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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - DAGCombiner never finishes"
href="https://bugs.llvm.org/show_bug.cgi?id=43414">43414</a>
</td>
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<tr>
<th>Summary</th>
<td>DAGCombiner never finishes
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>trass3r@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22549" name="attach_22549" title="test files">attachment 22549</a> <a href="attachment.cgi?id=22549&action=edit" title="test files">[details]</a></span>
test files
$ clang++ -O2 -fno-exceptions -fno-rtti -c test.cpp -ftime-trace
seems to be stuck in DAGCombiner, even after 20 minutes.
test.smaller.cpp finishes after 2 minutes and spends its time in InstCombine
mainly. The generated code is really bad, tens of thousands of mov dword ptr
[rsp + i], x
It's possible to force it to do the right thing with an explicit constexpr but
that shouldn't be necessary.
$ clang++ -v
clang version 10.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
a1d86857fff28f37e186f0bf99ede37d18dd2448)
Target: x86_64-pc-windows-msvc</pre>
</div>
</p>
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