Issues with generate_series using integer boundaries

Hi,

I've noticed that if I try to use generate_series to include the upper
boundary of int4, it never returns:

SELECT x FROM generate_series(2147483643::int4, 2147483647::int4) AS a(x);

But the same query with int8 returns instantly:

SELECT x FROM generate_series(2147483643::int8, 2147483647::int8) AS a(x);

However, the int8 version of generate_series has the same problem.
This never returns:

SELECT x FROM generate_series(9223372036854775803::int8,
9223372036854775807::int8) AS a(x);

Another issue happens when using the lower boundaries:

postgres=# SELECT x FROM generate_series(-2147483648::int4,
-2147483644::int4) AS a(x);
ERROR:  integer out of range
postgres=# SELECT x FROM generate_series(-9223372036854775808::int8,
-9223372036854775804::int8) AS a(x);
ERROR:  bigint out of range

I've recreated this on 9.0.1 and 9.1devel on a 64-bit platform.

Bug?

--
Thom Brown
Twitter: @darkixion
IRC (freenode): dark_ixion
Registered Linux user: #516935