A transaction is initiated via a transaction begin instruction. During execution of the transaction, the transaction may abort. If the transaction aborts, a determination is made as to the type of transaction. Based on the transaction being a first type of transaction, resuming execution at the transaction begin instruction, and based on the transaction being a second type, resuming execution at an instruction following the transaction begin instruction. Regardless of transaction type, resuming execution includes restoring one or more registers specified in the transaction begin instruction and discarding transactional stores. For one type of transaction, the nonconstrained transaction, the resuming includes storing information in a transaction diagnostic block.