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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - phi node arguments oscillate with passes licm and simplifycfg"
href="https://llvm.org/bugs/show_bug.cgi?id=27665">27665</a>
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<tr>
<th>Summary</th>
<td>phi node arguments oscillate with passes licm and simplifycfg
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
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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>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>nwilson20@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16316" name="attach_16316" title="licm_simplifycfg.ll">attachment 16316</a> <a href="attachment.cgi?id=16316&action=edit" title="licm_simplifycfg.ll">[details]</a></span>
licm_simplifycfg.ll
When using the flags -licm and -simplifycfg on the attached IR
(licm_simplifycfg.ll) the phi node arguments will keep flipping. This was
produced by using the attached IR and using the output as input back to opt.
For example:
$ ~/install_dir/llvm/bin/opt -S -licm -simplifycfg licm_simplifycfg.ll >
out1.ll
$ ~/install_dir/llvm/bin/opt -S -licm -simplifycfg out1.ll > out2.ll
$ ~/install_dir/llvm/bin/opt -S -licm -simplifycfg out2.ll > out3.ll
$ ~/install_dir/llvm/bin/opt -S -licm -simplifycfg out3.ll > out4.ll
$ diff out2.ll out1.ll
1c1
< ; ModuleID = 'out1.ll'
---
<span class="quote">> ; ModuleID = 'licm_simplifycfg.ll'</span >
24c24
< land.rhs.i.i: ; preds = %while.body.i.i1,
%land.rhs.i.i.preheader
---
<span class="quote">> land.rhs.i.i: ; preds = %land.rhs.i.i.preheader, %while.body.i.i1</span >
34c34
< %6 = phi i64 [ %1, %while.body.i.i.i ], [ %1, %land.rhs.i.i ], [ undef,
%while.body.i.i1 ]
---
<span class="quote">> %6 = phi i64 [ %1, %while.body.i.i.i ], [ undef, %while.body.i.i1 ], [ %1, %land.rhs.i.i ]</span >
$ diff out3.ll out2.ll
1c1
< ; ModuleID = 'out2.ll'
---
<span class="quote">> ; ModuleID = 'out1.ll'</span >
34c34
< %6 = phi i64 [ %1, %while.body.i.i.i ], [ undef, %while.body.i.i1 ], [ %1,
%land.rhs.i.i ]
---
<span class="quote">> %6 = phi i64 [ %1, %while.body.i.i.i ], [ %1, %land.rhs.i.i ], [ undef, %while.body.i.i1 ]</span >
$ diff out4.ll out3.ll
1c1
< ; ModuleID = 'out3.ll'
---
<span class="quote">> ; ModuleID = 'out2.ll'</span >
34c34
< %6 = phi i64 [ %1, %while.body.i.i.i ], [ %1, %land.rhs.i.i ], [ undef,
%while.body.i.i1 ]
---
<span class="quote">> %6 = phi i64 [ %1, %while.body.i.i.i ], [ undef, %while.body.i.i1 ], [ %1, %land.rhs.i.i ]</span ></pre>
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