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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Missed optimization for constant remainder of loop induction variable"
href="http://llvm.org/bugs/show_bug.cgi?id=20627">20627</a>
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<th>Summary</th>
<td>Missed optimization for constant remainder of loop induction variable
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Loop Optimizer
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>daniel@zuster.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The optimizer should be able to eliminate the remainder operation in:
--
_Bool cond();
int f0(int N) {
int i = 0, res = 0;
while (cond()) {
if ((i % 3) == 0)
res++;
++i;
}
return res;
}
--
by introducing a new loop carried variable i' == (i % 3) and rewriting to:
--
...
if (i' == 0) {
...
}
...
++i'
if (i' == 3)
i' = 0
...
--</pre>
</div>
</p>
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