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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - missing mflr/mtlr (link register save/restore) when using inline asm w/ "lr" clobber"
href="https://bugs.llvm.org/show_bug.cgi?id=50147">50147</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>missing mflr/mtlr (link register save/restore) when using inline asm w/ "lr" clobber
</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>All
</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: PowerPC
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ndesaulniers@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, natechancellor@gmail.com, nemanja.i.ibm@gmail.com, srhines@google.com, ulrich.weigand@de.ibm.com, uweigand@de.ibm.com
</td>
</tr>
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<th>Blocks</th>
<td>4068
</td>
</tr></table>
<p>
<div>
<pre>example:
void foo (void) {
asm ("":::"lr");
}
powerpc64le-linux-gnu-gcc -O2:
foo:
mflr 0
std 0,16(1)
ld 0,16(1)
mtlr 0
blr
clang --target=powerpc64le-linux-gnu -O2:
foo:
blr
This is causing ppc32 Linux kernels to hang when powering down, resulting in CI
failures, as reported by Nathan Chancellor and debugged by Christophe Leroy in
<a href="https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-April/228246.html">https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-April/228246.html</a>.</pre>
</div>
</p>
<div id="referenced">
<hr style="border: 1px dashed #969696">
<b>Referenced Bugs:</b>
<ul>
<li>
[<a class="bz_bug_link
bz_status_CONFIRMED "
title="CONFIRMED - [Meta] Compiling the Linux kernel with clang"
href="https://bugs.llvm.org/show_bug.cgi?id=4068">Bug 4068</a>] [Meta] Compiling the Linux kernel with clang
</li>
</ul>
</div>
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