<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 - Randomly emitted all-zeros or all-ones XMM constants generate invalid code (x86-64, MCJIT, small code model)"
href="https://bugs.llvm.org/show_bug.cgi?id=37289">37289</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Randomly emitted all-zeros or all-ones XMM constants generate invalid code (x86-64, MCJIT, small code model)
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>6.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>release blocker
</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>nekotekina@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Example of the faulty instruction (crashes with access violation):
0: c5 c9 74 2c 25 b0 0a 00 00 vpcmpeqb xmm5,xmm6,XMMWORD PTR ds:0xab0
I'm not completely sure what's going on, but I think it's supposed to emit
RIP-relative address location. But instead, it uses ds segment register, which
is assumed to be zero.
I noticed that the constant in question is all zeros or all ones. They are
usually generated by PXOR or PCMPEQD-alike idiom.
Attachment contains ELF file produced by MCJIT, with broken function.</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>