https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110702
Bug ID: 110702 Summary: Wrong code at -O1 on x86_64-linux-gnu (regression since GCC-12.2) 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-12.2. Compiler explorer: https://godbolt.org/z/655af97j7 $ cat a.c int printf(const char *, ...); int a, b, c, d; long e[9][7][4]; void f() { for (; a >= 0; a--) { b = 0; for (; b <= 3; b++) { c = 0; for (; c <= 3; c++) { int *g = &d; *g = e[0][0][b] | e[a][b][a]; } } } } int main() { f(); printf("%d\n", a); } $ $ gcc-tk -O0 a.c && ./a.out -1 $ gcc-tk -O1 a.c && ./a.out 0 $ $ 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) $