From: "\"Markus Fröschle\"" <markus@mubf.de>
To: gcc@gcc.gnu.org
Subject: Aw: Re: asking for __attribute__((aligned()) clarification
Date: Tue, 20 Aug 2019 05:46:00 -0000 [thread overview]
Message-ID: <trinity-02ba671e-c260-4ad9-a277-b1169d3026c8-1566279973304@3c-app-1and1-bs05> (raw)
In-Reply-To: <alpine.LNX.2.20.13.1908191706100.32047@monopod.intra.ispras.ru>
Thank you (and others) for your answers. Now I'm just as smart as before, however.
Is it a supported, documented, 'long term' feature we can rely on or not?
If yes, I would expect it to be properly documented. If not, never mind.
> Gesendet: Montag, 19. August 2019 um 16:08 Uhr
> Von: "Alexander Monakov" <amonakov@ispras.ru>
> An: "Richard Earnshaw (lists)" <Richard.Earnshaw@arm.com>
> Cc: "Paul Koning" <paulkoning@comcast.net>, "Markus Fröschle" <markus@mubf.de>, gcc@gcc.gnu.org
> Betreff: Re: asking for __attribute__((aligned()) clarification
>
> On Mon, 19 Aug 2019, Richard Earnshaw (lists) wrote:
>
> > Correct, but note that you can only pack structs and unions, not basic types.
> > there is no way of under-aligning a basic type except by wrapping it in a
> > struct.
>
> I don't think that's true. In GCC-9 the doc for 'aligned' attribute has been
> significantly revised, and now ends with
>
> When used as part of a typedef, the aligned attribute can both increase and
> decrease alignment, and specifying the packed attribute generates a warning.
>
> (but I'm sure defacto behavior of accepting and honoring reduced alignment on
> a typedef'ed scalar type goes way earlier than gcc-9)
>
> Alexander
>
next prev parent reply other threads:[~2019-08-20 5:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 12:46 "Markus Fröschle"
2019-08-19 13:57 ` Paul Koning
2019-08-19 14:01 ` Richard Earnshaw (lists)
2019-08-19 14:08 ` Alexander Monakov
2019-08-19 14:12 ` Paul Koning
2019-08-20 5:46 ` "Markus Fröschle" [this message]
2019-08-21 14:29 ` Aw: " Alexander Monakov
2019-08-21 14:32 ` Paul Koning
2019-08-21 14:58 ` Alexander Monakov
2019-08-21 16:50 ` Paul Koning
2019-08-21 17:35 ` Jonathan Wakely
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