From: Stefan Monnier <monnier@iro.umontreal.ca>
To: emacs-devel@gnu.org
Subject: Re: emacs-26 9e59de9: Use GCALIGNED properly for GCC
Date: Fri, 10 Nov 2017 13:02:57 -0500 [thread overview]
Message-ID: <jwvr2t6xbbe.fsf-monnier+gmane.emacs.devel@gnu.org> (raw)
In-Reply-To: 8d9c169a-5f58-6958-9fca-4c68fa547ba3@cs.ucla.edu
>>> union gcaligned_foo { struct foo s; int64_t gcaligned; };
>> Are int64_t necessarily aligned on multiples of 8 on 32bit platforms?
> No, unfortunately.
That was my impression as well.
> That does not work either, alas, as C11 says 'alignas (8)' is an error when
> the natural alignment of the object is less than 8. This is one of the
> problems that we have encountered in earlier attempts to fix this bug. 'char
> alignas (8)' avoids this problem.
I don't follow: the natural alignment for `char` is definitely less than
8, so if "'alignas (8)' is an error when the natural alignment of the
object is less than 8", how can "char alignas (8)" avoid the problem?
Stefan
next prev parent reply other threads:[~2017-11-10 18:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171109031206.7056.28312@vcs0.savannah.gnu.org>
[not found] ` <20171109031208.D2CAF2033E@vcs0.savannah.gnu.org>
2017-11-09 23:31 ` emacs-26 9e59de9: Use GCALIGNED properly for GCC Glenn Morris
2017-11-10 7:10 ` martin rudalics
2017-11-10 8:06 ` Eli Zaretskii
2017-11-10 8:26 ` Paul Eggert
2017-11-10 9:57 ` Eli Zaretskii
2017-11-10 16:23 ` Stefan Monnier
2017-11-10 17:58 ` Paul Eggert
2017-11-10 18:02 ` Stefan Monnier [this message]
2017-11-10 18:11 ` Philipp Stephani
2017-11-10 19:19 ` Paul Eggert
2017-11-10 20:31 ` Stefan Monnier
2017-11-10 20:45 ` Paul Eggert
2017-11-11 7:08 ` Paul Eggert
2017-11-11 7:57 ` Paul Eggert
2017-11-11 8:34 ` martin rudalics
2017-11-11 8:50 ` Paul Eggert
2017-11-11 9:46 ` martin rudalics
2017-11-11 8:33 ` martin rudalics
2017-11-13 18:19 ` Paul Eggert
2017-11-13 18:45 ` martin rudalics
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