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Re: GCC 5.1.1 Status Report (2015-06-22)
- From: Richard Biener <rguenther at suse dot de>
- To: Jason Merrill <jason at redhat dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Wed, 1 Jul 2015 09:20:07 +0200 (CEST)
- Subject: Re: GCC 5.1.1 Status Report (2015-06-22)
- Authentication-results: sourceware.org; auth=none
- References: <alpine dot LSU dot 2 dot 11 dot 1506221355330 dot 31770 at zhemvz dot fhfr dot qr> <55930669 dot 6020300 at redhat dot com>
On Tue, 30 Jun 2015, Jason Merrill wrote:
> I'm interested in your thoughts on fixing c++/65945 in 5.2.
> It's trivial to fix the alignment of nullptr_t, but I was concerned about ABI
> impact. On further research it seems that it won't cause any trouble with
> argument alignment, since that doesn't seem to rely on TYPE_ALIGN at all; I
> think the only ABI breakage would come from unaligned nullptr_t fields in
> classes, which I expect to be very rare. The testcases that were breaking on
> SPARC and ARM without this fix have to do with local stack slots, which are
> not part of an interface.
> So I think we can change this without breaking a significant amount of code,
> and better to break it now than after we've settled into the new library ABI.
> We should certainly mention it prominently in the release notes if we do, and
> I've added a -Wabi warning for the field alignment change.
> Does this make sense to you?
Yes, that makes sense to me.
Richard Biener <firstname.lastname@example.org>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham Norton, HRB 21284 (AG Nuernberg)