-! Copyright (C) 2008 Slava Pestov.
+! Copyright (C) 2008 Slava Pestov, Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors combinators combinators.short-circuit
-compiler.cfg.hats compiler.cfg.instructions
+arrays compiler.cfg.hats compiler.cfg.instructions
 compiler.cfg.value-numbering.expressions
 compiler.cfg.value-numbering.graph
 compiler.cfg.value-numbering.simplify fry kernel layouts math
-namespaces sequences cpu.architecture math.bitwise locals ;
+namespaces sequences cpu.architecture math.bitwise ;
 IN: compiler.cfg.value-numbering.rewrite
 
 GENERIC: rewrite ( insn -- insn' )

    dup \ ##xor-imm combine-imm?
    [ [ bitxor ] \ ##xor-imm combine-imm ] when ;

M: ##add rewrite
    dup src2>> vreg>expr constant-expr? [
        [ dst>> ]
        [ src1>> ]
        [ src2>> vreg>constant ] tri \ ##add-imm new-insn

        ] when
    ] when ;

: (new-imm-insn) ( insn dst src1 n op -- new-insn/insn )
    [ cell-bits bits ] dip over small-enough? [
        new-insn dup number-values nip
    ] [
        2drop 2drop
    ] if ; inline

: new-imm-insn ( insn dst src n op -- n' op' )
    2dup [ sgn ] dip 2array
    {
        { { -1 ##add-imm } [ drop neg \ ##sub-imm (new-imm-insn) ] }
        { { -1 ##sub-imm } [ drop neg \ ##add-imm (new-imm-insn) ] }
        [ drop (new-imm-insn) ]
    } case ; inline

: combine-imm? ( insn op -- ? )
    [ src1>> vreg>expr op>> ] dip = ;

: combine-imm ( insn quot op -- insn )
    [
        {
            [ ]
            [ dst>> ]
            [ src1>> vreg>expr [ in1>> vn>vreg ] [ in2>> vn>constant ] bi ]
            [ src2>> ]
        } cleave
    ] [ call ] [ ] tri* new-imm-insn ; inline

M: ##add-imm rewrite
    {
        { [ dup \ ##add-imm combine-imm? ] [ [ + ] \ ##add-imm combine-imm ] }
        { [ dup \ ##sub-imm combine-imm? ] [ [ - ] \ ##sub-imm combine-imm ] }
        [ ]
    } cond ;

M: ##sub-imm rewrite
    {
        { [ dup \ ##add-imm combine-imm? ] [ [ - ] \ ##add-imm combine-imm ] }
        { [ dup \ ##sub-imm combine-imm? ] [ [ + ] \ ##sub-imm combine-imm ] }
        [ ]
    } cond ;

