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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Cyclic PHI nodes"
href="https://bugs.llvm.org/show_bug.cgi?id=34935">34935</a>
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<th>Summary</th>
<td>Cyclic PHI nodes
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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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>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
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<th>Assignee</th>
<td>davide@freebsd.org
</td>
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<th>Reporter</th>
<td>davide@freebsd.org
</td>
</tr>
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<th>CC</th>
<td>dberlin@dberlin.org, llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>define void @patatino() {
bb:
br label %bb1
bb1:
%tmp = phi i1 [ undef, %bb ], [ %tmp3, %bb1 ]
%tmp3 = and i1 %tmp, true
br label %bb1
}
This is the bug that we think we defeated, many times, and instead, keeps
coming back.
NewGVN keeps moving instructions between classes and never reaches convergence.
Eventually we hit an assertion because we processed an instruction too many
times.
I'll take a stab at debugging it, but this is a FYI.</pre>
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</p>
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