diff --git a/src/isl/isl_priv.h b/src/isl/isl_priv.h
index 1c9343a7d1f..b399e0f8116 100644
--- a/src/isl/isl_priv.h
+++ b/src/isl/isl_priv.h
@@ -67,7 +67,7 @@ isl_is_aligned(uintmax_t n, uintmax_t a)
 static inline uintmax_t
 isl_align(uintmax_t n, uintmax_t a)
 {
-   assert(isl_is_pow2(a));
+   assert(a != 0 && isl_is_pow2(a));
    return (n + a - 1) & ~(a - 1);
 }