rust/tests/codegen/noalias-unpin.rs

//@ compile-flags: -O -Z mutable-noalias=yes

#![crate_type = "lib"]

pub struct SelfRef {
    self_ref: *mut SelfRef,
    _pin: std::marker::PhantomPinned
}

// CHECK-LABEL: @test_self_ref(
// CHECK-NOT: noalias
#[no_mangle]
pub unsafe fn test_self_ref(s: &mut SelfRef) {
    (*s.self_ref).self_ref = std::ptr::null_mut();
}
Don't compute optimized PointerKind for unoptimized builds This saves us both the Freeze/Unpin queries, and avoids placing noalias attributes, which have a compile-time impact on LLVM even in optnone builds (due to always_inline functions). 2021-03-19 21:49:51 +00:00			`//@ compile-flags: -O -Z mutable-noalias=yes`
Don't consider !Unpin references as noalias Such structures may contain self-references, in which case the same location may be accessible through a pointer that is not based-on the noalias pointer. This is still grey area as far as language semantics are concerned, but checking for !Unpin as an indicator for self-referential sturctures seems like a good approach for the meantime. 2021-03-18 21:44:36 +00:00
			`#![crate_type = "lib"]`

			`pub struct SelfRef {`
			`self_ref: *mut SelfRef,`
			`_pin: std::marker::PhantomPinned`
			`}`

			`// CHECK-LABEL: @test_self_ref(`
			`// CHECK-NOT: noalias`
			`#[no_mangle]`
			`pub unsafe fn test_self_ref(s: &mut SelfRef) {`
			`(*s.self_ref).self_ref = std::ptr::null_mut();`
			`}`