[Patch, fortran] [13/21] Remove coarray support in the scalarizer: Add specific walk_coarray function.

[Mikael Morin]

We have two contradictory needs: 
we want to make gfc_walk_expr free of coarray hacks as much as possible,
we want to have a gfc_ss generated for scalar coarrays suitable for
gfc_conv_expr_descriptor.

This patch creates a wrapper around gfc_walk_expr, so that in the scalar case
(i.e. value returned is gfc_ss_terminator) we generate the needed gfc_ss struct.

The new function includes at the same time the code (made slightly more
assertive) previously present in convert_element_to_coarray_ref.

OK?

Note: I haven't understood why walk_coarray is needed in the intrinsic case, 
but not in the general function call case (cf also my comment about patch 6).
On the other hand, it was also the case for the convert_element_to_coarray_ref
function before the patch.

Note2: This patch may need some adjustments to fix PR50420.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50420

2011-09-14  Mikael Morin  <mikael.mo...@sfr.fr>

        * trans-intrinsic.c (walk_coarray): New function.
        (convert_element_to_coarray_ref): Move code to walk_coarray. Remove.
        (trans-this_image, trans_image_index, conv_intrinsic_cobound):
        Use walk_coarray.

diff --git a/trans-intrinsic.c b/trans-intrinsic.c
index c216873..bc21b02 100644
--- a/trans-intrinsic.c
+++ b/trans-intrinsic.c
@@ -924,18 +924,32 @@ gfc_conv_intrinsic_exponent (gfc_se *se, gfc_expr *expr)
 /* Convert the last ref of a scalar coarray from an AR_ELEMENT to an
    AR_FULL, suitable for the scalarizer.  */
 
-static void
-convert_element_to_coarray_ref (gfc_expr *expr)
+static gfc_ss *
+walk_coarray (gfc_expr *e)
 {
-  gfc_ref *ref;
+  gfc_ss *ss;
 
-  for (ref = expr->ref; ref; ref = ref->next)
-    if (ref->type == REF_ARRAY && ref->next == NULL
-	&& ref->u.ar.codimen)
-      {
-	ref->u.ar.type = AR_FULL;
-	break;
-      }
+  gcc_assert (gfc_get_corank (e) > 0);
+
+  ss = gfc_walk_expr (e);
+
+  /* Fix scalar coarray.  */
+  if (ss == gfc_ss_terminator)
+    {
+      gfc_ref *ref;
+
+      ss = gfc_get_array_ss (gfc_ss_terminator, e, 0, GFC_SS_SECTION);
+
+      ref = e->ref;
+      while (ref->next)
+	ref = ref->next;
+
+      gcc_assert (ref->type == REF_ARRAY && ref->u.ar.codimen > 0);
+      ref->u.ar.type = AR_FULL;
+      ss->data.info.ref = ref;
+    }
+
+  return ss;
 }
 
 
@@ -969,9 +983,7 @@ trans_this_image (gfc_se * se, gfc_expr *expr)
 
   /* Obtain the descriptor of the COARRAY.  */
   gfc_init_se (&argse, NULL);
-  if (expr->value.function.actual->expr->rank == 0)
-    convert_element_to_coarray_ref (expr->value.function.actual->expr);
-  ss = gfc_walk_expr (expr->value.function.actual->expr);
+  ss = walk_coarray (expr->value.function.actual->expr);
   gcc_assert (ss != gfc_ss_terminator);
   ss->data.info.codimen = corank;
   argse.want_coarray = 1;
@@ -1157,9 +1169,7 @@ trans_image_index (gfc_se * se, gfc_expr *expr)
 
   /* Obtain the descriptor of the COARRAY.  */
   gfc_init_se (&argse, NULL);
-  if (expr->value.function.actual->expr->rank == 0)
-    convert_element_to_coarray_ref (expr->value.function.actual->expr);
-  ss = gfc_walk_expr (expr->value.function.actual->expr);
+  ss = walk_coarray (expr->value.function.actual->expr);
   gcc_assert (ss != gfc_ss_terminator);
   ss->data.info.codimen = corank;
   argse.want_coarray = 1;
@@ -1484,9 +1494,7 @@ conv_intrinsic_cobound (gfc_se * se, gfc_expr * expr)
   gcc_assert (arg->expr->expr_type == EXPR_VARIABLE);
   corank = gfc_get_corank (arg->expr);
 
-  if (expr->value.function.actual->expr->rank == 0)
-    convert_element_to_coarray_ref (expr->value.function.actual->expr);
-  ss = gfc_walk_expr (arg->expr);
+  ss = walk_coarray (arg->expr);
   gcc_assert (ss != gfc_ss_terminator);
   ss->data.info.codimen = corank;
   gfc_init_se (&argse, NULL);