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<body><span class="vcard"><a class="email" href="mailto:ndesaulniers@google.com" title="Nick Desaulniers <ndesaulniers@google.com>"> <span class="fn">Nick Desaulniers</span></a>
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<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Linux kernel build: Regression due memcmp to bcmp optimization"
href="https://bugs.llvm.org/show_bug.cgi?id=41035">bug 41035</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
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<td style="text-align:right;">Status</td>
<td>REOPENED
</td>
<td>RESOLVED
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Linux kernel build: Regression due memcmp to bcmp optimization"
href="https://bugs.llvm.org/show_bug.cgi?id=41035#c28">Comment # 28</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Linux kernel build: Regression due memcmp to bcmp optimization"
href="https://bugs.llvm.org/show_bug.cgi?id=41035">bug 41035</a>
from <span class="vcard"><a class="email" href="mailto:ndesaulniers@google.com" title="Nick Desaulniers <ndesaulniers@google.com>"> <span class="fn">Nick Desaulniers</span></a>
</span></b>
<pre>The fix for this is on the kernel side is now in mainline (I expect LTS
backports this week).
<a href="https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5f074f3e192f10c9fade898b9b3b8812e3d83342">https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5f074f3e192f10c9fade898b9b3b8812e3d83342</a>
Next time a "compiler optimization" that relies on library support is written,
please ensure that relevant libraries for environments that use LLVM actually
have the proper support. Otherwise such "compiler optimizations" will regress
builds for environments that don't have the library support.
Specifically in this case, I think it would have been better to ship the
optimized version in glibc first thus proving why such a compiler optimization
would be worthwhile, then verify that all relevant targets support bcmp, then
ship the optimization in LLVM.
Closing this issue now as fixed (it was originally filed because of the kernel
regression). Please reopen if there's more to do here.</pre>
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