Merge branch 'master' into simpa_trailing_comment

Author: kmill

.github/workflows/ci.yml

@@ -217,7 +217,7 @@ jobs:
                 "release": true,
                 "check-level": 2,
                 "shell": "msys2 {0}",
-                "CMAKE_OPTIONS": "-G \"Unix Makefiles\" -DUSE_GMP=OFF",
+                "CMAKE_OPTIONS": "-G \"Unix Makefiles\"",
                 // for reasons unknown, interactivetests are flaky on Windows
                 "CTEST_OPTIONS": "--repeat until-pass:2",
                 "llvm-url": "https://github.com/leanprover/lean-llvm/releases/download/15.0.1/lean-llvm-x86_64-w64-windows-gnu.tar.zst",
@@ -227,7 +227,7 @@ jobs:
               {
                 "name": "Linux aarch64",
                 "os": "nscloud-ubuntu-22.04-arm64-4x8",
-                "CMAKE_OPTIONS": "-DUSE_GMP=OFF -DLEAN_INSTALL_SUFFIX=-linux_aarch64",
+                "CMAKE_OPTIONS": "-DLEAN_INSTALL_SUFFIX=-linux_aarch64",
                 "release": true,
                 "check-level": 2,
                 "shell": "nix develop .#oldGlibcAArch -c bash -euxo pipefail {0}",

flake.nix

@@ -38,7 +38,11 @@
           # more convenient `ctest` output
           CTEST_OUTPUT_ON_FAILURE = 1;
         } // pkgs.lib.optionalAttrs pkgs.stdenv.isLinux {
-          GMP = pkgsDist.gmp.override { withStatic = true; };
+          GMP = (pkgsDist.gmp.override { withStatic = true; }).overrideAttrs (attrs:
+            pkgs.lib.optionalAttrs (pkgs.stdenv.system == "aarch64-linux") {
+              # would need additional linking setup on Linux aarch64, we don't use it anywhere else either
+              hardeningDisable = [ "stackprotector" ];
+            });
           LIBUV = pkgsDist.libuv.overrideAttrs (attrs: {
             configureFlags = ["--enable-static"];
             hardeningDisable = [ "stackprotector" ];

src/Init/Control/Basic.lean

@@ -35,6 +35,15 @@ instance (priority := 500) instForInOfForIn' [ForIn' m ρ α d] : ForIn m ρ α
   simp [h]
   rfl
 
+/-- Extract the value from a `ForInStep`, ignoring whether it is `done` or `yield`. -/
+def ForInStep.value (x : ForInStep α) : α :=
+  match x with
+  | ForInStep.done b => b
+  | ForInStep.yield b => b
+
+@[simp] theorem ForInStep.value_done (b : β) : (ForInStep.done b).value = b := rfl
+@[simp] theorem ForInStep.value_yield (b : β) : (ForInStep.yield b).value = b := rfl
+
 @[reducible]
 def Functor.mapRev {f : Type u → Type v} [Functor f] {α β : Type u} : f α → (α → β) → f β :=
   fun a f => f <$> a

src/Init/Conv.lean

@@ -7,6 +7,7 @@ Notation for operators defined at Prelude.lean
 -/
 prelude
 import Init.Tactics
+import Init.Meta
 
 namespace Lean.Parser.Tactic.Conv
 
@@ -46,12 +47,20 @@ scoped syntax (name := withAnnotateState)
 /-- `skip` does nothing. -/
 syntax (name := skip) "skip" : conv
 
-/-- Traverses into the left subterm of a binary operator.
-(In general, for an `n`-ary operator, it traverses into the second to last argument.) -/
+/--
+Traverses into the left subterm of a binary operator.
+
+In general, for an `n`-ary operator, it traverses into the second to last argument.
+It is a synonym for `arg -2`.
+-/
 syntax (name := lhs) "lhs" : conv
 
-/-- Traverses into the right subterm of a binary operator.
-(In general, for an `n`-ary operator, it traverses into the last argument.) -/
+/--
+Traverses into the right subterm of a binary operator.
+
+In general, for an `n`-ary operator, it traverses into the last argument.
+It is a synonym for `arg -1`.
+-/
 syntax (name := rhs) "rhs" : conv
 
