diff --git a/library/md4.c b/library/md4.c
index 563c653..dcd9313 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -47,13 +47,13 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST */
 
+#if !defined(MBEDTLS_MD4_ALT)
+
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
 }
 
-#if !defined(MBEDTLS_MD4_ALT)
-
 /*
  * 32-bit integer manipulation macros (little endian)
  */