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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Incorrect vectorization of a long double array by packed vectors"
href="http://llvm.org/bugs/show_bug.cgi?id=15758">15758</a>
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<th>Summary</th>
<td>Incorrect vectorization of a long double array by packed vectors
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>3.2
</td>
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<th>Hardware</th>
<td>Macintosh
</td>
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<th>OS</th>
<td>MacOS X
</td>
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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
</td>
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>dtakahashi42@gmail.com
</td>
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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>With loop-vectorizer is enabled by -mllvm -vectorize-loops, clang automatically
vectorizes the assignment on a long-double array (16 bytes aligned) by
assignment on 16-bytes-aligned-x86_fp80-packed vectors. Because of the
alignment mismatch between array's elements and packed elements, subsequent
access on the array produces incorrect result.
Below is the test case.
int main (void) {
long double x[1027];
for (int i = 0; i < 1027; i++) {
x[i] = (long double) i;
}
for (int i = 0; i < 1027; i++) {
assert (x[i] == (long double) i);
}
return 0;
}</pre>
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