Abstract
In compilers, in addition to generating the object code in machine language, various transformations are made to improve the efficiency of the execution of the object code. This is called optimization. Previous methods for optimization generally use the data flow analysis of variable definitions and variable uses on the intermediate code. However, optimization methods using the static single assignment form (SSA form) attract compiler writers' recent attention. An SSA form is an intermediate representation, in which all variables are renamed so that for all uses of each variable, the point defining (assigning) its value is made unique in the program text. Various optimizations can be written clearly and easily utilizing this property. In this paper (introduction part) we explain the outline of SSA form, translation from normal form to SSA form, and back translation from SSA form to normal form.
