diff --git a/flate/fast_encoder.go b/flate/fast_encoder.go
index 347ac2c902..a746eb7338 100644
--- a/flate/fast_encoder.go
+++ b/flate/fast_encoder.go
@@ -215,24 +215,15 @@ func (e *fastGen) Reset() {
 func matchLen(a, b []byte) int {
 	b = b[:len(a)]
 	var checked int
-	if len(a) >= 4 {
-		// Try 4 bytes first
-		if diff := binary.LittleEndian.Uint32(a) ^ binary.LittleEndian.Uint32(b); diff != 0 {
-			return bits.TrailingZeros32(diff) >> 3
-		}
-		// Switch to 8 byte matching.
-		checked = 4
-		a = a[4:]
-		b = b[4:]
-		for len(a) >= 8 {
-			b = b[:len(a)]
-			if diff := binary.LittleEndian.Uint64(a) ^ binary.LittleEndian.Uint64(b); diff != 0 {
-				return checked + (bits.TrailingZeros64(diff) >> 3)
-			}
-			checked += 8
-			a = a[8:]
-			b = b[8:]
+
+	for len(a) >= 8 {
+		b = b[:len(a)]
+		if diff := binary.LittleEndian.Uint64(a) ^ binary.LittleEndian.Uint64(b); diff != 0 {
+			return checked + (bits.TrailingZeros64(diff) >> 3)
 		}
+		checked += 8
+		a = a[8:]
+		b = b[8:]
 	}
 	b = b[:len(a)]
 	for i := range a {