https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110640
Bug ID: 110640
Summary: Wrong code at -O2/3 on x86_64-linux-gnu since GCC-13
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: ---
This looks like a regression since GCC-13. gcc produces wrong code at -O2/3.
Compiler explorer: https://godbolt.org/z/5MWe6eK8M
$ cat a.c
unsigned short a = 65535;
int b, f, g;
int *c = &b;
long d;
short e;
static int *h(int);
void i() { h(a); }
int *h(int j) {
unsigned char k;
for (; e != 8; e = e + 4)
k = 0;
for (; (unsigned char)(j-181249535) + k <= 1; k++) {
*c = d;
for (; f; f++)
;
}
return &g;
}
int main() { i(); }
$
$ gcc-tk -O0 a.c && ./a.out
$
$ gcc-tk -O2 a.c
$ ./a.out
Killed
$ gcc-tk -O3 a.c
$ ./a.out
Killed
$
$ gcc-tk -v
Using built-in specs.
COLLECT_GCC=gcc-tk
COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-322d17ae51ea0137167424e0018d7fa355948f9f/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-322d17ae51ea0137167424e0018d7fa355948f9f
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230711 (experimental) (GCC)
$
