From 712c80da10d7111e3f511fcfd28a572c3afe6457 Mon Sep 17 00:00:00 2001
From: Dave Collins <davec@conformal.com>
Date: Sat, 23 Jul 2022 23:40:25 -0500
Subject: [PATCH] secp256k1: Store constant on stack instead of heap.

This modifies the constant that houses the order as a field val to store
it on the stack instead of the heap to save an unnecessary allocation.
---
 dcrec/secp256k1/ecdsa/signature.go | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/dcrec/secp256k1/ecdsa/signature.go b/dcrec/secp256k1/ecdsa/signature.go
index 4fd64f9c..cfa7a487 100644
--- a/dcrec/secp256k1/ecdsa/signature.go
+++ b/dcrec/secp256k1/ecdsa/signature.go
@@ -29,10 +29,10 @@ var (
 	// orderAsFieldVal is the order of the secp256k1 curve group stored as a
 	// field value.  It is provided here to avoid the need to create it multiple
 	// times.
-	orderAsFieldVal = func() *secp256k1.FieldVal {
+	orderAsFieldVal = func() secp256k1.FieldVal {
 		var f secp256k1.FieldVal
 		f.SetByteSlice(secp256k1.Params().N.Bytes())
-		return &f
+		return f
 	}()
 )
 
@@ -282,7 +282,7 @@ func (sig *Signature) Verify(hash []byte, pubKey *secp256k1.PublicKey) bool {
 	// Step 10.
 	//
 	// Verified if (R + N) * z == X.x (mod P)
-	sigRModP.Add(orderAsFieldVal)
+	sigRModP.Add(&orderAsFieldVal)
 	result.Mul2(&sigRModP, z).Normalize()
 	return result.Equals(&X.X)
 }
@@ -919,7 +919,7 @@ func RecoverCompact(signature, hash []byte) (*secp256k1.PublicKey, bool, error)
 		// Step 3.2.
 		//
 		// r = r + N (mod P)
-		fieldR.Add(orderAsFieldVal)
+		fieldR.Add(&orderAsFieldVal)
 	}
 
 	// Step 4.