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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Vector shuffle punpck+pshufb+punpck+pshufb should be just a single pshufb"
href="http://llvm.org/bugs/show_bug.cgi?id=22415">22415</a>
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<th>Summary</th>
<td>Vector shuffle punpck+pshufb+punpck+pshufb should be just a single pshufb
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: X86
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>grosbach@apple.com
</td>
</tr>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=13786" name="attach_13786" title="Test case.">attachment 13786</a> <a href="attachment.cgi?id=13786&action=edit" title="Test case.">[details]</a></span>
Test case.
#include <simd/simd.h>
vector_char4 bar(vector_short4 x) { return ((vector_char8)x).even; }
vector_char3 baz(vector_short3 x) { return bar(x.xyzz).xyz; }
Generates the shuffle sequence for baz() as:
punpcklwd %xmm0, %xmm0 ## xmm0 = xmm0[0,0,1,1,2,2,3,3]
pshufb LCPI1_0(%rip), %xmm0 ## xmm0 =
xmm0[0,1,4,5,8,9,8,9,8,9,8,9,8,9,10,11]
movd %xmm0, %rax
movd %rax, %xmm0
punpcklbw %xmm0, %xmm0 ## xmm0 =
xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
pshufb LCPI1_1(%rip), %xmm0 ## xmm0 =
xmm0[0,4,8,12,u,u,u,u,u,u,u,u,u,u,u,u]
The operation can be done instead in a single pshufb.
IR attached.</pre>
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