From: Jeffrey Walton <noloader@gmail.com>
To: musl@lists.openwall.com
Subject: Re: max_align_t mess on i386
Date: Sun, 15 Dec 2019 13:06:29 -0500 [thread overview]
Message-ID: <CAH8yC8kKok5EuXoRBdNANvEum3R5aSr8e2HNidhfJ9qW9nxwKQ@mail.gmail.com> (raw)
In-Reply-To: <20191214151932.GW1666@brightrain.aerifal.cx>
On Sat, Dec 14, 2019 at 10:19 AM Rich Felker <dalias@libc.org> wrote:
>
> In reserching how much memory could be saved, and how practical it
> would be, for the new malloc to align only to 8-byte boundaries
> instead of 16-byte on archs where alignof(max_align_t) is 8 (pretty
> much all 32-bit archs), I discovered that GCC quietly changed its
> idead of i386 max_align_t to 16-byte alignment in GCC 7, to better
> accommodate the new _Float128 access via SSE. Presumably (I haven't
> checked) the change is reflected with changes in the psABI document to
> make it "official".
Be careful with policy changes like this. The malloc (3) man page says:
The malloc() and calloc() functions return a pointer to the
allocated memory that is suitably aligned for any kind of variable.
I expect to be able to use a pointer returned by malloc (and friends)
in MMX, SSE and AVX functions.
Jeff
next prev parent reply other threads:[~2019-12-15 18:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-14 15:19 Rich Felker
2019-12-14 17:51 ` Florian Weimer
2019-12-14 18:17 ` Rich Felker
2019-12-14 18:53 ` Daniel Kolesa
2019-12-15 18:04 ` Rich Felker
2019-12-15 5:47 ` Markus Wichmann
2019-12-15 18:06 ` Jeffrey Walton [this message]
2019-12-15 18:22 ` Rich Felker
2019-12-16 15:30 ` Jeffrey Walton
2019-12-16 15:56 ` Rich Felker
2019-12-16 16:36 ` Jeffrey Walton
2019-12-16 17:49 ` Rich Felker
2019-12-16 16:40 ` Florian Weimer
2019-12-16 17:45 ` Rich Felker
2019-12-16 17:49 ` Florian Weimer
2019-12-16 17:51 ` Rich Felker
2019-12-15 18:23 ` Joakim Sindholt
2019-12-15 18:51 ` Rich Felker
2019-12-15 20:03 ` Alexander Monakov
2019-12-15 20:50 ` Szabolcs Nagy
2019-12-15 21:51 ` Jeffrey Walton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAH8yC8kKok5EuXoRBdNANvEum3R5aSr8e2HNidhfJ9qW9nxwKQ@mail.gmail.com \
--to=noloader@gmail.com \
--cc=musl@lists.openwall.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).