lean4-htt/tests/lean/run/match_expr_perf.lean
Leonardo de Moura a4d41beab1
perf: match_expr join points (#3580)
We use `let_delayed` to elaborate `match_expr` join points, which
elaborate the body of the `let` before its value. Thus, there is a
difference between:
- `let_delayed f (x : Expr) := <val>; <body>`
- `let_delayed f := fun (x : Expr) => <val>; <body>`

In the latter, when `<body>` is elaborated, the elaborator does not know
that `f` takes an argument of type `Expr`, and that `f` is a function.
Before this commit ensures the former representation is used.
2024-03-03 18:15:49 +00:00

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/-
Copyright (c) 2023 Lean FRO, LLC. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Scott Morrison
-/
prelude
import Lean.Elab.Tactic.Omega.Core
import Lean.Elab.Tactic.FalseOrByContra
import Lean.Meta.Tactic.Cases
import Lean.Elab.Tactic.Config
open Lean Meta Omega
set_option maxHeartbeats 5000
def pushNot (h P : Expr) : MetaM (Option Expr) := do
let P ← whnfR P
trace[omega] "pushing negation: {P}"
match P with
| .forallE _ t b _ =>
if (← isProp t) && (← isProp b) then
return some (mkApp4 (.const ``Decidable.and_not_of_not_imp []) t b
(.app (.const ``Classical.propDecidable []) t) h)
else
return none
| .app _ _ =>
match_expr P with
| LT.lt α _ x y => match_expr α with
| Nat => return some (mkApp3 (.const ``Nat.le_of_not_lt []) x y h)
| Int => return some (mkApp3 (.const ``Int.le_of_not_lt []) x y h)
| Fin n => return some (mkApp4 (.const ``Fin.le_of_not_lt []) n x y h)
| _ => return none
| LE.le α _ x y => match_expr α with
| Nat => return some (mkApp3 (.const ``Nat.lt_of_not_le []) x y h)
| Int => return some (mkApp3 (.const ``Int.lt_of_not_le []) x y h)
| Fin n => return some (mkApp4 (.const ``Fin.lt_of_not_le []) n x y h)
| _ => return none
| Eq α x y => match_expr α with
| Nat => return some (mkApp3 (.const ``Nat.lt_or_gt_of_ne []) x y h)
| Int => return some (mkApp3 (.const ``Int.lt_or_gt_of_ne []) x y h)
| Fin n => return some (mkApp4 (.const ``Fin.lt_or_gt_of_ne []) n x y h)
| _ => return none
| Dvd.dvd α _ k x => match_expr α with
| Nat => return some (mkApp3 (.const ``Nat.emod_pos_of_not_dvd []) k x h)
| Int =>
-- This introduces a disjunction that could be avoided by checking `k ≠ 0`.
return some (mkApp3 (.const ``Int.emod_pos_of_not_dvd []) k x h)
| _ => return none
| Prod.Lex _ _ _ _ _ _ => return some (← mkAppM ``Prod.of_not_lex #[h])
| Not P =>
return some (mkApp3 (.const ``Decidable.of_not_not []) P
(.app (.const ``Classical.propDecidable []) P) h)
| And P Q =>
return some (mkApp5 (.const ``Decidable.or_not_not_of_not_and []) P Q
(.app (.const ``Classical.propDecidable []) P)
(.app (.const ``Classical.propDecidable []) Q) h)
| Or P Q =>
return some (mkApp3 (.const ``and_not_not_of_not_or []) P Q h)
| Iff P Q =>
return some (mkApp5 (.const ``Decidable.and_not_or_not_and_of_not_iff []) P Q
(.app (.const ``Classical.propDecidable []) P)
(.app (.const ``Classical.propDecidable []) Q) h)
| _ => return none
| _ => return none