diff mbox series

[2/7] OpenMP: middle-end support for dispatch + adjust_args

Message ID 20240527115439.3967217-3-parras@baylibre.com
State New
Headers show
Series OpenMP: dispatch + adjust_args support | expand

Commit Message

Paul-Antoine Arras May 27, 2024, 11:54 a.m. UTC
This patch adds middle-end support for the `dispatch` construct and the
`adjust_args` clause. The heavy lifting is done in `gimplify_omp_dispatch` and
`gimplify_call_expr` respectively. For `adjust_args`, this mostly consists in
emitting a call to `gomp_get_mapped_ptr` for the adequate device.

For dispatch, the following steps are performed:

* Handle the device clause, if any. This may affect `need_device_ptr` arguments.

* Handle novariants and nocontext clauses, if any. Evaluate compile-time
constants and select a variant, if possible. Otherwise, emit code to handle all
possible cases at run time.

* Create an explicit task, as if the `task` construct was used, that wraps the
body of the `dispatch` statement. Move relevant clauses to the task.

gcc/ChangeLog:

	* gimple-low.cc (lower_stmt): Handle GIMPLE_OMP_DISPATCH.
	* gimple-pretty-print.cc (dump_gimple_omp_dispatch): New function.
	(pp_gimple_stmt_1): Handle GIMPLE_OMP_DISPATCH.
	* gimple-walk.cc (walk_gimple_stmt): Likewise.
	* gimple.cc (gimple_build_omp_dispatch): New function.
	(gimple_copy): Handle GIMPLE_OMP_DISPATCH.
	* gimple.def (GIMPLE_OMP_DISPATCH): Define.
	* gimple.h (gimple_build_omp_dispatch): Declare.
	(gimple_has_substatements): Handle GIMPLE_OMP_DISPATCH.
	(gimple_omp_dispatch_clauses): New function.
	(gimple_omp_dispatch_clauses_ptr): Likewise.
	(gimple_omp_dispatch_set_clauses): Likewise.
	(gimple_return_set_retval): Handle GIMPLE_OMP_DISPATCH.
	* gimplify.cc (enum omp_region_type): Add ORT_DISPATCH.
	(gimplify_call_expr): Handle need_device_ptr arguments.
	(is_gimple_stmt): Handle OMP_DISPATCH.
	(gimplify_scan_omp_clauses): Handle OMP_CLAUSE_DEVICE in a dispatch
	construct. Handle OMP_CLAUSE_NOVARIANTS and OMP_CLAUSE_NOCONTEXT.
	(gimplify_adjust_omp_clauses): Handle OMP_CLAUSE_NOVARIANTS and
	OMP_CLAUSE_NOCONTEXT.
	(omp_construct_selector_matches): Handle OMP_DISPATCH with nocontext
	clause.
	(omp_has_novariants): New function.
	(omp_has_nocontext): Likewise.
	(gimplify_omp_dispatch): Likewise.
	(gimplify_expr): Handle OMP_DISPATCH.
	* gimplify.h (omp_has_novariants): Declare.
	(omp_has_nocontext): Declare.
	* omp-builtins.def (BUILT_IN_OMP_GET_MAPPED_PTR): Define.
	(BUILT_IN_OMP_GET_DEFAULT_DEVICE): Define.
	(BUILT_IN_OMP_SET_DEFAULT_DEVICE): Define.
	* omp-expand.cc (expand_omp_dispatch): New function.
	(expand_omp): Handle GIMPLE_OMP_DISPATCH.
	(omp_make_gimple_edges): Likewise.
	* omp-general.cc (omp_construct_traits_to_codes): Add OMP_DISPATCH.
	(struct omp_ts_info): Add dispatch.
	(omp_context_selector_matches): Handle OMP_TRAIT_SET_NEED_DEVICE_PTR.
	(omp_resolve_declare_variant): Handle novariants. Adjust
	DECL_ASSEMBLER_NAME.
---
 gcc/gimple-low.cc          |   1 +
 gcc/gimple-pretty-print.cc |  33 +++
 gcc/gimple-walk.cc         |   1 +
 gcc/gimple.cc              |  20 ++
 gcc/gimple.def             |   5 +
 gcc/gimple.h               |  33 ++-
 gcc/gimplify.cc            | 417 ++++++++++++++++++++++++++++++++++++-
 gcc/gimplify.h             |   2 +
 gcc/omp-builtins.def       |   6 +
 gcc/omp-expand.cc          |  18 ++
 gcc/omp-general.cc         |  16 +-
 gcc/omp-low.cc             |  35 ++++
 gcc/tree-inline.cc         |   7 +
 13 files changed, 583 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/gcc/gimple-low.cc b/gcc/gimple-low.cc
index e0371988705..712a1ebf776 100644
--- a/gcc/gimple-low.cc
+++ b/gcc/gimple-low.cc
@@ -746,6 +746,7 @@  lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data)
     case GIMPLE_EH_MUST_NOT_THROW:
     case GIMPLE_OMP_FOR:
     case GIMPLE_OMP_SCOPE:
+    case GIMPLE_OMP_DISPATCH:
     case GIMPLE_OMP_SECTIONS:
     case GIMPLE_OMP_SECTIONS_SWITCH:
     case GIMPLE_OMP_SECTION:
diff --git a/gcc/gimple-pretty-print.cc b/gcc/gimple-pretty-print.cc
index a71e1e0efc7..d9a24ad2169 100644
--- a/gcc/gimple-pretty-print.cc
+++ b/gcc/gimple-pretty-print.cc
@@ -1726,6 +1726,35 @@  dump_gimple_omp_scope (pretty_printer *buffer, const gimple *gs,
     }
 }
 
