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<head>
<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 at -O3 on x86_64-linux-gnu (in both 32-bit and 64-bit modes)"
href="https://llvm.org/bugs/show_bug.cgi?id=30448">30448</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -O3 on x86_64-linux-gnu (in 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>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 281848)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/clang-trunk/bin
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/4.8.4
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
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-3.8.1 -O3 small.c; ./a.out
0
$ clang -O2 small.c; ./a.out
0
$
$ clang -O3 small.c
$ ./a.out
1
$
----------------------------------------------------
int printf (const char *, ...);
int a, c, d = 8, e, f, g, h, l, k, m, n, o, p, q;
long b, r;
volatile long i;
long j[] = { 6069905 };
char fn1 (int p1, int p2)
{
return p1 >> p2;
}
int fn2 (int p1)
{
return p1;
}
static char fn3 (int p1, int p2)
{
if (a)
L1:
if (!g)
goto L2;
for (o = 0; o < 2; o++)
for (; p; p++)
;
for (b = 3; b < 9; b++)
{
q = (n && (e = p2)) || r;
for (; d; d--)
for (r = 2; r < 9; r++)
{
if (p2)
break;
fn1 (7, p2) && (j[r] = 1);
}
}
for (; p1 < 2;)
L2:
for (; f; g++)
;
p2 && i;
for (;; k++)
{
char s;
for (; o;)
{
char t = 1 << c;
c = t;
if (t)
goto L1;
printf ("%d\n", h);
p2 = 1;
return n;
}
}
}
int main ()
{
m = fn2 (38);
fn3 (7, m);
return 0;
}</pre>
</div>
</p>
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