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<base href="https://bugs.llvm.org/">
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<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [AVX512] cannot select: extract f64 from splatted "movemask""
href="https://bugs.llvm.org/show_bug.cgi?id=43750">43750</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[AVX512] cannot select: extract f64 from splatted "movemask"
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>9.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: X86
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>andrew@scheidecker.net
</td>
</tr>
<tr>
<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
</td>
</tr></table>
<p>
<div>
<pre>I can reproduce this error in my local build of LLVM 9 and "LLC (trunk)" on
Compiler Explorer, but LLC 8.0.0 on Compiler Explorer does not reproduce the
error.
It also only repros with '-mcpu=skylake-avx512', or some other CPU with AVX-512
support. If I use '-mcpu=skylake' or '-mattr=-avx512f', the error does not
occur.
Repro module:
define double @0(<16 x i8>) {
entry:
%1 = icmp slt <16 x i8> %0, zeroinitializer
%2 = bitcast <16 x i1> %1 to i16
%.splatinsert = insertelement <8 x i16> undef, i16 %2, i32 0
%.splat = shufflevector <8 x i16> %.splatinsert, <8 x i16> undef, <8 x i32>
<i32 undef, i32 undef, i32 undef, i32 undef, i32 0, i32 0, i32 0, i32 0>
%3 = bitcast <8 x i16> %.splat to <2 x double>
%4 = extractelement <2 x double> %3, i64 1
ret double %4
}
Run:
llc -mcpu=skylake-avx512 repro.ll
Output:
LLVM ERROR: Cannot select: 0x5608e0d8ba08: f64 = bitcast 0x5608e0d8bc78
0x5608e0d8bc78: v64i1 = concat_vectors 0x5608e0d8c2f8, 0x5608e0d8c2f8
0x5608e0d8c2f8: v32i1 = concat_vectors 0x5608e0d8bad8, 0x5608e0d8bad8
0x5608e0d8bad8: v16i1 = setcc 0x5608e0d8b9a0, 0x5608e0d8b8d0, setgt:ch
0x5608e0d8b9a0: v16i8 = BUILD_VECTOR Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>,Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b8d0: v16i8 = bitcast 0x5608e0d8b868
0x5608e0d8b868: v2i64,ch = CopyFromReg 0x5608e0cf7998,
Register:v2i64 %0
0x5608e0d8b800: v2i64 = Register %0
0x5608e0d8bad8: v16i1 = setcc 0x5608e0d8b9a0, 0x5608e0d8b8d0, setgt:ch
0x5608e0d8b9a0: v16i8 = BUILD_VECTOR Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>,Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b8d0: v16i8 = bitcast 0x5608e0d8b868
0x5608e0d8b868: v2i64,ch = CopyFromReg 0x5608e0cf7998,
Register:v2i64 %0
0x5608e0d8b800: v2i64 = Register %0
0x5608e0d8c2f8: v32i1 = concat_vectors 0x5608e0d8bad8, 0x5608e0d8bad8
0x5608e0d8bad8: v16i1 = setcc 0x5608e0d8b9a0, 0x5608e0d8b8d0, setgt:ch
0x5608e0d8b9a0: v16i8 = BUILD_VECTOR Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>,Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b8d0: v16i8 = bitcast 0x5608e0d8b868
0x5608e0d8b868: v2i64,ch = CopyFromReg 0x5608e0cf7998,
Register:v2i64 %0
0x5608e0d8b800: v2i64 = Register %0
0x5608e0d8bad8: v16i1 = setcc 0x5608e0d8b9a0, 0x5608e0d8b8d0, setgt:ch
0x5608e0d8b9a0: v16i8 = BUILD_VECTOR Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0>,
Constant:i8<0>,Constant:i8<0>, Constant:i8<0>, Constant:i8<0>, Constant:i8<0
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b938: i8 = Constant<0>
0x5608e0d8b8d0: v16i8 = bitcast 0x5608e0d8b868
0x5608e0d8b868: v2i64,ch = CopyFromReg 0x5608e0cf7998,
Register:v2i64 %0
0x5608e0d8b800: v2i64 = Register %0</pre>
</div>
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