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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Why FeatureSlowPMULLD is not set for Haswell+?"
href="https://bugs.llvm.org/show_bug.cgi?id=35948">35948</a>
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<th>Summary</th>
<td>Why FeatureSlowPMULLD is not set for Haswell+?
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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>All
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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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>nekotekina@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<pre>Hello, it seems that LLVM sets this flag for Silvermont processors, but not
others. On Haswell or Skylake processors (for example), PMULLD has latency 10,
when other vector multiplication instructions have latency 5.
<a class="bz_bug_link
bz_status_NEW "
title="NEW - auto vectorizer makes code run slower"
href="show_bug.cgi?id=28128">https://bugs.llvm.org/show_bug.cgi?id=28128</a> seems related.</pre>
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