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// compile-flags: -O
#![crate_type = "lib"]
// 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: [[RANGE_META]] = !{[[USIZE]] 1, [[USIZE]] 0}
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