 /-- Traverses into the function of a (unary) function application.
@@ -74,13 +83,17 @@ subgoals for all the function arguments. For example, if the target is `f x y` t
 `congr` produces two subgoals, one for `x` and one for `y`. -/
 syntax (name := congr) "congr" : conv
 
+syntax argArg := "@"? "-"? num
+
 /--
 * `arg i` traverses into the `i`'th argument of the target. For example if the
   target is `f a b c d` then `arg 1` traverses to `a` and `arg 3` traverses to `c`.
+  The index may be negative; `arg -1` traverses into the last argument,
+  `arg -2` into the second-to-last argument, and so on.
 * `arg @i` is the same as `arg i` but it counts all arguments instead of just the
   explicit arguments.
 * `arg 0` traverses into the function. If the target is `f a b c d`, `arg 0` traverses into `f`. -/
-syntax (name := arg) "arg " "@"? num : conv
+syntax (name := arg) "arg " argArg : conv
 
 /-- `ext x` traverses into a binder (a `fun x => e` or `∀ x, e` expression)
 to target `e`, introducing name `x` in the process. -/
@@ -130,11 +143,11 @@ For example, if we are searching for `f _` in `f (f a) = f b`:
 syntax (name := pattern) "pattern " (occs)? term : conv
 
 /-- `rw [thm]` rewrites the target using `thm`. See the `rw` tactic for more information. -/
-syntax (name := rewrite) "rewrite" (config)? rwRuleSeq : conv
+syntax (name := rewrite) "rewrite" optConfig rwRuleSeq : conv
 
 /-- `simp [thm]` performs simplification using `thm` and marked `@[simp]` lemmas.
 See the `simp` tactic for more information. -/
-syntax (name := simp) "simp" (config)? (discharger)? (&" only")?
+syntax (name := simp) "simp" optConfig (discharger)? (&" only")?
   (" [" withoutPosition((simpStar <|> simpErase <|> simpLemma),*) "]")? : conv
 
