https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109107
Bug ID: 109107
Summary: UBsan since GCC-8 misses an integer-overflow
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, marxin at
gcc dot gnu.org
Target Milestone: ---
For the following code, UBsan since GCC-8 at -O1 and above misses the integer
overflow. GCC-7 can detect it at all opt levels.
Clang can detect it at all opt levels.
Compiler explorer: https://godbolt.org/z/Pez4jd5aj
% cat a.c
int a = -2147468918, c;
const long b = 676540;
int main() {
c = 1 + a - (short)b;
return c;
}
%
% gcc-tk -O1 -fsanitize=undefined a.c &&./a.out
%
% gcc-7 -O1 -fsanitize=undefined a.c &&./a.out
/a.c:4:15: runtime error: signed integer overflow: -2147468918 - 21179 cannot
be represented in type 'int'
%
