diff --git a/src/bytes/bytes_s390x.go b/src/bytes/bytes_s390x.go
index 9eec3b7b5d..988c6034aa 100644
--- a/src/bytes/bytes_s390x.go
+++ b/src/bytes/bytes_s390x.go
@@ -32,6 +32,13 @@ func Index(s, sep []byte) int {
 		return 0
 	case n == 1:
 		return IndexByte(s, sep[0])
+	case n == len(s):
+		if Equal(sep, s) {
+			return 0
+		}
+		return -1
+	case n > len(s):
+		return -1
 	case n <= shortStringLen:
 		// Use brute force when s and sep both are small
 		if len(s) <= 64 {
@@ -68,13 +75,6 @@ func Index(s, sep []byte) int {
 			}
 		}
 		return -1
-	case n == len(s):
-		if Equal(sep, s) {
-			return 0
-		}
-		return -1
-	case n > len(s):
-		return -1
 	}
 	// Rabin-Karp search
 	hashsep, pow := hashStr(sep)
diff --git a/src/strings/strings_s390x.go b/src/strings/strings_s390x.go
index 64204ab09e..316a1b896b 100644
--- a/src/strings/strings_s390x.go
+++ b/src/strings/strings_s390x.go
@@ -32,6 +32,13 @@ func Index(s, sep string) int {
 		return 0
 	case n == 1:
 		return IndexByte(s, sep[0])
+	case n == len(s):
+		if sep == s {
+			return 0
+		}
+		return -1
+	case n > len(s):
+		return -1
 	case n <= shortStringLen:
 		// Use brute force when s and sep both are small
 		if len(s) <= 64 {
@@ -68,13 +75,6 @@ func Index(s, sep string) int {
 			}
 		}
 		return -1
-	case n == len(s):
-		if sep == s {
-			return 0
-		}
-		return -1
-	case n > len(s):
-		return -1
 	}
 	// Rabin-Karp search
 	hashsep, pow := hashStr(sep)