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