public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "nfxjfg at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/114923] gcc ignores escaping pointer and applies invalid optimization
Date: Thu, 02 May 2024 13:44:35 +0000	[thread overview]
Message-ID: <bug-114923-4-2hOIcMfXUv@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114923-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114923

--- Comment #3 from nfxjfg at googlemail dot com ---
I'm expecting gcc to realize that the pointer escaped into the unknown, and
that it can't assume that the memory won't change. This is just causality, not
any vague made up viralyness.

Anyway, a 'asm volatile("":::"memory")' is too radical and increased code size
too much in my case (but it's a good suggestion). Making the buffer volatile
will inhibit optimizations before or after the DMA.

  parent reply	other threads:[~2024-05-02 13:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-02 12:51 [Bug c/114923] New: " nfxjfg at googlemail dot com
2024-05-02 12:52 ` [Bug c/114923] " nfxjfg at googlemail dot com
2024-05-02 13:24 ` amonakov at gcc dot gnu.org
2024-05-02 13:44 ` nfxjfg at googlemail dot com [this message]
2024-05-02 13:56 ` amonakov at gcc dot gnu.org
2024-05-02 19:07 ` [Bug middle-end/114923] " pinskia at gcc dot gnu.org
2024-05-02 19:15 ` pinskia at gcc dot gnu.org
2024-05-02 23:03 ` nfxjfg at googlemail dot com
2024-05-02 23:42 ` pinskia at gcc dot gnu.org
2024-05-03  0:30 ` nfxjfg at googlemail dot com

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-114923-4-2hOIcMfXUv@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).