1 files changed, 1 insertions, 1 deletions
diff --git a/common.h b/common.h
index 77d24c4..26e4b61 100644
--- a/common.h
+++ b/common.h
@@ -79,7 +79,7 @@ ispo2(uvlong x) {
 static inline uint
 ilog2(uvlong x) { /* assumes x is a power of 2 */
 #if HAS_BUILTIN(ctz)
-   return __builtin_ctz(x);
+   return __builtin_ctzll(x);
 #else
    uint n = 0;
    while (x >>= 1) ++n;