rust/tests/ui/issues/issue-29663.rs

// run-pass
#![allow(stable_features)]
// write_volatile causes an LLVM assert with composite types

#![feature(volatile)]
use std::ptr::{read_volatile, write_volatile};

#[derive(Debug, Eq, PartialEq)]
struct A(u32);
#[derive(Debug, Eq, PartialEq)]
struct B(u64);
#[derive(Debug, Eq, PartialEq)]
struct C(u32, u32);
#[derive(Debug, Eq, PartialEq)]
struct D(u64, u64);
#[derive(Debug, Eq, PartialEq)]
struct E([u64; 32]);

fn main() {
    unsafe {
        let mut x: u32 = 0;
        write_volatile(&mut x, 1);
        assert_eq!(read_volatile(&x), 1);
        assert_eq!(x, 1);

        let mut x: u64 = 0;
        write_volatile(&mut x, 1);
        assert_eq!(read_volatile(&x), 1);
        assert_eq!(x, 1);

        let mut x = A(0);
        write_volatile(&mut x, A(1));
        assert_eq!(read_volatile(&x), A(1));
        assert_eq!(x, A(1));

        let mut x = B(0);
        write_volatile(&mut x, B(1));
        assert_eq!(read_volatile(&x), B(1));
        assert_eq!(x, B(1));

        let mut x = C(0, 0);
        write_volatile(&mut x, C(1, 1));
        assert_eq!(read_volatile(&x), C(1, 1));
        assert_eq!(x, C(1, 1));

        let mut x = D(0, 0);
        write_volatile(&mut x, D(1, 1));
        assert_eq!(read_volatile(&x), D(1, 1));
        assert_eq!(x, D(1, 1));

        let mut x = E([0; 32]);
        write_volatile(&mut x, E([1; 32]));
        assert_eq!(read_volatile(&x), E([1; 32]));
        assert_eq!(x, E([1; 32]));
    }
}