https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87868
--- Comment #2 from Jan Hubicka <hubicka at ucw dot cz> ---
I am attaching testcase and patch I am lto-botstrapping now. It copies
canonical from original type which is important for us to not lose TBAA
during ealry opts as well.
typedef struct rtx_def *rtx;
typedef struct cselib_val_struct
{
union
{
} u;
struct elt_loc_list *locs;
}
cselib_val;
struct elt_loc_list
{
struct elt_loc_list *next;
rtx loc;
};
static int n_useless_values;
unchain_one_elt_loc_list (pl)
struct elt_loc_list **pl;
{
struct elt_loc_list *l = *pl;
*pl = l->next;
}
discard_useless_locs (x, info)
void **x;
{
cselib_val *v = (cselib_val *) * x;
struct elt_loc_list **p = &v->locs;
int had_locs = v->locs != 0;
while (*p)
{
unchain_one_elt_loc_list (p);
p = &(*p)->next;
}
if (had_locs && v->locs == 0)
{
n_useless_values++;
}
}
* tree.c (fld_incomplete_type_of): Copy type_canonical.
Index: tree.c
===================================================================
--- tree.c (revision 265712)
+++ tree.c (working copy)
@@ -5146,6 +5146,7 @@ fld_incomplete_type_of (tree t, struct f
else
first = build_reference_type_for_mode (t2, TYPE_MODE (t),
TYPE_REF_CAN_ALIAS_ALL (t));
+ TYPE_CANONICAL (first) = TYPE_CANONICAL (TYPE_MAIN_VARIANT (t));
add_tree_to_fld_list (first, fld);
return fld_type_variant (first, t, fld);
}
