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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wrong code at -O3 on x86_64-linux-gnu"
href="https://bugs.llvm.org/show_bug.cgi?id=51086">51086</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -O3 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>enhancement
</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>qrzhang@gatech.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
</td>
</tr></table>
<p>
<div>
<pre>It appears to be a recent regression. clang-12 works fine.
$ clang-trunk -v
clang version 13.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
20176bc7dd3f431db4c3d59b51a9f53d52190c82)
Target: x86_64-unknown-linux-gnu
Thread model: posix
$ clang-trunk abc.c ; ./a.out
-26
$ clang-trunk -O3 abc.c ; ./a.out
0
$ cat abc.c
int a, b;
static int c = 92;
long d;
short(e)(f) { return f; }
long g() {
short h;
int i = d >= 0;
for (; b > -26; --b) {
if (i)
continue;
for (; i - 30; i--) {
h = a << c;
if (h)
return 7;
}
}
}
int main() {
g();
if (e(0))
c++;
printf("%d\n", b);
}</pre>
</div>
</p>
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