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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [InstCombine] Compare known true or false was not folded"
href="https://bugs.llvm.org/show_bug.cgi?id=35846">35846</a>
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<th>Summary</th>
<td>[InstCombine] Compare known true or false was not folded
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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
</td>
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<th>Status</th>
<td>NEW
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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>Common Code Generator Code
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>llvm-dev@redking.me.uk
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<th>CC</th>
<td>craig.topper@gmail.com, david.majnemer@gmail.com, davide@freebsd.org, djasper@google.com, llvm-bugs@lists.llvm.org, spatel+llvm@rotateright.com
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<p>
<div>
<pre>Reduced from <a href="https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4718">https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4718</a>
opt -instcombine
define i32 @bar4(i32 %a, i32 %b) {
%and1 = and i32 %b, 3
%B1 = ashr i32 %and1, %and1
%B3 = shl i32 %and1, %B1
%cmp = icmp eq i32 %B3, 1
tail call void @llvm.assume(i1 %cmp)
%cmp2 = icmp eq i32 %B1, %B3
tail call void @llvm.assume(i1 %cmp2)
ret i32 %and1
}
declare void @llvm.assume(i1)
Assertion failed: C.ashr(*ShiftAmt).shl(*ShiftAmt) == C && "Compare known true
or false was not folded", file
C:\LLVM\llvm\lib\Transforms\InstCombine\InstCombineCompares.cpp, line 1900</pre>
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