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From: "jason at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/103483] context-sensitive ranges change triggers stringop-overread
Date: Sat, 11 Dec 2021 22:43:52 +0000	[thread overview]
Message-ID: <bug-103483-4-9KW7BrvtRC@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-103483-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103483

--- Comment #14 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Martin Sebor from comment #13)
> static inline void copy (const char *p)
> {
>   int N = null_safe_strlen (p);
>   if (N) /* disabling this branch prevents the warning */
>     __builtin_memcpy (sink, p, N);
>   else
>     *sink = 0;
> }

This testcase is importantly different from mine; in mine the branch itself is
what introduces the range information that causes the warning, we only decide
that the statement is invalid because of the if.  In your testcase, if you made
the memcpy unconditional we would still warn; in mine we only warn *because*
it's conditional.

  parent reply	other threads:[~2021-12-11 22:43 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-30  4:27 [Bug c++/103483] New: constexpr basic_string " john at mcfarlane dot name
2021-11-30  4:39 ` [Bug c++/103483] context-sensitive ranges change " pinskia at gcc dot gnu.org
2021-11-30 12:11 ` redi at gcc dot gnu.org
2021-11-30 17:56 ` [Bug middle-end/103483] " msebor at gcc dot gnu.org
2021-11-30 18:13 ` msebor at gcc dot gnu.org
2021-11-30 22:33 ` john at mcfarlane dot name
2021-12-01 16:38 ` aldyh at gcc dot gnu.org
2021-12-01 16:53 ` redi at gcc dot gnu.org
2021-12-01 23:38 ` pinskia at gcc dot gnu.org
2021-12-01 23:44 ` pinskia at gcc dot gnu.org
2021-12-02 22:14 ` msebor at gcc dot gnu.org
2021-12-09 23:24 ` cvs-commit at gcc dot gnu.org
2021-12-10 22:10 ` jason at gcc dot gnu.org
2021-12-11  0:56 ` msebor at gcc dot gnu.org
2021-12-11 22:43 ` jason at gcc dot gnu.org [this message]
2022-01-17 22:44 ` [Bug middle-end/103483] [12 regression] " jason at gcc dot gnu.org
2022-01-17 23:10 ` amacleod at redhat dot com
2022-01-18  0:47 ` msebor at gcc dot gnu.org
2022-01-28  2:02 ` pinskia at gcc dot gnu.org
2022-01-28  5:03 ` jason at gcc dot gnu.org
2022-01-28  6:38 ` law at gcc dot gnu.org
2022-01-28  7:48 ` redi at gcc dot gnu.org
2022-01-28 15:23 ` law at gcc dot gnu.org
2022-03-09 14:11 ` rguenth at gcc dot gnu.org
2022-03-14 23:58 ` msebor at gcc dot gnu.org
2022-05-06  8:32 ` [Bug middle-end/103483] [12/13 " jakub at gcc dot gnu.org
2022-10-19  9:43 ` rguenth at gcc dot gnu.org
2023-05-08 12:23 ` [Bug middle-end/103483] [12/13/14 " rguenth at gcc dot gnu.org

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