Partial value number redundancy elimination

When exploiting instruction level parallelism in a runtime optimizing compiler, it is indispensable to quickly remove redundant computations and memory accesses to make resources available. We propose a fast and efficient algorithm called Partial Value Number Redundancy Elimination (PVNRE), which completely fuses Partial Redundancy Elimination (PRE) and Global Value Numbering (GVN). Using value numbers in the data-flow analyses, PVNRE can deal with data-dependent redundancy, and can quickly remove path-dependent partial redundancy by converting value numbers at join nodes on demand during the data-flow analyses. Compared with the naive combination of GVN, PRE, and copy propagation, PVNRE has a maximum 45% faster analyses speed, but the same optimizing power on SPECjvm98.