+/* Dump a GIMPLE_OMP_DISPATCH tuple on the pretty_printer BUFFER.  */
+
+static void
+dump_gimple_omp_dispatch (pretty_printer *buffer, const gimple *gs, int spc,
+			  dump_flags_t flags)
+{
+  if (flags & TDF_RAW)
+    {
+      dump_gimple_fmt (buffer, spc, flags, "%G <%+BODY <%S>%nCLAUSES <", gs,
+		       gimple_omp_body (gs));
+      dump_omp_clauses (buffer, gimple_omp_dispatch_clauses (gs), spc, flags);
+      dump_gimple_fmt (buffer, spc, flags, " >");
+    }
+  else
+    {
+      pp_string (buffer, "#pragma omp dispatch");
+      dump_omp_clauses (buffer, gimple_omp_dispatch_clauses (gs), spc, flags);
+      if (!gimple_seq_empty_p (gimple_omp_body (gs)))
+	{
+	  newline_and_indent (buffer, spc + 2);
+	  pp_left_brace (buffer);
+	  pp_newline (buffer);
+	  dump_gimple_seq (buffer, gimple_omp_body (gs), spc + 4, flags);
+	  newline_and_indent (buffer, spc + 2);
+	  pp_right_brace (buffer);
+	}
+    }
+}
+
 /* Dump a GIMPLE_OMP_TARGET tuple on the pretty_printer BUFFER.  */
 
 static void
@@ -2805,6 +2834,10 @@  pp_gimple_stmt_1 (pretty_printer *buffer, const gimple *gs, int spc,
       dump_gimple_omp_scope (buffer, gs, spc, flags);
       break;
 
+    case GIMPLE_OMP_DISPATCH:
+      dump_gimple_omp_dispatch (buffer, gs, spc, flags);
+      break;
+
     case GIMPLE_OMP_MASTER:
     case GIMPLE_OMP_SECTION:
     case GIMPLE_OMP_STRUCTURED_BLOCK:
diff --git a/gcc/gimple-walk.cc b/gcc/gimple-walk.cc
index 9f768ca20fd..1122713a98b 100644
--- a/gcc/gimple-walk.cc
+++ b/gcc/gimple-walk.cc
@@ -707,6 +707,7 @@  walk_gimple_stmt (gimple_stmt_iterator *gsi, walk_stmt_fn callback_stmt,
     case GIMPLE_OMP_PARALLEL:
     case GIMPLE_OMP_TASK:
     case GIMPLE_OMP_SCOPE:
+    case GIMPLE_OMP_DISPATCH:
     case GIMPLE_OMP_SECTIONS:
     case GIMPLE_OMP_SINGLE:
     case GIMPLE_OMP_TARGET:
diff --git a/gcc/gimple.cc b/gcc/gimple.cc
index a9f968cb038..3a26c74a105 100644
--- a/gcc/gimple.cc
+++ b/gcc/gimple.cc
@@ -1235,6 +1235,21 @@  gimple_build_omp_scope (gimple_seq body, tree clauses)
   return p;
 }
 
+/* Build a GIMPLE_OMP_DISPATCH statement.
+
+   BODY is the target function call to be dispatched.
+   CLAUSES are any of the OMP dispatch construct's clauses: ...  */
+
+gimple *
+gimple_build_omp_dispatch (gimple_seq body, tree clauses)
+{
+  gimple *p = gimple_alloc (GIMPLE_OMP_DISPATCH, 0);
+  gimple_omp_dispatch_set_clauses (p, clauses);
+  if (body)
+    gimple_omp_set_body (p, body);
+
+  return p;
+}
 
 /* Build a GIMPLE_OMP_TARGET statement.
 
@@ -2148,6 +2163,11 @@  gimple_copy (gimple *stmt)
 	  gimple_omp_scope_set_clauses (copy, t);
 	  goto copy_omp_body;
 
+	case GIMPLE_OMP_DISPATCH:
+	  t = unshare_expr (gimple_omp_dispatch_clauses (stmt));
+	  gimple_omp_dispatch_set_clauses (copy, t);
+	  goto copy_omp_body;
+
 	case GIMPLE_OMP_TARGET:
 	  {
 	    gomp_target *omp_target_stmt = as_a <gomp_target *> (stmt);
diff --git a/gcc/gimple.def b/gcc/gimple.def
index fbcd727f945..21c7405875d 100644
--- a/gcc/gimple.def
+++ b/gcc/gimple.def
@@ -350,6 +350,11 @@  DEFGSCODE(GIMPLE_OMP_SCAN, "gimple_omp_scan", GSS_OMP_SINGLE_LAYOUT)
    CLAUSES is an OMP_CLAUSE chain holding the associated clauses.  */
 DEFGSCODE(GIMPLE_OMP_SCOPE, "gimple_omp_scope", GSS_OMP_SINGLE_LAYOUT)
 
+/* GIMPLE_OMP_DISPATCH <BODY, CLAUSES> represents #pragma omp dispatch
+   BODY is the target function call to be dispatched.
+   CLAUSES is an OMP_CLAUSE chain holding the associated clauses.  */
+DEFGSCODE(GIMPLE_OMP_DISPATCH, "gimple_omp_dispatch", GSS_OMP_SINGLE_LAYOUT)
+
 /* OMP_SECTION <BODY> represents #pragma omp section.
    BODY is the sequence of statements in the section body.  */
 DEFGSCODE(GIMPLE_OMP_SECTION, "gimple_omp_section", GSS_OMP)
diff --git a/gcc/gimple.h b/gcc/gimple.h
index bd315ffc2dd..25590a22ffb 100644
--- a/gcc/gimple.h
+++ b/gcc/gimple.h
@@ -746,7 +746,7 @@  struct GTY((tag("GSS_OMP_CONTINUE")))
 };
 
 /* GIMPLE_OMP_SINGLE, GIMPLE_OMP_ORDERED, GIMPLE_OMP_TASKGROUP,
-   GIMPLE_OMP_SCAN, GIMPLE_OMP_MASKED, GIMPLE_OMP_SCOPE.  */
+   GIMPLE_OMP_SCAN, GIMPLE_OMP_MASKED, GIMPLE_OMP_SCOPE, GIMPLE_OMP_DISPATCH. */
 
 struct GTY((tag("GSS_OMP_SINGLE_LAYOUT")))
   gimple_statement_omp_single_layout : public gimple_statement_omp
@@ -1595,6 +1595,7 @@  gomp_task *gimple_build_omp_task (gimple_seq, tree, tree, tree, tree,
 gimple *gimple_build_omp_section (gimple_seq);
 gimple *gimple_build_omp_structured_block (gimple_seq);
 gimple *gimple_build_omp_scope (gimple_seq, tree);
+gimple *gimple_build_omp_dispatch (gimple_seq, tree);
 gimple *gimple_build_omp_master (gimple_seq);
 gimple *gimple_build_omp_masked (gimple_seq, tree);
 gimple *gimple_build_omp_taskgroup (gimple_seq, tree);
@@ -1886,6 +1887,7 @@  gimple_has_substatements (gimple *g)
     case GIMPLE_OMP_PARALLEL:
     case GIMPLE_OMP_TASK:
     case GIMPLE_OMP_SCOPE:
+    case GIMPLE_OMP_DISPATCH:
     case GIMPLE_OMP_SECTIONS:
     case GIMPLE_OMP_SINGLE:
     case GIMPLE_OMP_TARGET:
@@ -5437,6 +5439,34 @@  gimple_omp_scope_set_clauses (gimple *gs, tree clauses)
     = clauses;
 }
 
