Unbounded/large offsets are the critical part. Minimum unit where memory protection can be set is one page (4096 bytes on x86), so compiler could reasonably ass

Unbounded/large offsets are the critical part. Minimum unit where memory protection can be set is one page (4096 bytes on x86), so compiler could reasonably assume that offsets 0-4095 are always safe to dereference (in the sense that SIGSEGV is guaranteed, which can be then turned into a NullPointerException in the SIGSEGV signal handler) without a NULL check. For anything larger or array accesses, add a explicit check for NULL before dereference.