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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 -Os and above on x86_64-linux-gnu (produced code hangs)"
href="https://bugs.llvm.org/show_bug.cgi?id=50952">50952</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -Os and above on x86_64-linux-gnu (produced code hangs)
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</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>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>zhendong.su@inf.ethz.ch
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Possibly duplicate of or related to:
- <a class="bz_bug_link
bz_status_NEW "
title="NEW - wrong code at -Os and above on x86_64-linux-gnu"
href="show_bug.cgi?id=50944">https://bugs.llvm.org/show_bug.cgi?id=50944</a>
- <a class="bz_bug_link
bz_status_NEW "
title="NEW - wrong code at -Os and above on x86_64-linux-gnu"
href="show_bug.cgi?id=50947">https://bugs.llvm.org/show_bug.cgi?id=50947</a>
[531] % clangtk -v
clang version 13.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
b9c24257c7b4da398798934ffefdd30015152180)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /local/suz-local/opfuzz/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
[532] %
[532] % clangtk -O1 small.c; ./a.out
small.c:7:11: warning: shift count >= width of type [-Wshift-count-overflow]
a = 0 >> 32;
^ ~~
1 warning generated.
[533] %
[533] % clangtk -Os small.c
small.c:7:11: warning: shift count >= width of type [-Wshift-count-overflow]
a = 0 >> 32;
^ ~~
1 warning generated.
[534] %
[534] % timeout -s 9 5 ./a.out
Killed
[535] %
[535] % cat small.c
static int a, *b = &a;
int c;
int main() {
while (a)
;
while (c) {
a = 0 >> 32;
}
b = 0;
return 0;
}</pre>
</div>
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