https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63164
--- Comment #13 from Thomas de Bock <tdebock at DRWUK dot com> ---
(In reply to Jakub Jelinek from comment #12)
> I'd think it should just optimize __dynamic_cast to
> std::type_info::operator== in that case (if that is available) or, if not
> (i.e. <typeinfo> not included) to
> if (__name == __arg.__name)
> return true;
> return __name[0] != '*' && __builtin_strcmp (__name, __arg.__name) == 0;
> or so.
I think that would be insufficient, since from looking at the definition:
type_info::operator==(const type_info& __arg) const _GLIBCXX_NOEXCEPT
{
if (std::__is_constant_evaluated())
return this == &__arg;
if (__name == __arg.__name)
return true;
#if !__GXX_TYPEINFO_EQUALITY_INLINE
// ABI requires comparisons to be non-inline.
return __equal(__arg);
#elif !__GXX_MERGED_TYPEINFO_NAMES
// Need to do string comparison.
return __name[0] != '*' && __builtin_strcmp (__name, __arg.name()) == 0;
#else
return false;
#endif
besides compile-time evaluation, it always compares the type names, which still
leaves much room for optimization.
