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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Alignment not respected in containers for over-aligned enumeration types"
href="https://bugs.llvm.org/show_bug.cgi?id=42396">42396</a>
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<th>Summary</th>
<td>Alignment not respected in containers for over-aligned enumeration types
</td>
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<th>Product</th>
<td>libc++
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<th>Version</th>
<td>unspecified
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>All
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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>All Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>mclow.lists@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
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<pre>Created <span class=""><a href="attachment.cgi?id=22140" name="attach_22140" title="Reproducer">attachment 22140</a> <a href="attachment.cgi?id=22140&action=edit" title="Reproducer">[details]</a></span>
Reproducer
Inspired by:
<a href="https://stackoverflow.com/questions/56760874/discrepancy-in-c-between-over-aligned-struct-and-enum-within-container">https://stackoverflow.com/questions/56760874/discrepancy-in-c-between-over-aligned-struct-and-enum-within-container</a>
Given an enumeration type with a specified alignment, the elements in a vector
of such a type should be aligned correctly. This appears not to be the case -
and can lead to UBSAN going off.
In the reproducer, I also check the size of a 16-element array of these two
types.
Clang says they're different sizes - that suggests to me that there's a clang
problem here.
The alignment in the containers bit could be related to
<a class="bz_bug_link
bz_status_CONFIRMED "
title="CONFIRMED - operator new and STL containers silently ignore element alignment"
href="show_bug.cgi?id=22634">https://bugs.llvm.org/show_bug.cgi?id=22634</a>. (might even be the same bug)</pre>
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