Fixed bug #22129: A small double precision number becomes zero

Better checks for underflow/overflow

mysql-test/r/type_float.result

@@ -272,3 +272,10 @@ desc t3;
 Field	Type	Null	Key	Default	Extra
 a	double			0	
 drop table t1,t2,t3;
+select 1e-308, 1.00000001e-300, 100000000e-300;
+1e-308	1.00000001e-300	100000000e-300
+0	1.00000001e-300	1e-292
+select 10e307;
+10e307
+1e+308
+End of 4.1 tests

mysql-test/t/type_float.test

@@ -179,4 +179,13 @@ show warnings;
 desc t3;
 drop table t1,t2,t3;
 
-# End of 4.1 tests
+#
+# Bug #22129: A small double precision number becomes zero
+#
+# check if underflows are detected correctly
+select 1e-308, 1.00000001e-300, 100000000e-300;
+
+# check if overflows are detected correctly
+select 10e307;
+
+--echo End of 4.1 tests