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<base href="http://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - wrong code by LTO at -Os and above on x86_64-linux-gnu (both 32-bit and 64-bit modes)"
href="http://llvm.org/bugs/show_bug.cgi?id=19093">19093</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code by LTO at -Os and above on x86_64-linux-gnu (both 32-bit and 64-bit modes)
</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 current clang trunk miscompiles the following code when using LTO at -Os
and above on x86_64-linux-gnu (in both 32-bit and 64-bit modes).
$ clang-trunk -v
clang version 3.5.0 (trunk 203396)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8.1
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/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.1
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
$
$ clang-trunk -Os small.c; a.out
1
$ clang-trunk -flto -O1 small.c; a.out
1
$
$ clang-trunk -flto -Os small.c; a.out
0
$
---------------------------------
int printf (const char *, ...);
int a[2], b = 2, c, *d = &c, **e = &d, ***f = &e, *g = &b, *h = &b, i;
static int
fn1 ()
{
for (c = 2; c; c--)
for (;;)
{
*g &= **e;
for (; i; i++)
;
if (*h)
break;
return 0;
}
return 0;
}
int
main ()
{
a[1] = 1;
fn1 ();
printf ("%d\n", a[c]);
return 0;
}</pre>
</div>
</p>
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