+/* Return the clauses associated with OMP_DISPATCH statement GS.  */
+
+inline tree
+gimple_omp_dispatch_clauses (const gimple *gs)
+{
+  GIMPLE_CHECK (gs, GIMPLE_OMP_DISPATCH);
+  return static_cast<const gimple_statement_omp_single_layout *> (gs)->clauses;
+}
+
+/* Return a pointer to the clauses associated with OMP dispatch statement
+   GS.  */
+
+inline tree *
+gimple_omp_dispatch_clauses_ptr (gimple *gs)
+{
+  GIMPLE_CHECK (gs, GIMPLE_OMP_DISPATCH);
+  return &static_cast<gimple_statement_omp_single_layout *> (gs)->clauses;
+}
+
+/* Set CLAUSES to be the clauses associated with OMP dispatch statement
+   GS.  */
+
+inline void
+gimple_omp_dispatch_set_clauses (gimple *gs, tree clauses)
+{
+  GIMPLE_CHECK (gs, GIMPLE_OMP_DISPATCH);
+  static_cast<gimple_statement_omp_single_layout *> (gs)->clauses = clauses;
+}
 
 /* Return the kind of the OMP_FOR statemement G.  */
 
@@ -6771,6 +6801,7 @@  gimple_return_set_retval (greturn *gs, tree retval)
     case GIMPLE_OMP_TARGET:			\
     case GIMPLE_OMP_TEAMS:			\
     case GIMPLE_OMP_SCOPE:			\
+    case GIMPLE_OMP_DISPATCH:			\
     case GIMPLE_OMP_SECTION:			\
     case GIMPLE_OMP_STRUCTURED_BLOCK:		\
     case GIMPLE_OMP_MASTER:			\
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index b0ed58ed0f9..1dd69dbb1de 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -161,7 +161,8 @@  enum omp_region_type
 {
   ORT_WORKSHARE = 0x00,
   ORT_TASKGROUP = 0x01,
-  ORT_SIMD 	= 0x04,
+  ORT_DISPATCH	= 0x02,
+  ORT_SIMD	= 0x04,
 
   ORT_PARALLEL	= 0x08,
   ORT_COMBINED_PARALLEL = ORT_PARALLEL | 1,
@@ -4051,6 +4052,7 @@  gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value)
   /* Gimplify the function arguments.  */
   if (nargs > 0)
     {
+    tree device_num = NULL_TREE;
       for (i = (PUSH_ARGS_REVERSED ? nargs - 1 : 0);
            PUSH_ARGS_REVERSED ? i >= 0 : i < nargs;
            PUSH_ARGS_REVERSED ? i-- : i++)
@@ -4061,8 +4063,99 @@  gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value)
              be the plain PARM_DECL.  */
           if ((i != 1) || !builtin_va_start_p)
             {
-              t = gimplify_arg (&CALL_EXPR_ARG (*expr_p, i), pre_p,
-				EXPR_LOCATION (*expr_p), ! returns_twice);
+	      tree *arg_p = &CALL_EXPR_ARG (*expr_p, i);
+	      if (flag_openmp && EXPR_P (CALL_EXPR_FN (*expr_p))
+		  && lookup_attribute ("omp declare variant variant",
+				       DECL_ATTRIBUTES (TREE_OPERAND (
+					 CALL_EXPR_FN (*expr_p), 0)))
+		       != NULL_TREE)
+		{
+		  tree param
+		    = DECL_ARGUMENTS (TREE_OPERAND (CALL_EXPR_FN (*expr_p), 0));
+
+		  if (param != NULL_TREE)
+		    {
+		      for (int param_idx = 0; param_idx < i; param_idx++)
+			param = TREE_CHAIN (param);
+
+		      bool is_device_ptr = false;
+		      if (gimplify_omp_ctxp != NULL
+			  && gimplify_omp_ctxp->code == OMP_DISPATCH)
+			{
+			  for (tree c = gimplify_omp_ctxp->clauses; c;
+			       c = TREE_CHAIN (c))
+			    {
+			      if (OMP_CLAUSE_CODE (c)
+				  == OMP_CLAUSE_IS_DEVICE_PTR)
+				{
+				  tree decl1 = DECL_NAME (OMP_CLAUSE_DECL (c));
+				  tree decl2
+				    = tree_strip_nop_conversions (*arg_p);
+				  if (TREE_CODE (decl2) == ADDR_EXPR)
+				    decl2 = TREE_OPERAND (decl2, 0);
+				  gcc_assert (TREE_CODE (decl2) == VAR_DECL
+					      || TREE_CODE (decl2)
+						   == PARM_DECL);
+				  decl2 = DECL_NAME (decl2);
+				  if (decl1 == decl2)
+				    {
+				      is_device_ptr = true;
+				      break;
+				    }
+				}
+			      else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEVICE)
+				device_num = OMP_CLAUSE_OPERAND (c, 0);
+			    }
+			}
+
+		      if (!is_device_ptr
+			  && lookup_attribute ("omp declare variant "
+					       "adjust_args need_device_ptr",
+					       DECL_ATTRIBUTES (param))
+			       != NULL_TREE)
+			{
+			  if (device_num == NULL_TREE)
+			    {
+			      // device_num = omp_get_default_device();
+			      tree fn = builtin_decl_explicit (
+				BUILT_IN_OMP_GET_DEFAULT_DEVICE);
+			      gcall *call = gimple_build_call (fn, 0);
+			      device_num = create_tmp_var (
+				gimple_call_return_type (call));
+			      gimple_call_set_lhs (call, device_num);
+			      gimplify_seq_add_stmt (pre_p, call);
+			    }
+
+			  // mapped_arg = omp_get_mapped_ptr(arg, device_num);
+			  tree fn = builtin_decl_explicit (
+			    BUILT_IN_OMP_GET_MAPPED_PTR);
+			  *arg_p = (TREE_CODE (*arg_p) == NOP_EXPR)
+				     ? TREE_OPERAND (*arg_p, 0)
+				     : *arg_p;
+			  gimplify_arg (arg_p, pre_p, loc);
+			  gimplify_arg (&device_num, pre_p, loc);
+			  call = gimple_build_call (fn, 2, *arg_p, device_num);
+			  tree mapped_arg
+			    = create_tmp_var (gimple_call_return_type (call));
+			  gimple_call_set_lhs (call, mapped_arg);
+			  gimplify_seq_add_stmt (pre_p, call);
+
+			  *arg_p = mapped_arg;
+
+			  // Mark mapped argument as device pointer to ensure
+			  // idempotency in gimplification
+			  gcc_assert (gimplify_omp_ctxp->code == OMP_DISPATCH);
+			  tree c = build_omp_clause (input_location,
+						     OMP_CLAUSE_IS_DEVICE_PTR);
+			  OMP_CLAUSE_DECL (c) = *arg_p;
+			  OMP_CLAUSE_CHAIN (c) = gimplify_omp_ctxp->clauses;
+			  gimplify_omp_ctxp->clauses = c;
+			}
+		    }
+		}
+
+	      t = gimplify_arg (arg_p, pre_p, EXPR_LOCATION (*expr_p),
+				!returns_twice);
 
