https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108584
Bug ID: 108584 Summary: wrong code at -O2 and -O3 with "-fno-tree-ccp" 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: --- It appears to be a recent regression from 12.2. Compiler Explorer: https://godbolt.org/z/ssjeaxd8a [594] % 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/13.0.1/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 13.0.1 20230128 (experimental) [master r12-4647-g3f861a5c8fd] (GCC) [595] % [595] % gcctk -O3 small.c; ./a.out [596] % [596] % gcctk -O3 -fno-tree-ccp small.c [597] % ./a.out Floating point exception [598] % [598] % cat small.c char a; volatile int b; short c; void d() { int e = 0, f; b = 1; if (!b) goto L; unsigned h = 1; for (f = 0; f < 2; f++) { char i = ~c % h; short j = ~(i & e & (0 || a & c)); h && a; if (h < 3) L: j = h; e = c = h = j; } } int main() { d(); return 0; }