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From: "eggert at cs dot ucla.edu" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug analyzer/109577] -Wanalyzer-allocation-size mishandles __builtin_mul_overflow Date: Fri, 12 May 2023 20:39:58 +0000 [thread overview] Message-ID: <bug-109577-4-HrMikQEo78@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-109577-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109577 Paul Eggert <eggert at cs dot ucla.edu> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |eggert at cs dot ucla.edu --- Comment #1 from Paul Eggert <eggert at cs dot ucla.edu> --- I ran into the same problem with gcc (GCC) 13.1.1 20230426 (Red Hat 13.1.1-1) but I don't know how to update the version number in Bugzilla. Also, I came up with the following simpler test case. Compile this with "gcc -O2 -S -fanalyzer foo.c", and it will complain "allocated buffer size is not a multiple of the pointee's size" in the function "safer", but it will not complain about the function "unsafe" (which, unlike "safer", does not check for integer overflow and so is less safe). void *malloc (unsigned long); double * unsafe (unsigned long n) { return malloc (n * sizeof (double)); } double * safer (unsigned long n) { unsigned long nbytes; if (__builtin_mul_overflow (n, sizeof (double), &nbytes)) return 0; return malloc (nbytes); }
next prev parent reply other threads:[~2023-05-12 20:39 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-04-20 20:33 [Bug analyzer/109577] New: " eggert at gnu dot org 2023-05-12 20:39 ` eggert at cs dot ucla.edu [this message] 2023-06-10 12:29 ` [Bug analyzer/109577] " cvs-commit at gcc dot gnu.org 2023-06-10 12:29 ` cvs-commit at gcc dot gnu.org 2023-06-12 13:17 ` dmalcolm at gcc dot gnu.org 2024-01-28 8:06 ` nightstrike at gmail dot com 2024-02-15 19:57 ` [Bug analyzer/109577] [13 Regression] " dmalcolm at gcc dot gnu.org 2024-04-14 5:20 ` pinskia at gcc dot gnu.org 2024-05-09 17:10 ` cvs-commit at gcc dot gnu.org 2024-05-09 17:11 ` cvs-commit at gcc dot gnu.org 2024-05-09 17:54 ` [Bug analyzer/109577] " dmalcolm at gcc dot gnu.org 2024-05-11 16:40 ` nightstrike at gmail dot com 2024-05-11 17:50 ` segher at gcc dot gnu.org 2024-05-21 9:14 ` jakub at gcc dot gnu.org
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