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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Invalid undef splat in instcombine"
href="https://bugs.llvm.org/show_bug.cgi?id=45455">45455</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Invalid undef splat in instcombine
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Keywords</th>
<td>miscompilation
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>nunoplopes@sapo.pt
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, regehr@cs.utah.edu, spatel+llvm@rotateright.com
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</tr></table>
<p>
<div>
<pre>Test: Transforms/InstCombine/unfold-masked-merge-with-const-mask-vector.ll
define <3 x i4> @splat_undef(<3 x i4> %x, <3 x i4> %y) {
%n0 = xor <3 x i4> %x, %y
%n1 = and <3 x i4> %n0, { 14, undef, 14 }
%r = xor <3 x i4> %n1, %y
ret <3 x i4> %r
}
=>
define <3 x i4> @splat_undef(<3 x i4> %x, <3 x i4> %y) {
%1 = and <3 x i4> %x, { 14, undef, 14 }
%2 = and <3 x i4> %y, { 1, undef, 1 }
%r = or <3 x i4> %1, %2
ret <3 x i4> %r
}
Transformation doesn't verify!
ERROR: Value mismatch
Example:
<3 x i4> %x = < #x0 (0), #xd (13, -3), #x0 (0) >
<3 x i4> %y = < undef, #x8 (8, -8), #x0 (0) >
Source:
<3 x i4> %n0 = < #x0 (0), #x5 (5), #x0 (0) >
<3 x i4> %n1 = < #x0 (0), #x0 (0) [based on undef value], #x0 (0) >
<3 x i4> %r = < #x0 (0), #x8 (8, -8), #x0 (0) >
Target:
<3 x i4> %1 = < #x0 (0), #x1 (1), #x0 (0) >
<3 x i4> %2 = < #x0 (0), #x0 (0), #x0 (0) >
<3 x i4> %r = < #x0 (0), #x1 (1), #x0 (0) >
Source value: < #x0 (0), #x8 (8, -8), #x0 (0) >
Target value: < #x0 (0), #x1 (1), #x0 (0) >
<a href="https://web.ist.utl.pt/nuno.lopes/alive2/index.php?hash=2009353267698970&test=Transforms%2FInstCombine%2Funfold-masked-merge-with-const-mask-vector.ll">https://web.ist.utl.pt/nuno.lopes/alive2/index.php?hash=2009353267698970&test=Transforms%2FInstCombine%2Funfold-masked-merge-with-const-mask-vector.ll</a></pre>
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