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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - -Wdivision-by-zero does not warn on "1000 / (unsigned char)(a << 8)""
href="http://llvm.org/bugs/show_bug.cgi?id=22253">22253</a>
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<th>Summary</th>
<td>-Wdivision-by-zero does not warn on "1000 / (unsigned char)(a << 8)"
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Frontend
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>chengniansun@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>I think the current -Wdivision-by-zero can be improved by considering to
support the following case, where "(unsigned char)(a << 8)" is zero.
$: cat s.c
int a;
int fn1() {
return 1000 / (unsigned char)(a << 8);
}
$:
$: gcc-trunk -c s.c -Wdiv-by-zero
s.c: In function ‘fn1’:
s.c:3:15: warning: division by zero [-Wdiv-by-zero]
return 1000 / (unsigned char)(a << 8);
^
$:
$: clang-trunk -c s.c -Wdivision-by-zero
$:</pre>
</div>
</p>
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