Add tests

Author: oli-obk

src/test/ui/consts/zst_no_llvm_alloc.rs

@@ -0,0 +1,19 @@
+// run-pass
+
+#[repr(align(4))]
+struct Foo;
+
+static FOO: Foo = Foo;
+
+fn main() {
+    let x: &'static () = &();
+    assert_eq!(x as *const () as usize, 1);
+    let x: &'static Foo = &Foo;
+    assert_eq!(x as *const Foo as usize, 4);
+
+    // statics must have a unique address
+    assert_ne!(&FOO as *const Foo as usize, 4);
+
+    assert_eq!(<Vec<i32>>::new().as_ptr(), <&[i32]>::default().as_ptr());
+    assert_eq!(<Box<[i32]>>::default().as_ptr(), (&[]).as_ptr());
+}