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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Reduction loop with std::vector not vectorized due to cost model"
href="https://bugs.llvm.org/show_bug.cgi?id=47862">47862</a>
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<th>Summary</th>
<td>Reduction loop with std::vector not vectorized due to cost model
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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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
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</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>david.bolvansky@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>#include <vector>
std::size_t stdvecsum(std::vector<std::vector<float>> const & v) {
std::size_t ret = 0;
for (std::size_t i = 0; i < v.size(); ++i)
ret += v[i].size();
return ret;
}
ICC -O3 -mavx2 vectorizes this loop. Clang does not vectorize it due to cost
model.
<a href="https://godbolt.org/z/Peds78">https://godbolt.org/z/Peds78</a></pre>
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