b7360969ed
This PR changes `bv_decide`'s heuristic for what kinds of structures to split on to also allow splitting on structures where the fields have dependently typed widths. For example: ```lean structure Byte (w : Nat) where /-- A two's complement integer value of width `w`. -/ val : BitVec w /-- A per-bit poison mask of width `w`. -/ poison : BitVec w ``` This is to allow handling situations such as `(x : Byte 8)` where the width becomes concrete after splitting is done.
20 lines
547 B
Text
20 lines
547 B
Text
import Std.Tactic.BVDecide
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/--
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The `Byte` type can have any bitwidth `w`. It carries a two's complement integer
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value of width `w` and a per-bit poison mask modeling bitwise delayed undefined
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behavior.
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-/
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structure Byte (w : Nat) where
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/-- A two's complement integer value of width `w`. -/
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val : BitVec w
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/-- A per-bit poison mask of width `w`. -/
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poison : BitVec w
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def or {w : Nat} (x y : Byte w) : Byte w :=
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⟨x.val ||| y.val, x.poison ||| y.poison⟩
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example (x y : Byte 8) : or x y = or y x := by
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unfold _root_.or
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bv_decide
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