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    <head>
      <base href="https://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - phi node arguments oscillate with passes loop-load-elim and simplifycfg"
   href="https://llvm.org/bugs/show_bug.cgi?id=27692">27692</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>phi node arguments oscillate with passes loop-load-elim 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>
        </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=16339" name="attach_16339" title="loop-load-elim_simplifycfg.ll">attachment 16339</a> <a href="attachment.cgi?id=16339&action=edit" title="loop-load-elim_simplifycfg.ll">[details]</a></span>
loop-load-elim_simplifycfg.ll

When using the flags -loop-load-elim and -simplifycfg on the attached IR
(loop-load-elim_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:
$ ./opt -S -loop-load-elim -simplifycfg bugpoint-reduced-simplified.ll >
out1.ll
$ ./opt -S -loop-load-elim -simplifycfg out1.ll > out2.ll
$ ./opt -S -loop-load-elim -simplifycfg out2.ll > out3.ll

$ diff out2.ll out1.ll
1c1
< ; ModuleID = 'out1.ll'
---
<span class="quote">> ; ModuleID = 'bugpoint-reduced-simplified.ll'</span >
20c20
<   %2 = phi i64 [ 0, %entry ], [ 0, %while.body.i.i ], [ undef, %land.rhs.i.i
]
---
<span class="quote">>   %2 = phi i64 [ 0, %entry ], [ undef, %land.rhs.i.i ], [ 0, %while.body.i.i ]</span >


$ diff out3.ll out2.ll
1c1
< ; ModuleID = 'out2.ll'
---
<span class="quote">> ; ModuleID = 'out1.ll'</span >
20c20
<   %2 = phi i64 [ 0, %entry ], [ undef, %land.rhs.i.i ], [ 0, %while.body.i.i
]
---
<span class="quote">>   %2 = phi i64 [ 0, %entry ], [ 0, %while.body.i.i ], [ undef, %land.rhs.i.i ]</span ></pre>
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