The following seed seems to cause csmith (github version) to hang. If these hangs aren't interesting, just let me know. /* * This is a RANDOMLY GENERATED PROGRAM. * * Generator: csmith 2.1.0 * Git version: a5e5fd1 * Options: --bitfields --packed-struct --output test4.c * Seed: 386941147 */ #include "csmith.h" static long __undefined;