               if (t == GS_ERROR)
                 ret = GS_ERROR;
@@ -6307,6 +6400,7 @@  is_gimple_stmt (tree t)
     case OACC_LOOP:
     case OMP_SCAN:
     case OMP_SCOPE:
+    case OMP_DISPATCH:
     case OMP_SECTIONS:
     case OMP_SECTION:
     case OMP_STRUCTURED_BLOCK:
@@ -13080,6 +13174,21 @@  gimplify_scan_omp_clauses (tree *list_p, gimple_seq *pre_p,
 		    break;
 		  }
 	    }
+	  else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEVICE
+		   && code == OMP_DISPATCH)
+	    {
+	      bool saved_into_ssa = gimplify_ctxp->into_ssa;
+	      gimplify_ctxp->into_ssa = false;
+	      if (gimplify_expr (&OMP_CLAUSE_DEVICE_ID (c), pre_p, NULL,
+				 is_gimple_val, fb_rvalue)
+		  == GS_ERROR)
+		remove = true;
+	      else if (DECL_P (OMP_CLAUSE_DEVICE_ID (c)))
+		omp_add_variable (ctx, OMP_CLAUSE_DEVICE_ID (c),
+				  GOVD_SHARED | GOVD_SEEN);
+	      gimplify_ctxp->into_ssa = saved_into_ssa;
+	      break;
+	    }
 	  /* Fall through.  */
 
 	case OMP_CLAUSE_PRIORITY:
@@ -13309,6 +13418,20 @@  gimplify_scan_omp_clauses (tree *list_p, gimple_seq *pre_p,
 	  }
 	  break;
 
+	case OMP_CLAUSE_NOVARIANTS:
+	  {
+	    OMP_CLAUSE_NOVARIANTS_EXPR (c);
+	    tree t = gimple_boolify (OMP_CLAUSE_NOVARIANTS_EXPR (c));
+	    OMP_CLAUSE_NOVARIANTS_EXPR (c) = t;
+	  }
+	  break;
+	case OMP_CLAUSE_NOCONTEXT:
+	  {
+	    OMP_CLAUSE_NOCONTEXT_EXPR (c);
+	    tree t = gimple_boolify (OMP_CLAUSE_NOCONTEXT_EXPR (c));
+	    OMP_CLAUSE_NOCONTEXT_EXPR (c) = t;
+	  }
+	  break;
 	case OMP_CLAUSE_NOHOST:
 	default:
 	  gcc_unreachable ();
@@ -13763,7 +13886,9 @@  gimplify_adjust_omp_clauses (gimple_seq *pre_p, gimple_seq body, tree *list_p,
     {
       struct gimplify_omp_ctx *octx;
       for (octx = ctx; octx; octx = octx->outer_context)
-	if ((octx->region_type & (ORT_PARALLEL | ORT_TASK | ORT_TEAMS)) != 0)
+	if ((octx->region_type
+	     & (ORT_DISPATCH | ORT_PARALLEL | ORT_TASK | ORT_TEAMS))
+	    != 0)
 	  break;
       if (octx)
 	{
@@ -14574,6 +14699,8 @@  gimplify_adjust_omp_clauses (gimple_seq *pre_p, gimple_seq body, tree *list_p,
 	case OMP_CLAUSE_FINALIZE:
 	case OMP_CLAUSE_INCLUSIVE:
 	case OMP_CLAUSE_EXCLUSIVE:
+	case OMP_CLAUSE_NOVARIANTS:
+	case OMP_CLAUSE_NOCONTEXT:
 	  break;
 
 	case OMP_CLAUSE_NOHOST:
@@ -14663,9 +14790,9 @@  omp_construct_selector_matches (enum tree_code *constructs, int nconstructs,
 	      == ORT_TARGET && ctx->code == OMP_TARGET)
 	  || ((ctx->region_type & ORT_TEAMS) && ctx->code == OMP_TEAMS)
 	  || (ctx->region_type == ORT_WORKSHARE && ctx->code == OMP_FOR)
-	  || (ctx->region_type == ORT_SIMD
-	      && ctx->code == OMP_SIMD
-	      && !omp_find_clause (ctx->clauses, OMP_CLAUSE_BIND)))
+	  || (ctx->region_type == ORT_SIMD && ctx->code == OMP_SIMD
+	      && !omp_find_clause (ctx->clauses, OMP_CLAUSE_BIND))
+	  || (ctx->code == OMP_DISPATCH && omp_has_nocontext () != 1))
 	{
 	  ++cnt;
 	  if (scores)
@@ -14783,6 +14910,60 @@  omp_construct_selector_matches (enum tree_code *constructs, int nconstructs,
   return 0;
 }
 
