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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Not bug. Performance. Loop optimization. clang++ 1.6x slower than g++"
href="https://bugs.llvm.org/show_bug.cgi?id=50301">50301</a>
</td>
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<th>Summary</th>
<td>Not bug. Performance. Loop optimization. clang++ 1.6x slower than g++
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
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<th>Version</th>
<td>12.0
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>h0tc0d3@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24850" name="attach_24850" title="Affected C++ Source">attachment 24850</a> <a href="attachment.cgi?id=24850&action=edit" title="Affected C++ Source">[details]</a></span>
Affected C++ Source
It this case <a href="https://pastebin.com/rhpWvssR">https://pastebin.com/rhpWvssR</a>
g++ -O2 fib.cpp -o /tmp/fib;clang++ -O2 -fdiagnostics-color=always fib.cpp -o
/tmp/fib2;/tmp/fib;/tmp/fib2
GCC Execution time: 37.622s
Clag Execution time: 61.858s
With OMP and little bit change algo
GCC Execution time: ~23s
Clag Execution time: ~38s
GCC Version 10.2.0
LLVM 11.1.0 and 12.0.0 git branch
This also happens in more complex code. I simplified code for minimal
instructions.</pre>
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