 /--
@@ -151,7 +164,7 @@ example (a : Nat): (0 + 0) = a - a := by
     rw [← Nat.sub_self a]
 ```
 -/
-syntax (name := dsimp) "dsimp" (config)? (discharger)? (&" only")?
+syntax (name := dsimp) "dsimp" optConfig (discharger)? (&" only")?
   (" [" withoutPosition((simpErase <|> simpLemma),*) "]")? : conv
 
 /-- `simp_match` simplifies match expressions. For example,
@@ -247,12 +260,12 @@ macro (name := failIfSuccess) tk:"fail_if_success " s:convSeq : conv =>
 
 /-- `rw [rules]` applies the given list of rewrite rules to the target.
 See the `rw` tactic for more information. -/
-macro "rw" c:(config)? s:rwRuleSeq : conv => `(conv| rewrite $[$c]? $s)
+macro "rw" c:optConfig s:rwRuleSeq : conv => `(conv| rewrite $c:optConfig $s)
 
-/-- `erw [rules]` is a shorthand for `rw (config := { transparency := .default }) [rules]`.
+/-- `erw [rules]` is a shorthand for `rw (transparency := .default) [rules]`.
 This does rewriting up to unfolding of regular definitions (by comparison to regular `rw`
 which only unfolds `@[reducible]` definitions). -/
-macro "erw" s:rwRuleSeq : conv => `(conv| rw (config := { transparency := .default }) $s:rwRuleSeq)
+macro "erw" c:optConfig s:rwRuleSeq : conv => `(conv| rw $[$(getConfigItems c)]* (transparency := .default) $s:rwRuleSeq)
 
 /-- `args` traverses into all arguments. Synonym for `congr`. -/
 macro "args" : conv => `(conv| congr)
@@ -263,7 +276,7 @@ macro "right" : conv => `(conv| rhs)
 /-- `intro` traverses into binders. Synonym for `ext`. -/
 macro "intro" xs:(ppSpace colGt ident)* : conv => `(conv| ext $xs*)
 
-syntax enterArg := ident <|> ("@"? num)
+syntax enterArg := ident <|> argArg
 
 /-- `enter [arg, ...]` is a compact way to describe a path to a subterm.
 It is a shorthand for other conv tactics as follows:
@@ -272,12 +285,7 @@ It is a shorthand for other conv tactics as follows:
 * `enter [x]` (where `x` is an identifier) is equivalent to `ext x`.
 For example, given the target `f (g a (fun x => x b))`, `enter [1, 2, x, 1]`
 will traverse to the subterm `b`. -/
-syntax "enter" " [" withoutPosition(enterArg,+) "]" : conv
-macro_rules
-  | `(conv| enter [$i:num]) => `(conv| arg $i)
-  | `(conv| enter [@$i]) => `(conv| arg @$i)
-  | `(conv| enter [$id:ident]) => `(conv| ext $id)
-  | `(conv| enter [$arg, $args,*]) => `(conv| (enter [$arg]; enter [$args,*]))
+syntax (name := enter) "enter" " [" withoutPosition(enterArg,+) "]" : conv
 
 /-- The `apply thm` conv tactic is the same as `apply thm` the tactic.
 There are no restrictions on `thm`, but strange results may occur if `thm`

src/Init/Data/Array/Lemmas.lean

@@ -10,6 +10,7 @@ import Init.Data.List.Monadic
 import Init.Data.List.Range
 import Init.Data.List.Nat.TakeDrop
 import Init.Data.List.Nat.Modify
+import Init.Data.List.Monadic
 import Init.Data.Array.Mem
 import Init.Data.Array.DecidableEq
 import Init.TacticsExtra
@@ -211,17 +212,25 @@ theorem foldrM_push [Monad m] (f : α → β → m β) (init : β) (arr : Array
     (arr.push a).foldrM f init = f a init >>= arr.foldrM f := by
   simp [foldrM_eq_reverse_foldlM_toList, -size_push]
 
-/-- Variant of `foldrM_push` with the `start := arr.size + 1` rather than `(arr.push a).size`. -/
-@[simp] theorem foldrM_push' [Monad m] (f : α → β → m β) (init : β) (arr : Array α) (a : α) :
-    (arr.push a).foldrM f init (start := arr.size + 1) = f a init >>= arr.foldrM f := by
-  simp [← foldrM_push]
+/--
+Variant of `foldrM_push` with `h : start = arr.size + 1`
+rather than `(arr.push a).size` as the argument.
+-/
+@[simp] theorem foldrM_push' [Monad m] (f : α → β → m β) (init : β) (arr : Array α) (a : α)
