<html>
<head>
<base href="https://bugs.llvm.org/">
</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 - Recognise vector rotations with non-splat constants"
href="https://bugs.llvm.org/show_bug.cgi?id=33691">33691</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Recognise vector rotations with non-splat constants
</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>Common Code Generator Code
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>Andrew.Zhogin@gmail.com, elena.demikhovsky@intel.com, llvm-bugs@lists.llvm.org, zvi.rackover@intel.com
</td>
</tr></table>
<p>
<div>
<pre>We fail to recognise or(lshr(x,c1),shl(x,c1)) style patterns for vectors where
the constant values are not splats:
define <4 x i32> @rot_v4i32(<4 x i32> %x) {
%1 = lshr <4 x i32> %x, <i32 1, i32 2, i32 3, i32 4>
%2 = shl <4 x i32> %x, <i32 31, i32 30, i32 29, i32 28>
%3 = or <4 x i32> %1, %2
ret <4 x i32> %3
}
llc -mcpu=bdver4
vpshld {{.*}}(%rip), %xmm0, %xmm1
vpshld {{.*}}(%rip), %xmm0, %xmm0
vpor %xmm0, %xmm1, %xmm0
retq</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>