https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108007
Bug ID: 108007
Summary: wrong code at -Os and above with "-fno-dce
-fno-tree-dce" on x86_64-linux-gnu
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zhendong.su at inf dot ethz.ch
Target Milestone: ---
Compiler Explorer: https://godbolt.org/z/51r5Kqr9q
It appears to be a regression from 9.*, and affects 10.* till trunk.
[599] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/13.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++ --disable-werror --enable-multilib
--with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221207 (experimental) [master r13-4532-gda7fb32d403] (GCC)
[600] %
[600] % gcctk -Os -fno-dce -fno-tree-dce small.c
[601] % ./a.out
Segmentation fault
[602] %
[602] % cat small.c
int a, b, d, e, f = 10000000, h;
short c, g;
static int *i() {
g = f;
L:
h = e = ~g;
g = ~f % g & e;
if (!g)
goto L;
c++;
while (g < 1)
;
return &a;
}
static void k() {
int *l, m = 2;
l = i();
for (; d < 1; d++)
m |= *l >= b;
}
int main() {
k();
return 0;
}
