BUG #4114: Inconsistent shift operator

The following bug has been logged online:

Bug reference:      4114
Logged by:          Roman Kononov
Email address:      kononov@dls.net
PostgreSQL version: 8.3.1
Operating system:   x86_64 GNU/Linux
Description:        Inconsistent shift operator
Details:

The below test cases show the obvious inconsistency between different
integer types.

test=# \t
Showing only tuples.
test=# select 1::int2 << 17;
         0

test=# select 1::int4 << 33;
         2

test=# select 1::int8 << 65;
         2

test=# select 2::int2 >> 17;
         0

test=# select 2::int4 >> 33;
         1

test=# select 2::int8 >> 65;
         1