File: early_otherwise_branch_soundness.rs

package info (click to toggle)
rustc-web 1.78.0%2Bdfsg1-2~deb11u3
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 1,245,360 kB
  • sloc: xml: 147,985; javascript: 18,022; sh: 11,083; python: 10,265; ansic: 6,172; cpp: 5,023; asm: 4,390; makefile: 4,269
file content (33 lines) | stat: -rw-r--r-- 877 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
// skip-filecheck
//@ unit-test: EarlyOtherwiseBranch

// Tests various cases that the `early_otherwise_branch` opt should *not* optimize

// From #78496
enum E<'a> {
    Empty,
    Some(&'a E<'a>),
}

// EMIT_MIR early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
fn no_downcast(e: &E) -> u32 {
    if let E::Some(E::Some(_)) = e { 1 } else { 2 }
}

// SAFETY: if `a` is `Some`, `b` must point to a valid, initialized value
// EMIT_MIR early_otherwise_branch_soundness.no_deref_ptr.EarlyOtherwiseBranch.diff
unsafe fn no_deref_ptr(a: Option<i32>, b: *const Option<i32>) -> i32 {
    match a {
        // `*b` being correct depends on `a == Some(_)`
        Some(_) => match *b {
            Some(v) => v,
            _ => 0,
        },
        _ => 0,
    }
}

fn main() {
    no_downcast(&E::Empty);
    unsafe { no_deref_ptr(None, std::ptr::null()) };
}