Live-variable analysis: Difference between revisions

Revision as of 19:47, 14 March 2014

Revision as of 11:43, 14 April 2014

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The in-state of b3 only contains ''b'' and ''d'', since ''c'' has been written. The out-state of b1 is the union of the in-states of b2 and b3. The definition of ''c'' in b2 can be removed, since ''c'' is not live immediately after the statement.

Solving the data flow equations starts with initializing all in-states and out-states to the empty set. The work list is initialized by inserting the exit point (b3) in the work list (typical for backward flow). Its computed outin-state differs from the previous one, so its predecessors b1 and b2 are inserted and the process continues. The progress is summarized in the table below.

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