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<body><span class="vcard"><a class="email" href="mailto:simachijun@gmail.com" title="Chijun Sima <simachijun@gmail.com>"> <span class="fn">Chijun Sima</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - JumpThreading can take take several minutes on large functions"
href="https://bugs.llvm.org/show_bug.cgi?id=37929">bug 37929</a>
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<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">CC</td>
<td>
</td>
<td>simachijun@gmail.com
</td>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
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<td style="text-align:right;">Fixed By Commit(s)</td>
<td>
</td>
<td>r345353
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - JumpThreading can take take several minutes on large functions"
href="https://bugs.llvm.org/show_bug.cgi?id=37929#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - JumpThreading can take take several minutes on large functions"
href="https://bugs.llvm.org/show_bug.cgi?id=37929">bug 37929</a>
from <span class="vcard"><a class="email" href="mailto:simachijun@gmail.com" title="Chijun Sima <simachijun@gmail.com>"> <span class="fn">Chijun Sima</span></a>
</span></b>
<pre>The issue exposed by the reproducer is that JumpThreading is trying to update
the dominator tree with a great number of updates, which causes poor
performance because the time complexity of the incremental updating algorithm
is proportional to the number of updates.
Fixed in r345353 (<a href="https://reviews.llvm.org/rL345353">https://reviews.llvm.org/rL345353</a>) by reconstructing the
dominator tree in this case. The time used by Dominator Tree updating reduces
from 297s to 0.15s by the commit when compiling the reproducer with -O3 + UBSan
locally.</pre>
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