The warnings look like this:

main.subquery_cache                      w2 [ fail ]  Found warnings/errors in server log file!
        Test ended at 2010-07-15 18:44:58
line
==17469== Thread 4:
==17469== Conditional jump or move depends on uninitialised value(s)
==17469==    at 0x8B141F: hp_search (hp_hash.c:213)
==17469==    by 0x8B51DA: heap_rkey (hp_rkey.c:61)
==17469==    by 0x8AED92: ha_heap::index_read_map(unsigned char*, unsigned char const*, unsigned long, ha_rkey_function) (ha_heap.cc:279)
==17469==    by 0x6D90B5: join_read_key2(THD*, st_join_table*, st_table*, st_table_ref*) (sql_class.h:3393)
==17469==    by 0x8468EA: Expression_cache_tmptable::check_value(Item**) (sql_expression_cache.cc:248)
==17469==    by 0x579804: Item_cache_wrapper::val_bool() (item.cc:6710)
==17469==    by 0x5B5EC1: Item_func_not::val_int() (item_cmpfunc.cc:287)
==17469==    by 0x6CC522: evaluate_join_record(JOIN*, st_join_table*, int) (sql_select.cc:13197)
==17469==    by 0x6CC95D: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:13142)
==17469==    by 0x6E832C: do_select(JOIN*, List<Item>*, st_table*, Procedure*) (sql_select.cc:12649)
==17469==    by 0x6E94C0: JOIN::exec() (sql_select.cc:2355)
==17469==    by 0x6EAC59: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:2556)
==17469==    by 0x6EF418: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:276)
==17469==    by 0x65F882: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5081)
==17469==    by 0x666FFD: mysql_execute_command(THD*) (sql_parse.cc:2265)
==17469==    by 0x66BB8F: mysql_parse(THD*, char const*, unsigned int, char const**) (sql_parse.cc:6027)
==17469== Conditional jump or move depends on uninitialised value(s)
==17469==    at 0x8AFD4E: hp_mask (hp_hash.c:213)
==17469==    by 0x8B29DA: hp_write_key (hp_write.c:236)
==17469==    by 0x8B2D85: heap_write (hp_write.c:51)
==17469==    by 0x8AEF28: ha_heap::write_row(unsigned char*) (ha_heap.cc:224)
==17469==    by 0x78D798: handler::ha_write_row(unsigned char*) (handler.cc:4715)
==17469==    by 0x845CC4: Expression_cache_tmptable::put_value(Item*) (sql_expression_cache.cc:294)
==17469==    by 0x579852: Item_cache_wrapper::val_bool() (item.cc:6726)
==17469==    by 0x5B5EC1: Item_func_not::val_int() (item_cmpfunc.cc:287)
==17469==    by 0x6CC522: evaluate_join_record(JOIN*, st_join_table*, int) (sql_select.cc:13197)
==17469==    by 0x6CC95D: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:13142)
==17469==    by 0x6E832C: do_select(JOIN*, List<Item>*, st_table*, Procedure*) (sql_select.cc:12649)
==17469==    by 0x6E94C0: JOIN::exec() (sql_select.cc:2355)
==17469==    by 0x6EAC59: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:2556)
==17469==    by 0x6EF418: handle_select(THD*, st_lex*, select_result*, unsigned long) (sql_select.cc:276)
==17469==    by 0x65F882: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5081)
==17469==    by 0x666FFD: mysql_execute_command(THD*) (sql_parse.cc:2265)