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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - wrong code at -O3 on x86_64-linux-gnu (affecting clang 3.0 till the trunk)"
href="http://llvm.org/bugs/show_bug.cgi?id=18223">18223</a>
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<tr>
<th>Summary</th>
<td>wrong code at -O3 on x86_64-linux-gnu (affecting clang 3.0 till the trunk)
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</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>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>su@cs.ucdavis.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following code is miscompiled by the current clang trunk (and older
versions from 3.0) on x86_64-linux-gnu at -O3 in both 32-bit and 64-bit modes.
It also seems to affect MacOS X.
This is a regression from 2.9.
$ clang-trunk -v
clang version 3.5 (trunk 197135)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.3
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
$
$ clang-trunk -O2 small.c; a.out
0
$ clang-trunk -O3 small.c; a.out
1
$
-----------------------------------
int printf (const char *, ...);
int b, c, d, f, h;
int
main ()
{
for (b = 0; b < 5; b++)
{
f = b - (unsigned int) (d = 1) >= b;
if (c)
h = 0;
}
printf ("%d\n", f);
return 0;
}</pre>
</div>
</p>
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