Clarify gcc/gimplify.c:oacc_default_clause

	gcc/
	* gimplify.c (oacc_default_clause): Clarify.

From-SVN: r248279

gcc/ChangeLog

+2017-05-19  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* gimplify.c (oacc_default_clause): Clarify.
+
 2017-05-19  Nathan Sidwell  <nathan@acm.org>
 
 	LANG_HOOK_REGISTER_DUMPS

gcc/gimplify.c

@@ -6952,30 +6952,34 @@ oacc_default_clause (struct gimplify_omp_ctx *ctx, tree decl, unsigned flags)
 
   switch (ctx->region_type)
     {
-    default:
-      gcc_unreachable ();
-
     case ORT_ACC_KERNELS:
-      /* Scalars are default 'copy' under kernels, non-scalars are default
-	 'present_or_copy'.  */
-      flags |= GOVD_MAP;
-      if (!AGGREGATE_TYPE_P (type))
-	flags |= GOVD_MAP_FORCE;
-
       rkind = "kernels";
+
+      if (AGGREGATE_TYPE_P (type))
+	/* Aggregates default to 'present_or_copy'.  */
+	flags |= GOVD_MAP;
+      else
+	/* Scalars default to 'copy'.  */
+	flags |= GOVD_MAP | GOVD_MAP_FORCE;
+
       break;
 
     case ORT_ACC_PARALLEL:
-      {
-	if (on_device || AGGREGATE_TYPE_P (type) || declared)
-	  /* Aggregates default to 'present_or_copy'.  */
-	  flags |= GOVD_MAP;
-	else
-	  /* Scalars default to 'firstprivate'.  */
-	  flags |= GOVD_FIRSTPRIVATE;
-	rkind = "parallel";
-      }
+      rkind = "parallel";
+
+      if (on_device || declared)
+	flags |= GOVD_MAP;
+      else if (AGGREGATE_TYPE_P (type))
+	/* Aggregates default to 'present_or_copy'.  */
+	flags |= GOVD_MAP;
+      else
+	/* Scalars default to 'firstprivate'.  */
+	flags |= GOVD_FIRSTPRIVATE;
+
       break;
+
+    default:
+      gcc_unreachable ();
     }
 
   if (DECL_ARTIFICIAL (decl))