1 ! Copyright (C) 2008, 2010 Slava Pestov.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: namespaces arrays assocs kernel accessors fry grouping
4 sorting sets sequences locals
10 compiler.cfg.utilities
11 compiler.cfg.instructions
12 compiler.cfg.gvn.alien
13 compiler.cfg.gvn.comparisons
14 compiler.cfg.gvn.graph
16 compiler.cfg.gvn.rewrite
17 compiler.cfg.gvn.slots
19 compiler.cfg.gvn.expressions ;
22 GENERIC: process-instruction ( insn -- insn' )
24 : redundant-instruction ( insn vn -- insn' )
25 [ dst>> ] dip [ swap set-vn ] [ <copy> ] 2bi ;
27 :: useful-instruction ( insn expr -- insn' )
30 vn expr exprs>vns get set-at
31 insn vn vns>insns get set-at
34 : check-redundancy ( insn -- insn' )
35 dup >expr dup exprs>vns get at
36 [ redundant-instruction ] [ useful-instruction ] ?if ;
38 M: insn process-instruction
39 dup rewrite [ process-instruction ] [ ] ?if ;
41 M: foldable-insn process-instruction
43 [ process-instruction ]
44 [ dup defs-vregs length 1 = [ check-redundancy ] when ] ?if ;
46 M: ##copy process-instruction
47 dup [ src>> vreg>vn ] [ dst>> ] bi set-vn ;
49 M: ##phi process-instruction
51 [ process-instruction ] [ check-redundancy ] ?if ;
53 M: array process-instruction
54 [ process-instruction ] map ;
56 : value-numbering-step ( insns -- insns' )
57 [ process-instruction ] map flatten ;
59 ! XXX there's going to be trouble with certain rewrites that
60 ! modify the cfg / instructions destructively; namely those in
61 ! comparisons.factor, alien.factor, and slots.factor
63 : value-numbering-iteration ( cfg -- )
65 [ value-numbering-step drop ] simple-analysis ;
67 : identify-redundancies ( cfg -- )
71 _ value-numbering-iteration
75 : eliminate-redundancies ( cfg -- )
77 [ value-numbering-step ] simple-optimization ;
79 : value-numbering ( cfg -- cfg )
80 dup identify-redundancies
81 dup eliminate-redundancies
82 cfg-changed predecessors-changed ;