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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/99578] gcc-11 -Warray-bounds or -Wstringop-overread warning when accessing a pointer from integer literal
Date: Sat, 13 Mar 2021 20:40:41 +0000	[thread overview]
Message-ID: <bug-99578-4-S8jfyJOBm4@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99578-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |msebor at gcc dot gnu.org

--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
The warning is by design.  Its purpose is to detect invalid accesses at
non-zero offsets to null pointers, like in the memset call below:

  struct S { int a, b[4]; };

  void f (struct S *p)
  {
    if (p) return;
    memset (p->b, 0, 4 * sizeof p->b);
  }

For now, I recommend suppressing the warning either by #pragma GCC diagnostic
or by making the pointer volatile.  In the future, providing an attribute to
annotate constant addresses with (or extending the io() attribute supported by
some targets to all targets) might be another way to avoid it.

  reply	other threads:[~2021-03-13 20:40 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-13 14:23 [Bug c/99578] New: " arnd at linaro dot org
2021-03-13 20:40 ` msebor at gcc dot gnu.org [this message]
2021-03-13 21:40 ` [Bug c/99578] " arnd at linaro dot org
2021-03-13 22:38 ` arnd at linaro dot org
2021-03-14  0:57 ` [Bug middle-end/99578] " msebor at gcc dot gnu.org
2021-03-14 11:54 ` arnd at linaro dot org
2021-03-14 21:25 ` arnd at linaro dot org
2021-03-15  8:38 ` rguenth at gcc dot gnu.org
2021-03-15 19:57 ` msebor at gcc dot gnu.org
2021-03-15 20:24 ` msebor at gcc dot gnu.org
2021-04-21 19:34 ` pinskia at gcc dot gnu.org
2021-04-28 16:11 ` msebor at gcc dot gnu.org
2021-05-01 15:08 ` andi-gcc at firstfloor dot org
2021-05-19 15:07 ` msebor at gcc dot gnu.org
2021-05-19 18:01 ` andrew.cooper3 at citrix dot com
2021-05-19 19:19 ` andrew.cooper3 at citrix dot com
2021-05-19 20:48 ` msebor at gcc dot gnu.org
2021-05-30 23:40 ` msebor at gcc dot gnu.org
2021-08-24 16:03 ` pinskia at gcc dot gnu.org
2021-09-14 18:46 ` [Bug middle-end/99578] [11/12 Regression] " pinskia at gcc dot gnu.org
2021-12-19 11:36 ` pinskia at gcc dot gnu.org
2021-12-21 13:53 ` pmenzel+gcc at molgen dot mpg.de
2022-01-14 15:57 ` pmenzel+gcc at molgen dot mpg.de
2022-01-21 13:18 ` rguenth at gcc dot gnu.org
2022-02-23 10:36 ` pinskia at gcc dot gnu.org
2022-02-23 12:53 ` jakub at gcc dot gnu.org
2022-02-23 16:50 ` msebor at gcc dot gnu.org
2022-02-23 16:57 ` jakub at gcc dot gnu.org
2022-02-23 17:55 ` msebor at gcc dot gnu.org
2022-03-07 19:30 ` pinskia at gcc dot gnu.org
2022-03-07 20:53 ` goswin-v-b at web dot de
2022-03-16 19:49 ` kees at outflux dot net
2022-03-16 21:15 ` msebor at gcc dot gnu.org
2022-03-16 23:10 ` jwerner at chromium dot org
2022-03-17 10:49 ` redi at gcc dot gnu.org
2022-03-17 10:53 ` redi at gcc dot gnu.org
2022-03-17 12:52 ` jakub at gcc dot gnu.org
2022-03-18 18:02 ` cvs-commit at gcc dot gnu.org
2022-03-18 18:05 ` [Bug middle-end/99578] [11 " jakub at gcc dot gnu.org
2022-03-19 11:02 ` goswin-v-b at web dot de
2022-03-29  5:54 ` cvs-commit at gcc dot gnu.org
2022-03-30  8:04 ` marxin at gcc dot gnu.org
2022-03-30  8:16 ` jakub at gcc dot gnu.org

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