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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Loop hoisting"
href="https://bugs.llvm.org/show_bug.cgi?id=39207">39207</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Loop hoisting
</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>
<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>Loop Optimizer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>david.bolvansky@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Not sure how often this happens in the real world apps but anyway idea is..
int foo(void)
{
double *array = calloc(ARRAY_SIZE, sizeof(double));
double sum = 0;
int i;
for (i = 0; i < N_TIMES; i++) {
// lot of code
// well, this loop does not even depend on "i", hoist it?
for (int j = 0; j < ARRAY_SIZE; j += 8) {
sum += array[j] + array[j+1] + array[j+2] + array[j+3] + array[j+4]
+ array[j+5] + array[j+6] + array[j+7];
}
}
return sum;
}
Let's say we have the big outer loop with many inner loops. Can LLVM check if
these loops really depend on the outer loop and if not, hoist them?</pre>
</div>
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