==2761== Thread 10:
==2761== Conditional jump or move depends on uninitialised value(s)
==2761==    at 0x8115FD2: Item_func_uncompressed_length::val_int() (sql_string.h:90)
==2761==    by 0x8105658: Arg_comparator::compare_int() (item_cmpfunc.cc:356)
and
==2761== Thread 10:
==2761== Conditional jump or move depends on uninitialised value(s)
==2761==    at 0x8116101: Item_func_compress::val_str(String*) (sql_string.h:90)
==2761==    by 0x80E9193: Item::save_in_field(Field*, bool) (item.cc:1155)


sql/item_strfunc.cc:
  ptr() is used instead of c_ptr(), because it is safe enough, more efficient and do not confuse valgrind