+/* Try to evaluate a novariants clause. Return 1 if true, 0 if false or absent,
+ * -1 if run-time evaluation is needed. */
+
+int
+omp_has_novariants (void)
+{
+  for (struct gimplify_omp_ctx *ctx = gimplify_omp_ctxp; ctx;
+       ctx = ctx->outer_context)
+    {
+      if (ctx->code == OMP_DISPATCH)
+	{
+	  tree c = omp_find_clause (ctx->clauses, OMP_CLAUSE_NOVARIANTS);
+	  if (c != NULL_TREE)
+	    {
+	      if (integer_nonzerop (OMP_CLAUSE_NOVARIANTS_EXPR (c)))
+		return 1;
+	      else if (integer_zerop (OMP_CLAUSE_NOVARIANTS_EXPR (c)))
+		return 0;
+	      else
+		return -1;
+	    }
+	  return 0;
+	}
+    }
+  return 0;
+}
+
+/* Try to evaluate a nocontext clause. Return 1 if true, 0 if false or absent,
+ * -1 if run-time evaluation is needed. */
+
+int
+omp_has_nocontext (void)
+{
+  for (struct gimplify_omp_ctx *ctx = gimplify_omp_ctxp; ctx;
+       ctx = ctx->outer_context)
+    {
+      if (ctx->code == OMP_DISPATCH)
+	{
+	    tree c = omp_find_clause (ctx->clauses, OMP_CLAUSE_NOCONTEXT);
+	    if (c != NULL_TREE)
+	    {
+	      if (integer_nonzerop (OMP_CLAUSE_NOCONTEXT_EXPR (c)))
+		return 1;
+	      else if (integer_zerop (OMP_CLAUSE_NOCONTEXT_EXPR (c)))
+		return 0;
+	      else
+		return -1;
+	    }
+	    return 0;
+	}
+    }
+  return 0;
+}
+
 /* Gimplify OACC_CACHE.  */
 
 static void
@@ -17614,6 +17795,221 @@  gimplify_omp_ordered (tree expr, gimple_seq body)
   return gimple_build_omp_ordered (body, OMP_ORDERED_CLAUSES (expr));
 }
 
