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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Inconsistencies with weak member symbols"
href="https://bugs.llvm.org/show_bug.cgi?id=47127">47127</a>
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<th>Summary</th>
<td>Inconsistencies with weak member symbols
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
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<th>Hardware</th>
<td>PC
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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
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>srhines@google.com
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk, rprichard@google.com
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<pre>Filing this bug on behalf of Steven Moreland (smoreland@) and Ryan Prichard
(rprichard@). I tried searching to see if there was a duplicate or to find a
reasonable explanation for why this would behave differently, but ultimately, I
think that there is some bug here.
Expected behavior: The static or non-static member function can be nullptr if
it is weak, so the compiler must output a run-time check. For non-weak
functions, the compiler should optimize out the check. GCC works as expected,
and Clang also works for static member functions, but it sometimes assumes that
a non-static weak member function is non-null.
Clang's behavior seems inconsistent. In particular, it optimizes "if
(&A::instance_weak != nullptr) ..." but not "return &A::instance_weak !=
nullptr;".
<a href="https://godbolt.org/z/4xec88">https://godbolt.org/z/4xec88</a></pre>
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