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<base href="https://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 (segfault) at -O3 on x86_64-linux-gnu in the 32-bit mode"
href="https://llvm.org/bugs/show_bug.cgi?id=28824">28824</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code (segfault) at -O3 on x86_64-linux-gnu in the 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>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>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>This is a regression from 3.8.x.
$ clang -v
clang version 4.0.0 (trunk 277497)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/clang-trunk/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
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/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.1.1
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$
$ clang -m32 -O2 -w small.c; ./a.out
$ clang-3.8 -m32 -O3 -w small.c; ./a.out
$
$ clang -m32 -O3 -w small.c
$ ./a.out
Segmentation fault (core dumped)
$
--------------------------------------------------------------------
struct
{
int f0;
} a = {1}, b;
volatile int c;
int d, e, f, g, h, i, j, k, l, m[1], n, o, p, q, r[1], s, t, u;
void fn1 (int p1)
{
n = n >> 8 ^ m[n ^ p1];
}
void fn2 ()
{
fn1 (l > 0);
fn1 (l >> 8);
fn1 (l & 5);
n = n >> 8 ^ n;
}
static void fn3 (int p1, int p2, int p3, short p4)
{
q = q && (p1 = p4);
for (; o; o++)
{
h = e ? 0 : s;
g = j;
s = p2 | (p3 == (f < h)) | j;
if (p1)
c;
}
}
int fn4 ()
{
short v, x = i;
fn2 ();
v = x >> d;
fn3 (2, 5, v, i);
fn3 (4, 0, 0, p);
if (v < 1)
return t;
a = b;
return 0;
}
int fn5 ()
{
for (; i < 2; i++)
fn4 ();
if (!a.f0)
return u;
k = r[2000];
return 0;
}
int main ()
{
fn5 ();
return 0;
}</pre>
</div>
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