https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110599
Bug ID: 110599 Summary: wrong code at -Os and above with "-fno-tree-forwprop -fno-tree-fre" 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. Compiler Explorer: https://godbolt.org/z/jdrTeEser [501] % 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/14.0.0/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 --disable-multilib Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.0 20230708 (experimental) (GCC) [502] % [502] % gcctk -O2 small.c; ./a.out 1 [503] % gcctk -O2 -fno-tree-forwprop -fno-tree-fre small.c; ./a.out -1 [504] % cat small.c int printf(const char *, ...); int a, b; int main() { b = ~b; a = b ^ (a && 1) || b; printf("%d\n", a); return 0; }