One embodiment of the present invention provides a system that performs a fast-scanning operation to generate fetch bundles within an instruction fetch unit (IFU) of a processor. During operation, the system obtains a cache line containing instructions at the IFU. Next, the system performs a complete-scanning operation on the cache line to identify control transfer instructions (CTIs) in the cache line. At the same time, the system performs a fast-scanning operation to identify CTIs in a group of initial instructions in the cache line, wherein the initial instructions are executed before other instructions in the cache line. Next, the system obtains results from the fast-scanning operation before results of the complete-scanning operation are available. The system then uses results from the fast-scanning operation to form an initial fetch bundle containing initial instructions, and sends the initial fetch bundle to the instruction-issue unit.