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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [Vectorizer] Implement stride access"
href="http://llvm.org/bugs/show_bug.cgi?id=17677">17677</a>
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<th>Summary</th>
<td>[Vectorizer] Implement stride access
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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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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<th>Reporter</th>
<td>renato.golin@linaro.org
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>Implement stride access detection for induction variables with Step > 1, with
cost-model support for the (currently unclear) benefits, and make sure that the
vectorization happens later on.
The basic loop in which this should work is:
for (i..N/3) {
a[3*i] = b[3*i];
a[3*i+1] = b[3*i+1];
a[3*i+2] = b[3*i+2];
}
With S = sizeof(a[0]);
Since the loop stride is { 3 * S } and the evolutions are:
{a, +, 3S}
{a+S, +, 3S}
{a+2S, +, 3S}
The reads/writes don't overlap, and they're sequential, so we can vectorize.</pre>
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