cleanup for Item_func_regex (Bug #4199)

mysql-test/r/func_regexp.result:
  test of cleaning regex in PS
mysql-test/t/func_regexp.test:
  test of cleaning regex in PS
sql/item_cmpfunc.cc:
  cleanup for Item_func_regex
sql/item_cmpfunc.h:
  cleanup for Item_func_regex

mysql-test/r/func_regexp.result

@@ -81,3 +81,20 @@ _latin1'a' regexp _latin1'A' collate latin1_general_ci
 select _latin1'a' regexp _latin1'A' collate latin1_bin;
 _latin1'a' regexp _latin1'A' collate latin1_bin
 0
+create table t1 (a varchar(40));
+insert into t1 values ('C1'),('C2'),('R1'),('C3'),('R2'),('R3');
+prepare stmt1 from 'select a from t1 where a rlike ? order by a';
+set @a="^C.*";
+execute stmt1 using @a;
+a
+C1
+C2
+C3
+set @a="^R.*";
+execute stmt1 using @a;
+a
+R1
+R2
+R3
+deallocate prepare stmt1;
+drop table t1;

mysql-test/t/func_regexp.test

@@ -60,3 +60,16 @@ select _koi8r  0xF7 regexp _koi8r  '[[:alpha:]]';
 
 select _latin1'a' regexp _latin1'A' collate latin1_general_ci;
 select _latin1'a' regexp _latin1'A' collate latin1_bin;
+
+#
+# regexp cleanup()
+#
+create table t1 (a varchar(40));
+insert into t1 values ('C1'),('C2'),('R1'),('C3'),('R2'),('R3');
+prepare stmt1 from 'select a from t1 where a rlike ? order by a';
+set @a="^C.*";
+execute stmt1 using @a;
+set @a="^R.*";
+execute stmt1 using @a;
+deallocate prepare stmt1;
+drop table t1;

sql/item_cmpfunc.cc

@@ -2298,15 +2298,19 @@ longlong Item_func_regex::val_int()
 }
 
 
-Item_func_regex::~Item_func_regex()
+void Item_func_regex::cleanup()
 {
+  DBUG_ENTER("Item_func_regex::cleanup");
+  Item_bool_func::cleanup();
   if (regex_compiled)
   {
     regfree(&preg);
     regex_compiled=0;
   }
+  DBUG_VOID_RETURN;
 }
 
+
 #endif /* USE_REGEX */
 
 

sql/item_cmpfunc.h

@@ -869,7 +869,7 @@ class Item_func_regex :public Item_bool_func
 public:
   Item_func_regex(Item *a,Item *b) :Item_bool_func(a,b),
     regex_compiled(0),regex_is_const(0) {}
-  ~Item_func_regex();
+  void cleanup();
   longlong val_int();
   bool fix_fields(THD *thd, struct st_table_list *tlist, Item **ref);
   const char *func_name() const { return "regexp"; }