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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/109151] UBsan misses a divide-by-zero Date: Sun, 19 Mar 2023 05:31:10 +0000 [thread overview] Message-ID: <bug-109151-4-naTfXd5fHa@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-109151-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109151 --- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>: https://gcc.gnu.org/g:ffb22189be90216e6af386aaef8b76d2dcd05b84 commit r12-9292-gffb22189be90216e6af386aaef8b76d2dcd05b84 Author: Jakub Jelinek <jakub@redhat.com> Date: Fri Mar 17 16:10:14 2023 +0100 c, ubsan: Instrument even shortened divisions [PR109151] On the following testcase, the C FE decides to shorten the division because it has a guarantee that INT_MIN / -1 division won't be encountered, the first operand is widened from narrower unsigned and/or the second operand is a constant other than all ones (in this case both are true). The problem is that the narrower type in this case is _Bool and ubsan_instrument_division only instruments it if op0's type is INTEGER_TYPE or REAL_TYPE. Strangely this doesn't happen in C++ FE. Anyway, we only shorten divisions if the INT_MIN / -1 case is impossible, so I think we should be fine even with -fstrict-enums in C++ in case it shortened to ENUMERAL_TYPEs. The following patch just instruments those on the ubsan_instrument_division side. Perhaps only the first hunk and testcase might be needed because we shouldn't shorten if the other case could be triggered. 2023-03-17 Jakub Jelinek <jakub@redhat.com> PR c/109151 * c-ubsan.cc (ubsan_instrument_division): Handle all scalar integral types rather than just INTEGER_TYPE. * c-c++-common/ubsan/div-by-zero-8.c: New test. (cherry picked from commit 103d423f6ce72ccb03d55b7b1dfa2dabd5854371)
next prev parent reply other threads:[~2023-03-19 5:31 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-15 21:51 [Bug sanitizer/109151] New: " shaohua.li at inf dot ethz.ch 2023-03-15 21:54 ` [Bug c/109151] " pinskia at gcc dot gnu.org 2023-03-15 22:02 ` pinskia at gcc dot gnu.org 2023-03-16 9:17 ` jakub at gcc dot gnu.org 2023-03-17 15:11 ` cvs-commit at gcc dot gnu.org 2023-03-19 5:31 ` cvs-commit at gcc dot gnu.org [this message] 2023-03-20 10:29 ` jakub at gcc dot gnu.org 2023-05-02 20:15 ` cvs-commit at gcc dot gnu.org 2023-05-03 10:44 ` jakub at gcc dot gnu.org 2023-05-03 15:22 ` cvs-commit at gcc dot gnu.org 2023-05-04 7:25 ` jakub at gcc dot gnu.org
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