---

yaml
---
r: 275766
b: refs/heads/auto
c: 7b33d39
h: refs/heads/master

Author: ranma42

[refs]

@@ -8,7 +8,7 @@ refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/tags/release-0.3.1: 495bae036dfe5ec6ceafd3312b4dca48741e845b
 refs/tags/release-0.4: e828ea2080499553b97dfe33b3f4d472b4562ad7
 refs/tags/release-0.5: 7e3bcfbf21278251ee936ad53e92e9b719702d73
-refs/heads/auto: 2fd2670ea0a55b7f7481c5ce2a95c5c5033941d5
+refs/heads/auto: 7b33d39da93a9873fa002c6875c934fd13ec7d4a
 refs/tags/release-0.6: b4ebcfa1812664df5e142f0134a5faea3918544c
 refs/tags/0.1: b19db808c2793fe2976759b85a355c3ad8c8b336
 refs/tags/0.2: 1754d02027f2924bed83b0160ee340c7f41d5ea1

branches/auto/src/libcore/char.rs

@@ -299,14 +299,16 @@ impl CharExt for char {
 
     #[inline]
     fn escape_unicode(self) -> EscapeUnicode {
-        let mut n = 0;
-        while (self as u32) >> (4 * (n + 1)) != 0 {
-            n += 1;
-        }
+        let c = self as u32;
+        // or-ing 1 ensures that for c==0 the code computes that one
+        // digit should be printed and (which is the same) avoids the
+        // (31 - 32) underflow
+        let msb = 31 - (c | 1).leading_zeros();
+        let msdigit = msb / 4;
         EscapeUnicode {
             c: self,
             state: EscapeUnicodeState::Backslash,
-            offset: n,
+            offset: msdigit as usize,
         }
     }