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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 - Incorrect code generated with ext_vector_type(16)"
href="https://bugs.llvm.org/show_bug.cgi?id=43453">43453</a>
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<th>Summary</th>
<td>Incorrect code generated with ext_vector_type(16)
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>9.0
</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
</td>
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>warp@iki.fi
</td>
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>Consider the following code:
//--------------------------------------------------------------
typedef double Double16 __attribute__((ext_vector_type(16)));
// or
// typedef double Double16 __attribute__((vector_size(8*16)));
Double16 mult(const Double16& v1, const Double16& v2)
{
return v1 * v2;
}
//--------------------------------------------------------------
When compiling with clang 9.0.0 using -Ofast -march=skylake, the following
result is produced:
//--------------------------------------------------------------
vmovapd ymm0, ymmword ptr [rsi]
vmovapd ymm1, ymmword ptr [rsi + 32]
vmovapd ymm2, ymmword ptr [rsi + 64]
vmovapd ymm3, ymmword ptr [rsi + 96]
vmulpd ymm0, ymm0, ymmword ptr [rdi]
vmulpd ymm1, ymm1, ymmword ptr [rdi + 32]
vmulpd ymm2, ymm2, ymmword ptr [rdi + 64]
vmulpd ymm3, ymm3, ymmword ptr [rdi + 96]
ret
//--------------------------------------------------------------
I believe this is erroneous, as the result is not stored into the function
return value according to the ABI.</pre>
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