diff --git a/lib/string.c b/lib/string.c
index 89f0f8d..4781312 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -74,16 +74,6 @@ void *memmove(void *dest, const void *src, size_t n)
     return dest;
 }
 
-void *memset(void *s, int c, size_t n)
-{
-    char *d = (char *)s;
-
-    for (size_t i = 0; i < n; i++) {
-        d[i] = c;
-    }
-    return s;
-}
-
 size_t strlen(const char *s)
 {
     size_t len = 0;
diff --git a/lib/string.h b/lib/string.h
index 37bd392..b6e877a 100644
--- a/lib/string.h
+++ b/lib/string.h
@@ -37,8 +37,9 @@ void *memmove(void *dest, const void *src, size_t n);
 /**
  * Fills the first n bytes of the memory area pointed to by s with the byte
  * value c.
+ * void *memset(void *s, int c, size_t n);
  */
-void *memset(void *s, int c, size_t n);
+#define memset(s, c, n) __builtin_memset((s), (c), (n))
 
 /**
  * Returns the string length, excluding the terminating null character.