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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [AVX512BW] Crash with shuffle lowering as zero extend"
href="https://llvm.org/bugs/show_bug.cgi?id=26661">26661</a>
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<th>Summary</th>
<td>[AVX512BW] Crash with shuffle lowering as zero extend
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Backend: X86
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>AVX512 bw targets fail to select VZEXT (pmovzxbw)for the below example.
define <16 x i16> @zext_32x8_to_16x16(<32 x i8> %a) nounwind readnone {
%1 = shufflevector <32 x i8> %a, <32 x i8> zeroinitializer, <32 x i32> <i32
0, i32 32, i32 1, i32 32, i32 2, i32 32, i32 3, i32 32, i32 4, i32 32, i32 5,
i32 32, i32 6, i32 32, i32 7, i32 32, i32 8, i32 32, i32 9, i32 32, i32 10, i32
32, i32 11, i32 32, i32 12, i32 32, i32 13, i32 32, i32 14, i32 32, i32 15, i32
32>
%2 = bitcast <32 x i8> %1 to <16 x i16>
ret <16 x i16> %2
}
llc -mtriple=x86_64-unknown -mcpu=skx test.ll -o -
LLVM ERROR: Cannot select: t12: v16i16 = X86ISD::VZEXT t2
t2: v32i8,ch = CopyFromReg t0, Register:v32i8 %vreg0
t1: v32i8 = Register %vreg0
In function: zext_32x8_to_16x16
This appears to be related to the changes to the predicate filtering from
D16595 / rL258915.</pre>
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