https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103152
Bug ID: 103152 Summary: wrong code at -O1 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. [577] % 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/12.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-trunk/configure --disable-bootstrap --prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++ --disable-werror --enable-multilib --with-system-zlib Thread model: posix Supported LTO compression algorithms: zlib gcc version 12.0.0 20211109 (experimental) [master r12-5011-g2abd924f91e] (GCC) [578] % [578] % gcctk -O0 small.c; ./a.out [579] % [579] % gcctk -O1 small.c [580] % ./a.out Aborted [581] % [581] % cat small.c struct { int a:1; } b; int *c = (int *)&b, d; int main() { d = c && (b.a = (d < 0) ^ 3); if (d != 1) __builtin_abort(); return 0; }