https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114787
Bug ID: 114787 Summary: wrong code at -O1 on x86_64-linux-gnu (the generated code hangs) 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 and does not reproduce with 13.2 and earlier. Compiler Explorer: https://godbolt.org/z/6sbh8Wr1e [663] % 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/14.0.1/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 --enable-multilib Thread model: posix Supported LTO compression algorithms: zlib gcc version 14.0.1 20240420 (experimental) (GCC) [664] % [664] % gcctk -O0 small.c; ./a.out [665] % [665] % gcctk -O1 small.c [666] % timeout -s 9 10 ./a.out Killed [667] % [667] % cat small.c int a, b, c, d, e = -1, f, g, h, j, k, n, o, p; int main() { int i, l = 2, m; for (b = 0; b < 1; b++) l = 0; for (; a >= 0; a--) for (m = 3; m; m--) { k = g; i = 0; for (; i < 1; i++) for (; f < 1; f++) h = g; n = 2 & ((e ^ d) | 1) * j; o = ~(e & n); q: if (c <= e) return 0; e = o; } p = l; l = 0; if (p) goto q; return 0; }