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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [X86][SSE2] Failure to vectorize int16_t[8] to pminsw pattern"
href="https://bugs.llvm.org/show_bug.cgi?id=48879">48879</a>
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<th>Summary</th>
<td>[X86][SSE2] Failure to vectorize int16_t[8] to pminsw pattern
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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>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Backend: X86
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, pengfei.wang@intel.com, spatel+llvm@rotateright.com
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<p>
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<pre><a href="https://gcc.godbolt.org/z/57nGK3">https://gcc.godbolt.org/z/57nGK3</a>
typedef int16_t T;
constexpr int N = 8;
std::array<T,N> compute_min(std::array<T,N>& x, std::array<T,N>& y) {
std::array<T,N> result;
for (int i = 0; i != N; ++i) {
result[i] = std::min(x[i], y[i]);
}
return result;
}
This ends up as a horrid mix of scalar and <2 x i16> smin patterns.
Much of the problem seems to be that we end up trying to store the final array
as { i64, i64 } aggregate, resulting in a load of zext+shift+or to pack the
i16's.
Even more impressive with -march=atom we end up with masked gather calls....</pre>
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