A GENERALIZED METHOD FOR REALIZING PARTIAL REDUNDANCY ELIMINATION FOR NORMAL FORMS IN STATIC SINGLE ASSIGNMENT FORMS
Masataka Sassa, Takanori Imahashi, Yo Ito · 2011
Partial Redundancy Elimination (PRE) is an effective optimization for eliminating partially redundant expressions and includes the effects of common subexpression elimination and hoisting loop invariant expressions. There have been some previous attempts to realize PRE on the Static Single Assignment (SSA) form, which is a suitable intermediate form for optimization. However, such attempts are generally difficult because of the uniqueness of variable names in the SSA form. For example, a variable that is used in several contexts in the normal form may be assigned a new name for each context in the SSA form, so it is difficult to identify the same variables in the two forms. To handle such problems, previous methods performed complicated processing by using special data structures.