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Re: GCC 5.1.1 Status Report (2015-06-22)
- From: Jason Merrill <jason at redhat dot com>
- To: Richard Biener <rguenther at suse dot de>, gcc at gcc dot gnu dot org
- Date: Tue, 30 Jun 2015 17:13:13 -0400
- 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>
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
Does this make sense to you?