https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115661
--- Comment #1 from Zhendong Su <zhendong.su at inf dot ethz.ch> --- The following might be the same or related although it needs several flags to trigger. Compiler Explorer: https://godbolt.org/z/Y9414PbTh [567] % 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/15.0.0/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 --enable-multilib Thread model: posix Supported LTO compression algorithms: zlib gcc version 15.0.0 20240626 (experimental) (GCC) [568] % [568] % gcctk -O2 small.c; ./a.out [569] % [569] % gcctk -O2 -fno-tree-pre -fschedule-insns -fno-forward-propagate -fno-guess-branch-probability -fno-gcse small.c [570] % ./a.out 0 [571] % [571] % cat small.c int printf(const char *, ...); struct { unsigned : 8; volatile unsigned b : 1; int c : 31; int d : 5; } g, k, m, n, p; unsigned e = 5; volatile int f = 1; int h, i, l, o, r, q; long j, a; int main() { if (0) L: for (; e; e++) ; for (; j < 5; j = 0) if (f) { int t = 7 - (((k.d | 7) ^ m.c) - a) - ~(n.b & -o), u, v = -t ^ q, w = e - h; u = k.d; if (i) { if (w > 6) goto L; printf("%d", l); } g.d = (g.d & (n.b - 5)) - (-((k.d - 7 - o) & t) ^ (v & q)); n.b = t; m.c = ~(t - (7L & m.c)); k.d = ~(a & (m.c | ~o) & ~u) & g.d; if ((unsigned) p.d >= e) printf("0\n"); return 0; } return 0; }
