https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114787
Bug ID: 114787
Summary: wrong code at -O1 on x86_64-linux-gnu (the generated
code hangs)
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 and does not reproduce with 13.2 and
earlier.
Compiler Explorer: https://godbolt.org/z/6sbh8Wr1e
[663] % 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/14.0.1/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
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.1 20240420 (experimental) (GCC)
[664] %
[664] % gcctk -O0 small.c; ./a.out
[665] %
[665] % gcctk -O1 small.c
[666] % timeout -s 9 10 ./a.out
Killed
[667] %
[667] % cat small.c
int a, b, c, d, e = -1, f, g, h, j, k, n, o, p;
int main() {
int i, l = 2, m;
for (b = 0; b < 1; b++)
l = 0;
for (; a >= 0; a--)
for (m = 3; m; m--) {
k = g;
i = 0;
for (; i < 1; i++)
for (; f < 1; f++)
h = g;
n = 2 & ((e ^ d) | 1) * j;
o = ~(e & n);
q:
if (c <= e)
return 0;
e = o;
}
p = l;
l = 0;
if (p)
goto q;
return 0;
}
