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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - clang 300x slower to compile recursive constexpr template vs. gcc"
href="https://llvm.org/bugs/show_bug.cgi?id=25729">25729</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang 300x slower to compile recursive constexpr template vs. gcc
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Frontend
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>paul_robinson@playstation.sony.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=15391" name="attach_15391" title="repro with recursive constexpr template">attachment 15391</a> <a href="attachment.cgi?id=15391&action=edit" title="repro with recursive constexpr template">[details]</a></span>
repro with recursive constexpr template
The attached source takes > 10 seconds for me to compile with a
Release build of clang, versus much < .1 seconds for gcc 5.2.1.
The resulting compiled table looks identical.
$ $UP/clang --version
clang version 3.8.0 (trunk 253958)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/probinson/projects/llvm-org/trunk/cobj/bin
$ time $UP/clang -c -std=c++14 h.cpp
real 0m10.348s
user 0m10.311s
sys 0m0.022s
$ gcc-5 --version
gcc-5 (Ubuntu 5.2.1-27ubuntu1~14.04.1) 5.2.1 20141129
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ time gcc-5 -c -std=c++14 h.cpp
real 0m0.027s
user 0m0.015s
sys 0m0.012s</pre>
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