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feat: add a few more BitVec terms to bv_decide #15616

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Merged
hargoniX merged 1 commit into from
Oct 11, 2026
Merged

feat: add a few more BitVec terms to bv_decide #15616

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19 changes: 19 additions & 0 deletions src/Std/Tactic/BVDecide/Normalize/BitVec.lean
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Expand Up @@ -66,6 +66,11 @@ theorem BitVec.sle_eq_ult (x y : BitVec w) :
theorem BitVec.ofNatLT_reduce (n : Nat) (h) : BitVec.ofNatLT n h = BitVec.ofNat w n := by
simp [BitVec.ofNatLT, BitVec.ofNat, Fin.ofNat, Nat.mod_eq_of_lt h]

@[bv_normalize]
theorem BitVec.ofNat_toNat' (w : Nat) (b : Bool) :
BitVec.ofNat w b.toNat = (BitVec.ofBool b).zeroExtend w := by
cases b <;> simp [BitVec.setWidth_ofNat_one_eq_ofNat_one_of_lt]

@[bv_normalize]
theorem BitVec.ofBool_eq_ite (b : Bool) : BitVec.ofBool b = bif b then 1#1 else 0#1 := by
revert b
Expand Down Expand Up @@ -146,6 +151,19 @@ theorem BitVec.abs_eq (x : BitVec w) : x.abs = bif x.getLsbD (w - 1) then -x els

attribute [bv_normalize] BitVec.twoPow_eq

@[bv_normalize]
theorem BitVec.carry_eq_ite_le_lt (i : Nat) (x y : BitVec w) (c : Bool) :
BitVec.carry i x y c =
bif c then
(~~~(x.setWidth i)).ule (y.setWidth i)
else
(~~~(x.setWidth i)).ult (y.setWidth i) := by
have : 0 < 2 ^ i := Nat.two_pow_pos i
cases c
all_goals
simp [BitVec.carry, BitVec.ult_eq_decide, BitVec.ule_eq_decide]
omega

@[bv_normalize]
theorem BitVec.getElem_eq_getLsbD (a : BitVec w) (i : Nat) (h : i < w) :
a[i]'h = a.getLsbD i := by
Expand All @@ -159,6 +177,7 @@ end Reduce

section Constant

attribute [bv_normalize] BitVec.zero_eq
attribute [bv_normalize] BitVec.add_zero
attribute [bv_normalize] BitVec.zero_add
attribute [bv_normalize] BitVec.mul_one
Expand Down
20 changes: 20 additions & 0 deletions tests/elab/15580.lean
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@@ -0,0 +1,20 @@
module
import Std.Tactic.BVDecide
meta import Std.Tactic.BVDecide


example (x y : BitVec 64) : BitVec.carry 64 x y false = (x.zeroExtend 65 + y.zeroExtend 65).msb := by
bv_decide

example (x y : BitVec 64) : BitVec.carry 64 x y true = BitVec.carry 64 y x true := by
bv_decide

example (x y : BitVec 64) (b : Bool) : BitVec.carry 32 x y b = BitVec.carry 32 y x b := by
bv_decide

example (x : BitVec 64) (c : Bool) :
x + BitVec.ofNat 64 c.toNat = x + (BitVec.ofBool c).zeroExtend 64 := by
bv_decide

example (x : BitVec 64) : x + BitVec.zero 64 = x := by
bv_decide
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