From: Joseph Myers <joseph@codesourcery.com>
To: Marek Polacek <polacek@redhat.com>
Cc: Paul Eggert <eggert@cs.ucla.edu>, <gcc-patches@gcc.gnu.org>,
<fweimer@redhat.com>
Subject: Re: Make max_align_t respect _Float128
Date: Mon, 29 Aug 2016 15:40:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1608291534510.6854@digraph.polyomino.org.uk> (raw)
In-Reply-To: <20160829132935.GB11131@redhat.com>
On Mon, 29 Aug 2016, Marek Polacek wrote:
> On Fri, Aug 26, 2016 at 02:51:38PM -0700, Paul Eggert wrote:
> > > Well, the patch could use __SIZEOF_FLOAT128__ just as well as __i386__
> > > (the effect would be an extra union member
> >
> > s/union/struct/. Though I've always wondered why it is a struct and not a
> > union. Maybe change it to union while we're doing an ABI change anyway?
>
> Yeah, me too. The initial implementation is here
> <https://gcc.gnu.org/ml/gcc-patches/2011-11/msg00841.html> but I don't see any
> comments wrt max_align_t being a struct or a union there.
I'm not aware of a specific reason for struct versus union (naming via a
typedef without a struct tag, so that no identifiers from the tag
namespace are used for C and so that the name for linkage purposes in C++
is max_align_t, is deliberate, however).
While the chance of any code's ABI being affected by the size of the type
should be small, the minimum change is certainly the one that uses
__i386__ and so doesn't affect the type at all except in the case where
it's necessary to do so.
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2016-08-29 15:40 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-26 20:55 Joseph Myers
2016-08-26 21:10 ` Marc Glisse
2016-08-26 21:30 ` Joseph Myers
2016-08-26 21:45 ` Florian Weimer
2016-08-26 21:57 ` Paul Eggert
2016-08-26 22:25 ` Joseph Myers
2016-08-26 21:51 ` Paul Eggert
2016-08-29 13:29 ` Marek Polacek
2016-08-29 15:40 ` Joseph Myers [this message]
2016-09-01 14:18 ` Ping " Joseph Myers
2016-09-05 17:07 ` Make max_align_t respect _Float128 [version 2] Joseph Myers
2016-09-06 9:06 ` Richard Biener
2016-09-06 11:26 ` Joseph Myers
2016-09-06 9:19 ` Florian Weimer
2016-09-06 9:24 ` Richard Biener
2016-09-07 7:45 ` Florian Weimer
2016-09-07 17:53 ` Joseph Myers
2016-09-08 9:35 ` Florian Weimer
2016-09-06 11:40 ` Joseph Myers
2016-09-06 15:06 ` Florian Weimer
2016-09-06 15:20 ` Joseph Myers
2016-09-06 15:59 ` Paul Eggert
2016-09-06 20:47 ` Joseph Myers
2016-09-06 21:41 ` Paul Eggert
2016-09-07 9:22 ` Florian Weimer
2016-09-07 11:52 ` Mark Wielaard
2016-09-08 1:58 ` Paul Eggert
2016-09-08 11:58 ` Mark Wielaard
2016-09-08 12:22 ` Florian Weimer
2016-09-08 14:59 ` Paul Eggert
2016-09-08 12:30 ` Bernd Schmidt
2016-09-08 12:34 ` Florian Weimer
2016-09-07 9:15 ` Florian Weimer
2016-09-06 21:03 ` Jason Merrill
2016-09-06 21:18 ` Joseph Myers
2016-09-06 21:53 ` Jason Merrill
2016-09-06 21:56 ` Joseph Myers
2016-09-06 12:06 ` Bernd Schmidt
2016-09-06 14:59 ` Florian Weimer
2016-09-12 18:02 ` Make max_align_t respect _Float128 [version 3] Joseph Myers
2016-09-19 16:08 ` Ping " Joseph Myers
2016-09-19 17:11 ` Paul Eggert
2016-09-26 16:35 ` Jeff Law
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