作者: Lyle Ramshaw
DOI: 10.1145/48014.48021
关键词:
摘要: Suppose we want to eliminate the local go statements of a Pascal program by replacing them with multilevel loop exit statements. The standard ground rules for eliminating to's require that preserve flow graph program, but they allow us completely rewrite control structures glue together program's atomic tests and actions. can be eliminated from under those if only has graph-theoretic property named reducibility.This paper considers stricter set rules, introduced Peterson, Kasami, Tokura, which demand original structures, as well its graph, while to's. In particular, are allowed delete labels jump insert various labeled repeat-endloop pairs out of. But forbidden change rest text in any way. critical issue determines whether these turns static order actions text. This encoded augmenting it extra edges. It then shown reducibility augmented edges all, is necessary sufficient condition eliminability rules.