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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Documentation for AtomicCmpXchgInst seems to state wrong return type"
href="https://bugs.llvm.org/show_bug.cgi?id=42325">42325</a>
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<th>Summary</th>
<td>Documentation for AtomicCmpXchgInst seems to state wrong return type
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<th>Product</th>
<td>Documentation
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Doxygen
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>post+llvm@ralfj.de
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>At <a href="https://llvm.org/doxygen/classllvm_1_1AtomicCmpXchgInst.html">https://llvm.org/doxygen/classllvm_1_1AtomicCmpXchgInst.html</a>, the
documentation says
<span class="quote">> an instruction that atomically checks whether a specified value is in a memory location, and, if it is, stores a new value there.
>
> Returns the value that was loaded. </span >
However, that does not seem to be correct: what it really returns (judging from
how it is used in Rust, and also e.g. at clang/lib/CodeGen/CGAtomic.cpp) is a
pair with two fields, the first field is the old value and the second field
indicates whether the comparison succeeded.</pre>
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