diff --git a/x86_64/pclmul/ghash-update.asm b/x86_64/pclmul/ghash-update.asm
index 1c30e7d8a0e72c79ca8ea8b01296fdc478fea7fe..67b8f11116038b0a3a360860f3980bcd209cf011 100644
--- a/x86_64/pclmul/ghash-update.asm
+++ b/x86_64/pclmul/ghash-update.asm
@@ -140,7 +140,7 @@ PROLOGUE(_nettle_ghash_update)
 	jnz		.Loop
 
 .L1_block:
-	and		$1, BLOCKS
+	test		$1, BLOCKS
 	jz		.Ldone
 
 	movups		(DATA), M