From 38df9b2c63bf4a41d78f601187d0d8556202e972 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Fri, 4 Oct 2019 17:57:53 +0300
Subject: [PATCH] Detect CPU features in Sum()

---
 tz/hash.go | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/tz/hash.go b/tz/hash.go
index 1ec8612..b617d40 100644
--- a/tz/hash.go
+++ b/tz/hash.go
@@ -70,9 +70,19 @@ func New() hash.Hash {
 
 // Sum returns Tillich-Zémor checksum of data.
 func Sum(data []byte) [hashSize]byte {
-	d := newAVX2Inline()
-	_, _ = d.Write(data) // no errors
-	return d.checkSum()
+	if hasAVX2 {
+		d := newAVX2Inline()
+		_, _ = d.Write(data) // no errors
+		return d.checkSum()
+	} else if hasAVX {
+		d := newAVX()
+		_, _ = d.Write(data) // no errors
+		return d.checkSum()
+	} else {
+		d := newPure()
+		_, _ = d.Write(data) // no errors
+		return d.checkSum()
+	}
 }
 
 // Concat performs combining of hashes based on homomorphic property.