+    {start} (h : start = arr.size + 1) :
+    (arr.push a).foldrM f init start = f a init >>= arr.foldrM f := by
+  simp [← foldrM_push, h]
 
 theorem foldr_push (f : α → β → β) (init : β) (arr : Array α) (a : α) :
     (arr.push a).foldr f init = arr.foldr f (f a init) := foldrM_push ..
 
-/-- Variant of `foldr_push` with the `start := arr.size + 1` rather than `(arr.push a).size`. -/
-@[simp] theorem foldr_push' (f : α → β → β) (init : β) (arr : Array α) (a : α) :
-    (arr.push a).foldr f init (start := arr.size + 1) = arr.foldr f (f a init) := foldrM_push' ..
+/--
+Variant of `foldr_push` with the `h : start = arr.size + 1`
+rather than `(arr.push a).size` as the argument.
+-/
+@[simp] theorem foldr_push' (f : α → β → β) (init : β) (arr : Array α) (a : α) {start}
+    (h : start = arr.size + 1) : (arr.push a).foldr f init start = arr.foldr f (f a init) :=
+  foldrM_push' _ _ _ _ h
 
 /-- A more efficient version of `arr.toList.reverse`. -/
 @[inline] def toListRev (arr : Array α) : List α := arr.foldl (fun l t => t :: l) []
@@ -1608,6 +1617,13 @@ theorem filterMap_toArray (f : α → Option β) (l : List α) :
 
 end List
 
+namespace Array
+
+@[simp] theorem mapM_id {l : Array α} {f : α → Id β} : l.mapM f = l.map f := by
+  induction l; simp_all
+
+end Array
+
 /-! ### Deprecations -/
 
 namespace List

src/Init/Data/BitVec/Bitblast.lean

@@ -174,6 +174,30 @@ theorem carry_succ (i : Nat) (x y : BitVec w) (c : Bool) :
     exact mod_two_pow_add_mod_two_pow_add_bool_lt_two_pow_succ ..
   cases x.toNat.testBit i <;> cases y.toNat.testBit i <;> (simp; omega)
 
+theorem carry_succ_one (i : Nat) (x : BitVec w) (h : 0 < w) :
+    carry (i+1) x (1#w) false = decide (∀ j ≤ i, x.getLsbD j = true) := by
+  induction i with
+  | zero => simp [carry_succ, h]
+  | succ i ih =>
+    rw [carry_succ, ih]
+    simp only [getLsbD_one, add_one_ne_zero, decide_False, Bool.and_false, atLeastTwo_false_mid]
+    cases hx : x.getLsbD (i+1)
+    case false =>
+      have : ∃ j ≤ i + 1, x.getLsbD j = false :=
+        ⟨i+1, by omega, hx⟩
+      simpa
+    case true =>
+      suffices
+          (∀ (j : Nat), j ≤ i → x.getLsbD j = true)
+          ↔ (∀ (j : Nat), j ≤ i + 1 → x.getLsbD j = true) by
+        simpa
+      constructor
+      · intro h j hj
+        rcases Nat.le_or_eq_of_le_succ hj with (hj' | rfl)
+        · apply h; assumption
+        · exact hx
+      · intro h j hj; apply h; omega
+
 /--
 If `x &&& y = 0`, then the carry bit `(x + y + 0)` is always `false` for any index `i`.
 Intuitively, this is because a carry is only produced when at least two of `x`, `y`, and the
@@ -352,6 +376,117 @@ theorem bit_neg_eq_neg (x : BitVec w) : -x = (adc (((iunfoldr (fun (i : Fin w) c
     simp [← sub_toAdd, BitVec.sub_add_cancel]
   · simp [bit_not_testBit x _]
 
+/--
+Remember that negating a bitvector is equal to incrementing the complement
+by one, i.e., `-x = ~~~x + 1`. See also `neg_eq_not_add`.
+
+This computation has two crucial properties:
+- The least significant bit of `-x` is the same as the least significant bit of `x`, and
+- The `i+1`-th least significant bit of `-x` is the complement of the `i+1`-th bit of `x`, unless
+  all of the preceding bits are `false`, in which case the bit is equal to the `i+1`-th bit of `x`
+-/
+theorem getLsbD_neg {i : Nat} {x : BitVec w} :
+    getLsbD (-x) i =
+      (getLsbD x i ^^ decide (i < w) && decide (∃ j < i, getLsbD x j = true)) := by
+  rw [neg_eq_not_add]
+  by_cases hi : i < w
+  · rw [getLsbD_add hi]
+    have : 0 < w := by omega
