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<base href="http://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - wrong code (SIGFPE) at -O3 (affecting both clang trunk and 3.3)"
href="http://llvm.org/bugs/show_bug.cgi?id=17524">17524</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code (SIGFPE) at -O3 (affecting both clang trunk and 3.3)
</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>All
</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>LLVM Codegen
</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>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following code is miscompiled by the current clang trunk and clang 3.3 on
x86_64-linux-gnu at -O3 in both 32-bit and 64-bit modes.
It also affects MacOS X.
$ clang-trunk -v
clang version 3.4 (trunk 192279)
Target: x86_64-pc-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
$ clang-3.2 -O3 small.c; a.out
$ gcc-trunk -O3 small.c; a.out
$
$ clang-trunk -O3 small.c; a.out
Floating point exception (core dumped)
$ clang-3.3 -O3 small.c; a.out
Floating point exception (core dumped)
$
---------------------------------
int a, b, c, d, f, g, h, i;
unsigned int e;
int
fn1 ()
{
short j = 0;
for (; j != 8; ++j)
{
if (b)
return 0;
g = 0;
short k = b;
f = k == 0 ? 0 : e / k;
h = f + j < 0 ? 0 : 1;
c = 0;
if (1 != b)
return 0;
if (j)
i = a ? 0 : 1 % a;
}
return 1;
}
int
main ()
{
for (; d != -6; d--)
fn1 ();
return 0;
}</pre>
</div>
</p>
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