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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [InstCombine] fold multiply and equality compare with constant"
href="https://bugs.llvm.org/show_bug.cgi?id=52402">52402</a>
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<th>Summary</th>
<td>[InstCombine] fold multiply and equality compare with constant
</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
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
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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>
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<p>
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<pre>Forking this off from <a class="bz_bug_link
bz_status_CONFIRMED "
title="CONFIRMED - Dead Code Elimination Regression at -O3 (trunk vs 13.0.0)"
href="show_bug.cgi?id=52289">bug 52289</a> - I don't know what the generalization is, but
we're missing some kind of overflowing/shifting/multiplying magic:
define i1 @src(i32 %x) {
%m = mul i32 %x, 1355350016 ; 0x50c90000
%r = icmp eq i32 %m, 65536 ; 0x00010000
ret i1 %r
}
define i1 @tgt(i32 %x) {
%t = trunc i32 %x to i16
%r = icmp eq i16 %t, 51577 ; 0xc979
ret i1 %r
}
<a href="https://alive2.llvm.org/ce/z/7Ft6jA">https://alive2.llvm.org/ce/z/7Ft6jA</a></pre>
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