[Bug tree-optimization/107273] New: wrong code at -O3 on x86_64-linux-gnu
zhendong.su at inf dot ethz.ch
gcc-bugzilla@gcc.gnu.org
Sat Oct 15 20:53:04 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107273
Bug ID: 107273
Summary: wrong code at -O3 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: ---
It appears to be a recent regression.
Compiler Explorer: https://godbolt.org/z/Mo8sPhYW7
[538] % 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 20221015 (experimental) [master r13-3311-gbaeec7cc83b] (GCC)
[539] %
[539] % gcctk -O2 small.c; ./a.out
[540] %
[540] % gcctk -O3 small.c
[541] % ./a.out
Segmentation fault
[542] %
[542] % cat small.c
int printf(const char *, ...);
int a[1] = {1};
short b, c = 5500;
int d;
long e;
char f = 1;
int main() {
while (1) {
long g = b < 1;
e = g;
break;
}
for (; f; f--) {
if (e) {
d = -(6L | -(c & 1000));
}
char h = d;
if (b)
b = 0;
if (d < 200)
while (1)
printf("%d", a[c]);
short i = h * 210;
c = i;
}
return 0;
}
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