Add optimization codegen test

Author: oberien

src/test/codegen/repeat-trusted-len.rs

@@ -0,0 +1,30 @@
+// 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: -O
+
+#![crate_type = "lib"]
+
+use std::iter;
+
+// CHECK-LABEL: @repeat_take_collect
+#[no_mangle]
+pub fn repeat_take_collect() -> Vec<u8> {
+// CHECK: call void @llvm.memset.p0i8
+    iter::repeat(42).take(100000).collect()
+}
+
+// CHECK-LABEL: @range_from_take_collect
+#[no_mangle]
+pub fn range_from_take_collect() -> Vec<u8> {
+// CHECK: %broadcast.splatinsert = insertelement <{{[0-9]+}} x i8> undef, i8 %{{.*}}, i32 0
+// CHECK: %broadcast.splat = shufflevector <[[WIDTH:[0-9]+]] x i8> %broadcast.splatinsert, <[[WIDTH]] x i8> undef, <[[WIDTH]] x i32> zeroinitializer
+    (0..).take(100000).collect()
+}