https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113703
--- Comment #2 from Krister Walfridsson <kristerw at gcc dot gnu.org> --- Here is a runtime testcase: #include <sys/mman.h> #include <unistd.h> #include <stdint.h> __attribute__((noipa)) void f1 (char *p, uintptr_t i, uintptr_t n) { p += i; do { *p = '\0'; p += 1; i++; } while (i < n); } int main() { long pgsz = sysconf (_SC_PAGESIZE); void *p = mmap (NULL, pgsz * 2, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, 0, 0); if (p == MAP_FAILED) return 0; mprotect (p+pgsz, pgsz, PROT_NONE); uintptr_t n = -3 - (uintptr_t)p; f1 (p+2, -2, n); return 0; }