2018-09-20 20:57:25 +02:00
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// compile-flags: -O
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2022-03-21 15:30:54 -04:00
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// min-llvm-version: 15.0
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2018-09-20 20:57:25 +02:00
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#![crate_type="lib"]
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use std::mem::MaybeUninit;
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// Boxing a `MaybeUninit` value should not copy junk from the stack
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#[no_mangle]
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pub fn box_uninitialized() -> Box<MaybeUninit<usize>> {
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// CHECK-LABEL: @box_uninitialized
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// CHECK-NOT: store
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2019-02-05 22:26:30 +01:00
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// CHECK-NOT: alloca
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// CHECK-NOT: memcpy
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// CHECK-NOT: memset
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2019-03-19 09:46:11 +01:00
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Box::new(MaybeUninit::uninit())
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2018-09-20 20:57:25 +02:00
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}
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2019-03-19 09:46:11 +01:00
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// FIXME: add a test for a bigger box. Currently broken, see
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// https://github.com/rust-lang/rust/issues/58201.
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2022-03-21 15:30:54 -04:00
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// Hide the `allocalign` attribute in the declaration of __rust_alloc
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// from the CHECK-NOT above, and also verify the attributes got set reasonably.
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// CHECK: declare noalias ptr @__rust_alloc(i{{[0-9]+}}, i{{[0-9]+}} allocalign) unnamed_addr [[RUST_ALLOC_ATTRS:#[0-9]+]]
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// CHECK-DAG: attributes [[RUST_ALLOC_ATTRS]] = { {{.*}} allockind("alloc,uninitialized,aligned") allocsize(0) uwtable "alloc-family"="__rust_alloc" {{.*}} }
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