1 ! Copyright (C) 2008, 2010 Slava Pestov, 2011 Alex Vondrak
2 ! See https://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 [ 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 -- )
42 [ redundant-instruction ] [ useful-instruction ] ?if ;
45 dup inputs>> values [ vreg>vn ] map sift
47 [ drop ] [ first redundant-instruction ] if-empty
48 ] [ drop check-redundancy ] if ;
51 dup defs-vregs length 1 = [ check-redundancy ] [ drop ] if ;
53 : value-numbering-step ( insns -- )
54 [ simplify value-number ] each ;
56 : value-numbering-iteration ( cfg -- )
57 clear-exprs [ value-numbering-step ] simple-analysis ;
59 : determine-value-numbers ( cfg -- )
64 _ value-numbering-iteration
68 ! ! ! Global common subexpression elimination
70 GENERIC: gcse ( insn -- insn' )
72 M: array gcse [ gcse ] map ;
74 : defs-available ( insn -- insn )
75 dup defs-vregs [ make-available ] each ;
77 M: alien-call-insn gcse defs-available ;
78 M: ##callback-inputs gcse defs-available ;
79 M: ##copy gcse defs-available ;
81 : ?eliminate ( insn vn -- insn' )
83 [ dst>> dup make-available ] dip <copy>
84 ] [ drop defs-available ] if ;
86 : eliminate-redundancy ( insn -- insn' )
87 dup >expr exprs>vns get at >avail-vreg
88 [ ?eliminate ] [ defs-available ] if* ;
91 dup inputs>> values [ vreg>vn ] map sift
93 [ first ?eliminate ] unless-empty
94 ] [ drop eliminate-redundancy ] if ;
97 dup defs-vregs length 1 = [ eliminate-redundancy ] when ;
99 : gcse-step ( insns -- insns' )
100 [ simplify gcse ] map flatten ;
102 : eliminate-common-subexpressions ( cfg -- )
104 compute-congruence-classes
105 dup compute-avail-sets
106 [ gcse-step ] simple-optimization ;
108 : value-numbering ( cfg -- )
111 determine-value-numbers
112 eliminate-common-subexpressions