Introduction

Abstract

This first chapter introduces the static single assignment property, providing informal and intuitive motivations for representing programs in this manner. We show how several primitive program structures can be transformed into static single assignment form. We explain the purpose of the phi-function in terms of merging values from different incoming paths at control-flow merge points. We then review the historical context of SSA, including its relationship to functional programming. Finally, we discuss its widespread adoption in current compilation toolchains.