Brute forcing a single 32-bit input has also been usefully performed in some cases, such as for single-precision implementations of special functions[1].
[1] https://randomascii.wordpress.com/2014/01/27/theres-only-fou...
[1] https://randomascii.wordpress.com/2014/01/27/theres-only-fou...
Whether 4B is doable depends on how much work you're doing for each of those states, but yes, "4B" alone certainly doesn't rule it out. There's also a question of whether it goes with your most frequently run tests or is something that's only run occasionally.
> However a lot of algorithms can have more than 32 bits of states and so quickly get beyond what is doable.
I'm pretty confident we're all in agreement there.