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Compute static single assignment form of a graph.
This code is based on the algorithm from Efficiently computing static single assignment form and the control dependence graph, ACM Transactions on Programming Languages and Systems 1991 13(4), pp. 451-490.
Procedures[procedure] graph->ssa-graph:: G -> SSA-GRAPH
Computes the dominance frontiers of the nodes in the graph, and returns the list of nodes augmented with this information.[procedure] graph-ssa-find-joins:: SSA-GRAPH -> NODES
Given a list of SSA nodes, returns the list of nodes N for which there are (at least) two paths ... N_0 M_0 ... M_i N and ... N_1 P_0 ... P_j N such that N_0 and N_1 are distinct members of NODES and the M's and P's are disjoint sets.
(require-extension srfi-1) (require-extension digraph) (require-extension graph-dominators) (define used-by '((a . b) (b . c) (c . d) (c . b) (b . e) (d . d) (d . e) )) (define g (make-digraph 'cfg "control flow graph")) (define node-list (delete-duplicates (concatenate (list (map car used-by) (map cdr used-by))))) (define node-ids (list-tabulate (length node-list) values)) (for-each (lambda (i n) ((g 'add-node!) i (list #f n))) node-ids node-list) (define node-map (zip node-list node-ids)) (for-each (lambda (e) (match e ((ni . nj) (let ((i (car (alist-ref ni node-map))) (j (car (alist-ref nj node-map)))) ((g 'add-edge!) (list i j (format "~A->~A" ni nj))))) (else (error "invalid edge " e)))) used-by) (define ssa-graph (graph->ssa-graph g)) (graph-ssa-find-joins ssa-graph)
About this egg
Richard Kelsey; ported to Chicken by Ivan Raikov
- Documentation converted to wiki format
- Ported to Chicken 4
- Initial release
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