<html>
<head>
<base href="http://llvm.org/bugs/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - clang hangs at -O3 on expression"
href="http://llvm.org/bugs/show_bug.cgi?id=15714">15714</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang hangs at -O3 on expression
</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>Linux
</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>dhazeghi@yahoo.com
</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 snippet (generated by csmith) causes top-of-trunk clang to get
stuck in an infinite loop at -O3 (-O2 and below are fine, as is clang 3.2).
While it appears to invoke undefined behavior ((*d ^= 1 != (long)d)), hanging
is probably not the right thing to do.
$ clang-trunk -v
clang version 3.3 (trunk 179090)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ clang-trunk -O2 -c test.c
$ clang-trunk -O3 -c test.c
<hangs>
int a, b, c;
int fn2();
void fn1 ()
{
int *d, *e = &b;
d = &b;
*e = 0;
c = 0;
for (; c < 42; ++c)
{
(*d ^= 1 != (long)d) && fn2 ();
if (a)
break;
}
}
int fn2 ()
{
int *f = &b;
*f = 1;
return b;
}
void fn3 ()
{
fn1 ();
}</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>