Since fat pointers do not qualify as structural types, they got copied using load_ty and store_ty, which means that we load an FCA and use extractvalue to get the components of the fat pointer. This breaks certain optimizations in LLVM. Found via apasel422/ref_count#13
22 lines
668 B
Rust
22 lines
668 B
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// compile-flags: -C no-prepopulate-passes
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#![crate_type = "lib"]
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pub trait T {}
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// CHECK-LABEL: @copy_fat_ptr
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#[no_mangle]
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pub fn copy_fat_ptr(x: &T) {
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// CHECK-NOT: extractvalue
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let x2 = x;
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}
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