Merge mysql.com:/home/ram/work/b19690/b19690.4.1

into  mysql.com:/home/ram/work/b19690/b19690.5.0


mysql-test/r/type_float.result:
  Auto merged
mysql-test/t/type_float.test:
  Auto merged
sql/field.cc:
  Auto merged
sql/item_cmpfunc.h:
  Auto merged
sql/mysqld.cc:
  Auto merged
sql/field.h:
  merging
sql/init.cc:
  merging
sql/item_cmpfunc.cc:
  merging
sql/mysql_priv.h:
  merging
sql/sql_select.cc:
  merging

1 files changed, 49 insertions, 0 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 936ae04e93d..0daba495f62 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -422,6 +422,17 @@ int Arg_comparator::set_compare_func(Item_bool_func2 *item, Item_result type)
   default:
     DBUG_ASSERT(0);
   }
+  else if (type == REAL_RESULT)
+  {
+    if ((*a)->decimals < NOT_FIXED_DEC && (*b)->decimals < NOT_FIXED_DEC)
+    {
+      precision= 5 * log_01[max((*a)->decimals, (*b)->decimals)];
+      if (func == &Arg_comparator::compare_real)
+        func= &Arg_comparator::compare_real_fixed;
+      else if (func == &Arg_comparator::compare_e_real)
+        func= &Arg_comparator::compare_e_real_fixed;
+    }
+  }
   return 0;
 }
 
@@ -557,6 +568,44 @@ int Arg_comparator::compare_e_decimal()
   return test(my_decimal_cmp(val1, val2) == 0);
 }
 
+
+int Arg_comparator::compare_real_fixed()
+{
+  /*
+    Fix yet another manifestation of Bug#2338. 'Volatile' will instruct
+    gcc to flush double values out of 80-bit Intel FPU registers before
+    performing the comparison.
+  */
+  volatile double val1, val2;
+  val1= (*a)->val();
+  if (!(*a)->null_value)
+  {
+    val2= (*b)->val();
+    if (!(*b)->null_value)
+    {
+      owner->null_value= 0;
+      if (val1 == val2 || fabs(val1 - val2) < precision)
+        return 0;
+      if (val1 < val2)
+        return -1;
+      return 1;
+    }
+  }
+  owner->null_value= 1;
+  return -1;
+}
+
+
+int Arg_comparator::compare_e_real_fixed()
+{
+  double val1= (*a)->val();
+  double val2= (*b)->val();
+  if ((*a)->null_value || (*b)->null_value)
+    return test((*a)->null_value && (*b)->null_value);
+  return test(val1 == val2 || fabs(val1 - val2) < precision);
+}
+
+
 int Arg_comparator::compare_int_signed()
 {
   longlong val1= (*a)->val_int();