public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/56785] std::tuple of two elements does not apply empty base class optimization when one of its elements is a std::tuple with two elements
Date: Mon, 16 Jun 2014 22:28:00 -0000	[thread overview]
Message-ID: <bug-56785-4-dAk5hzunaG@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-56785-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56785

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The cause is that every N-tuple hierarchy ends with an empty _Tuple_impl<N>
base, so when there are several of those in the same hierarchy they need to
have separate addresses.

It should be possible to fix by eliminating that terminal objet in the
inheritance hierarchy. The obvious way duplicates a chunk of code, I think it
should be possible to do it in a nicer way, which I'm experimenting with.


  parent reply	other threads:[~2014-06-16 22:28 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-30  2:58 [Bug libstdc++/56785] New: " david at doublewise dot net
2013-03-30  9:06 ` [Bug libstdc++/56785] " glisse at gcc dot gnu.org
2013-04-08  8:47 ` redi at gcc dot gnu.org
2014-06-16 19:01 ` gcc-bugzilla at contacts dot eelis.net
2014-06-16 22:10 ` redi at gcc dot gnu.org
2014-06-16 22:28 ` redi at gcc dot gnu.org [this message]
2014-06-17 17:02 ` gcc-bugzilla at contacts dot eelis.net
2014-06-18 13:43 ` redi at gcc dot gnu.org
2014-06-18 14:25 ` gcc-bugzilla at contacts dot eelis.net
2014-06-18 14:39 ` glisse at gcc dot gnu.org
2014-06-18 14:47 ` gcc-bugzilla at contacts dot eelis.net
2014-06-23 23:13 ` redi at gcc dot gnu.org
2014-06-23 23:21 ` gcc-bugzilla at contacts dot eelis.net
2014-06-23 23:21 ` redi at gcc dot gnu.org
2014-09-19 11:01 ` redi at gcc dot gnu.org
2015-01-17  0:22 ` redi at gcc dot gnu.org
2015-01-17  0:24 ` redi at gcc dot gnu.org

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=bug-56785-4-dAk5hzunaG@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@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).