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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - InstCombine transform missing associativity of boolean and operator"
href="http://llvm.org/bugs/show_bug.cgi?id=20814">20814</a>
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<th>Summary</th>
<td>InstCombine transform missing associativity of boolean and operator
</td>
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<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>listmail@philipreames.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=12964" name="attach_12964" title="Failing test case for InstCombine">attachment 12964</a> <a href="attachment.cgi?id=12964&action=edit" title="Failing test case for InstCombine">[details]</a></span>
Failing test case for InstCombine
InstCombine appears to be missing a transform based on the fact that it doesn't
recognize boolean and is associative. Without the extra 'b' variable, this
example nicely gets folded into a single equality check, but this optimization
is inhibited in this case.
define i1 @test1(i32 %i, i1 %b) {
; CHECK: icmp eq i32 %i, 0
; CHECK-NOT: slt
; todo: check and, return
entry:
%0 = icmp slt i32 %i, 1
%1 = icmp sgt i32 %i, -1
%and1 = and i1 %0, %b
%and2 = and i1 %and1, %1
ret i1 %and2
}</pre>
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