public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/101326] std::optional returns forced through stack
Date: Tue, 06 Jul 2021 06:38:14 +0000	[thread overview]
Message-ID: <bug-101326-4-2U0MxwWAI3@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-101326-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101326

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think the issue is simply that RTL expansion forces the object to memory
since that is what GIMPLE does:

struct optional foo ()
{
  struct optional D.12374;

  <bb 2> [local count: 1073741824]:
  MEM <long int> [(struct optional *)&D.12374] = 0;
  MEM <unsigned char> [(struct optional *)&D.12374 + 8B] = 1;
  return D.12374;
}

and yes, if it would have had TImode we could expand it to a register pair
but it has BLKmode because it's TYPE_NEEDS_CONSTRUCTING(?), the type
isn't TREE_ADDRESSABLE for me.

  parent reply	other threads:[~2021-07-06  6:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-05 16:37 [Bug c++/101326] New: " tnfchris at gcc dot gnu.org
2021-07-05 16:45 ` [Bug middle-end/101326] " tnfchris at gcc dot gnu.org
2021-07-05 17:07 ` pinskia at gcc dot gnu.org
2021-07-06  6:38 ` rguenth at gcc dot gnu.org [this message]
2021-07-06  7:40 ` pinskia at gcc dot gnu.org
2023-04-26  9:46 ` pinskia at gcc dot gnu.org
2023-07-12 21:35 ` pinskia 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-101326-4-2U0MxwWAI3@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).