     copies get dup assoc-empty? [ 2drop ] [
         renamings set
         [
-            instructions>>
-            [ update-insn ] filter-here
+            instructions>> [ update-insn ] filter-here
         ] each-basic-block
     ] if ;
 


M: ##copy visit-insn record-copy ;

M: ##phi visit-insn
    [ dst>> ] [ inputs>> values [ resolve ] map ] bi
    dup all-equal? [ first (record-copy) ] [ 2drop ] if ;

M: insn visit-insn drop ;

: collect-copies ( cfg -- )
    H{ } clone copies set
    [
        instructions>>
        [ visit-insn ] each
    ] each-basic-block ;

GENERIC: update-insn ( insn -- keep? )

! Copyright (C) 2008, 2009 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: kernel namespaces assocs accessors sequences grouping
combinators compiler.cfg.rpo compiler.cfg.renaming
compiler.cfg.instructions ;
IN: compiler.cfg.copy-prop

! The first three definitions are also used in compiler.cfg.alias-analysis.
SYMBOL: copies

! Initialized per-basic-block; a mapping from inputs to dst for eliminating
! redundant phi instructions
SYMBOL: phis

: resolve ( vreg -- vreg )
    copies get ?at drop ;
