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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - CTPOP(x) > 0 isn't optimized away before SelectionDAG?"
href="https://bugs.llvm.org/show_bug.cgi?id=47949">47949</a>
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<th>Summary</th>
<td>CTPOP(x) > 0 isn't optimized away before SelectionDAG?
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Common Code Generator Code
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>dave@znu.io
</td>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<pre>I committed exhaustive x86 CTPOP tests to the repo this morning
(test/CodeGen/X86/vector-popcnt-{128,256,512}-ult-ugt.ll).
Notably, unsigned greater-than-zero tests are generating actual CTPOP emulation
when they don't need to. It should just optimize down to a comparison against
zero.
My limited investigation shows that SelectionDAG can fix this, but shouldn't an
earlier pass have caught this?</pre>
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