+/* Gimplify an OMP_DISPATCH construct.  */
+
+static enum gimplify_status
+gimplify_omp_dispatch (tree *expr_p, gimple_seq *pre_p)
+{
+  tree expr = *expr_p;
+  gimple_seq body = NULL;
+
+  gimplify_scan_omp_clauses (&OMP_DISPATCH_CLAUSES (expr), pre_p, ORT_DISPATCH,
+			     OMP_DISPATCH);
+  push_gimplify_context ();
+
+  // If device clause, adjust ICV
+  tree device
+    = omp_find_clause (OMP_DISPATCH_CLAUSES (expr), OMP_CLAUSE_DEVICE);
+  if (device)
+    {
+      tree t = builtin_decl_explicit (BUILT_IN_OMP_SET_DEFAULT_DEVICE);
+      t = build_call_expr_loc (input_location, t, 1,
+			       OMP_CLAUSE_DEVICE_ID (device));
+      gimplify_and_add (t, &body);
+      if (DECL_P (OMP_CLAUSE_DEVICE_ID (device)))
+	omp_notice_variable (gimplify_omp_ctxp, OMP_CLAUSE_DEVICE_ID (device),
+			     true);
+    }
+
+  // If the novariants and nocontext clauses are not compile-time constants,
+  // we need to generate code for all possible cases:
+  //   if (novariants) // implies nocontext
+  //       base()
+  //   else if (nocontext)
+  //       variant1()
+  //   else
+  //       variant2()
+  tree dispatch_body = OMP_DISPATCH_BODY (expr);
+  if (TREE_CODE (dispatch_body) == BIND_EXPR)
+    dispatch_body = BIND_EXPR_BODY (dispatch_body);
+  if (TREE_CODE (dispatch_body) == STATEMENT_LIST)
+    {
+      // Fortran FE may insert some pre-call code, for instance when an
+      // array is passed as argument. Skip to the actual call.
+      dispatch_body = expr_last (dispatch_body);
+    }
+  gcc_assert (TREE_CODE (dispatch_body) == CALL_EXPR
+	      || TREE_CODE (dispatch_body) == MODIFY_EXPR);
+  tree base_call_expr = dispatch_body;
+  tree dst;
+  if (TREE_CODE (base_call_expr) == MODIFY_EXPR)
+    {
+      dst = TREE_OPERAND (base_call_expr, 0);
+      base_call_expr = TREE_OPERAND (base_call_expr, 1);
+      while (TREE_CODE (base_call_expr) == FLOAT_EXPR
+	     || TREE_CODE (base_call_expr) == CONVERT_EXPR
+	     || TREE_CODE (base_call_expr) == COMPLEX_EXPR)
+	base_call_expr = TREE_OPERAND (base_call_expr, 0);
+    }
+
+  tree base_fndecl = get_callee_fndecl (STRIP_NOPS (base_call_expr));
+  if (base_fndecl != NULL_TREE)
+    {
+      if (DECL_VIRTUAL_P (base_fndecl))
+	{
+	  error_at (
+	    EXPR_LOCATION (base_call_expr),
+	    "%qD is a virtual function but only a direct call is allowed "
+	    "in a dispatch construct",
+	    DECL_NAME (base_fndecl));
+	}
+
+      tree variant_fndecl = omp_resolve_declare_variant (base_fndecl);
+      if (base_fndecl != variant_fndecl
+	  && (omp_has_novariants () == -1 || omp_has_nocontext () == -1))
+	{
+	  tree novariants_clause = NULL_TREE, nocontext_clause = NULL_TREE,
+	       novariants_cond = NULL_TREE, nocontext_cond = NULL_TREE;
+	  for (tree c = OMP_DISPATCH_CLAUSES (expr); c; c = TREE_CHAIN (c))
+	    {
+	      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_NOVARIANTS)
+		{
+		  gcc_assert (novariants_cond == NULL_TREE);
+		  novariants_clause = c;
+		  novariants_cond = OMP_CLAUSE_NOVARIANTS_EXPR (c);
+		}
+	      else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_NOCONTEXT)
+		{
+		  gcc_assert (nocontext_cond == NULL_TREE);
+		  nocontext_clause = c;
+		  nocontext_cond = OMP_CLAUSE_NOCONTEXT_EXPR (c);
+		}
+	    }
+	  gcc_assert (novariants_cond != NULL_TREE
+		      || nocontext_cond != NULL_TREE);
+
+	  enum gimplify_status ret
+	    = gimplify_expr (&novariants_cond, &body, NULL, is_gimple_val,
+			     fb_rvalue);
+	  if (ret == GS_ERROR || ret == GS_UNHANDLED)
+	    return ret;
+	  ret = gimplify_expr (&nocontext_cond, &body, NULL, is_gimple_val,
+			       fb_rvalue);
+	  if (ret == GS_ERROR || ret == GS_UNHANDLED)
+	    return ret;
+
+	  tree base_label = create_artificial_label (UNKNOWN_LOCATION);
+	  tree variant1_label = create_artificial_label (UNKNOWN_LOCATION);
+	  tree cond_label = create_artificial_label (UNKNOWN_LOCATION);
+	  tree variant2_label = create_artificial_label (UNKNOWN_LOCATION);
+	  tree end_label = create_artificial_label (UNKNOWN_LOCATION);
+
+	  if (novariants_cond != NULL_TREE)
+	    {
+	      gcond *novariants_cond_stmt
+		= gimple_build_cond_from_tree (novariants_cond, base_label,
+					       cond_label);
+	      gimplify_seq_add_stmt (&body, novariants_cond_stmt);
+
+	      gimplify_seq_add_stmt (&body, gimple_build_label (base_label));
+	      tree base_call_expr2 = copy_node (base_call_expr);
+	      if (TREE_CODE (dispatch_body) == MODIFY_EXPR)
+		{
+		  base_call_expr2 = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst,
+					    base_call_expr2);
+		}
+	      OMP_CLAUSE_NOVARIANTS_EXPR (novariants_clause)
+		= boolean_true_node;
+	      gimplify_and_add (base_call_expr2, &body);
+	      gimplify_seq_add_stmt (&body, gimple_build_goto (end_label));
+
+	      OMP_CLAUSE_NOVARIANTS_EXPR (novariants_clause)
+		= boolean_false_node;
+	    }
+
+	  gimplify_seq_add_stmt (&body, gimple_build_label (cond_label));
+	  if (nocontext_cond != NULL_TREE)
+	    {
+	      gcond *nocontext_cond_stmt
+		= gimple_build_cond_from_tree (nocontext_cond, variant1_label,
+					       variant2_label);
+	      gimplify_seq_add_stmt (&body, nocontext_cond_stmt);
+
+	      gimplify_seq_add_stmt (&body,
+				     gimple_build_label (variant1_label));
+	      tree variant_call_expr = copy_node (base_call_expr);
+	      if (TREE_CODE (dispatch_body) == MODIFY_EXPR)
+		{
+		  variant_call_expr = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst,
+					      variant_call_expr);
+		}
+	      OMP_CLAUSE_NOCONTEXT_EXPR (nocontext_clause) = boolean_true_node;
+	      gimplify_and_add (variant_call_expr, &body);
+	      gimplify_seq_add_stmt (&body, gimple_build_goto (end_label));
+	      OMP_CLAUSE_NOCONTEXT_EXPR (nocontext_clause) = boolean_false_node;
+	    }
+
+	  gimplify_seq_add_stmt (&body, gimple_build_label (variant2_label));
+	  tree variant_call_expr = copy_node (base_call_expr);
+	  if (TREE_CODE (dispatch_body) == MODIFY_EXPR)
+	    {
+	      variant_call_expr
+		= build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, variant_call_expr);
+	    }
+	  gimplify_and_add (variant_call_expr, &body);
+	  gimplify_seq_add_stmt (&body, gimple_build_goto (end_label));
+	  gimplify_seq_add_stmt (&body, gimple_build_label (end_label));
+	}
+      else
+	gimplify_and_add (OMP_DISPATCH_BODY (expr), &body);
+    }
+  else
+    gimplify_and_add (OMP_DISPATCH_BODY (expr), &body);
+
+  // Wrap dispatch body into a bind
+  gimple *bind = gimple_build_bind (NULL_TREE, body, NULL_TREE);
+  pop_gimplify_context (bind);
+
+  gimplify_adjust_omp_clauses (pre_p, bind, &OMP_DISPATCH_CLAUSES (expr),
+			       OMP_DISPATCH);
+
+  // Move relevant clauses to the task construct
+  tree task_clauses = NULL_TREE;
+  tree *task_clauses_ptr = &task_clauses;
+  bool has_nowait = false;
+  for (tree c = OMP_DISPATCH_CLAUSES (expr); c; c = OMP_CLAUSE_CHAIN (c))
+    {
+      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SHARED
+	  || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_DEPEND)
+	{
+	  *task_clauses_ptr = c;
+	  task_clauses_ptr = &OMP_CLAUSE_CHAIN (c);
+	}
+      else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_IS_DEVICE_PTR)
+	{
+	  *task_clauses_ptr
+	    = build_omp_clause (input_location, OMP_CLAUSE_SHARED);
+	  OMP_CLAUSE_DECL (*task_clauses_ptr) = OMP_CLAUSE_DECL (c);
+	  task_clauses_ptr = &OMP_CLAUSE_CHAIN (*task_clauses_ptr);
+	}
+      else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_NOWAIT)
+	has_nowait = true;
+    }
+  *task_clauses_ptr = build_omp_clause (input_location, OMP_CLAUSE_IF);
+  OMP_CLAUSE_IF_EXPR (*task_clauses_ptr)
+    = has_nowait ? boolean_true_node : boolean_false_node;
+
+  // Wrap bind into a task
+  gimple *task
+    = gimple_build_omp_task (bind, task_clauses, NULL_TREE, NULL_TREE,
+			     NULL_TREE, NULL_TREE, NULL_TREE);
+
+  gimple *stmt = gimple_build_omp_dispatch (task, OMP_DISPATCH_CLAUSES (expr));
+  gimplify_seq_add_stmt (pre_p, stmt);
+  *expr_p = NULL_TREE;
+  return GS_ALL_DONE;
+}
+
 /* Convert the GENERIC expression tree *EXPR_P to GIMPLE.  If the
    expression produces a value to be used as an operand inside a GIMPLE
    statement, the value will be stored back in *EXPR_P.  This value will
@@ -18540,6 +18936,10 @@  gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 	  ret = gimplify_omp_atomic (expr_p, pre_p);
 	  break;
 
