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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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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 jump-threading and loop-simplify"
href="https://llvm.org/bugs/show_bug.cgi?id=27660">27660</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>phi node arguments oscillate with passes jump-threading and loop-simplify
</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>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<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>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16313" name="attach_16313" title="jump-threading_loop-simplify.ll">attachment 16313</a> <a href="attachment.cgi?id=16313&action=edit" title="jump-threading_loop-simplify.ll">[details]</a></span>
jump-threading_loop-simplify.ll
When using the flags -jump-threading and -loop-simplify on the attached IR
(jump-threading_loop-simplify.ll) the phi nodes will keep flipping. This was
produced by using the attached IR and using the output as input back to opt.
For example:
$ ./opt -S -jump-threading -loop-simplify jump-threading_loop-simplify.ll >
out1.ll
$ ./opt -S -jump-threading -loop-simplify out1.ll > out2.ll
$ ./opt -S -jump-threading -loop-simplify out2.ll > out3.ll
diff out2.ll out1.ll
1c1
< ; ModuleID = 'out1.ll'
---
<span class="quote">> ; ModuleID = 'jump-threading_loop-simplify.ll'</span >
29,30c29,30
< _ZNK4pugi8xml_text5_dataEv.exit.loopexit: ; preds = %for.inc.i,
%for.body.i
< %.ph = phi %"struct.pugi::xml_node_struct.1.85.421"* [ null, %for.inc.i ],
[ undef, %for.body.i ]
---
<span class="quote">> _ZNK4pugi8xml_text5_dataEv.exit.loopexit: ; preds = %for.body.i, %for.inc.i
> %.ph = phi %"struct.pugi::xml_node_struct.1.85.421"* [ undef, %for.body.i ], [ null, %for.inc.i ]</span >
$ diff out3.ll out2.ll
1c1
< ; ModuleID = 'out2.ll'
---
<span class="quote">> ; ModuleID = 'out1.ll'</span >
30c30
< %.ph = phi %"struct.pugi::xml_node_struct.1.85.421"* [ undef, %for.body.i
], [ null, %for.inc.i ]
---
<span class="quote">> %.ph = phi %"struct.pugi::xml_node_struct.1.85.421"* [ null, %for.inc.i ], [ undef, %for.body.i ]</span ></pre>
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