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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Inline asm with constraint 'i' fails with --fsanitize=undefined"
href="http://llvm.org/bugs/show_bug.cgi?id=19763">19763</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Inline asm with constraint 'i' fails with --fsanitize=undefined
</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>
<tr>
<th>OS</th>
<td>Linux
</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>
<tr>
<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>kdev@fishzet.co.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=12517" name="attach_12517" title="Preprocessed source code from Libav which triggers the bug (3x)">attachment 12517</a> <a href="attachment.cgi?id=12517&action=edit" title="Preprocessed source code from Libav which triggers the bug (3x)">[details]</a></span>
Preprocessed source code from Libav which triggers the bug (3x)
% cat min.i
fn1() { __asm__("" ::"r"(0), "i"(0 * 0)); }
% clang -fsanitize=undefined -c -o obj.o min.i 2>&1 | grep -A 2 error
dsputil_mmx.i:1:17: error: invalid operand for inline asm constraint 'i'
fn1() { __asm__("" ::"r"(0), "i"(0 * 0)); }
Without -fsanitize=undefined, the above code compiles. The above code is
generated with creduce from the attached file (dsputil_mmx.i) and the following
creduce script:
% cat <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED DUPLICATE - x86fastcc and allocas cause stange crashes"
href="show_bug.cgi?id=683">bug683</a>libav.sh
#!/bin/bash
rm -f out.txt *.o
ulimit -t 1
if
clang -c -o good.o dsputil_mmx.i &&\
! clang -fsanitize=undefined -c -o no.o dsputil_mmx.i > out.txt 2>&1 &&\
grep "invalid operand for inline asm constraint" out.txt
then exit 0
else exit 1
fi
References:
<a href="https://bugzilla.libav.org/show_bug.cgi?id=683">https://bugzilla.libav.org/show_bug.cgi?id=683</a> (the original Libav bug)
<a href="http://git.videolan.org/?p=ffmpeg.git;a=blobdiff;f=libavcodec/x86/dsputil_mmx.c;h=86100ba6ff86e9c6791364b3b4b00be1fea03b41;hp=c574458a20639d90567627e99d105bd20d5d570f;hb=bebce653e5601ceafa004db0eb6b2c7d4d16f0c0;hpb=d1310c591eb24202ecc28af4adb28cce690109e5">http://git.videolan.org/?p=ffmpeg.git;a=blobdiff;f=libavcodec/x86/dsputil_mmx.c;h=86100ba6ff86e9c6791364b3b4b00be1fea03b41;hp=c574458a20639d90567627e99d105bd20d5d570f;hb=bebce653e5601ceafa004db0eb6b2c7d4d16f0c0;hpb=d1310c591eb24202ecc28af4adb28cce690109e5</a>
(the FFmpeg workaround).
% clang --version
Ubuntu clang version 3.5-1ubuntu1 (trunk) (based on LLVM 3.5)
Target: x86_64-pc-linux-gnu
Thread model: posix</pre>
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