+	case OMP_DISPATCH:
+	  ret = gimplify_omp_dispatch (expr_p, pre_p);
+	  break;
+
 	case TRANSACTION_EXPR:
 	  ret = gimplify_transaction (expr_p, pre_p);
 	  break;
@@ -18865,7 +19265,8 @@  gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
 		  && code != OMP_SECTION
 		  && code != OMP_STRUCTURED_BLOCK
 		  && code != OMP_SINGLE
-		  && code != OMP_SCOPE);
+		  && code != OMP_SCOPE
+		  && code != OMP_DISPATCH);
     }
 #endif
 
diff --git a/gcc/gimplify.h b/gcc/gimplify.h
index ac3cc8eb552..55aece2b65b 100644
--- a/gcc/gimplify.h
+++ b/gcc/gimplify.h
@@ -77,6 +77,8 @@  extern enum gimplify_status gimplify_expr (tree *, gimple_seq *, gimple_seq *,
 					   bool (*) (tree), fallback_t);
 
 int omp_construct_selector_matches (enum tree_code *, int, int *);
+int omp_has_novariants (void);
+int omp_has_nocontext (void);
 
 extern void gimplify_type_sizes (tree, gimple_seq *);
 extern void gimplify_one_sizepos (tree *, gimple_seq *);
diff --git a/gcc/omp-builtins.def b/gcc/omp-builtins.def
index 044d5d087b6..c83edabbcc3 100644
--- a/gcc/omp-builtins.def
+++ b/gcc/omp-builtins.def
@@ -76,6 +76,12 @@  DEF_GOMP_BUILTIN (BUILT_IN_OMP_GET_TEAM_NUM, "omp_get_team_num",
 		  BT_FN_INT, ATTR_CONST_NOTHROW_LEAF_LIST)
 DEF_GOMP_BUILTIN (BUILT_IN_OMP_GET_NUM_TEAMS, "omp_get_num_teams",
 		  BT_FN_INT, ATTR_CONST_NOTHROW_LEAF_LIST)
+DEF_GOMP_BUILTIN (BUILT_IN_OMP_GET_MAPPED_PTR, "omp_get_mapped_ptr",
+		  BT_FN_PTR_CONST_PTR_INT, ATTR_NOTHROW_LEAF_LIST)
+DEF_GOMP_BUILTIN (BUILT_IN_OMP_GET_DEFAULT_DEVICE, "omp_get_default_device",
+		  BT_FN_INT, ATTR_NOTHROW_LEAF_LIST)
+DEF_GOMP_BUILTIN (BUILT_IN_OMP_SET_DEFAULT_DEVICE, "omp_set_default_device",
+		  BT_FN_INT, ATTR_NOTHROW_LEAF_LIST)
 
 DEF_GOMP_BUILTIN (BUILT_IN_GOMP_ATOMIC_START, "GOMP_atomic_start",
 		  BT_FN_VOID, ATTR_NOTHROW_LEAF_LIST)
diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc
index 24287826444..6fa372a550b 100644
--- a/gcc/omp-expand.cc
+++ b/gcc/omp-expand.cc
@@ -8636,6 +8636,19 @@  expand_omp_single (struct omp_region *region)
   single_succ_edge (exit_bb)->flags = EDGE_FALLTHRU;
 }
 
+/* Expand code for an OpenMP dispatch directive...  */
+
+static void
+expand_omp_dispatch (struct omp_region *region)
+{
+  basic_block entry_bb = region->entry;
+  gimple_stmt_iterator si = gsi_last_nondebug_bb (entry_bb);
+  enum gimple_code code = gimple_code (gsi_stmt (si));
+  gcc_assert (code == GIMPLE_OMP_DISPATCH);
+  gsi_remove (&si, true);
+  single_succ_edge (entry_bb)->flags = EDGE_FALLTHRU;
+}
+
 /* Generic expansion for OpenMP synchronization directives: master,
    ordered and critical.  All we need to do here is remove the entry
    and exit markers for REGION.  */
@@ -10654,6 +10667,10 @@  expand_omp (struct omp_region *region)
 	  expand_omp_single (region);
 	  break;
 
+	case GIMPLE_OMP_DISPATCH:
+	  expand_omp_dispatch (region);
+	  break;
+
 	case GIMPLE_OMP_ORDERED:
 	  {
 	    gomp_ordered *ord_stmt
@@ -11001,6 +11018,7 @@  omp_make_gimple_edges (basic_block bb, struct omp_region **region,
     case GIMPLE_OMP_MASTER:
     case GIMPLE_OMP_MASKED:
     case GIMPLE_OMP_SCOPE:
+    case GIMPLE_OMP_DISPATCH:
     case GIMPLE_OMP_CRITICAL:
     case GIMPLE_OMP_SECTION:
       cur_region = new_omp_region (bb, code, cur_region);
diff --git a/gcc/omp-general.cc b/gcc/omp-general.cc
index 2c095200d5b..d585df400d1 100644
--- a/gcc/omp-general.cc
+++ b/gcc/omp-general.cc
@@ -1037,7 +1037,7 @@  omp_construct_traits_to_codes (tree ctx, int nconstructs,
   /* Order must match the OMP_TRAIT_CONSTRUCT_* enumerators in
      enum omp_ts_code.  */
   static enum tree_code code_map[]
-    = { OMP_TARGET, OMP_TEAMS, OMP_PARALLEL, OMP_FOR, OMP_SIMD };
+    = { OMP_TARGET, OMP_TEAMS, OMP_PARALLEL, OMP_FOR, OMP_SIMD, OMP_DISPATCH };
 
   for (tree ts = ctx; ts; ts = TREE_CHAIN (ts), i--)
     {
@@ -1130,6 +1130,7 @@  const char *omp_tss_map[] =
    "target_device",
    "implementation",
    "user",
+   "need_device_ptr",
    NULL
 };
 
