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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 --- - incorrect loop optimization at -O3 in 32-bit mode"
href="http://llvm.org/bugs/show_bug.cgi?id=16036">16036</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>incorrect loop optimization at -O3 in 32-bit mode
</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>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>dhazeghi@yahoo.com
</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>On x86_64-linux, the code below is miscompiled at -O3 optimization with the
current clang trunk, but only in 32-bit mode.
$ clang-trunk --version
clang version 3.4 (trunk 181995)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ clang-trunk -O2 -m32 small.c
$ ./a.out
0
$ clang-trunk -O3 -m64 small.c
$ ./a.out
0
$ clang-trunk -O3 -m32 small.c
$ ./a.out
1
--------------------
int printf (const char *, ...);
char a;
int b, c, d = 1;
void
fn1 ()
{
b = 1;
for (; b <= 4; b++)
{
c &= (
{
int e = ((
{
a;
}) ^ 1) > 0;
e << 1;
});
d = 0;
for (; d <= 0; d++)
if (b)
break;
}
}
int
main ()
{
fn1 ();
printf ("%d\n", d);
return 0;
}</pre>
</div>
</p>
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