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Source code

#[inline(never)]
fn has_zero_index(xs: &[u8]) -> bool {
    for i in 0..xs.len() {
        if xs[i] == 0 {
            return true
        }
    }
    false
}

#[inline(never)]
pub fn has_zero_memchr(xs: &[u8]) -> bool {
    xs.contains(&0)
}

#[inline(never)]
pub fn has_zero_iter(xs: &[u8]) -> bool {
    xs.iter().any(|&x| x == 0)
}

#[inline(never)]
fn has_zero_ptr(xs: &[u8]) -> bool {
    let range = xs.as_ptr_range();
    let mut start = range.start;
    let end = range.end;
    while start < end {
        unsafe {
            if *start == 0 {
                return true
            }
            start = start.add(1);
        }
    }
    false
}

pub fn foo_index(xs: &[u8])  {
    // CSE
    println!("a: {}", has_zero_index(xs));
    println!("b: {}", has_zero_index(xs));
}

pub fn foo_memchr(xs: &[u8]) {
    // No CSE
    println!("a: {}", has_zero_memchr(xs));
    println!("b: {}", has_zero_memchr(xs));
}

pub fn foo_iter(xs: &[u8]) {
    // No CSE
    println!("a: {}", has_zero_iter(xs));
    println!("b: {}", has_zero_iter(xs));
}

pub fn foo_ptr(xs: &[u8]) {
    // No CSE
    println!("a: {}", has_zero_ptr(xs));
    println!("b: {}", has_zero_ptr(xs));
}