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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - icmp eq/ne (and X, (neg X)), 0 not optimized to just icmp eq/ne X, 0"
href="https://bugs.llvm.org/show_bug.cgi?id=40102">40102</a>
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<th>Summary</th>
<td>icmp eq/ne (and X, (neg X)), 0 not optimized to just icmp eq/ne X, 0
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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>Windows NT
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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>craig.topper@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
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<pre>As mentioned in D55870, this can be optimized to just a compare of X with 0.
Test case taken from test/CodeGen/bmi.ll
define i32 @blsi32_z2(i32 %a, i32 %b, i32 %c) nounwind {
%t0 = sub i32 0, %a
%t1 = and i32 %t0, %a
%t2 = icmp eq i32 %t1, 0
%t3 = select i1 %t2, i32 %b, i32 %c
ret i32 %t3
}</pre>
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