http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60906
--- Comment #7 from Sriraman Tallam <tmsriram at google dot com> ---
(In reply to Jakub Jelinek from comment #6)
> GCC has like 60 or 70 target independent attributes plus sometimes various
> target dependent attributes. Figuring out which are ABI changing and must
> be errored out on mismatch, which are safe to ignore, which are only
> affecting function generation and not callers is going to be hard even for
> the existing ones, and would be a maintainance burden for the future, as for
> each new attribute (every year a few of them are added) it would be another
> place to modify and think about what the behavior should be. Keying
> something on default attribute would be weird, for multi-versioning you
> don't have to have target ("default") I think.
Multi-versioning needs the target("default") version or error.
If you want to inherit the
> attributes, perhaps from the first decl only, and if the second/further
> multi-versioned declarations or definitions add attributes (other than the
> target attribute), it would be only allowed if the attribute wouldn't modify
> the attribute list (i.e. contain attribute that is already present).
