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[smlnj] Annotation of /sml/trunk/src/MLRISC/sparc/instructions/sparcPeephole.sml
Annotation of /sml/trunk/src/MLRISC/sparc/instructions/sparcPeephole.sml
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functor SparcPeephole(SparcInstr : SPARCINSTR) : PEEPHOLE =
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struct
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structure I = SparcInstr
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(* IMPORTANT: instructions are given in reversed order *)
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fun peephole regmap instrs =
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let fun isZero(I.LAB le) = I.LabelExp.valueOf le = 0
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| isZero(I.REG r) = regmap r = 0
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| isZero(I.IMMED i) = i = 0
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| isZero _ = false
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fun removable(I.ARITH{a=(I.ADD | I.SUB), r, i, d}) =
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regmap r = regmap d andalso isZero i
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| removable(I.ANNOTATION{i,a}) = removable i
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| removable _ = false
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fun loop([], instrs) = rev instrs
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| loop(i::rest, instrs) =
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if removable i then loop(rest, instrs)
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else loop(rest, i::instrs)
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in loop(instrs, [])
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end
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end
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