ssa: binop check shl/shr

cl/_testrt/mask/in.go

@@ -2,7 +2,41 @@ package main
 
 func main() {
 	println(mask(1))
+	println(mask_shl(127, 5))
+	println(mask_shl8(127, 5))
+	println(mask_shl8u(127, 5))
+	println(mask_shl8(127, 16))
+	println(mask_shl8u(127, 16))
+	println(mask_shr(127, 5))
+	println(mask_shr8(127, 5))
+	println(mask_shr8u(127, 5))
+	println(mask_shr8(127, 16))
 }
+
 func mask(x int8) int32 {
 	return int32(x) << 31 >> 31
 }
+
+func mask_shl8(x int8, y int) int8 {
+	return x << y
+}
+
+func mask_shl8u(x uint8, y int) uint8 {
+	return x << y
+}
+
+func mask_shl(x int, y int) int {
+	return x << y
+}
+
+func mask_shr8(x int8, y int) int8 {
+	return x >> y
+}
+
+func mask_shr8u(x uint8, y int) uint8 {
+	return x >> y
+}
+
+func mask_shr(x int, y int) int {
+	return x >> y
+}