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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [InstCombine] sub (and %x, -16), %x -> 0-(and %x, 15)"
href="https://bugs.llvm.org/show_bug.cgi?id=44427">44427</a>
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<th>Summary</th>
<td>[InstCombine] sub (and %x, -16), %x -> 0-(and %x, 15)
</td>
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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>Linux
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<th>Status</th>
<td>NEW
</td>
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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>lebedev.ri@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<pre>Looks like missed canonicalization to me. Not sure how much matters overall.
Name: sub (and %x, -16), %x -> 0-(and %x, 15)
Pre: isPowerOf2OrZero(-C1)
%o = and i64 %x, C1
%r = sub i64 %o, %x
=>
%n = and i64 %x, (-C1-1)
%r = sub i64 0, %n
<a href="https://rise4fun.com/Alive/t0hD">https://rise4fun.com/Alive/t0hD</a>
<a href="https://godbolt.org/z/R_RMfM">https://godbolt.org/z/R_RMfM</a></pre>
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