diff --git a/fse/compress.go b/fse/compress.go
index 6f341914c6..dac97e58a2 100644
--- a/fse/compress.go
+++ b/fse/compress.go
@@ -146,54 +146,51 @@ func (s *Scratch) compress(src []byte) error {
 		c1.encodeZero(tt[src[ip-2]])
 		ip -= 2
 	}
+	src = src[:ip]
 
 	// Main compression loop.
 	switch {
 	case !s.zeroBits && s.actualTableLog <= 8:
 		// We can encode 4 symbols without requiring a flush.
 		// We do not need to check if any output is 0 bits.
-		for ip >= 4 {
+		for ; len(src) >= 4; src = src[:len(src)-4] {
 			s.bw.flush32()
-			v3, v2, v1, v0 := src[ip-4], src[ip-3], src[ip-2], src[ip-1]
+			v3, v2, v1, v0 := src[len(src)-4], src[len(src)-3], src[len(src)-2], src[len(src)-1]
 			c2.encode(tt[v0])
 			c1.encode(tt[v1])
 			c2.encode(tt[v2])
 			c1.encode(tt[v3])
-			ip -= 4
 		}
 	case !s.zeroBits:
 		// We do not need to check if any output is 0 bits.
-		for ip >= 4 {
+		for ; len(src) >= 4; src = src[:len(src)-4] {
 			s.bw.flush32()
-			v3, v2, v1, v0 := src[ip-4], src[ip-3], src[ip-2], src[ip-1]
+			v3, v2, v1, v0 := src[len(src)-4], src[len(src)-3], src[len(src)-2], src[len(src)-1]
 			c2.encode(tt[v0])
 			c1.encode(tt[v1])
 			s.bw.flush32()
 			c2.encode(tt[v2])
 			c1.encode(tt[v3])
-			ip -= 4
 		}
 	case s.actualTableLog <= 8:
 		// We can encode 4 symbols without requiring a flush
-		for ip >= 4 {
+		for ; len(src) >= 4; src = src[:len(src)-4] {
 			s.bw.flush32()
-			v3, v2, v1, v0 := src[ip-4], src[ip-3], src[ip-2], src[ip-1]
+			v3, v2, v1, v0 := src[len(src)-4], src[len(src)-3], src[len(src)-2], src[len(src)-1]
 			c2.encodeZero(tt[v0])
 			c1.encodeZero(tt[v1])
 			c2.encodeZero(tt[v2])
 			c1.encodeZero(tt[v3])
-			ip -= 4
 		}
 	default:
-		for ip >= 4 {
+		for ; len(src) >= 4; src = src[:len(src)-4] {
 			s.bw.flush32()
-			v3, v2, v1, v0 := src[ip-4], src[ip-3], src[ip-2], src[ip-1]
+			v3, v2, v1, v0 := src[len(src)-4], src[len(src)-3], src[len(src)-2], src[len(src)-1]
 			c2.encodeZero(tt[v0])
 			c1.encodeZero(tt[v1])
 			s.bw.flush32()
 			c2.encodeZero(tt[v2])
 			c1.encodeZero(tt[v3])
-			ip -= 4
 		}
 	}
 
@@ -459,15 +456,17 @@ func (s *Scratch) countSimple(in []byte) (max int) {
 	for _, v := range in {
 		s.count[v]++
 	}
-	m := uint32(0)
+	m, symlen := uint32(0), s.symbolLen
 	for i, v := range s.count[:] {
+		if v == 0 {
+			continue
+		}
 		if v > m {
 			m = v
 		}
-		if v > 0 {
-			s.symbolLen = uint16(i) + 1
-		}
+		symlen = uint16(i) + 1
 	}
+	s.symbolLen = symlen
 	return int(m)
 }