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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 --- - wrong code at -Os and above on x86_64-linux-gnu (affecting 3.1 till trunk)"
href="http://llvm.org/bugs/show_bug.cgi?id=18101">18101</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -Os and above on x86_64-linux-gnu (affecting 3.1 till trunk)
</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>-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>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following code is miscompiled by the current clang trunk (and earlier
versions starting from 3.1) on x86_64-linux-gnu at -Os and above in both 32-bit
and 64-bit modes.
$ clang-trunk -v
clang version 3.5 (trunk 195973)
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 -O1 small.c; a.out
0
$ clang-3.0 -Os small.c; a.out
0
$ gcc-trunk -Os small.c; a.out
0
$ icc -Os small.c; a.out
0
$
$ clang-trunk -Os small.c; a.out
1
$ clang-3.3 -Os small.c; a.out
1
$ clang-3.2 -Os small.c; a.out
1
$ clang-3.1 -Os small.c; a.out
1
$
----------------------------------
int printf (const char *, ...);
struct S
{
int f0;
int f1:25;
};
int a, b, *c = &b, d;
struct S
fn1 ()
{
struct S e = {0, 0};
if (!d)
{
struct S f = {0, -1};
return f;
}
return e;
}
int
main ()
{
struct S g = fn1 (), h = g;
for (a = 0; a < 1; a++)
{
*c = 0;
*c = 1 <= ((h.f0 >= *c) ^ (h.f1 |= 1));
}
printf ("%d\n", b);
return 0;
}</pre>
</div>
</p>
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