+    simp only [getLsbD_not, hi, decide_True, Bool.true_and, getLsbD_one, this, not_bne,
+      _root_.true_and, not_eq_eq_eq_not]
+    cases i with
+    | zero =>
+      have carry_zero : carry 0 ?x ?y false = false := by
+        simp [carry]; omega
+      simp [hi, carry_zero]
+    | succ =>
+      rw [carry_succ_one _ _ (by omega), ← Bool.xor_not, ← decide_not]
+      simp only [add_one_ne_zero, decide_False, getLsbD_not, and_eq_true, decide_eq_true_eq,
+        not_eq_eq_eq_not, Bool.not_true, false_bne, not_exists, _root_.not_and, not_eq_true,
+        bne_left_inj, decide_eq_decide]
+      constructor
+      · rintro h j hj; exact And.right <| h j (by omega)
+      · rintro h j hj; exact ⟨by omega, h j (by omega)⟩
+  · have h_ge : w ≤ i := by omega
+    simp [getLsbD_ge _ _ h_ge, h_ge, hi]
+
+theorem getMsbD_neg {i : Nat} {x : BitVec w} :
+    getMsbD (-x) i =
+      (getMsbD x i ^^ decide (∃ j < w, i < j ∧ getMsbD x j = true)) := by
+  simp only [getMsbD, getLsbD_neg, Bool.decide_and, Bool.and_eq_true, decide_eq_true_eq]
+  by_cases hi : i < w
+  case neg =>
+    simp [hi]; omega
+  case pos =>
+    have h₁ : w - 1 - i < w := by omega
+    simp only [hi, decide_True, h₁, Bool.true_and, Bool.bne_left_inj, decide_eq_decide]
+    constructor
+    · rintro ⟨j, hj, h⟩
+      refine ⟨w - 1 - j, by omega, by omega, by omega, _root_.cast ?_ h⟩
+      congr; omega
+    · rintro ⟨j, hj₁, hj₂, -, h⟩
+      exact ⟨w - 1 - j, by omega, h⟩
+
+theorem msb_neg {w : Nat} {x : BitVec w} :
+    (-x).msb = ((x != 0#w && x != intMin w) ^^ x.msb) := by
+  simp only [BitVec.msb, getMsbD_neg]
+  by_cases hmin : x = intMin _
+  case pos =>
+    have : (∃ j, j < w ∧ 0 < j ∧ 0 < w ∧ j = 0) ↔ False := by
+      simp; omega
+    simp [hmin, getMsbD_intMin, this]
+  case neg =>
+    by_cases hzero : x = 0#w
+    case pos => simp [hzero]
+    case neg =>
+      have w_pos : 0 < w := by
+        cases w
+        · rw [@of_length_zero x] at hzero
+          contradiction
+        · omega
+      suffices ∃ j, j < w ∧ 0 < j ∧ x.getMsbD j = true
+        by simp [show x != 0#w by simpa, show x != intMin w by simpa, this]
+      false_or_by_contra
+      rename_i getMsbD_x
+      simp only [not_exists, _root_.not_and, not_eq_true] at getMsbD_x
+      /- `getMsbD` says that all bits except the msb are `false` -/
+      cases hmsb : x.msb
+      case true =>
+        apply hmin
+        apply eq_of_getMsbD_eq
+        rintro ⟨i, hi⟩
+        simp only [getMsbD_intMin, w_pos, decide_True, Bool.true_and]
+        cases i
+        case zero => exact hmsb
+        case succ => exact getMsbD_x _ hi (by omega)
+      case false =>
+        apply hzero
+        apply eq_of_getMsbD_eq
+        rintro ⟨i, hi⟩
+        simp only [getMsbD_zero]
+        cases i
+        case zero => exact hmsb
+        case succ => exact getMsbD_x _ hi (by omega)
+
+/-! ### abs -/
+
+theorem msb_abs {w : Nat} {x : BitVec w} :
+    x.abs.msb = (decide (x = intMin w) && decide (0 < w)) := by
+  simp only [BitVec.abs, getMsbD_neg, ne_eq, decide_not, Bool.not_bne]
+  by_cases h₀ : 0 < w
+  · by_cases h₁ : x = intMin w
+    · simp [h₁, msb_intMin]
+    · simp only [neg_eq, h₁, decide_False]
+      by_cases h₂ : x.msb
+      · simp [h₂, msb_neg]
+        and_intros
+        · by_cases h₃ : x = 0#w
+          · simp [h₃] at h₂
+          · simp [h₃]
+        · simp [h₁]
+      · simp [h₂]
+  · simp [BitVec.msb, show w = 0 by omega]
+
 /-! ### Inequalities (le / lt) -/
 
 theorem ult_eq_not_carry (x y : BitVec w) : x.ult y = !carry w x (~~~y) true := by