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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [InstCombine] reduce icmp ult with or operand"
href="https://bugs.llvm.org/show_bug.cgi?id=45666">45666</a>
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<th>Summary</th>
<td>[InstCombine] reduce icmp ult with or operand
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<th>Product</th>
<td>libraries
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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
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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>Scalar Optimizations
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>spatel+llvm@rotateright.com
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</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>define i1 @cmp_or_limit(i8 %x) {
%or = or i8 %x, 5
%cmp = icmp ult i8 %or, 43
ret i1 %cmp
}
This can reduce to:
define i1 @cmp_or_limit(i8 %x) {
%R = icmp ult i8 %x, 40
ret i1 %R
}
<a href="http://volta.cs.utah.edu:8080/z/k3sykE">http://volta.cs.utah.edu:8080/z/k3sykE</a>
I think there's some leading zeros + masking relationship for those constants
that we're not getting.
The old Alive lets us specify constant preconditions. Is there an equivalent
with Alive2?</pre>
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