestor'.
	* tree.h (OMP_CLAUSE_DEVICE_ANCESTOR): Define macro.

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/target-device-1.c: New test.
	* c-c++-common/gomp/target-device-2.c: New test.
	* c-c++-common/gomp/target-device-ancestor-1.c: New test.
	* c-c++-common/gomp/target-device-ancestor-2.c: New test.
	* c-c++-common/gomp/target-device-ancestor-3.c: New test.
	* c-c++-common/gomp/target-device-ancestor-4.c: New test.
	* gfortran.dg/gomp/target-device-1.f90: New test.
	* gfortran.dg/gomp/target-device-2.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-1.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-2.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-3.f90: New test.
	* gfortran.dg/gomp/target-device-ancestor-4.f90: New test.

3 files changed, 50 insertions, 2 deletions

diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 48cdcdf..fdf556e 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -1482,6 +1482,7 @@ typedef struct gfc_omp_clauses
   struct gfc_expr *dist_chunk_size;
   struct gfc_expr *message;
   const char *critical_name;
+  bool ancestor;
   enum gfc_omp_default_sharing default_sharing;
   enum gfc_omp_atomic_op atomic_op;
   enum gfc_omp_defaultmap defaultmap[OMP_DEFAULTMAP_CAT_NUM];
diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c
index 715fd32..64ecd54 100644
--- a/gcc/fortran/openmp.c
+++ b/gcc/fortran/openmp.c
@@ -1825,11 +1825,54 @@ gfc_match_omp_clauses (gfc_omp_clauses **cp, const omp_mask mask,
 	    continue;
 	  if ((mask & OMP_CLAUSE_DEVICE)
 	      && !openacc
-	      && (m = gfc_match_dupl_check (!c->device, "device", true,
-					    &c->device)) != MATCH_NO)
+	      && ((m = gfc_match_dupl_check (!c->device, "device", true))
+		  != MATCH_NO))
 	    {
 	      if (m == MATCH_ERROR)
 		goto error;
+	      c->ancestor = false;
+	      if (gfc_match ("device_num : ") == MATCH_YES)
+		{
+		  if (gfc_match ("%e )", &c->device) != MATCH_YES)
+		    {
+		      gfc_error ("Expected integer expression at %C");
+		      break;
+		    }
+		}
+	      else if (gfc_match ("ancestor : ") == MATCH_YES)
+		{
+		  c->ancestor = true;
+		  if (!(gfc_current_ns->omp_requires & OMP_REQ_REVERSE_OFFLOAD))
+		    {
+		      gfc_error ("%<ancestor%> device modifier not "
+				 "preceded by %<requires%> directive "
+				 "with %<reverse_offload%> clause at %C");
+		      break;
+		    }
+		  locus old_loc2 = gfc_current_locus;
+		  if (gfc_match ("%e )", &c->device) == MATCH_YES)
+		    {
+		      int device = 0;
+		      if (!gfc_extract_int (c->device, &device) && device != 1)
+		      {
+			gfc_current_locus = old_loc2;
+			gfc_error ("the %<device%> clause expression must "
+				   "evaluate to %<1%> at %C");
+			break;
+		      }
+		    }
+		  else
+		    {
+		      gfc_error ("Expected integer expression at %C");
+		      break;
+		    }
+		}
+	      else if (gfc_match ("%e )", &c->device) != MATCH_YES)
+		{
+		  gfc_error ("Expected integer expression or a single device-"
+			      "modifier %<device_num%> or %<ancestor%> at %C");
+		  break;
+		}
 	      continue;
 	    }
 	  if ((mask & OMP_CLAUSE_DEVICE)
diff --git a/gcc/fortran/trans-openmp.c b/gcc/fortran/trans-openmp.c
index 40d2fd2..6f9b0e3 100644
--- a/gcc/fortran/trans-openmp.c
+++ b/gcc/fortran/trans-openmp.c
@@ -3950,6 +3950,10 @@ gfc_trans_omp_clauses (stmtblock_t *block, gfc_omp_clauses *clauses,
 
       c = build_omp_clause (gfc_get_location (&where), OMP_CLAUSE_DEVICE);
       OMP_CLAUSE_DEVICE_ID (c) = device;
+
+      if (clauses->ancestor)
+	OMP_CLAUSE_DEVICE_ANCESTOR (c) = 1;
+
       omp_clauses = gfc_trans_add_clause (c, omp_clauses);
     }