https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117480
Bug ID: 117480
Summary: wrong code at -O1 and above 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: ---
This appears to be a recent regression as it doesn't reproduce with 14.2 and
earlier.
Compiler Explorer: https://godbolt.org/z/91fxrzE49
[607] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/home/suz/suz-local/software/local/gcc-trunk/bin/../libexec/gcc/x86_64-pc-linux-gnu/15.0.0/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
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 15.0.0 20241107 (experimental) (GCC)
[608] %
[608] % gcctk -O0 small.c; ./a.out
[609] %
[609] % gcctk -O1 small.c
[610] % ./a.out
Aborted
[611] %
[611] % cat small.c
int c = 0x1FF;
int main() {
if (((c ^ 0xFF) & 0xFF) != 0)
__builtin_abort();
return 0;
}