Should you check if the map containsKey before using ConcurrentMap's putIfAbsent

I have been using Java's ConcurrentMap for a map that can be used from multiple threads. The putIfAbsent is a great method and is much easier to read/write than using standard map operations. I have some code that looks like this:

ConcurrentMap<String, Set<X>> map = new ConcurrentHashMap<String, Set<X>>();

// ...

map.putIfAbsent(name, new HashSet<X>());
map.get(name).add(Y);

Readability wise this is great but it does require creating a new HashSet every time even if it is already in the map. I could write this:

if (!map.containsKey(name)) {
    map.putIfAbsent(name, new HashSet<X>());
}
map.get(name).add(Y);

With this change it loses a bit of readability but does not need to create the HashSet every time. Which is better in this case? I tend to side with the first one since it is more readable. The second would perform better and may be more correct. Maybe there is a better way to do this than either of these.

What is the best practice for using a putIfAbsent in this manner?