<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 - [ARM][Thumb2] LowerCONCAT_VECTORS_i1 assumes concatenation of only 2 vectors"
href="https://bugs.llvm.org/show_bug.cgi?id=51365">51365</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[ARM][Thumb2] LowerCONCAT_VECTORS_i1 assumes concatenation of only 2 vectors
</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: ARM
</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>david.green@arm.com, llvm-bugs@lists.llvm.org, smithp352@googlemail.com, Ties.Stuij@arm.com
</td>
</tr></table>
<p>
<div>
<pre>I'm currently investigating adding this style of fold as an extension to
D107068:
concat(concat(x,y,z,w),concat(a,b,c,d)) -> concat(x,y,z,w,a,b,c,d)
This has exposed an issue with LowerCONCAT_VECTORS_i1 - it assumes that it only
ever has 2 operands:
static SDValue LowerCONCAT_VECTORS_i1(SDValue Op, SelectionDAG &DAG,
const ARMSubtarget *ST) {
SDValue V1 = Op.getOperand(0);
SDValue V2 = Op.getOperand(1);
SDLoc dl(Op);
EVT VT = Op.getValueType();
EVT Op1VT = V1.getValueType();
EVT Op2VT = V2.getValueType();
unsigned NumElts = VT.getVectorNumElements();
and with my fold the active_lane_mask.ll v16i8 test can now generate:
(v16i1 concat(v4i1,v4i1,v4i1,v4i1))
This needs generalizing to repeatedly concatenate pairs of subvectors together
using the existing lowering approach.</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>