+static size_t mal0_clear(char *p, size_t n)
+{
+ const size_t pagesz = 4096; /* arbitrary */
+ if (n < pagesz) return n;
+#ifdef __GNUC__
+ typedef uint64_t __attribute__((__may_alias__)) T;
+#else
+ typedef unsigned char T;
+#endif
+ char *pp = p + n;
+ size_t i = (uintptr_t)pp & (pagesz - 1);
+ for (;;) {
+ pp = memset(pp - i, 0, i);
+ if (pp - p < pagesz) return pp - p;
+ for (i = pagesz; i; i -= 2*sizeof(T), pp -= 2*sizeof(T))
+ if (((T *)pp)[-1] | ((T *)pp)[-2])
+ break;
+ }
+}
+
+static int allzerop(void *p)
+{
+ return 0;
+}
+weak_alias(allzerop, __malloc_allzerop);