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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - AVX-512: VPBROADCASTD from general purpose register is suboptimal?"
href="https://bugs.llvm.org/show_bug.cgi?id=36212">36212</a>
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<th>Summary</th>
<td>AVX-512: VPBROADCASTD from general purpose register is suboptimal?
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<th>Product</th>
<td>libraries
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<th>Version</th>
<td>6.0
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
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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>nekotekina@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<pre>Hello, I notice that LLVM likes to emit instructions like:
mov r9d, ...
vpbroadcastd xmm0{k1}, r9d
On the other hand, broadcast from the xmm register should have better latency:
vpbroadcastd xmm0{k1}, xmm1
I'm not an expert, but from what I know it's better to avoid any gpr<>xmm
transition because it's penalized.</pre>
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