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<base href="http://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 --- - clang hangs on valid code at -Os and above on x86_64-linux-gnu"
href="http://llvm.org/bugs/show_bug.cgi?id=21377">21377</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang hangs on valid code at -Os and above on x86_64-linux-gnu
</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 test case causes the current clang trunk to hang when compiling
at -Os and above in both 32-bit and 64-bit modes on x86_64-linux-gnu.
It also affects all earlier versions of clang and MacOS X.
$ clang-trunk -v
clang version 3.6.0 (trunk 220587)
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 -O1 small.c; a.out
$
$ timeout -s 9 30 clang-trunk -Os small.c
Killed
$
$ time gcc-trunk -Os small.c
0.02user 0.00system 0:00.12elapsed 26%CPU (0avgtext+0avgdata 50752maxresident)k
0inputs+32outputs (1major+6636minor)pagefaults 0swaps
$
$ time icc -Os small.c
0.05user 0.06system 0:00.43elapsed 27%CPU (0avgtext+0avgdata 84848maxresident)k
0inputs+240outputs (1major+20231minor)pagefaults 0swaps
$
$ time clang-trunk -O1 small.c
0.00user 0.02system 0:00.11elapsed 30%CPU (0avgtext+0avgdata 63872maxresident)k
0inputs+32outputs (1major+6322minor)pagefaults 0swaps
$
--------------------
int a, c, d;
unsigned int b;
static int e[1];
long long f;
long long
fn1 ()
{
return a;
}
void
fn2 ()
{
int g;
while (c)
{
f = b;
g |= f;
while (c)
g = e[0];
g |= fn1 ();
}
}
int
main ()
{
fn2 ();
return 0;
}</pre>
</div>
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