Float/Double cast to int

Hi, Hackers,

Here is a query, server was built witch GCC on Linux, AMD64.

ftian=#
ftian=# select 1.5::int, 1.5::double precision::int, 314.5::int,
314.5::double precision::int;
int4 | int4 | int4 | int4
------+------+------+------
2 | 2 | 315 | 314
(1 row)

I believe this is because rint is broken -- can some expert on IEEE754
please help confirm that this is a bug?

Thanks,
Feng