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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 - [AVX512] LLVM ERROR: Cannot select: v8i16 = vselect v8i16, v8i16, v8i16"
href="https://bugs.llvm.org/show_bug.cgi?id=37499">37499</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[AVX512] LLVM ERROR: Cannot select: v8i16 = vselect v8i16, v8i16, v8i16
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ilia.taraban@intel.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>This test fails at "X86 DAG->DAG Instruction Selection" with error "Cannot
select: 0x1ad76e8: v8i16 = vselect 0x1ad7ea0, undef:v8i16, 0x1ad7548" :
================= nice.c ==============
#include <x86intrin.h>
void foo (void)
{
__m128i x = _mm_setr_epi16(1, 1, 1, 1, 1, 1, 1, 1);
__m512i y;
int mask = 0x1;
x = _mm512_mask_cvtepi64_epi16(x, mask, y);
goo(x);
}
=======================================
<span class="quote">>>> clang -v</span >
clang version 7.0.0 (trunk 332600)
Target: x86_64-unknown-linux-gnu
Thread model: posix
...
<span class="quote">>>> clang -c nice.c -O2 -march=knl</span >
fatal error: error in backend: Cannot select: t29: v8i16 = vselect t38,
undef:v8i16, t25
t38: v8i16 = extract_subvector t37, Constant:i64<0>
t37: v16i16 = truncate t36
t36: v16i32 = vselect t32, t34, t35
t32: v16i1 = insert_subvector undef:v16i1, t19, Constant:i64<0>
t31: v16i1 = undef
t19: v8i1 = bitcast Constant:i8<1>
t5: i8 = Constant<1>
t30: i64 = Constant<0>
t34: v16i32 = BUILD_VECTOR Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t33: i32 = Constant<-1>
t35: v16i32 = BUILD_VECTOR Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>, Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>, Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>, Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t14: i32 = Constant<0>
t30: i64 = Constant<0>
t17: v8i16 = undef
t25: v8i16 = bitcast t24
t24: v2i64,ch = load<(load 16 from constant-pool)> t0, t27, undef:i64
t27: i64 = X86ISD::Wrapper TargetConstantPool:i64<<8 x i16> <i16 1, i16
1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1>> 0
t26: i64 = TargetConstantPool<<8 x i16> <i16 1, i16 1, i16 1, i16 1,
i16 1, i16 1, i16 1, i16 1>> 0
t22: i64 = undef
In function: foo
clang-7: error: clang frontend command failed with exit code 70 (use -v to see
invocation)
clang version 7.0.0 (trunk 332600)
Target: x86_64-unknown-linux-gnu
...
Here is IR reproducer:
================= fine.ll =============
define void @foo()#0 {
%1 = tail call <8 x i16> @llvm.x86.avx512.mask.pmov.qw.512(<8 x i64> undef,
<8 x i16> <i16 1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1>, i8 1)
%2 = tail call i32 @goo(<8 x i16> %1)
ret void
}
declare i32 @goo(<8 x i16>)
declare <8 x i16> @llvm.x86.avx512.mask.pmov.qw.512(<8 x i64>, <8 x i16>, i8)
attributes #0 = { "target-features"="+avx512f" }
=======================================
<span class="quote">>>> llc fine.ll</span >
LLVM ERROR: Cannot select: t26: v8i16 = vselect t35, undef:v8i16, t22
t35: v8i16 = extract_subvector t34, Constant:i64<0>
t34: v16i16 = truncate t33
t33: v16i32 = vselect t29, t31, t32
t29: v16i1 = insert_subvector undef:v16i1, t16, Constant:i64<0>
t28: v16i1 = undef
t16: v8i1 = bitcast Constant:i8<1>
t5: i8 = Constant<1>
t27: i64 = Constant<0>
t31: v16i32 = BUILD_VECTOR Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t30: i32 = Constant<-1>
t32: v16i32 = BUILD_VECTOR Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>, Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>, Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>, Constant:i32<0>, Constant:i32<0>,
Constant:i32<0>, Constant:i32<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t11: i32 = Constant<0>
t27: i64 = Constant<0>
t14: v8i16 = undef
t22: v8i16 = bitcast t21
t21: v2i64,ch = load<(load 16 from constant-pool)> t0, t24, undef:i64
t24: i64 = X86ISD::Wrapper TargetConstantPool:i64<<8 x i16> <i16 1, i16
1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1>> 0
t23: i64 = TargetConstantPool<<8 x i16> <i16 1, i16 1, i16 1, i16 1,
i16 1, i16 1, i16 1, i16 1>> 0
t19: i64 = undef
In function: foo</pre>
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