diff --git a/src/libcollections/bitv.rs b/src/libcollections/bitv.rs
index 9f26c0980131f..6da998b136f9e 100644
--- a/src/libcollections/bitv.rs
+++ b/src/libcollections/bitv.rs
@@ -33,7 +33,7 @@
 //!     bv.set(0, false);
 //!     bv.set(1, false);
 //!
-//!     for i in range(2, max_prime) {
+//!     for i in iter::range_inclusive(2, (max_prime as f64).sqrt() as uint) {
 //!         // if i is a prime
 //!         if bv[i] {
 //!             // Mark all multiples of i as non-prime (any multiples below i * i