diff --git a/internal.h b/internal.h
index a9b3ee4824..06f61d85fe 100644
--- a/internal.h
+++ b/internal.h
@@ -25,8 +25,8 @@ extern "C" {
 
 /* likely */
 #if __GNUC__ >= 3
-#define LIKELY(x)   (__builtin_expect(!(x), 0))
-#define UNLIKELY(x) (__builtin_expect(!(x), 1))
+#define LIKELY(x)   (__builtin_expect(!!(x), 1))
+#define UNLIKELY(x) (__builtin_expect(!!(x), 0))
 #else /* __GNUC__ >= 3 */
 #define LIKELY(x)   (x)
 #define UNLIKELY(x) (x)