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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - LVI misses opportunities to conclude overdefined"
href="https://llvm.org/bugs/show_bug.cgi?id=27433">27433</a>
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<th>Summary</th>
<td>LVI misses opportunities to conclude overdefined
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<th>Product</th>
<td>new-bugs
</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
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>new bugs
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>regehr@cs.utah.edu
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<th>CC</th>
<td>listmail@philipreames.com, llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>Following each icmp ne + branch, LVI properly concludes that x is not 10 and
20, respectively. However, it should also put these facts together and conclude
that x is overdefined at cont2. Instead of intersecting the incoming dataflow
fact with the new one, it seems to only overwrite it, concluding at cont2 that
x != 20.
define void @foo8(i32 %x) #0 {
entry:
%cmp = icmp ne i32 %x, 10
br i1 %cmp, label %if.end3, label %cont
cont:
%cmp1 = icmp ne i32 %x, 20
br i1 %cmp1, label %if.end3, label %cont2
cont2:
;; LVI should be able to tell we can't get here!
br label %if.end3
if.end3:
ret void
}</pre>
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