http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59469
--- Comment #29 from Jan Hubicka <hubicka at ucw dot cz> ---
>
> That optimization seems invalid. There is a explicit template instantiation
> definition, so it is valid for other dsos to have an undefined reference.
Can I see the cgraph dump of the unreduced source file containing the explicit
instantiation?
In this case C++ FE should set forced_by_abi flag and that should
prevent us from bringing comdat local in:
/* A helper for comdat_can_be_unshared_p. */
static bool
comdat_can_be_unshared_p_1 (symtab_node *node)
{
/* When address is taken, we don't know if equality comparison won't
break eventually. Exception are virutal functions, C++
constructors/destructors and vtables, where this is not possible by
language standard. */
if (!DECL_VIRTUAL_P (node->decl)
&& (TREE_CODE (node->decl) != FUNCTION_DECL
|| (!DECL_CXX_CONSTRUCTOR_P (node->decl)
&& !DECL_CXX_DESTRUCTOR_P (node->decl)))
&& address_taken_from_non_vtable_p (node))
return false;
/* If the symbol is used in some weird way, better to not touch it. */
if (node->force_output)
return false;
/* Explicit instantiations needs to be output when possibly
used externally. */
if (node->forced_by_abi
&& TREE_PUBLIC (node->decl)
&& (node->resolution != LDPR_PREVAILING_DEF_IRONLY
&& !flag_whole_program))
return false;
Perhaps we forget about the flag, or perhaps the symbol is hidden by the
default
visibility overrride?
Honza
