https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109330
Bug ID: 109330
Summary: ASAN since GCC-9 missed a stack-use-after-scope at -O3
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, ASAN at -O3 since GCC-9 missed the use-after-scope.
I checked the code and found that `*f=*g` and `return *f` were not optimized
away by the compiler.
Compiler explorer: https://godbolt.org/z/c96a6jWrY
% cat a.c
int a, c, d;
char b, e;
int main() {
int *f = &a, *g = &c;
h:
&g;
for (; 0;)
goto h;
d = 0;
for (; d <= 3; d++) {
int i = *f;
b && (e = 1);
f = &i;
}
*f = *g;
return *f;
}
% gcc-tk -O3 -fsanitize=address a.c && ./a.out
%
% gcc-8 -O3 -fsanitize=address a.c && ./a.out
================================================================
==1==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffd6b6b94d0
at pc 0x0000004008e1 bp 0x7ffd6b6b94a0 sp 0x7ffd6b6b9498
WRITE of size 4 at 0x7ffd6b6b94d0 thread T0
#0 0x4008e0 in main /a.c:15
...
%
