https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116222
Bug ID: 116222
Summary: -Wmaybe-uninitialized in record_target_from_binfo in
ipa-devirt.cc
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: build
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
Blocks: 24639, 44756
Target Milestone: ---
During an LTO bootstrap, I saw:
```
/var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/ipa-devirt.cc:2590:31:
warning: ‘can_refer’ may be used uninitialized [-Wmaybe-uninitialized]
2590 | maybe_record_node (nodes, target, inserted, can_refer,
completep);
| ^
/var/tmp/portage/sys-devel/gcc-15.0.9999/work/gcc-15.0.9999/gcc/ipa-devirt.cc:2585:16:
note: ‘can_refer’ declared here
2585 | bool can_refer;
| ^
```
We have in ipa-devirt.cc:
```
static void
record_target_from_binfo (vec <cgraph_node *> &nodes,
[...]
bool can_refer;
tree target = gimple_get_virt_method_for_binfo (otr_token,
inner_binfo,
&can_refer);
if (!bases_to_consider)
maybe_record_node (nodes, target, inserted, can_refer, completep);
/* Destructors are never called via construction vtables. */
else if (!target || !DECL_CXX_DESTRUCTOR_P (target))
bases_to_consider->safe_push (target);
[...]
```
But in gimple-fold.cc:
```
tree
gimple_get_virt_method_for_binfo (HOST_WIDE_INT token, tree known_binfo,
bool *can_refer)
{
unsigned HOST_WIDE_INT offset;
tree v;
v = BINFO_VTABLE (known_binfo);
/* If there is no virtual methods table, leave the OBJ_TYPE_REF alone. */
if (!v)
return NULL_TREE;
if (!vtable_pointer_value_to_vtable (v, &v, &offset))
{
if (can_refer)
*can_refer = false;
return NULL_TREE;
}
return gimple_get_virt_method_for_vtable (token, v, offset, can_refer);
}
```
We don't always initialise can_refer there.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24639
[Bug 24639] [meta-bug] bug to track all Wuninitialized issues
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44756
[Bug 44756] [meta-bug] --enable-werror-always issues
