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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [LoopVectorizer] crash with -force-vector-width=2"
href="https://bugs.llvm.org/show_bug.cgi?id=40080">40080</a>
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<th>Summary</th>
<td>[LoopVectorizer] crash with -force-vector-width=2
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Loop Optimizer
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>paulsson@linux.vnet.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=21245" name="attach_21245" title="reduced testcase">attachment 21245</a> <a href="attachment.cgi?id=21245&action=edit" title="reduced testcase">[details]</a></span>
reduced testcase
This test case contains a loop with a load that gets a disabling (300000) cost,
so normally this would not get vectorized.
Still, if vectorization is forced bad code is generated, which should probably
be investigated:
opt -mtriple=s390x-unknown-linux -mcpu=z13 -o out.opt.ll tc_LV_width2.ll -O3
-S -force-vector-width=2 -unroll-count=1
Instruction does not dominate all uses!
%17 = phi <2 x double> [ %10, %pred.load.continue ], [ %16, %pred.load.if3 ]
%2 = shufflevector <2 x double> %vector.recur, <2 x double> %17, <2 x i32>
<i32 1, i32 2></pre>
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