From 3d53201538ca8faef39c80e15f229847e05fdd94 Mon Sep 17 00:00:00 2001
From: Nicholas Ward <npward@berkeley.edu>
Date: Thu, 1 Jul 2021 17:43:22 -0700
Subject: [PATCH] save a gate with arithmetic

---
 src/gadgets/insert.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/gadgets/insert.rs b/src/gadgets/insert.rs
index 7a1ee98d..1f69cb24 100644
--- a/src/gadgets/insert.rs
+++ b/src/gadgets/insert.rs
@@ -23,9 +23,7 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let y = self.mul(x, m);
 
         // Enforce that (1 - y) * x == 0.
-        let one = self.one();
-        let diff = self.sub(one, y);
-        let prod = self.mul(diff, x);
+        let prod = self.arithmetic(F::NEG_ONE, x, y, F::ONE, x);
         self.assert_zero(prod);
 
         y