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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - packed attribute should not apply to base classes"
href="https://bugs.llvm.org/show_bug.cgi?id=37275">37275</a>
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<th>Summary</th>
<td>packed attribute should not apply to base classes
</td>
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<th>Product</th>
<td>clang
</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
</td>
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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>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>richard-llvm@metafoo.co.uk
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<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>Per the GCC documentation, the 'packed' attribute on a class is applied to all
non-static data members of that class ("Specifying the packed attribute for
struct and union types is equivalent to specifying the packed attribute on each
of the structure or union members."). It should *not* be applied to base
classes. Testcase:
struct A { int n; };
static_assert(alignof(A) == alignof(int));
struct [[gnu::packed]] B : A {};
static_assert(alignof(B) == alignof(int));
This test passes with GCC, but fails with Clang because we incorrectly give B
1-byte alignment.</pre>
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