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//@ compile-flags: -O -Z merge-functions=disabled
#![crate_type = "lib"]
#![feature(core_intrinsics)]
// This test checks that we annotate alignment loads from vtables with nonzero range metadata,
// and that this allows LLVM to eliminate redundant `align >= 1` checks.
pub trait Trait {
fn f(&self);
}
pub struct WrapperWithAlign1<T: ?Sized> { x: u8, y: T }
pub struct WrapperWithAlign2<T: ?Sized> { x: u16, y: T }
pub struct Struct<W: ?Sized> {
_field: i8,
dst: W,
}
// CHECK-LABEL: @eliminates_runtime_check_when_align_1
#[no_mangle]
pub fn eliminates_runtime_check_when_align_1(
x: &Struct<WrapperWithAlign1<dyn Trait>>
) -> &WrapperWithAlign1<dyn Trait> {
// CHECK: load [[USIZE:i[0-9]+]], {{.+}} !range [[RANGE_META:![0-9]+]]
// CHECK-NOT: llvm.umax
// CHECK-NOT: icmp
// CHECK-NOT: select
// CHECK: ret
&x.dst
}
// CHECK-LABEL: @does_not_eliminate_runtime_check_when_align_2
#[no_mangle]
pub fn does_not_eliminate_runtime_check_when_align_2(
x: &Struct<WrapperWithAlign2<dyn Trait>>
) -> &WrapperWithAlign2<dyn Trait> {
// CHECK: [[X0:%[0-9]+]] = load [[USIZE]], {{.+}} !range [[RANGE_META]]
// CHECK: {{icmp|llvm.umax}}
// CHECK: ret
&x.dst
}
// CHECK-LABEL: @align_load_from_align_of_val
#[no_mangle]
pub fn align_load_from_align_of_val(x: &dyn Trait) -> usize {
// CHECK: {{%[0-9]+}} = load [[USIZE]], {{.+}} !range [[RANGE_META]]
core::mem::align_of_val(x)
}
// CHECK-LABEL: @align_load_from_vtable_align_intrinsic
#[no_mangle]
pub unsafe fn align_load_from_vtable_align_intrinsic(x: &dyn Trait) -> usize {
let (data, vtable): (*const (), *const ()) = core::mem::transmute(x);
// CHECK: {{%[0-9]+}} = load [[USIZE]], {{.+}} !range [[RANGE_META]]
core::intrinsics::vtable_align(vtable)
}
// CHECK: [[RANGE_META]] = !{[[USIZE]] 1, [[USIZE]] 0}
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