Merge remote-tracking branch 'origin/5.5' into bb-10.0-bar

sql/item.h

@@ -4027,7 +4027,7 @@ class Item_int_with_ref :public Item_int
   Base class to implement typed value caching Item classes
 
   Item_copy_ classes are very similar to the corresponding Item_
-  classes (e.g. Item_copy_int is similar to Item_int) but they add
+  classes (e.g. Item_copy_string is similar to Item_string) but they add
   the following additional functionality to Item_ :
     1. Nullability
     2. Possibility to store the value not only on instantiation time,

sql/sql_type_int.h

@@ -33,7 +33,11 @@ class Longlong_hybrid
   bool neg() const { return m_value < 0 && !m_unsigned; }
   ulonglong abs() const
   {
-    return neg() ? (ulonglong) -m_value : (ulonglong) m_value;
+    if (m_unsigned)
+      return (ulonglong) m_value;
+    if (m_value == LONGLONG_MIN) // avoid undefined behavior
+      return ((ulonglong) LONGLONG_MAX) + 1;
+    return m_value < 0 ? -m_value : m_value;
   }
 };