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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - New vector shuffle lowering misses to use movhps"
href="http://llvm.org/bugs/show_bug.cgi?id=21140">21140</a>
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<th>Summary</th>
<td>New vector shuffle lowering misses to use movhps
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</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>
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<th>Component</th>
<td>Backend: X86
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>qcolombet@apple.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</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=13124" name="attach_13124" title="IR to reproduce the problem.">attachment 13124</a> <a href="attachment.cgi?id=13124&action=edit" title="IR to reproduce the problem.">[details]</a></span>
IR to reproduce the problem.
With the attach IR, the new vector shuffle lowering generates a movq followed
by a shufps instead of the direct movhps.
To reproduce:
llc -x86-experimental-vector-shuffle-lowering=true none_shufps_movhps.ll -o
new.s
llc -x86-experimental-vector-shuffle-lowering=false none_shufps_movhps.ll -o
old.s
diff -U 10 old.s new.s
_foo: ## @foo
.cfi_startproc
## BB#0:
movq (%rsi), %xmm0
- movhps (%rdi), %xmm0
+ movq (%rdi), %xmm1
+ shufps $68, %xmm1, %xmm0 ## xmm0 = xmm0[0,1],xmm1[0,1]
retq</pre>
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