factor/basis/compiler/cfg/ssa/cssa/cssa.factor

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Factor

! Copyright (C) 2009, 2011 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors assocs kernel locals fry make namespaces
sequences cpu.architecture
compiler.cfg
compiler.cfg.rpo
compiler.cfg.utilities
compiler.cfg.predecessors
compiler.cfg.registers
compiler.cfg.instructions ;
FROM: assocs => change-at ;
IN: compiler.cfg.ssa.cssa
! Convert SSA to conventional SSA. This pass runs after representation
! selection, so it must keep track of representations when introducing
! new values.
SYMBOLS: edge-copies phi-copies ;
: init-copies ( bb -- )
V{ } clone phi-copies set
predecessors>> [ V{ } clone ] H{ } map>assoc edge-copies set ;
:: convert-operand ( src pred rep -- dst )
rep next-vreg-rep :> dst
{ dst src } pred edge-copies get at push
dst ;
:: convert-phi ( insn preds -- )
insn dst>> :> dst
dst rep-of :> rep
insn inputs>> :> inputs
rep next-vreg-rep :> dst'
{ dst dst' } phi-copies get push
dst' insn dst<<
preds [| pred |
pred inputs [ pred rep convert-operand ] change-at
] each ;
: insert-edge-copies ( from to copies -- )
[ ##parallel-copy, ##branch, ] { } make insert-basic-block ;
: insert-all-edge-copies ( bb -- )
[ edge-copies get ] dip '[
[ drop ] [ [ _ ] dip insert-edge-copies ] if-empty
] assoc-each ;
: phi-copy-insn ( -- insn )
phi-copies get f \ ##parallel-copy boa ;
: end-of-phis ( insns -- i )
[ [ ##phi? not ] find drop ] [ length ] bi or ;
: insert-phi-copies ( bb -- )
[
[
[ drop phi-copy-insn ] [ end-of-phis ] [ ] tri insert-nth
] change-instructions drop
] if-has-phis ;
: insert-copies ( bb -- )
[ insert-all-edge-copies ] [ insert-phi-copies ] bi ;
: convert-phis ( bb -- )
[ init-copies ]
[ dup predecessors>> '[ _ convert-phi ] each-phi ]
[ insert-copies ]
tri ;
: construct-cssa ( cfg -- )
needs-predecessors
dup [ convert-phis ] each-basic-block
cfg-changed drop ;