[PATCH, OpenACC, 3/8] Multi-dimensional dynamic array support for OpenACC data clauses, gimplify patch

This gimplify.c patch adds to the omp clause scanning to handle dynamic array
cases, mainly to properly handle dimension biases of GOMP_MAP_DYNAMIC_ARRAYs by
making sure the bias field is seen in the omp-ctx.

Thanks,
Chung-Lin

        gcc/
        * gimplify.c (gimplify_scan_omp_clauses): For dynamic array map kinds,
        make sure bias in each dimension are put into firstprivate variables.

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 781d430..09ef876 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -7901,8 +7901,28 @@ gimplify_scan_omp_clauses (tree *list_p, gimple_seq 
*pre_p,
          if (OMP_CLAUSE_SIZE (c) == NULL_TREE)
            OMP_CLAUSE_SIZE (c) = DECL_P (decl) ? DECL_SIZE_UNIT (decl)
                                  : TYPE_SIZE_UNIT (TREE_TYPE (decl));
-         if (gimplify_expr (&OMP_CLAUSE_SIZE (c), pre_p,
-                            NULL, is_gimple_val, fb_rvalue) == GS_ERROR)
+         if (OMP_CLAUSE_SIZE (c)
+             && TREE_CODE (OMP_CLAUSE_SIZE (c)) == TREE_LIST
+             && GOMP_MAP_DYNAMIC_ARRAY_P (OMP_CLAUSE_MAP_KIND (c)))
+           {
+             tree dims = OMP_CLAUSE_SIZE (c);
+             for (tree t = dims; t; t = TREE_CHAIN (t))
+               {
+                 /* If a dimension bias isn't a constant, we have to ensure
+                    that the value gets transferred to the offload target.  */
+                 tree low_bound = TREE_PURPOSE (t);
+                 if (TREE_CODE (low_bound) != INTEGER_CST)
+                   {
+                     low_bound = get_initialized_tmp_var (low_bound, pre_p,
+                                                          NULL, false);
+                     omp_add_variable (ctx, low_bound,
+                                       GOVD_FIRSTPRIVATE | GOVD_SEEN);
+                     TREE_PURPOSE (t) = low_bound;
+                   }
+               }
+           }
+         else if (gimplify_expr (&OMP_CLAUSE_SIZE (c), pre_p,
+                                 NULL, is_gimple_val, fb_rvalue) == GS_ERROR)
            {
              remove = true;
              break;