From be169fe3cec9efe2bfff98b3f645bca6cc7d09cd Mon Sep 17 00:00:00 2001
From: Uros Bizjak <ubizjak@gmail.com>
Date: Fri, 27 Nov 2020 11:18:12 +0100
Subject: [PATCH] crypto: x86/poly1305 - Use TEST %reg,%reg instead of CMP
 $0,%reg

CMP $0,%reg can't set overflow flag, so we can use shorter TEST %reg,%reg
instruction when only zero and sign flags are checked (E,L,LE,G,GE conditions).

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
index 7d56801..71fae5a 100644
--- a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
+++ b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
@@ -251,7 +251,7 @@ $code.=<<___;
 	mov	%rax,8($ctx)
 	mov	%rax,16($ctx)
 
-	cmp	\$0,$inp
+	test	$inp,$inp
 	je	.Lno_key
 ___
 $code.=<<___ if (!$kernel);
-- 
2.7.4