http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50294
--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-09-05
14:06:57 UTC ---
Index: gcc/varasm.c
===================================================================
--- gcc/varasm.c (revision 178527)
+++ gcc/varasm.c (working copy)
@@ -4746,9 +4746,13 @@ output_constructor_regular_field (oc_loc
if (local->index != NULL_TREE)
{
+ /* Perform the index calculation in modulo arithmetic but
+ sign-extend the result because Ada has negative DECL_FIELD_OFFSETs
+ but we are using an unsigned sizetype. */
+ unsigned prec = TYPE_PRECISION (sizetype);
double_int idx = double_int_sub (tree_to_double_int (local->index),
tree_to_double_int (local->min_index));
- gcc_assert (double_int_fits_in_shwi_p (idx));
+ idx = double_int_sext (idx, prec);
fieldpos = (tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (local->val)), 1)
* idx.low);
}
fixes this, but loses the check for index - min_index overflowing a HWI
(arguably that should have been detected earlier in the FEs). Fact is
we lose information when forcing offsets / indices to an unsigned type.
