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 c++/96717] -flifetime-dse=2 breaks webkit-gtk-2.28.4
Date: Tue, 15 Feb 2022 10:47:15 +0000	[thread overview]
Message-ID: <bug-96717-4-wbQ74Du2We@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-96717-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96717

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced:

template<typename T>
struct vector
{
  using pointer = T*;

  pointer begin, end, end_of_storage;

  void pop_back()
  {
    (end--)->~T();
  }
};

using size_t = decltype(sizeof(0));

void pop_many(vector<int>& v, size_t n) {
    for (size_t i = 0; i < n; ++i) {
        v.pop_back();
    }
}


With -O2 -fno-lifetime-dse we get the expected code back.

  parent reply	other threads:[~2022-02-15 10:47 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-19 22:25 [Bug c++/96717] New: " slyfox at gcc dot gnu.org
2020-08-20  8:10 ` [Bug c++/96717] " redi at gcc dot gnu.org
2020-08-20  8:14 ` redi at gcc dot gnu.org
2020-08-20  9:19 ` jakub at gcc dot gnu.org
2020-08-20  9:31 ` jakub at gcc dot gnu.org
2022-02-15 10:41 ` redi at gcc dot gnu.org
2022-02-15 10:47 ` redi at gcc dot gnu.org [this message]
2022-02-15 10:50 ` pinskia at gcc dot gnu.org
2022-02-15 11:01 ` jakub at gcc dot gnu.org
2022-02-15 11:46 ` 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-96717-4-wbQ74Du2We@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).