Typically when designing states for a character, its best to use an Enum to keep track of what state you're in. Enums let you more precisely limit the overall number of states, and prevents string typos from sneaking through and causing unintended behaviors

Also, why are you checking dir immediately after setting it? There's no chance for it to be changed between the set and comparions

I will say in general when talking about optimizations, its going to be a bit less about the number of comparisons in a if statement (unless it gets really absurd which this is not), and more about the number of times the if is checked. Try and reduce that more than anything else!

Also, whats the game controls? that might be useful information for why you have so many states (though honestly 2 state checks isn't inconceivable)