Data dependence analysis of assembly code

Determination of data dependences is a task typically performed with high-level language source code in today 's optimizing and parallelizing compilers. Very little work has been done in the field of data dependence analysis on assembly language code, but this area will be of growing importance, e.g. for increasing ILP. A central element of a data dependence analysis in this case is a method for memory reference disambiguation which decides whether two memory operations may/must access the same memory location. In this paper we describe a new approach for determination of data dependences in assembly code. Our method is based on a sophisticated algorithm for symbolic value propagation, and it can derive value-based dependences between memory operations instead of address-based dependences, only. We have integrated our method into the SALTO system for assembly language optimization. Experimental results show that our approach greatly improves the accuracy of the dependence analysis in many cases.