Allow optional arguments to be used in the use_device OpenACC clause

Optional arguments should be treated as references rather than pointers
in the lowering.  However, for non-present arguments, this would result
in a null dereference, so conditionals need to be added to detect and
handle this.

	gcc/
	* omp-low.c (lower_omp_target): For use_device clauses, generate
	conditional statements to treat Fortran optional arguments like
	references if non-null, or propogate null arguments into offloaded
	code otherwise.

Reviewed-by: Julian Brown <julian@codesourcery.com>
(cherry picked from openacc-gcc-9-branch commit
4fba24cfbbd3738216a3551483744f82888741f3)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index 94da6334a7096ef085f5a43cce2e9418eaf6a72c..10138ae1b0008730f5cd8629c7e6e236b3035e4c 100644 (file)
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,10 @@
+2019-01-31  Kwok Cheung Yeung  <kcy@codesourcery.com>
+
+       * omp-low.c (lower_omp_target): For use_device clauses, generate
+       conditional statements to treat Fortran optional arguments like
+       references if non-null, or propogate null arguments into offloaded
+       code otherwise.
+
 2019-01-31  Kwok Cheung Yeung  <kcy@codesourcery.com>
 
        * omp-general.c (omp_is_optional_argument): Add comment.  Add extra

diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 919ffad565b92c108d509297a66740426fa6516c..1fd29e88ef93ff9c90efdb860b2fae5a0f8dfeb2 100644 (file)
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -10316,18 +10316,51 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
              tkind = GOMP_MAP_FIRSTPRIVATE_INT;
            type = TREE_TYPE (ovar);
            if (TREE_CODE (type) == ARRAY_TYPE)
-             var = build_fold_addr_expr (var);
+             {
+               var = build_fold_addr_expr (var);
+               gimplify_assign (x, var, &ilist);
+             }
            else
              {
-               if (omp_is_reference (ovar))
+               tree opt_arg_label;
+               bool optional_arg_p = omp_is_optional_argument (ovar);
+
+               if (optional_arg_p)
+                 {
+                   tree null_label
+                     = create_artificial_label (UNKNOWN_LOCATION);
+                   tree notnull_label
+                     = create_artificial_label (UNKNOWN_LOCATION);
+                   opt_arg_label
+                     = create_artificial_label (UNKNOWN_LOCATION);
+                   tree new_x = copy_node (x);
+                   gcond *cond = gimple_build_cond (EQ_EXPR, ovar,
+                                                    null_pointer_node,
+                                                    null_label,
+                                                    notnull_label);
+                   gimple_seq_add_stmt (&ilist, cond);
+                   gimple_seq_add_stmt (&ilist,
+                                        gimple_build_label (null_label));
+                   gimplify_assign (new_x, null_pointer_node, &ilist);
+                   gimple_seq_add_stmt (&ilist,
+                                        gimple_build_goto (opt_arg_label));
+                   gimple_seq_add_stmt (&ilist,
+                                        gimple_build_label (notnull_label));
+                 }
+
+               if (omp_is_reference (ovar) || optional_arg_p)
                  {
                    type = TREE_TYPE (type);
                    if (TREE_CODE (type) != ARRAY_TYPE)
                      var = build_simple_mem_ref (var);
                    var = fold_convert (TREE_TYPE (x), var);
                  }
+
+               gimplify_assign (x, var, &ilist);
+               if (optional_arg_p)
+                 gimple_seq_add_stmt (&ilist,
+                                      gimple_build_label (opt_arg_label));
              }
-           gimplify_assign (x, var, &ilist);
            s = size_int (0);
            purpose = size_int (map_idx++);
            CONSTRUCTOR_APPEND_ELT (vsize, purpose, s);
@@ -10509,11 +10542,43 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
              {
                tree type = TREE_TYPE (var);
                tree new_var = lookup_decl (var, ctx);
-               if (omp_is_reference (var))
+               tree opt_arg_label = NULL_TREE;
+
+               if (omp_is_reference (var) || omp_is_optional_argument (var))
                  {
                    type = TREE_TYPE (type);
                    if (TREE_CODE (type) != ARRAY_TYPE)
                      {
+                       if (omp_is_optional_argument (var))
+                         {
+                           tree null_label
+                             = create_artificial_label (UNKNOWN_LOCATION);
+                           tree notnull_label
+                             = create_artificial_label (UNKNOWN_LOCATION);
+                           opt_arg_label
+                             = create_artificial_label (UNKNOWN_LOCATION);
+                           glabel *null_glabel
+                             = gimple_build_label (null_label);
+                           glabel *notnull_glabel
+                             = gimple_build_label (notnull_label);
+                           ggoto *opt_arg_ggoto
+                             = gimple_build_goto (opt_arg_label);
+                           gcond *cond;
+
+                           gimplify_expr (&x, &new_body, NULL, is_gimple_val,
+                                          fb_rvalue);
+                           cond = gimple_build_cond (EQ_EXPR, x,
+                                                     null_pointer_node,
+                                                     null_label,
+                                                     notnull_label);
+                           gimple_seq_add_stmt (&new_body, cond);
+                           gimple_seq_add_stmt (&new_body, null_glabel);
+                           gimplify_assign (new_var, null_pointer_node,
+                                            &new_body);
+                           gimple_seq_add_stmt (&new_body, opt_arg_ggoto);
+                           gimple_seq_add_stmt (&new_body, notnull_glabel);
+                         }
+
                        tree v = create_tmp_var_raw (type, get_name (var));
                        gimple_add_tmp_var (v);
                        TREE_ADDRESSABLE (v) = 1;
@@ -10530,6 +10595,10 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
                gimplify_expr (&x, &new_body, NULL, is_gimple_val, fb_rvalue);
                gimple_seq_add_stmt (&new_body,
                                     gimple_build_assign (new_var, x));
+
+               if (opt_arg_label != NULL_TREE)
+                 gimple_seq_add_stmt (&new_body,
+                                      gimple_build_label (opt_arg_label));
              }
            break;
          }