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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [x86, AVX] vbroadcast not used to splat constant"
href="https://llvm.org/bugs/show_bug.cgi?id=27141">27141</a>
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<th>Summary</th>
<td>[x86, AVX] vbroadcast not used to splat constant
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: X86
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
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<th>Reporter</th>
<td>spatel+llvm@rotateright.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>This was noticed in the output of <a href="http://reviews.llvm.org/D18566">http://reviews.llvm.org/D18566</a> (<a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Optimize memset for AVX2"
href="show_bug.cgi?id=27100">bug 27100</a>):
define void @hoo(<4 x i32>* %x, i8 %c) {
%ins = insertelement <4 x i32> undef, i32 42, i32 0
%splat = shufflevector <4 x i32> %ins, <4 x i32> undef, <4 x i32>
zeroinitializer
store <4 x i32> %splat, <4 x i32>* %x
ret void
}
$ ./llc -o - memset.ll -mattr=avx
...
vmovaps LCPI0_0(%rip), %xmm0 ## xmm0 = [42,42,42,42]
vmovaps %xmm0, (%rdi)
$ ./llc -o - memset.ll -mattr=avx2
...
vbroadcastss LCPI0_0(%rip), %xmm0
vmovaps %xmm0, (%rdi)
vbroadcastss from memory is available with AVX, so these should produce
identical asm.</pre>
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