diff --git a/mysql-test/r/group_min_max_innodb.result b/mysql-test/r/group_min_max_innodb.result
index 6607e1babf6..0e7841e979d 100644
--- a/mysql-test/r/group_min_max_innodb.result
+++ b/mysql-test/r/group_min_max_innodb.result
@@ -94,3 +94,27 @@ pk
 drop view v1;
 drop table t1;
 End of 5.1 tests
+#
+# Bug#12540545 61101: ASSERTION FAILURE IN THREAD 1256741184 IN
+# FILE /BUILDDIR/BUILD/BUILD/MYSQ
+#
+CREATE TABLE t1 (a CHAR(1), b CHAR(1), PRIMARY KEY (a,b)) ENGINE=InnoDB;
+INSERT INTO t1 VALUES ('a', 'b'), ('c', 'd');
+EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	PRIMARY	2	NULL	2	Using where; Using index
+SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+COUNT(DISTINCT a)
+1
+DROP TABLE t1;
+CREATE TABLE t1 (a CHAR(1) NOT NULL, b CHAR(1) NOT NULL, UNIQUE KEY (a,b))
+ENGINE=InnoDB;
+INSERT INTO t1 VALUES ('a', 'b'), ('c', 'd');
+EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	a	2	NULL	2	Using where; Using index
+SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+COUNT(DISTINCT a)
+1
+DROP TABLE t1;
+End of 5.5 tests
diff --git a/mysql-test/t/group_min_max_innodb.test b/mysql-test/t/group_min_max_innodb.test
index 643b4f7d55e..7038eb2ff47 100644
--- a/mysql-test/t/group_min_max_innodb.test
+++ b/mysql-test/t/group_min_max_innodb.test
@@ -117,3 +117,23 @@ drop view v1;
 drop table t1;
 
 --echo End of 5.1 tests
+
+--echo #
+--echo # Bug#12540545 61101: ASSERTION FAILURE IN THREAD 1256741184 IN
+--echo # FILE /BUILDDIR/BUILD/BUILD/MYSQ
+--echo #
+
+CREATE TABLE t1 (a CHAR(1), b CHAR(1), PRIMARY KEY (a,b)) ENGINE=InnoDB;
+INSERT INTO t1 VALUES ('a', 'b'), ('c', 'd');
+EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+DROP TABLE t1;
+
+CREATE TABLE t1 (a CHAR(1) NOT NULL, b CHAR(1) NOT NULL, UNIQUE KEY (a,b))
+ENGINE=InnoDB;
+INSERT INTO t1 VALUES ('a', 'b'), ('c', 'd');
+EXPLAIN SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+SELECT COUNT(DISTINCT a) FROM t1 WHERE b = 'b';
+DROP TABLE t1;
+
+--echo End of 5.5 tests
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 730024f4389..8a6607cf343 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -9318,6 +9318,11 @@ cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
          except MIN and MAX. For queries with DISTINCT, aggregate functions
          are allowed.
     SA5. The select list in DISTINCT queries should not contain expressions.
+    SA6. Clustered index can not be used by GROUP_MIN_MAX quick select
+         for AGG_FUNC(DISTINCT ...) optimization because cursor position is
+         never stored after a unique key lookup in the clustered index and
+         furhter index_next/prev calls can not be used. So loose index scan
+         optimization can not be used in this case.
     GA1. If Q has a GROUP BY clause, then GA is a prefix of I. That is, if
          G_i = A_j => i = j.
     GA2. If Q has a DISTINCT clause, then there is a permutation of SA that
@@ -9804,6 +9809,13 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree, double read_time)
                                       Field::itMBR : Field::itRAW))
     DBUG_RETURN(NULL);
 
+  /*
+    Check (SA6) if clustered key is used
+  */
+  if (is_agg_distinct && index == table->s->primary_key &&
+      table->file->primary_key_is_clustered())
+    DBUG_RETURN(NULL);
+
   /* The query passes all tests, so construct a new TRP object. */
   read_plan= new (param->mem_root)
                  TRP_GROUP_MIN_MAX(have_min, have_max, is_agg_distinct,