National University of Singapore
Extensible processors allow addition of application-specific custom instructions to the core instruction set architecture. These custom instructions are selected through an analysis of the program's dataflow graphs. The characteristics of certain applications and the modern compiler optimization techniques (e.g., loop unrolling, region formation, etc.) have lead to substantially larger dataflow graphs. Hence, it is computationally expensive to automatically select the optimal set of custom instructions. Heuristic techniques are often employed to quickly search the design space.