public inbox for gcc-patches@gcc.gnu.org
 help / color / mirror / Atom feed
From: Richard Guenther <richard.guenther@gmail.com>
To: Eric Botcazou <ebotcazou@adacore.com>
Cc: Duncan Sands <baldrick@free.fr>, gcc-patches@gcc.gnu.org
Subject: Re: [Ada] Fix bugs with volatile and components of aggregate types
Date: Mon, 20 Jun 2011 11:46:00 -0000	[thread overview]
Message-ID: <BANLkTi=GN56VEKg4UdQSZHrYGkHn5QJUiQ@mail.gmail.com> (raw)
In-Reply-To: <201106200124.49880.ebotcazou@adacore.com>

On Mon, Jun 20, 2011 at 1:24 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> if T is a non-volatile composite type with volatile components, and O is an
>> object of type T, are the optimizers allowed to remove the assignment "O :=
>> O"?
>
> Good question, that I'm not really qualified to answer.  Any language lawyer?

Optimizers will test the TREE_THIS_VOLATILE flag on the expression
codes performing the load/store.  So if O is not TREE_THIS_VOLATILE
they won't care.  If frontends want something different in the above case
they have to make sure to properly set TREE_THIS_VOLATILE.

Richard.

> --
> Eric Botcazou
>

      parent reply	other threads:[~2011-06-20 11:23 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-18 13:01 Eric Botcazou
2011-06-19 18:01 ` Duncan Sands
2011-06-19 23:43   ` Eric Botcazou
2011-06-19 23:53     ` Mike Stump
2011-06-20 14:20       ` Michael Matz
2011-06-20 11:46     ` Richard Guenther [this message]

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='BANLkTi=GN56VEKg4UdQSZHrYGkHn5QJUiQ@mail.gmail.com' \
    --to=richard.guenther@gmail.com \
    --cc=baldrick@free.fr \
    --cc=ebotcazou@adacore.com \
    --cc=gcc-patches@gcc.gnu.org \
    /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.
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 read-only IMAP folder(s) and NNTP newsgroup(s).