diff --git a/tcctest.c b/tcctest.c
index 69c5bf6..b68ce7b 100644
--- a/tcctest.c
+++ b/tcctest.c
@@ -311,7 +311,11 @@ test\14\
 
 void string_test()
 {
+#if defined(__x86_64__) && defined(__GNUC__)
+    unsigned int b;
+#else
     int b;
+#endif
     printf("string:\n");
     printf("\141\1423\143\n");/* dezdez test */
     printf("\x41\x42\x43\x3a\n");