Loop unrolling with fine grained power gating for runtime leakage power reduction

The present work introduces a compilation technique to reduce runtime leakage power of functional units of a processor by combining loop unrolling with power gating. The instructions in the unrolled loop are scheduled to provide opportunities for power gating the functional units which are not in need for a considerable amount of time. The number of clock cycles taken by the power gating instructions is less than or equal to the number of clock cycles saved by loop unrolling. This results in 23-64% reduction of the total energy consumed by the benchmark programs without any degradation of performance.