<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 - [x86] Cost model for v2i32 masked load/store looks incorrect"
href="https://bugs.llvm.org/show_bug.cgi?id=39812">39812</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[x86] Cost model for v2i32 masked load/store looks incorrect
</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>Backend: X86
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>craig.topper@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
</td>
</tr></table>
<p>
<div>
<pre>The code model for masked load/store contains this code
if (VT.isSimple() && LT.second != VT.getSimpleVT() &&
LT.second.getVectorNumElements() == NumElem)
// Promotion requires expand/truncate for data and a shuffle for mask.
Cost += getShuffleCost(TTI::SK_Select, SrcVTy, 0, nullptr) +
getShuffleCost(TTI::SK_Select, MaskTy, 0, nullptr);
But SK_Select does not describe an expand/truncate action. This code said
SK_Alternate when it was originally written, but was renamed to SK_Select in
r334513. I'm not sure if SK_Alternate was the same as select and was
confusingly named before?
The mask legalization cost also seems weird on AVX512 targets. We don't need to
expand/truncate it there as it would be an i1 type.</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>