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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wrong code with -disable-licm-promotion"
href="https://bugs.llvm.org/show_bug.cgi?id=39126">39126</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code with -disable-licm-promotion
</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>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>paulsson@linux.vnet.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Program:
a[6];
b = 15, c, d = 11, h;
short e, g;
short *f = &e;
main() {
for (; c < 6; c++)
a[1] = c;
lbl_71:
++d;
h = &h;
g = 1;
if ((*f = d) & 1)
goto lbl_71;
b = a[b ^ e];
printf("checksum = %X\n", b);
}
Runs:
gcc -O1 -march=z10 -o a.out
gcc -O0 -march=z13 -o a.out
gcc -O1 -march=z13 -o a.out
clang -O0 -march=z10 -o a.out
clang -O0 -march=z13 -o a.out
clang -O3 -march=z10 -o a.out
clang -O3 -march=z13 -o a.out
All the above prints 0, while this one prints 5:
clang -O3 -march=z13 -o a.out -mllvm -disable-licm-promotion</pre>
</div>
</p>
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