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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 -O3 on x86_64-linux-gnu (affecting trunk and 3.3)"
href="http://llvm.org/bugs/show_bug.cgi?id=17079">17079</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -O3 on x86_64-linux-gnu (affecting trunk and 3.3)
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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.
This is a regression from clang 3.2.
$ clang-trunk -v
clang version 3.4 (trunk 189735)
$ clang-trunk -O2 small.c
$ a.out
1
$ clang-trunk -O3 small.c
$ a.out
0
$ clang-3.3 -O3 small.c
$ a.out
0
$ clang-3.2 -O3 small.c
$ a.out
1
$
-------------------------------------------
int printf (const char *, ...);
int a = 0, e, f, g = 0, h, *j = &g, k, l, m, n;
volatile int b, d;
short c[2];
static void foo (int *p)
{
int i;
for (m = 0;; m = 0)
{
short *o = &c[1];
for (a = 2; a >= 0; a--)
{
int *t = &e;
b;
for (h = 0; h <= 1; h++)
if (c[0])
{
n = c[1];
*t = 0;
}
int q[3][8] = { 0, 0, 0, 0, 0, l, 1, 1, 0, 0, 0, f, l, e, e, k };
short *r = &c[1];
for (i = 0; i < 3; i++)
{
*r = 0;
b;
c[0] = 0;
*p = 1;
}
}
d;
*o = 1;
b;
if (*p)
break;
}
}
int
main ()
{
int *s = &g;
foo (s);
*j = c[1];
printf ("%d\n", g);
return 0;
}</pre>
</div>
</p>
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