RFC: Update Intel386, x86-64 and IA MCU psABIs for passing/returning empty struct

[Jason Merrill via cfe-commits]

On 03/01/2016 11:43 AM, Michael Matz wrote:
> Hi,
>
> On Mon, 29 Feb 2016, Jason Merrill wrote:
>
>>> Also this insistence that all of "trivially copyable" is already quite
>>> nicely specified in the C++ ABI is still not really relevant because
>>> C++ _is not the only language out there_.  I'm not sure how often I
>>> have to repeat this until people get it.
>>
>> Other language ABIs can handle language specific calling conventions as
>> appropriate for them.  The psABI can only talk about things that are in
>> its domain.
>
> Naturally.  How far to follow that road, though?  Remove the word "class"
> from the description of empty types again?  Why is that in-domain and the
> notion of trivially copyable isn't?

Yes, dropping "class" seems appropriate, especially since the psABI uses 
that word to refer to register classes.

Jason