diff --git a/library/common.h b/library/common.h
index 839b7d1..2d35814 100644
--- a/library/common.h
+++ b/library/common.h
@@ -291,8 +291,8 @@
 /* Define compiler branch hints */
 #if defined(__has_builtin)
 #if __has_builtin(__builtin_expect)
-#define MBEDTLS_LIKELY(x)       __builtin_expect((x), 1)
-#define MBEDTLS_UNLIKELY(x)     __builtin_expect((x), 0)
+#define MBEDTLS_LIKELY(x)       __builtin_expect(!!(x), 1)
+#define MBEDTLS_UNLIKELY(x)     __builtin_expect(!!(x), 0)
 #endif
 #endif
 #if !defined(MBEDTLS_LIKELY)