--- a/xmlstring.c	2016-05-13 17:24:58.870079372 +0900
+++ b/xmlstring.c	2016-04-25 13:58:09.879238595 +0900
@@ -835,16 +835,20 @@
     while ( len-- > 0) {
         if ( !*ptr )
             break;
-        if ( (ch = *ptr++) & 0x80)
-            while ((ch<<=1) & 0x80 ) {
-		if (*ptr == 0) break;
+        if ( (ch = *ptr++) & 0x80) {
+            // Workaround for an optimization bug in VS 2015 Update 2, remove
+            // once the fix is released. crbug.com/599427
+            // https://connect.microsoft.com/VisualStudio/feedback/details/2582138
+            xmlChar ch2 = ch;
+            while ((ch2<<=1) & 0x80 ) {
                 ptr++;
-	    }
+                if (*ptr == 0) break;
+            }
+        }
     }
     return (ptr - utf);
 }
 
-
 /**
  * xmlUTF8Strndup:
  * @utf:  the input UTF8 *