1 ! Copyright (C) 2008, 2010 Slava Pestov, 2011 Alex Vondrak
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: namespaces arrays assocs hashtables kernel accessors fry
4 grouping sorting sets sequences locals
11 compiler.cfg.utilities
12 compiler.cfg.instructions
13 compiler.cfg.predecessors
14 compiler.cfg.gvn.alien
15 compiler.cfg.gvn.avail
16 compiler.cfg.gvn.comparisons
17 compiler.cfg.gvn.graph
19 compiler.cfg.gvn.rewrite
20 compiler.cfg.gvn.slots
22 compiler.cfg.gvn.expressions ;
25 GENERIC: simplify ( insn -- insn' )
27 M: insn simplify dup rewrite [ simplify ] [ dup >avail-insn-uses ] ?if ;
28 M: array simplify [ simplify ] map ;
31 ! ! ! Global value numbering
33 GENERIC: value-number ( insn -- )
35 M: array value-number [ value-number ] each ;
37 : record-defs ( insn -- ) defs-vregs [ dup set-vn ] each ;
39 M: alien-call-insn value-number record-defs ;
40 M: ##callback-inputs value-number record-defs ;
42 M: ##copy value-number [ src>> vreg>vn ] [ dst>> ] bi set-vn ;
44 : redundant-instruction ( insn vn -- )
47 :: useful-instruction ( insn expr -- )
50 vn expr exprs>vns get set-at
51 insn vn vns>insns get set-at ;
53 : check-redundancy ( insn -- )
54 dup >expr dup exprs>vns get at
55 [ redundant-instruction ] [ useful-instruction ] ?if ;
58 dup inputs>> values [ vreg>vn ] map sift
60 [ drop ] [ first redundant-instruction ] if-empty
61 ] [ drop check-redundancy ] if ;
64 dup defs-vregs length 1 = [ check-redundancy ] [ drop ] if ;
66 : value-numbering-step ( insns -- )
67 [ simplify value-number ] each ;
69 : value-numbering-iteration ( cfg -- )
70 clear-exprs [ value-numbering-step ] simple-analysis ;
72 : determine-value-numbers ( cfg -- )
77 _ value-numbering-iteration
81 ! ! ! Global common subexpression elimination
83 GENERIC: gcse ( insn -- insn' )
85 M: array gcse [ gcse ] map ;
87 : defs-available ( insn -- insn )
88 dup defs-vregs [ make-available ] each ;
90 M: alien-call-insn gcse defs-available ;
91 M: ##callback-inputs gcse defs-available ;
92 M: ##copy gcse defs-available ;
94 : ?eliminate ( insn vn -- insn' )
96 [ dst>> dup make-available ] dip <copy>
97 ] [ drop defs-available ] if ;
99 : eliminate-redundancy ( insn -- insn' )
100 dup >expr exprs>vns get at >avail-vreg
101 [ ?eliminate ] [ defs-available ] if* ;
104 dup inputs>> values [ vreg>vn ] map sift
106 [ first ?eliminate ] unless-empty
107 ] [ drop eliminate-redundancy ] if ;
110 dup defs-vregs length 1 = [ eliminate-redundancy ] when ;
112 : gcse-step ( insns -- insns' )
113 [ simplify gcse ] map flatten ;
115 : eliminate-common-subexpressions ( cfg -- )
117 compute-congruence-classes
118 dup compute-avail-sets
119 [ gcse-step ] simple-optimization ;
121 : value-numbering ( cfg -- )
124 determine-value-numbers
125 eliminate-common-subexpressions