ssa: checkIndex for index/indexAddr

cl/_testdata/utf8/in.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"unicode/utf8"
+)
+
+func main() {
+	var str = "中abcd"
+	for i := 0; i < len(str); {
+		r, n := utf8.DecodeRuneInString(str[i:])
+		i += n
+		println(r)
+	}
+	println(index(2) == 3)
+}
+
+var array = [...]uint8{
+	1, 2, 3, 4, 5, 6, 7, 8,
+}
+
+func index(n int8) uint8 {
+	return array[n]
+}