BUG #3289: SIN(PI()) expected to return 0, but returns garbage

The following bug has been logged online:

Bug reference:      3289
Logged by:          Daniel Kastenholz
Email address:      mail@danielkastenholz.de
PostgreSQL version: 8.1, 8.2.4
Operating system:   Linux, Windows
Description:        SIN(PI()) expected to return 0, but returns garbage
Details:

Trouble case:

Action:
Type in SELECT SIN(PI())

Expected output:
0

Actual output:
* Windows, using 8.2.4:
  garbage (-2.2......)

* Linux, using 8.1:
  garbage (1.22.......)

--

Comments:
SIN(3.1414) and SIN(3.1417) come close to 0 and work on both platforms.
SIN(3.1415) and SIN(3.1416) produce the same garbage output as using PI() on
both platforms.