So, here's the thing about your question: it sounds like a case of a A vs. B problem, that is very subjective as to whether it's on-topic or not, but, generally, we lean towards the side of on-topic.
But, Code Review is generally for a "anything and everything" query -- that is, "I have this code, where might I do something better?" You can ask about focus points, but usually something along the lines of "I would appreciate any thoughts on <x> particularly."
Yours sounds like a case of "Why is this code slow?" To which, we have a Meta question: Are questions about performance on-topic?, to quote:
If a question specifically restricts the answer to a particular area like performance and is not interested in a general code review, it is IMHO too narrow in scope for this site.
Even Jeff Atwood agreed in a comment:
I agree the answer is yes, but taken too far this would be the micro benchmarking code golf site which is not the intent.
Should you want a general review, now things are looking more promising.
The second problem I see here is that the code is very short, simple, and it isn't clear what the goal is. We need an explicit goal, not a "I have code that does some XOR's, how do I do that better?" We need to know why you are doing the XOR's, because there might be a better way to do those.
As an example, the very first question I asked here was improperly phrased: Massive 'switch' Optimization - Hundreds of simple/small 'case' Statements, to which it was edited: Removing accents from certain characters, because it was not the switch statement that was my problem, but the underlying use of it: the accent removal.
So, you'll want to include more context about why you are doing what you are doing, because we may be able to help you further there.
All-in-all: you can make this on-topic, but chances are that as-it-stands, it would not be so.