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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 --- - ARM code runs 2x slower compared to gcc"
href="https://llvm.org/bugs/show_bug.cgi?id=26450">26450</a>
</td>
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<th>Summary</th>
<td>ARM code runs 2x slower compared to gcc
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>3.7
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</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>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>tulipawn@gmail.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=15810" name="attach_15810" title="C source sample">attachment 15810</a> <a href="attachment.cgi?id=15810&action=edit" title="C source sample">[details]</a></span>
C source sample
I've recently discovered the sad fact code produced by LLVM on ARM was nowhere
near the speed of gcc:
<a href="https://users.rust-lang.org/t/executable-size-and-performance-vs-c/">https://users.rust-lang.org/t/executable-size-and-performance-vs-c/</a>
The same C code (as well as rust code) compiled with -O3 yields identical
performance on x86_64 between gcc/clang/rustc whereas on armv7:
gcc - 1.5s
clang/rustc - 3.4s (3.2s using --ffast-math)</pre>
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