Control flow optimization in loops using interval analysis

We present a novel loop transformation technique, particularly well suited for optimizing embedded compilers, where an increase in compilation time is acceptable in exchange for significant performance increase. The transformation technique optimizes loops containing nested conditional blocks. Specifically, the transformation takes advantage of the fact that the Boolean value of the conditional expression, determining the true/false paths, can be statically analyzed using a novel interval analysis technique that can evaluate conditional expressions in the general polynomial form. Results from interval analysis combined with loop dependency information is used to partition the iteration space of the nested loop. In such cases, the loop nest is decomposed such as to eliminate the conditional test, thus substantially reducing the execution time. Our technique completely eliminates the conditional from the loops (unlike previous techniques) thus further facilitating the application of oth...

• Type: Conference
• Year: 2008
• Where: CASES
• Authors: Mohammad Ali Ghodrat, Tony Givargis, Alex Nicolau
• Keywords: CASES 2008, Conditional Expressions, Loop Transformation Technique, System Software, Transformation Technique