Static single-assignment form: Difference between revisions

Revision as of 06:20, 23 November 2003

Revision as of 06:24, 23 November 2003

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=== Converting to SSA ===

==== Introduction ====

Converting ordinary code into SSA form is primarily a simple matter of replacing the target of each assignment with a new variable, and replacing each use of a variable with the "version" of the variable [[reaching definition|reaching]] that point. For example, consider the following [[control flow graph]]:

Line 50 ⟶ 52:

A more general question along the same lines is, given an arbitrary control flow graph, how can I tell where to insert &phi; functions, and for what variables? This is a difficult question, but one that has an efficient solution that can be computed using a concept called <i>dominance frontiers</i>.

==== Computing minimal SSA using dominance frontiers ====

<i>More needed here describing the dominance-frontier based algorithm for computing "minimal" SSA, and other things.</i>