From: Jonathan Wakely <jwakely@redhat.com>
To: Hans-Peter Nilsson <hp@bitrange.com>
Cc: Richard Henderson <rth@redhat.com>,
libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: [libstdc++/65033] Give alignment info to libatomic
Date: Tue, 07 Apr 2015 15:06:00 -0000 [thread overview]
Message-ID: <20150407150617.GH9755@redhat.com> (raw)
In-Reply-To: <alpine.BSF.2.02.1504070922410.45243@arjuna.pair.com>
On 07/04/15 10:51 -0400, Hans-Peter Nilsson wrote:
>I was more thinking of something like:
>
>#include <atomic>
>#include <iostream>
>using std::cout;
>using std::endl;
>
>struct SoSo {
> double d;
> int x alignas(sizeof(int));
>};
>
>SoSo s __attribute__((__aligned__(16)));
>
>int main(void)
>{
> cout << "alignof(s): " << alignof(s) << endl;
> cout << "alignof(s.d): " << alignof(s.d) << endl;
> cout << "alignof(s.x): " << alignof(s.x) << endl;
>}
>
>in which I fear s.x would get an alignof the same as the s.d or
>s, now or after a while, i.e. higher than specified.
>
>(I get for cris-elf at revision 221891:
>alignof(s): 16
>alignof(s.d): 1
>alignof(s.x): 4
>which is kind-of-expected except I thought s.d would get the s
>alignment so that just leaves it open whether that could
>possibly change.)
The docs are clear that alignof(s.x) is not related to its position in
struct SoSo: https://gcc.gnu.org/onlinedocs/gcc/Alignment.html
I'm not going to worry about that behaviour changing.
next prev parent reply other threads:[~2015-04-07 15:06 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-12 21:23 Richard Henderson
2015-02-18 12:15 ` Jonathan Wakely
2015-03-25 16:22 ` Jonathan Wakely
2015-03-25 18:36 ` Richard Henderson
2015-03-25 18:49 ` Jonathan Wakely
2015-03-25 19:04 ` Richard Henderson
2015-03-26 13:21 ` Jonathan Wakely
2015-03-31 13:41 ` Jonathan Wakely
2015-03-31 14:54 ` Richard Henderson
2015-03-31 15:03 ` Jonathan Wakely
2015-03-31 15:13 ` Richard Henderson
2015-03-31 15:41 ` Jonathan Wakely
2015-04-06 22:59 ` Hans-Peter Nilsson
2015-04-13 4:45 ` patch fix issue 1 with "[libstdc++/65033] Give alignment info to libatomic" Hans-Peter Nilsson
2015-04-13 11:59 ` Jonathan Wakely
2015-04-13 5:59 ` Issue 2 " Hans-Peter Nilsson
2015-04-13 17:53 ` Joseph Myers
2015-03-25 18:39 ` [libstdc++/65033] Give alignment info to libatomic Richard Henderson
2015-04-03 3:04 ` Hans-Peter Nilsson
2015-03-26 11:54 ` Jonathan Wakely
2015-04-03 3:57 ` Hans-Peter Nilsson
2015-04-03 9:25 ` Hans-Peter Nilsson
2015-04-03 14:13 ` Jonathan Wakely
2015-04-03 19:13 ` Richard Henderson
2015-04-07 13:14 ` Jonathan Wakely
2015-04-09 11:17 ` Jonathan Wakely
2015-04-06 1:07 ` Hans-Peter Nilsson
2015-04-07 9:45 ` Jonathan Wakely
2015-04-07 10:52 ` Hans-Peter Nilsson
2015-04-07 13:12 ` Jonathan Wakely
2015-04-07 14:51 ` Hans-Peter Nilsson
2015-04-07 15:06 ` Jonathan Wakely [this message]
2015-04-08 3:58 ` Hans-Peter Nilsson
2015-04-08 9:35 ` Jonathan Wakely
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