1 ! Copyright (C) 2008, 2010 Slava Pestov, 2011 Alex Vondrak
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: accessors arrays assocs compiler.cfg compiler.cfg.def-use
4 compiler.cfg.gvn.avail compiler.cfg.gvn.expressions
5 compiler.cfg.gvn.graph compiler.cfg.gvn.rewrite
6 compiler.cfg.instructions compiler.cfg.predecessors
7 compiler.cfg.rpo compiler.cfg.utilities grouping kernel
8 namespaces sequences sequences.deep ;
11 GENERIC: simplify ( insn -- insn' )
13 M: insn simplify dup rewrite [ simplify ] [ dup >avail-insn-uses ] ?if ;
14 M: array simplify [ simplify ] map ;
17 ! ! ! Global value numbering
19 GENERIC: value-number ( insn -- )
21 M: array value-number [ value-number ] each ;
23 : record-defs ( insn -- ) defs-vregs [ dup set-vn ] each ;
25 M: alien-call-insn value-number record-defs ;
26 M: ##callback-inputs value-number record-defs ;
28 M: ##copy value-number [ src>> vreg>vn ] [ dst>> ] bi set-vn ;
30 : redundant-instruction ( insn vn -- )
33 :: useful-instruction ( insn expr -- )
36 vn expr exprs>vns get set-at
37 insn vn vns>insns get set-at ;
39 : check-redundancy ( insn -- )
40 dup >expr dup exprs>vns get at
41 [ redundant-instruction ] [ useful-instruction ] ?if ;
44 dup inputs>> values [ vreg>vn ] map sift
46 [ drop ] [ first redundant-instruction ] if-empty
47 ] [ drop check-redundancy ] if ;
50 dup defs-vregs length 1 = [ check-redundancy ] [ drop ] if ;
52 : value-numbering-step ( insns -- )
53 [ simplify value-number ] each ;
55 : value-numbering-iteration ( cfg -- )
56 clear-exprs [ value-numbering-step ] simple-analysis ;
58 : determine-value-numbers ( cfg -- )
63 _ value-numbering-iteration
67 ! ! ! Global common subexpression elimination
69 GENERIC: gcse ( insn -- insn' )
71 M: array gcse [ gcse ] map ;
73 : defs-available ( insn -- insn )
74 dup defs-vregs [ make-available ] each ;
76 M: alien-call-insn gcse defs-available ;
77 M: ##callback-inputs gcse defs-available ;
78 M: ##copy gcse defs-available ;
80 : ?eliminate ( insn vn -- insn' )
82 [ dst>> dup make-available ] dip <copy>
83 ] [ drop defs-available ] if ;
85 : eliminate-redundancy ( insn -- insn' )
86 dup >expr exprs>vns get at >avail-vreg
87 [ ?eliminate ] [ defs-available ] if* ;
90 dup inputs>> values [ vreg>vn ] map sift
92 [ first ?eliminate ] unless-empty
93 ] [ drop eliminate-redundancy ] if ;
96 dup defs-vregs length 1 = [ eliminate-redundancy ] when ;
98 : gcse-step ( insns -- insns' )
99 [ simplify gcse ] map flatten ;
101 : eliminate-common-subexpressions ( cfg -- )
103 compute-congruence-classes
104 dup compute-avail-sets
105 [ gcse-step ] simple-optimization ;
107 : value-numbering ( cfg -- )
110 determine-value-numbers
111 eliminate-common-subexpressions