http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58346
--- Comment #9 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
And to actually fix this bug, the following should be enough...
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -2940,7 +2940,8 @@ fold_array_ctor_reference (tree type, tree ctor,
be larger than size of array element. */
if (!TYPE_SIZE_UNIT (type)
|| TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
- || elt_size.slt (tree_to_double_int (TYPE_SIZE_UNIT (type))))
+ || elt_size.slt (tree_to_double_int (TYPE_SIZE_UNIT (type)))
+ || elt_size.is_zero ())
return NULL_TREE;
/* Compute the array index we look for. */
