https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110115
Bug ID: 110115
Summary: Wrong code at -O1 on x86_64-linux-gnu
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
Target Milestone: ---
gcc at -O1 emits the wrong code. This seems to be a long latent bug.
Compiler explorer: https://godbolt.org/z/3h4TYEYjW
$ cat a.c
int a;
char b;
static int c(char *e, int f) {
int d = 0;
for (; d < f; d++)
e[d] = 0;
return d;
}
int g(char e, int f) {
char h[20];
int i = c(h, f);
return i;
}
int j() {
switch (a) {
case 'f':
return 0;
default:
return ~0;
}
}
int main() {
{
char *k[3];
int d = 0;
for (; g(8, 15) - 15 + d < 1; d++)
k[j()+1] = &b;
*k[0] = -*k[0];
}
}
$
$ gcc-tk -O0 a.c && ./a.out
$
$ gcc-tk -O1 a.c && ./a.out
Segmentation fault
$
$ gcc-tk -fsanitize=address,undefined a.c && ./a.out
$
$ gcc-tk -v
Using built-in specs.
COLLECT_GCC=gcc-tk
COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-8d5f050dabbf6dd3b992c3b46661848dbcf30d9e/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++
--prefix=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-8d5f050dabbf6dd3b992c3b46661848dbcf30d9e
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230523 (experimental) (GCC)
$
