Quantitative Evaluation of Common Subexpression Elimination on Queue Machines

Abstract

Queue computation model is a novel alternative for high performance architectures. Compiling for queue machines requires a different approach than compiling for traditional architectures. We have solved the problem of generating correct code with the queue compiler infrastructure. In this paper we introduce some problems encountered when optimizing code for queue machines. Common-subexpression elimination (CSE) is a widely used optimization to improve execution time. This paper makes a quantitative evaluation of how this optimization affects the characteristics of queue programs. We have found that in average, 28% of instructions are eliminated, and 15% of the critical path is reduced. We determine how enlarging the scope of compilation from expressions to basic blocks affects the distribution of offsetted instructions.