55 lines
1.4 KiB
Factor
55 lines
1.4 KiB
Factor
! Copyright (C) 2008, 2010 Slava Pestov, 2011 Alex Vondrak.
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! See http://factorcode.org/license.txt for BSD license.
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USING: accessors kernel math namespaces assocs ;
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IN: compiler.cfg.gvn.graph
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SYMBOL: input-expr-counter
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! assoc mapping vregs to value numbers
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! this is the identity on canonical representatives
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SYMBOL: vregs>vns
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! assoc mapping expressions to value numbers
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SYMBOL: exprs>vns
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! assoc mapping value numbers to instructions
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SYMBOL: vns>insns
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! assoc mapping each value number to a sequence of vregs
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! sharing that value number (i.e., the congruence class)
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SYMBOL: vns>vregs
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! boolean to track whether vregs>vns changes
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SYMBOL: changed?
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! boolean to track when it's safe to alter the CFG in a rewrite
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! method (i.e., after vregs>vns stops changing)
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SYMBOL: final-iteration?
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: vn>insn ( vn -- insn ) vns>insns get at ;
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: vreg>vn ( vreg -- vn ) vregs>vns get at ;
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: set-vn ( vn vreg -- )
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vregs>vns get maybe-set-at [ changed? on ] when ;
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: vreg>insn ( vreg -- insn ) vreg>vn vn>insn ;
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: congruence-class ( vreg -- vregs )
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vreg>vn vns>vregs get at ;
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: clear-exprs ( -- )
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exprs>vns get clear-assoc
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vns>insns get clear-assoc ;
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: compute-congruence-classes ( -- )
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vregs>vns get H{ } clone [
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[ push-at ] curry assoc-each
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] keep vns>vregs set ;
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: init-value-graph ( -- )
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0 input-expr-counter set
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H{ } clone vregs>vns set
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H{ } clone exprs>vns set
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H{ } clone vns>insns set ;
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