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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - IndVars creates an invalid phi node after r367485"
href="https://bugs.llvm.org/show_bug.cgi?id=45835">45835</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>IndVars creates an invalid phi node after r367485
</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>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</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>dmajor@mozilla.com
</td>
</tr>
<tr>
<th>CC</th>
<td>efriedma@quicinc.com, florian_hahn@apple.com, froydnj@gmail.com, listmail@philipreames.com, llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Blocks</th>
<td>45309
</td>
</tr></table>
<p>
<div>
<pre><a href="https://godbolt.org/z/Me95yj">https://godbolt.org/z/Me95yj</a>
After r367485/llvmorg-10-init-991-gf8e7b536571, this phi node:
%a.mux.lcssa4 = phi i8* [ %a.mux, %switch.early.test.i ], [ %a.mux,
%switch.early.test.i ], [ %a.mux, %cond.end ]
becomes
%a.mux.lcssa4 = phi i8* [ %a.mux, %switch.early.test.i ], [ %scevgep,
%switch.early.test.i ], [ %scevgep, %cond.end ]
which has two different values for %switch.early.test.i.
This started out as an investigation of a clang hang in LICM (full repro
available on request) but this phi node is the first place that the verifier
started complaining, so I assume the rest is GIGO from there.
The bad phi is no longer seen after llvmorg-11-init-4213-gd6f47aeb519, but as
that is a cost model patch, I assume it's not really a fix but just an
avoidance.</pre>
</div>
</p>
<div id="referenced">
<hr style="border: 1px dashed #969696">
<b>Referenced Bugs:</b>
<ul>
<li>
[<a class="bz_bug_link
bz_status_NEW "
title="NEW - [meta] 10.0.1 Release Blockers"
href="https://bugs.llvm.org/show_bug.cgi?id=45309">Bug 45309</a>] [meta] 10.0.1 Release Blockers
</li>
</ul>
</div>
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