test: add a basic test for the vectorcall calling convention

Author: steffengy

src/test/run-pass/extern-vectorcall.rs

@@ -0,0 +1,32 @@
+// 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.
+
+#![feature(abi_vectorcall)]
+
+trait A {
+    extern "vectorcall" fn test1(i: i32);
+}
+
+struct S;
+
+impl A for S {
+    extern "vectorcall" fn test1(i: i32) {
+        assert_eq!(i, 1);
+    }
+}
+
+extern "vectorcall" fn test2(i: i32) {
+    assert_eq!(i, 2);
+}
+
+fn main() {
+    <S as A>::test1(1);
+    test2(2);
+}