The following test case extracted from subselect_sj.test fails with MDEV-83 due to early subquery optimization.

drop table if exists t0, t1, t2, t10;

set @@storage_engine=myisam;

create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1(a int, b int);
insert into t1 values (0,0),(1,1),(2,2);
create table t10 (pk int, a int, primary key(pk));
insert into t10 select a,a from t0;
create table t2 as select * from t1;

– Force a very simple query plan
set join_cache_level=0;
set optimizer_switch='semijoin=off';

select *
from t1 left join t2 on (t2.a= t1.a and t2.a in (select pk from t10))
where t1.a < 5;

prepare s1 from
' select * from
t1 left join t2 on (t2.a= t1.a and t2.a in (select pk from t10))
where t1.a < 5';
execute s1;
execute s1;