mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-23 15:23:46 +00:00
44 lines
1.5 KiB
Rust
44 lines
1.5 KiB
Rust
// compile-flags: --crate-type=lib
|
|
// check-pass
|
|
|
|
#![feature(
|
|
core_intrinsics,
|
|
const_raw_ptr_comparison,
|
|
)]
|
|
|
|
const FOO: &usize = &42;
|
|
|
|
macro_rules! check {
|
|
(eq, $a:expr, $b:expr) => {
|
|
pub const _: () =
|
|
assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 1);
|
|
};
|
|
(ne, $a:expr, $b:expr) => {
|
|
pub const _: () =
|
|
assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 0);
|
|
};
|
|
(!, $a:expr, $b:expr) => {
|
|
pub const _: () =
|
|
assert!(std::intrinsics::ptr_guaranteed_cmp($a as *const u8, $b as *const u8) == 2);
|
|
};
|
|
}
|
|
|
|
check!(eq, 0, 0);
|
|
check!(ne, 0, 1);
|
|
check!(ne, FOO as *const _, 0);
|
|
check!(ne, unsafe { (FOO as *const usize).offset(1) }, 0);
|
|
check!(ne, unsafe { (FOO as *const usize as *const u8).offset(3) }, 0);
|
|
|
|
// We want pointers to be equal to themselves, but aren't checking this yet because
|
|
// there are some open questions (e.g. whether function pointers to the same function
|
|
// compare equal: they don't necessarily do at runtime).
|
|
check!(!, FOO as *const _, FOO as *const _);
|
|
|
|
// aside from 0, these pointers might end up pretty much anywhere.
|
|
check!(!, FOO as *const _, 1); // this one could be `ne` by taking into account alignment
|
|
check!(!, FOO as *const _, 1024);
|
|
|
|
// When pointers go out-of-bounds, they *might* become null, so these comparions cannot work.
|
|
check!(!, unsafe { (FOO as *const usize).wrapping_add(2) }, 0);
|
|
check!(!, unsafe { (FOO as *const usize).wrapping_sub(1) }, 0);
|