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From: Jakub Jelinek <jakub@redhat.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: "Carlos O'Donell" <carlos@redhat.com>,
	       John David Anglin <dave.anglin@bell.net>,
	       Jason Merrill <jason@redhat.com>,
	       Bernd Edlinger <bernd.edlinger@hotmail.de>,
	       "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
	       Jeff Law <law@redhat.com>
Subject: Re: [PATCH] Implement new hook for max_align_t_align
Date: Wed, 12 Oct 2016 08:02:00 -0000	[thread overview]
Message-ID: <20161012080208.GK7282@tucnak.redhat.com> (raw)
In-Reply-To: <ad86356d-db0e-58dc-a7e0-5603130c4bca@redhat.com>

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.

	Jakub

  reply	other threads:[~2016-10-12  8:02 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-08 17:01 Bernd Edlinger
2016-10-08 17:36 ` John David Anglin
2016-10-09  8:35   ` Bernd Edlinger
2016-10-09 17:52     ` John David Anglin
2016-10-10 18:21       ` John David Anglin
2016-10-11 18:51         ` Jason Merrill
2016-10-11 18:59           ` DJ Delorie
2016-10-11 20:12             ` Jason Merrill
2016-10-11 20:55               ` John David Anglin
2016-10-11 20:57                 ` Jakub Jelinek
2016-10-11 21:27                 ` Jason Merrill
2016-10-11 20:04           ` John David Anglin
2016-10-12  7:02             ` Carlos O'Donell
2016-10-12  7:25               ` Jakub Jelinek
2016-10-12  7:52                 ` Florian Weimer
2016-10-12  8:02                   ` Jakub Jelinek [this message]
2016-10-12 12:13                     ` John David Anglin
2016-10-12 12:33                       ` Bernd Schmidt
2016-10-12 12:43                         ` Richard Biener
2016-10-12 12:46                           ` Bernd Schmidt
2016-10-12 15:51                           ` Joseph Myers
2016-10-12 13:48                     ` Jason Merrill
2016-10-12 14:17                       ` John David Anglin
2016-10-12 19:59                         ` Carlos O'Donell
2016-10-12 16:14                     ` Jeff Law
2016-10-12 17:24                       ` John David Anglin
2017-02-25 17:46                         ` Gerald Pfeifer
2017-02-25 22:13                           ` John David Anglin
2017-02-25 22:46                             ` Gerald Pfeifer
2017-02-25 23:46                               ` John David Anglin
2016-10-12 18:01                       ` Florian Weimer
2016-10-12 18:13                         ` John David Anglin
  -- strict thread matches above, loose matches on Subject: below --
2016-10-08 16:43 Bernd Edlinger
2016-10-08 15:45 John David Anglin

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