https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68148
Jan Hubicka <hubicka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2016-01-10
Assignee|unassigned at gcc dot gnu.org |hubicka at gcc dot
gnu.org
Ever confirmed|0 |1
--- Comment #3 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
This is the result of analysis:
Procesing function void test(Interface&)/12
Introduced new external node (void __cxa_pure_virtual()/26).
Targets of polymorphic call of type 0:struct Interface token 3
Outer type (dynamic):struct Interface (or a derived type) offset 0
This is partial list; extra targets may be defined in other units. (derived
types included)
virtual void Concrete::virtualFunc2()/11
code.C:16:19: note: speculatively devirtualizing call in void
test(Interface&)/12 to virtual void Concrete::virtualFunc2()/11
Indirect call -> speculative call void test(Interface&)/12 => virtual void
Concrete::virtualFunc2()/11
Targets of polymorphic call of type 0:struct Interface token 2
Outer type (dynamic):struct Interface (or a derived type) offset 0
This is partial list; extra targets may be defined in other units. (derived
types included)
virtual void Concrete::virtualFunc()/10 (no definition inline)
Speculative targets:
the problem is that list of Speculative targets is empty which makes us to
ignore the fact that even non-speculatively there is only one possible target.
The reason is that the second function does not pass
can_refer_decl_in_current_unit_p:
149 snode = symtab_node::get (decl);
150 if (!snode
151 || ((!snode->definition || DECL_EXTERNAL (decl))
152 && (!snode->in_other_partition
153 || (!snode->forced_by_abi && !snode->force_output))))
154 return false;
and node is:
(gdb) p snode->debug ()
_ZN8Concrete11virtualFuncEv/10 (virtual void Concrete::virtualFunc())
@0x7ffff6c4f170
Type: function
Body removed by symtab_remove_unreachable_nodes
Visibility: externally_visible public weak comdat
comdat_group:_ZN8Concrete11virtualFuncEv one_only virtual
References:
Referring:
Availability: not_available
First run: 0
Function flags: icf_merged
Called by:
Calls:
which is done by ipa-icf::merge:
Wrapper cannot be created because of COMDAT
Unified; Function body was removed.
This is because ipa-icf thinks that since there are no calls or direct uses, it
may get rid of the function.
I am testing the following:
Index: ../../gcc/ipa-icf.c
===================================================================
--- ../../gcc/ipa-icf.c (revision 232179)
+++ ../../gcc/ipa-icf.c (working copy)
@@ -1305,6 +1305,7 @@ sem_function::merge (sem_item *alias_ite
/* If all callers was redirected, do not produce wrapper. */
if (alias->can_remove_if_no_direct_calls_p ()
+ && !DECL_VIRTUAL_P (alias->decl)
&& !alias->has_aliases_p ())
{
create_wrapper = false;
