[COMMITTED] ada: Add missing guards for degenerate storage models

[Marc Poulhiès via Gcc-patches]

From: Eric Botcazou <ebotca...@adacore.com>

gcc/ada/

        * gcc-interface/trans.cc (Attribute_to_gnu) <Attr_Size>: Check that
        the storage model has Copy_From before instantiating loads for it.
        <Attr_Length>: Likewise.
        <Attr_Bit_Position>: Likewise.
        (gnat_to_gnu) <N_Indexed_Component>: Likewise.
        <N_Slice>: Likewise.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/gcc-interface/trans.cc | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/gcc/ada/gcc-interface/trans.cc b/gcc/ada/gcc-interface/trans.cc
index 57933ceb8a3..18f7e73d45d 100644
--- a/gcc/ada/gcc-interface/trans.cc
+++ b/gcc/ada/gcc-interface/trans.cc
@@ -1978,7 +1978,8 @@ Attribute_to_gnu (Node_Id gnat_node, tree 
*gnu_result_type_p, int attribute)
       if (TREE_CODE (gnu_prefix) != TYPE_DECL)
        {
          gnu_result = SUBSTITUTE_PLACEHOLDER_IN_EXPR (gnu_result, gnu_prefix);
-         if (Present (gnat_smo))
+         if (Present (gnat_smo)
+             && Present (Storage_Model_Copy_From (gnat_smo)))
            gnu_result = INSTANTIATE_LOAD_IN_EXPR (gnu_result, gnat_smo);
        }
       else if (CONTAINS_PLACEHOLDER_P (gnu_result))
@@ -2211,7 +2212,8 @@ Attribute_to_gnu (Node_Id gnat_node, tree 
*gnu_result_type_p, int attribute)
           handling.  Note that these attributes could not have been used on
           an unconstrained array type.  */
        gnu_result = SUBSTITUTE_PLACEHOLDER_IN_EXPR (gnu_result, gnu_prefix);
-       if (Present (gnat_smo))
+       if (Present (gnat_smo)
+           && Present (Storage_Model_Copy_From (gnat_smo)))
          gnu_result = INSTANTIATE_LOAD_IN_EXPR (gnu_result, gnat_smo);
 
        /* Cache the expression we have just computed.  Since we want to do it
@@ -2373,7 +2375,8 @@ Attribute_to_gnu (Node_Id gnat_node, tree 
*gnu_result_type_p, int attribute)
        /* If this has a PLACEHOLDER_EXPR, qualify it by the object we are
           handling.  */
        gnu_result = SUBSTITUTE_PLACEHOLDER_IN_EXPR (gnu_result, gnu_prefix);
-       if (Present (gnat_smo))
+       if (Present (gnat_smo)
+           && Present (Storage_Model_Copy_From (gnat_smo)))
          gnu_result = INSTANTIATE_LOAD_IN_EXPR (gnu_result, gnat_smo);
        break;
       }
@@ -6701,7 +6704,8 @@ gnat_to_gnu (Node_Id gnat_node)
            gnu_result
              = build_binary_op (ARRAY_REF, NULL_TREE, gnu_result, gnu_expr);
 
-           if (Present (gnat_smo))
+           if (Present (gnat_smo)
+               && Present (Storage_Model_Copy_From (gnat_smo)))
              instantiate_load_in_array_ref (gnu_result, gnat_smo);
          }
 
@@ -6746,7 +6750,8 @@ gnat_to_gnu (Node_Id gnat_node)
        gnu_result = build_binary_op (ARRAY_RANGE_REF, gnu_result_type,
                                      gnu_array_object, gnu_expr);
 
-       if (Present (gnat_smo))
+       if (Present (gnat_smo)
+           && Present (Storage_Model_Copy_From (gnat_smo)))
          instantiate_load_in_array_ref (gnu_result, gnat_smo);
 
        /* If storage model access is required on the RHS, build the load.  */
-- 
2.40.0