[gcc r13-1454] Use default lower bound for vector types in debug info

[gcc r13-1454] Use default lower bound for vector types in debug info

[Eric Botcazou]

https://gcc.gnu.org/g:483bd9a02831d9cb615179e5758946f41622d6c9

commit r13-1454-g483bd9a02831d9cb615179e5758946f41622d6c9
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Mon Jul 4 12:14:03 2022 +0200

    Use default lower bound for vector types in debug info
    
    Vector types are represented as array types with DW_AT_GNU_vector attribute
    in the debug info and a range [0 .. TYPE_VECTOR_SUBPARTS - 1].  Now that's
    obviously skewed toward the C family of languages, therefore the attached
    patch changes the lower bound to the default for the language of the CU.
    
    gcc/
            * dwarf2out.cc (gen_array_type_die): Use the default lower bound of
            the language for vector types.

Diff:
---
 gcc/dwarf2out.cc | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index b468a4b9c0f..e3920c898f5 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -22539,11 +22539,14 @@ gen_array_type_die (tree type, dw_die_ref context_die)
 
   if (TREE_CODE (type) == VECTOR_TYPE)
     {
-      /* For VECTOR_TYPEs we use an array die with appropriate bounds.  */
+      /* For VECTOR_TYPEs we use an array DIE with appropriate bounds.  */
       dw_die_ref subrange_die = new_die (DW_TAG_subrange_type, array_die, NULL);
-      add_bound_info (subrange_die, DW_AT_lower_bound, size_zero_node, NULL);
+      int lb = lower_bound_default ();
+      if (lb == -1)
+	lb = 0;
+      add_bound_info (subrange_die, DW_AT_lower_bound, size_int (lb), NULL);
       add_bound_info (subrange_die, DW_AT_upper_bound,
-		      size_int (TYPE_VECTOR_SUBPARTS (type) - 1), NULL);
+		      size_int (lb + TYPE_VECTOR_SUBPARTS (type) - 1), NULL);
     }
   else
     add_subscript_info (array_die, type, collapse_nested_arrays);