diff --git a/util/romcc/romcc.c b/util/romcc/romcc.c
index c2f5deed6c..4f267c2243 100644
--- a/util/romcc/romcc.c
+++ b/util/romcc/romcc.c
@@ -14250,7 +14250,7 @@ static void compute_closure_variables(struct compile_state *state,
 		}
 		/* Find the lowest unused index value */
 		for(index = 0; index < MAX_INDICIES; index++) {
-			if (!(used_indicies & (1 << index))) {
+			if (!(used_indicies & ((uint64_t)1 << index))) {
 				break;
 			}
 		}