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From: "shaohua.li at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug sanitizer/109151] New: UBsan misses a divide-by-zero
Date: Wed, 15 Mar 2023 21:51:07 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: sanitizer
X-Bugzilla-Version: 13.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109151

            Bug ID: 109151
           Summary: UBsan misses a divide-by-zero
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: shaohua.li at inf dot ethz.ch
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxi=
n at gcc dot gnu.org
  Target Milestone: ---

For the following code, UBsan failed to report the divide-by-zero, while
Clang's UBsan could.

Compiler explorer: https://godbolt.org/z/Y73vrf8zK

%cat a.c
int a, c;
short b;
long d;
int main() {=20
    a =3D (short)(d =3D=3D c | b > 9) / 0;=20
    return a;
}
%
% gcc -fsanitize=3Dundefined a.c &&./a.out
Floating point exception
%
% clang -fsanitize=3Dundefined a.c &&./a.out
/a.c:5:42: runtime error: division by zero
%=