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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - LoopRotation's DomTree update logic doesn't handle nodes with no predecessors"
href="https://bugs.llvm.org/show_bug.cgi?id=33701">33701</a>
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<th>Summary</th>
<td>LoopRotation's DomTree update logic doesn't handle nodes with no predecessors
</td>
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<th>Product</th>
<td>new-bugs
</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
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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
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>kubakuderski@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<pre>Created <span class=""><a href="attachment.cgi?id=18760" name="attach_18760" title="reduced repro">attachment 18760</a> <a href="attachment.cgi?id=18760&action=edit" title="reduced repro">[details]</a></span>
reduced repro
LoopRotation::rotateLoop tries to manually update DomTree by iterating over all
predecessors of some basic block and computing NearestCommonDominator.
Is there's a predecessor that is unreachable, rotateLoop uses nullptr as a new
IDom for the blocks, which results in a crash.
===============================================
opt -S -loop-rotate -o - reduced9.ll</pre>
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