https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110243
Bug ID: 110243 Summary: Wrong code at -O3 on x86_64-linux-gnu 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: --- Since GCC-13, gcc at -O3 produces wrong code. Compiler explorer: https://godbolt.org/z/jnroxhddY $ cat a.c #define X 1100000000 char a; long b = X; int c[9][1]; unsigned d; static long *e = &b, *f = &b; int g() { if (a && a <= '9') return '0'; if (a) return 10; return -1; } int main() { d = 0; for (; (int)*f -(X-1) + d < 9; d++) c[g() + (int)*f + ((int)*e - X) -(X-1) + d] [0] = 0; } $ $ gcc-tk -O3 a.c &&./a.out Segmentation fault $ $ gcc-tk -O0 a.c &&./a.out $ $ gcc-tk -fsanitize=address,undefined a.c &&./a.out $ $ gcc-tk -v Using built-in specs. COLLECT_GCC=gcc-tk COLLECT_LTO_WRAPPER=/zdata/shaoli/compilers/ccbuilder-compilers/gcc-bf470895905e9152424076d1630a9d2c60de023b/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-bf470895905e9152424076d1630a9d2c60de023b Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 20230612 (experimental) (GCC) $