<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 on valid code at -O1 and above on x86_64-linux-gnu (affecting all clang versions)"
href="http://llvm.org/bugs/show_bug.cgi?id=19595">19595</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang hangs on valid code at -O1 and above on x86_64-linux-gnu (affecting all clang versions)
</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 following testcase causes the current clang trunk (as well as all earlier
versions from 2.9) to hang when compiling at -O1 and above in both 32-bit and
64-bit modes on x86_64-linux-gnu.
$ clang-trunk -v
clang version 3.5.0 (trunk 207415)
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 -O0 -c small.c
$
$ timeout -s 9 60 clang-trunk -O1 -c small.c
Killed
$
$ time gcc-trunk -O1 -c small.c
0.01user 0.00system 0:00.16elapsed 11%CPU (0avgtext+0avgdata 43360maxresident)k
0inputs+16outputs (0major+4851minor)pagefaults 0swaps
$
$ time gcc-trunk -O3 -c small.c
0.01user 0.01system 0:00.12elapsed 18%CPU (0avgtext+0avgdata 46272maxresident)k
0inputs+16outputs (0major+5046minor)pagefaults 0swaps
$
----------------------------
int a, b;
int
fn1 (int p)
{
return p;
}
void
fn2 ()
{
for (;;)
;
}
int
fn3 (short p)
{
fn2 ();
for (; b;)
;
lbl:
if (p)
return 0;
fn1 (p && a);
if (p)
for (;;)
;
goto lbl;
}</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>