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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - UBSan false positive vptr with -O1"
href="https://bugs.llvm.org/show_bug.cgi?id=51879">51879</a>
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<th>Summary</th>
<td>UBSan false positive vptr with -O1
</td>
</tr>
<tr>
<th>Product</th>
<td>compiler-rt
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>ubsan
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>maic23@live.de
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=25265" name="attach_25265" title="1.cpp">attachment 25265</a> <a href="attachment.cgi?id=25265&action=edit" title="1.cpp">[details]</a></span>
1.cpp
Steps to reproduce with -O1. (Other optimization levels pass fine.)
$ clang++-13 -std=c++17 -O1 -fsanitize=undefined ./1.cpp && ./a.out
1.cpp:12:25: runtime error: member call on address 0x000000d50238 which does
not point to an object of type 'A'
0x000000d50238: note: object has invalid vptr
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00
^~~~~~~~~~~~~~~~~~~~~~~
invalid vptr
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 1.cpp:12:25 in
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==462339==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address
0x000000000000 (pc 0x0000004274e7 bp 0x000000000000 sp 0x7ffecb558b00 T462339)
==462339==The signal is caused by a READ memory access.
==462339==Hint: address points to the zero page.</pre>
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