@@ -1236,10 +1237,14 @@  struct omp_ts_info omp_ts_map[] =
      OMP_TRAIT_PROPERTY_CLAUSE_LIST,  false,
      NULL
    },
+   { "dispatch",
+     (1 << OMP_TRAIT_SET_CONSTRUCT),
+     OMP_TRAIT_PROPERTY_NONE,  false,
+     NULL
+   },
    { NULL, 0, OMP_TRAIT_PROPERTY_NONE, false, NULL }  /* OMP_TRAIT_LAST */
   };
 
-
 /* Return a name from PROP, a property in selectors accepting
    name lists.  */
 
@@ -1445,6 +1450,8 @@  omp_context_selector_matches (tree ctx)
   for (tree tss = ctx; tss; tss = TREE_CHAIN (tss))
     {
       enum omp_tss_code set = OMP_TSS_CODE (tss);
+      if (set == OMP_TRAIT_SET_NEED_DEVICE_PTR)
+	continue;
       tree selectors = OMP_TSS_TRAIT_SELECTORS (tss);
 
       /* Immediately reject the match if there are any ignored
@@ -2484,6 +2491,9 @@  omp_resolve_declare_variant (tree base)
   if (cfun && (cfun->curr_properties & PROP_gimple_any) != 0)
     return omp_resolve_late_declare_variant (base);
 
+  if (omp_has_novariants () == 1)
+    return base;
+
   auto_vec <tree, 16> variants;
   auto_vec <bool, 16> defer;
   bool any_deferred = false;
@@ -2630,6 +2640,8 @@  omp_resolve_declare_variant (tree base)
       (*slot)->variants = entry.variants;
       tree alt = build_decl (DECL_SOURCE_LOCATION (base), FUNCTION_DECL,
 			     DECL_NAME (base), TREE_TYPE (base));
+      if (DECL_ASSEMBLER_NAME_SET_P (base))
+	SET_DECL_ASSEMBLER_NAME (alt, DECL_ASSEMBLER_NAME (base));
       DECL_ARTIFICIAL (alt) = 1;
       DECL_IGNORED_P (alt) = 1;
       TREE_STATIC (alt) = 1;
diff --git a/gcc/omp-low.cc b/gcc/omp-low.cc
index 4d003f42098..693d8ca7d8d 100644
--- a/gcc/omp-low.cc
+++ b/gcc/omp-low.cc
@@ -4185,6 +4185,11 @@  scan_omp_1_stmt (gimple_stmt_iterator *gsi, bool *handled_ops_p,
       scan_omp (gimple_omp_body_ptr (stmt), ctx);
       break;
 
+    case GIMPLE_OMP_DISPATCH:
+      ctx = new_omp_context (stmt, ctx);
+      scan_omp (gimple_omp_body_ptr (stmt), ctx);
+      break;
+
     case GIMPLE_OMP_SECTIONS:
       scan_omp_sections (as_a <gomp_sections *> (stmt), ctx);
       break;
@@ -8926,6 +8931,31 @@  lower_omp_scope (gimple_stmt_iterator *gsi_p, omp_context *ctx)
   if (BLOCK_VARS (block))
     TREE_USED (block) = 1;
 }
+
+/* Lower code for an OMP dispatch directive.  */
+
+static void
+lower_omp_dispatch (gimple_stmt_iterator *gsi_p, omp_context *ctx)
+{
+  tree block;
+  gimple *stmt = gsi_stmt (*gsi_p);
+  gbind *bind;
+
+  push_gimplify_context ();
+
+  block = make_node (BLOCK);
+  bind = gimple_build_bind (NULL, NULL, block);
+  gsi_replace (gsi_p, bind, true);
+
+  lower_omp (gimple_omp_body_ptr (stmt), ctx);
+  gimple_bind_set_body (bind, maybe_catch_exception (gimple_omp_body (stmt)));
+
+  pop_gimplify_context (bind);
+
+  gimple_bind_append_vars (bind, ctx->block_vars);
+  BLOCK_VARS (block) = ctx->block_vars;
+}
+
 /* Expand code for an OpenMP master or masked directive.  */
 
 static void
@@ -14399,6 +14429,11 @@  lower_omp_1 (gimple_stmt_iterator *gsi_p, omp_context *ctx)
       gcc_assert (ctx);
       lower_omp_scope (gsi_p, ctx);
       break;
+    case GIMPLE_OMP_DISPATCH:
+      ctx = maybe_lookup_ctx (stmt);
+      gcc_assert (ctx);
+      lower_omp_dispatch (gsi_p, ctx);
+      break;
     case GIMPLE_OMP_SINGLE:
       ctx = maybe_lookup_ctx (stmt);
       gcc_assert (ctx);
diff --git a/gcc/tree-inline.cc b/gcc/tree-inline.cc
index f31a34ac410..2e06b706025 100644
--- a/gcc/tree-inline.cc
+++ b/gcc/tree-inline.cc
@@ -1679,6 +1679,12 @@  remap_gimple_stmt (gimple *stmt, copy_body_data *id)
 		   (s1, gimple_omp_scope_clauses (stmt));
 	  break;
 
+	case GIMPLE_OMP_DISPATCH:
+	  s1 = remap_gimple_seq (gimple_omp_body (stmt), id);
+	  copy = gimple_build_omp_dispatch (s1,
+					    gimple_omp_dispatch_clauses (stmt));
+	  break;
+
 	case GIMPLE_OMP_TASKGROUP:
 	  s1 = remap_gimple_seq (gimple_omp_body (stmt), id);
 	  copy = gimple_build_omp_taskgroup
@@ -4609,6 +4615,7 @@  estimate_num_insns (gimple *stmt, eni_weights *weights)
     case GIMPLE_OMP_MASTER:
     case GIMPLE_OMP_MASKED:
     case GIMPLE_OMP_SCOPE:
+    case GIMPLE_OMP_DISPATCH:
     case GIMPLE_OMP_TASKGROUP:
     case GIMPLE_OMP_ORDERED:
     case GIMPLE_OMP_SCAN: