<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 - Failure to perform extract with variable index from splat vector"
href="https://bugs.llvm.org/show_bug.cgi?id=50817">50817</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Failure to perform extract with variable index from splat vector
</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>Scalar Optimizations
</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>llvm-bugs@lists.llvm.org, spatel+llvm@rotateright.com
</td>
</tr></table>
<p>
<div>
<pre><a href="https://c.godbolt.org/z/rq43Wqc5a">https://c.godbolt.org/z/rq43Wqc5a</a>
#include <x86intrin.h>
auto adjust_splat(float x, float y, int i) {
__m128 r = _mm_set1_ps(x);
r[i & 3] += y;
return r;
}
auto adjust_splat2(float x, float y, int i) {
__m128 r = _mm_set1_ps(x);
r[i & 3] = x + y;
return r;
}
If the variable-index of an extract from a splatted vector is known to be
inrange, we should be safe to use the original scalar directly.
Not sure if this can be done in IR or we wait until SelectionDAG?</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>