A framework for Compiler Level statistical analysis over customized VLIW architecture

Very Long Instruction Word (VLIW) application specific processors represent an attractive solution for embedded computing, offering significant computational power with reduced hardware complexity. However, they impose higher compiler complexity since the instructions are executed in parallel based on the static compiler schedule. Therefore, finding a promising set of compiler transformations and defining their effects have a significant impact on the overall system performance. The proposed methodology provides the designer with an integrated framework to automatically (i) generate optimized application-specific VLIW architectural configurations and (ii) analyze compiler level transformations, enabling application-specific compiler tuning over customized VLIW system architectures. We based the aforementioned analysis on a Design of Experiments (DoEs) procedure that captures in a statistical manner the higher order effects among different sets of activated compiler transformations. Applying the proposed methodology onto real-case embedded application scenarios, we show that (i) only a limited set of compiler transformations exposes high confidence level (over 95%) in affecting the performance and (ii) using them we could be able to achieve gains between (16-23)% in comparison to the default optimization levels.