Fix typecast warnings-as-errors on Windows.

mysql-test/main/opt_trace.result

@@ -2471,9 +2471,9 @@ explain  select * from t1 where a=1 and b=2 order by c limit 1	{
                   "index": "a_c",
                   "can_resolve_order": true,
                   "direction": 1,
-                  "rows_to_examine": 4,
+                  "rows_to_examine": 4.390243902,
                   "range_scan": true,
-                  "scan_cost": 10.5218905,
+                  "scan_cost": 11.5484164,
                   "chosen": true
                 },
                 {

sql/opt_subselect.cc

@@ -2555,8 +2555,12 @@ bool optimize_semijoin_nests(JOIN *join, table_map all_table_map)
           int tableno;
           double rows= 1.0;
           while ((tableno = tm_it.next_bit()) != Table_map_iterator::BITMAP_END)
-            rows= COST_MULT(rows,
-			    join->map2table[tableno]->table->opt_range_condition_rows);
+          {
+            ha_rows tbl_rows=join->map2table[tableno]->
+                             table->opt_range_condition_rows;
+
+            rows= COST_MULT(rows, rows2double(tbl_rows));
+          }
           sjm->rows= MY_MIN(sjm->rows, rows);
         }
         memcpy((uchar*) sjm->positions,

sql/sql_select.cc

@@ -30033,11 +30033,12 @@ void JOIN::cache_const_exprs()
 static bool get_range_limit_read_cost(const POSITION *pos,
                                       const TABLE *table,
                                       uint keynr,
-                                      ha_rows rows_limit,
+                                      ha_rows rows_limit_arg,
                                       ha_rows rows_to_scan,
                                       double *read_cost,
                                       double *read_rows)
 {
+  double rows_limit= rows2double(rows_limit_arg);
   if (table->opt_range_keys.is_set(keynr))
   {
     /*
@@ -30108,7 +30109,7 @@ static bool get_range_limit_read_cost(const POSITION *pos,
                                             HA_ROWS_MAX);
   *read_cost= (cost.read_cost +
                rows_to_scan * WHERE_COST_THD(table->in_use));
-  *read_rows= rows_to_scan;
+  *read_rows= rows2double(rows_to_scan);
   return 0;
 }