Minimum GCC version to safely compile 64-bit binaries for AMD64?

[Neil Ferguson <nferguso at eso dot org>]

Hi -

We are considering buying some AMD64 machines, but are presently standardised 
on GCC 3.3. We're one of those places that finds a version that works for us 
and sticks with it, so an update is hard to sell. People are especially leery 
of the latest stable release - we like our compilers to have been out there 
for a while, on the basis that they're more likely to have been exposed to 
everything the users could throw at them.

Can GCC 3.3 compile 64-bit binaries that work reliably on AMD64?

What would the minimum recommended version of GCC be? (I'd be curious to know 
even if GCC 3.3 is OK, for my own historical interest.)

I've tried searching gcc.gnu.org and with Google, but I'm having trouble 
finding an authoritative answer. As one would expect, the current up-front 
information on the GCC site focuses on 3.4 and 4.0.

Neil.