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<body><span class="vcard"><a class="email" href="mailto:ldionne@apple.com" title="Louis Dionne <ldionne@apple.com>"> <span class="fn">Louis Dionne</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - volatile copy assignment operator for std::atomic"
href="https://bugs.llvm.org/show_bug.cgi?id=41784">bug 41784</a>
<br>
<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">CC</td>
<td>
</td>
<td>ldionne@apple.com
</td>
</tr>
<tr>
<td style="text-align:right;">Fixed By Commit(s)</td>
<td>
</td>
<td>c448ea948c28878735fefec734d8326ca2e4b33a
</td>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - volatile copy assignment operator for std::atomic"
href="https://bugs.llvm.org/show_bug.cgi?id=41784#c5">Comment # 5</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - volatile copy assignment operator for std::atomic"
href="https://bugs.llvm.org/show_bug.cgi?id=41784">bug 41784</a>
from <span class="vcard"><a class="email" href="mailto:ldionne@apple.com" title="Louis Dionne <ldionne@apple.com>"> <span class="fn">Louis Dionne</span></a>
</span></b>
<pre>Should be fixed by <a href="https://reviews.llvm.org/D90968">https://reviews.llvm.org/D90968</a>:
commit c448ea948c28878735fefec734d8326ca2e4b33a
Author: Ruslan Arutyunyan <<a href="mailto:ruslan.arutyunyan@intel.com">ruslan.arutyunyan@intel.com</a>>
Date: Mon Feb 1 10:12:09 2021 -0500
[libc++] Fix for the <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - volatile copy assignment operator for std::atomic"
href="show_bug.cgi?id=41784">Bug 41784</a>
Add deleted volatile copy-assignment operator in the most derived atomic
to fix the <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - volatile copy assignment operator for std::atomic"
href="show_bug.cgi?id=41784">Bug 41784</a>. The root cause: there is an `operator=(T) volatile`
that has better match than the deleted copy-assignment operator of the base
class when `this` is `volatile`. The compiler sees that right operand of
the assignment operator can be converted to `T` and chooses that path
without taking into account the deleted copy-assignment operator of the
base class.
The current behavior on libstdc++ is different from what we have in libc++.
On the same test compilation fails with libstdc++. Proof:
<a href="https://godbolt.org/z/nebPYd">https://godbolt.org/z/nebPYd</a>
(everything is the same except the -stdlib option).
I choose the way with explicit definition of copy-assignment for atomic
in the most derived class. But probably we can fix that by moving
`operator=(T)` overloads to the base class from both specializations.
At first glance, it shouldn't break anything.
Differential Revision: <a href="https://reviews.llvm.org/D90968">https://reviews.llvm.org/D90968</a></pre>
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