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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [Polly] Exploit undefined behavior of out-of-bound accesses in C/C++"
href="https://llvm.org/bugs/show_bug.cgi?id=27067">27067</a>
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<th>Summary</th>
<td>[Polly] Exploit undefined behavior of out-of-bound accesses in C/C++
</td>
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<th>Product</th>
<td>Polly
</td>
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<th>Version</th>
<td>unspecified
</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
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Optimizer
</td>
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<th>Assignee</th>
<td>polly-dev@googlegroups.com
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<th>Reporter</th>
<td>tobias@grosser.es
</td>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16091" name="attach_16091" title="Example with signed check">attachment 16091</a> <a href="attachment.cgi?id=16091&action=edit" title="Example with signed check">[details]</a></span>
Example with signed check
In case an __assume statement is within a Scop, we do not yet exploit the
properties it describes.
A use case for this would to pass out-of-bound information for C arrays to
LLVM-IR. In C, accesses that leave the bounds of a defined array are undefined
behavior. Consequently, we can use this information to simplify our context /
run-time checks.
It should be easy to teach our assumption tracking to exploit such expressions,
assuming the conditions we look at are signed (example attached).</pre>
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