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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 - [X86][AVX] Failure to combine to HADDPD"
href="https://bugs.llvm.org/show_bug.cgi?id=44694">44694</a>
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<th>Summary</th>
<td>[X86][AVX] Failure to combine to HADDPD
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: X86
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
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<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
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<p>
<div>
<pre><a href="https://godbolt.org/z/U2jZo3">https://godbolt.org/z/U2jZo3</a>
#include <x86intrin.h>
__m256d add_pd(__m256d a, __m256d b) {
return __builtin_shufflevector(a, b, -1, 2, 4, 6) +
__builtin_shufflevector(a, b, -1, 3, 5, 7);
}
define <4 x double> @_Z6add_pdDv4_dS_(<4 x double> %0, <4 x double> %1) {
%3 = shufflevector <4 x double> %0, <4 x double> %1, <4 x i32> <i32 undef,
i32 2, i32 4, i32 6>
%4 = shufflevector <4 x double> %0, <4 x double> %1, <4 x i32> <i32 undef,
i32 3, i32 5, i32 7>
%5 = fadd <4 x double> %3, %4
ret <4 x double> %5
}
_Z6add_pdDv4_dS_: # @_Z6add_pdDv4_dS_
vperm2f128 $49, %ymm1, %ymm0, %ymm0 # ymm0 = ymm0[2,3],ymm1[2,3]
vinsertf128 $1, %xmm1, %ymm0, %ymm1
vunpcklpd %ymm0, %ymm1, %ymm2 # ymm2 = ymm1[0],ymm0[0],ymm1[2],ymm0[2]
vshufpd $14, %ymm0, %ymm1, %ymm0 # ymm0 = ymm1[0],ymm0[1],ymm1[3],ymm0[3]
vaddpd %ymm0, %ymm2, %ymm0
retq
Which should be combine to:
vperm2f128 $49, %ymm1, %ymm0, %ymm2 # ymm2 = ymm0[2,3],ymm1[2,3]
vinsertf128 $1, %xmm1, %ymm0, %ymm0
vhaddpd %ymm2, %ymm0, %ymm0
retq</pre>
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