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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Clang implementation of _InterlockedAnd in intrin.h doesn't follow official behavior"
href="https://llvm.org/bugs/show_bug.cgi?id=28326">28326</a>
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<th>Summary</th>
<td>Clang implementation of _InterlockedAnd in intrin.h doesn't follow official behavior
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<th>Product</th>
<td>clang
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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>Windows NT
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Headers
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>chris.cavalaria@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
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<pre>Looking at the source of intrin.h
(<a href="https://github.com/llvm-mirror/clang/blob/c0be6ec1bf4aeb27228c27cd807c3d4a9b759c4a/lib/Headers/intrin.h">https://github.com/llvm-mirror/clang/blob/c0be6ec1bf4aeb27228c27cd807c3d4a9b759c4a/lib/Headers/intrin.h</a>
for the most recent version) I can see that _InterlockedAnd is implemented with
a call to __atomic_and_fetch which if I'm not wrong returns the value in the
variable after then "and" is done. But the MSDN suggests it should return the
value before the "and"
<a href="https://msdn.microsoft.com/en-us/library/dsx2t7yd.aspx">https://msdn.microsoft.com/en-us/library/dsx2t7yd.aspx</a>
Return Value
The original value of the first operand.
It should probably be a call to __atomic_fetch_and instead.</pre>
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