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|
local
structure I =
struct
include "sparcInstr.sml"
end
in
functor SparcPeephole
(structure Instr : SPARCINSTR
structure Eval : MLTREE_EVAL
sharing Eval.T = Instr.T
) : PEEPHOLE =
struct
structure I = Instr
structure CB = CellsBasis
(* IMPORTANT: instructions are now given in forward order *)
fun peephole instrs =
let fun isZero(I.LAB le) = ((Eval.valueOf le = 0) handle _ => false)
| isZero(I.REG r) = CB.registerNum r = 0
| isZero(I.IMMED i) = i = 0
| isZero _ = false
fun removable(I.INSTR(I.ARITH{a=(I.ADD | I.SUB), r, i, d})) =
CB.sameColor(r,d) andalso isZero i
| removable(I.ANNOTATION{i,a}) = removable i
| removable _ = false
fun loop(current, instrs) =
case current of
[] => instrs
| i::rest where removable i => loop(rest, instrs)
| i::rest => loop(rest, i::instrs)
in loop(instrs, [])
end
end
end
|
