specialize zip: Add codegen test

src/test/codegen/zip.rs

@@ -0,0 +1,22 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -C no-prepopulate-passes -O
+
+#![crate_type = "lib"]
+
+// CHECK-LABEL: @zip_copy
+#[no_mangle]
+pub fn zip_copy(xs: &[u8], ys: &mut [u8]) {
+// CHECK: memcpy
+    for (x, y) in xs.iter().zip(ys) {
+        *y = *x;
+    }
+}