[PATCH] Implement new hook for max_align_t_align

Jason Merrill jason@redhat.com
Wed Oct 12 13:48:00 GMT 2016


On Wed, Oct 12, 2016 at 4:02 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Oct 12, 2016 at 09:52:04AM +0200, Florian Weimer wrote:
>> dropping the alignment means that the padding before the lock member
>> vanishes.  Consequently, we have just created a silent ABI change in
>> application code, which is a big no-no.
>
> Sure, it would be an ABI change, but how many users would it affect?
>
>> Since this is PA-RISC, which is essentially dead (neither HPE nor Debian
>> ship it anymore), I stand by my suggestion to bump the fundamental alignment
>
> Or just drop support for a dead arch?
>
>> instead.  Sure, it is a bit inefficient, but this will only affect PA-RISC
>> users.  It does not even cause work for PA-RISC porters. Conversely, if we
>> work on this to come up with a different fix, many more people will be
>> affected (because they don't get all the nice things we could work on
>> instead), and we may need to maintain a special GCC kludge for the
>> alternative solution, impacting GCC developers in particular.
>
> But sure, bumping malloc alignment is probably easiest.  And people who want
> performance have better options than to stay on 32-bit PA-RISC anyway.

Or we could do nothing and tell people to ignore the harmless warning.

Jason



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