Compiler directed automatic stack trimming for efficient non-volatile processors

Wearable devices are becoming increasingly important in our daily lives. Energy harvesting instead of battery is a better power source for these wearable devices due to many advantages. However, harvested energy is often unstable and program execution will be frequently interrupted. Non-volatile processors demonstrate promising advantages to back up volatile state before the system energy is depleted. But Non-volatile processors require additional memory for backing up, thus introducing non-negligible overhead in terms of energy, runtime as well as chIP area. In this work, we target at non-volatile register reduction for energy harvesting based wearable devices. This paper proposes to stack trimming the memory footprint via a novel compiler directed method. The evaluation results deliver on average 28.6% reduction of non-volatile register files for backing up stack area, with ultra low runtime overhead.