---

yaml
---
r: 104142
b: refs/heads/try
c: 7dc187a
h: refs/heads/master
v: v3

Author: pnkfelix

[refs]

@@ -2,7 +2,7 @@
 refs/heads/master: 62f1d68439dcfd509eaca29887afa97f22938373
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: 6e7f170fedd3c526a643c0b2d13863acd982be02
-refs/heads/try: 606c23a78920c03758e200004fd9d1f4257f0325
+refs/heads/try: 7dc187afd8a19dad05dbf1a689e6b6f400f7bc0a
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: 147ecfdd8221e4a4d4e090486829a06da1e0ca3c

branches/try/src/libnum/bigint.rs

@@ -784,11 +784,12 @@ impl BigUint {
         if n_bits == 0 || self.data.is_empty() { return (*self).clone(); }
 
         let mut borrow = 0;
-        let mut shifted = ~[];
+        let mut shifted_rev = vec::with_capacity(self.data.len());
         for elem in self.data.rev_iter() {
-            shifted = ~[(*elem >> n_bits) | borrow] + shifted;
+            shifted_rev.push((*elem >> n_bits) | borrow);
             borrow = *elem << (BigDigit::bits - n_bits);
         }
+        let shifted = { shifted_rev.reverse(); shifted_rev };
         return BigUint::new(shifted);
     }
 
@@ -2637,4 +2638,15 @@ mod bench {
             fib.to_str();
         });
     }
+
+    #[bench]
+    fn shr(bh: &mut BenchHarness) {
+        let n = { let one : BigUint = One::one(); one << 1000 };
+        bh.iter(|| {
+            let mut m = n.clone();
+            for _ in range(0, 10) {
+                m = m >> 1;
+            }
+        })
+    }
 }