From 584726e9c4e4378129a35f6cfbbbf934448d10a9 Mon Sep 17 00:00:00 2001
From: Son Ho
Date: Tue, 17 Oct 2023 09:36:55 +0200
Subject: Implement tactics for termination proofs which involve arithmetic

---
 backends/lean/Base/Arith/Scalar.lean | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'backends/lean/Base/Arith/Scalar.lean')

diff --git a/backends/lean/Base/Arith/Scalar.lean b/backends/lean/Base/Arith/Scalar.lean
index 47751c8a..66c31129 100644
--- a/backends/lean/Base/Arith/Scalar.lean
+++ b/backends/lean/Base/Arith/Scalar.lean
@@ -36,6 +36,17 @@ def scalarTac (splitGoalConjs : Bool) : Tactic.TacticM Unit := do
 elab "scalar_tac" : tactic =>
   scalarTac false
 
+-- For termination proofs
+syntax "scalar_decr_tac" : tactic
+macro_rules
+  | `(tactic| scalar_decr_tac) =>
+    `(tactic|
+      simp_wf;
+      -- TODO: don't use a macro (namespace problems)
+      (first | apply Arith.to_int_to_nat_lt
+             | apply Arith.to_int_sub_to_nat_lt) <;>
+      simp_all <;> scalar_tac)
+
 instance (ty : ScalarTy) : HasIntProp (Scalar ty) where
   -- prop_ty is inferred
   prop := λ x => And.intro x.hmin x.hmax
-- 
cgit v1.2.3


From 61368028027a7c160c33b05ec605c26833212667 Mon Sep 17 00:00:00 2001
From: Son Ho
Date: Tue, 17 Oct 2023 10:36:15 +0200
Subject: Refold the scalar types when applying progress

---
 backends/lean/Base/Arith/Scalar.lean | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'backends/lean/Base/Arith/Scalar.lean')

diff --git a/backends/lean/Base/Arith/Scalar.lean b/backends/lean/Base/Arith/Scalar.lean
index 66c31129..2342cce6 100644
--- a/backends/lean/Base/Arith/Scalar.lean
+++ b/backends/lean/Base/Arith/Scalar.lean
@@ -17,7 +17,7 @@ def scalarTacExtraPreprocess : Tactic.TacticM Unit := do
    add (← mkAppM ``Scalar.cMax_bound #[.const ``ScalarTy.Usize []])
    add (← mkAppM ``Scalar.cMax_bound #[.const ``ScalarTy.Isize []])
    -- Reveal the concrete bounds, simplify calls to [ofInt]
-   Utils.simpAt [``Scalar.min, ``Scalar.max, ``Scalar.cMin, ``Scalar.cMax,
+   Utils.simpAt true [``Scalar.min, ``Scalar.max, ``Scalar.cMin, ``Scalar.cMax,
                  ``I8.min, ``I16.min, ``I32.min, ``I64.min, ``I128.min,
                  ``I8.max, ``I16.max, ``I32.max, ``I64.max, ``I128.max,
                  ``U8.min, ``U16.min, ``U32.min, ``U64.min, ``U128.min,
-- 
cgit v1.2.3