Is it possible for a smart contract to access swarm-content to perform an operation? For example, lets say a user uploads a document to swarm. I would then like to take access the contents of the document from a smart contract to perform some computation on the contents of the document.
It is not possible. Smart contracts can only interact with data that is in EVM state.
You could store the hash of a related content with your data in the smart contract though, allowing for application logic which can access swarm to process this association.