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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - SCEV dropping NSW/NUW flags on non-unit stride access"
href="http://llvm.org/bugs/show_bug.cgi?id=17963">17963</a>
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<th>Summary</th>
<td>SCEV dropping NSW/NUW flags on non-unit stride access
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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
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Scalar Optimizations
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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>Created <span class=""><a href="attachment.cgi?id=11556" name="attach_11556" title="example in C and IR">attachment 11556</a> <a href="attachment.cgi?id=11556&action=edit" title="example in C and IR">[details]</a></span>
example in C and IR
The attached C code, compiled with Clang to the attached IR has a
multiplicative factor of 2, and SCEV::getMulExpr() is losing the NSW that is on
the multiplication for being too conservative.
Keeping the NSW flags will help the non-unit stride analysis on the vectorizer.</pre>
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