Add a ZUtil rewrite hint

After    | File Name                                       | Before   || Change
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1m47.58s | Total                                           | 1m48.64s || -0m01.06s
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0m33.26s | Specific/GF25519                                | 0m33.64s || -0m00.38s
0m15.83s | ModularArithmetic/ModularBaseSystemProofs       | 0m15.32s || +0m00.50s
0m12.07s | Experiments/SpecEd25519                         | 0m11.90s || +0m00.16s
0m07.18s | Specific/GF1305                                 | 0m07.17s || +0m00.00s
0m04.53s | ModularArithmetic/Pow2BaseProofs                | 0m04.31s || +0m00.22s
0m03.89s | ModularArithmetic/Tutorial                      | 0m04.09s || -0m00.19s
0m03.87s | BaseSystemProofs                                | 0m03.88s || -0m00.00s
0m03.24s | ModularArithmetic/ModularBaseSystemOpt          | 0m03.33s || -0m00.08s
0m02.60s | Util/ZUtil                                      | 0m02.59s || +0m00.01s
0m02.30s | Encoding/PointEncodingPre                       | 0m02.22s || +0m00.07s
0m01.60s | ModularArithmetic/ModularArithmeticTheorems     | 0m01.84s || -0m00.24s
0m01.58s | ModularArithmetic/PrimeFieldTheorems            | 0m01.61s || -0m00.03s
0m01.19s | BaseSystem                                      | 0m01.65s || -0m00.46s
0m01.17s | ModularArithmetic/ExtendedBaseVector            | 0m01.19s || -0m00.02s
0m01.01s | Experiments/DerivationsOptionRectLetInEncoding  | 0m01.34s || -0m00.33s
0m00.99s | Encoding/ModularWordEncodingTheorems            | 0m01.00s || -0m00.01s
0m00.97s | ModularArithmetic/BarrettReduction/Z            | 0m00.93s || +0m00.03s
0m00.92s | Util/NumTheoryUtil                              | 0m01.37s || -0m00.45s
0m00.92s | Testbit                                         | 0m00.87s || +0m00.05s
0m00.89s | ModularArithmetic/ModularBaseSystemField        | 0m00.94s || -0m00.04s
0m00.84s | ModularArithmetic/PseudoMersenneBaseParamProofs | 0m00.86s || -0m00.02s
0m00.84s | ModularArithmetic/ModularBaseSystemListProofs   | 0m00.84s || +0m00.00s
0m00.72s | Experiments/SpecificCurve25519                  | 0m00.73s || -0m00.01s
0m00.67s | ModularArithmetic/Pre                           | 0m00.55s || +0m00.12s
0m00.64s | ModularArithmetic/ModularBaseSystemList         | 0m00.60s || +0m00.04s
0m00.64s | Encoding/ModularWordEncodingPre                 | 0m00.67s || -0m00.03s
0m00.62s | ModularArithmetic/ExtPow2BaseMulProofs          | 0m00.62s || +0m00.00s
0m00.62s | Spec/ModularWordEncoding                        | 0m00.61s || +0m00.01s
0m00.61s | ModularArithmetic/ModularBaseSystem             | 0m00.60s || +0m00.01s
0m00.53s | ModularArithmetic/Pow2Base                      | 0m00.57s || -0m00.03s
0m00.43s | Spec/ModularArithmetic                          | 0m00.38s || +0m00.04s
0m00.41s | ModularArithmetic/PseudoMersenneBaseParams      | 0m00.42s || -0m00.01s

1 files changed, 1 insertions, 0 deletions

diff --git a/src/Util/ZUtil.v b/src/Util/ZUtil.v
index 670227ba8..6f0577fa5 100644
--- a/src/Util/ZUtil.v
+++ b/src/Util/ZUtil.v
@@ -26,6 +26,7 @@ Hint Resolve (fun a b H => proj1 (Z.mod_pos_bound a b H)) (fun a b H => proj2 (Z
 Create HintDb zsimplify discriminated.
 Hint Rewrite Z.div_1_r Z.mul_1_r Z.mul_1_l Z.sub_diag Z.mul_0_r Z.mul_0_l Z.add_0_l Z.add_0_r Z.opp_involutive Z.sub_0_r Z_mod_same_full Z.sub_simpl_r Z.sub_simpl_l : zsimplify.
 Hint Rewrite Z.div_mul Z.div_1_l Z.div_same Z.mod_same Z.div_small Z.mod_small Z.div_add Z.div_add_l Z.mod_add Z.div_0_l Z.mod_mod using lia : zsimplify.
+Hint Rewrite <- Z.opp_eq_mul_m1 : zsimplify.
 
 (** "push" means transform [-f x] to [f (-x)]; "pull" means go the other way *)
 Create HintDb push_Zopp discriminated.