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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [X86] Bug in shuffle-to-zero-extend transformation"
href="https://bugs.llvm.org/show_bug.cgi?id=34576">34576</a>
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<th>Summary</th>
<td>[X86] Bug in shuffle-to-zero-extend transformation
</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>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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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>ayman.musa@intel.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
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<pre>X86ISD::VZEXT node is defined to work on integer types only.
In the following IR code:
define internal fastcc <4 x float> @test(<4 x float> %inp) #0 {
entry:
%shuf = shufflevector <4 x float> %inp, <4 x float> zeroinitializer, <4 x
i32> <i32 0, i32 undef, i32 2, i32 4>
ret <4 x float> %shuf
}
the input for the shufflevector instruction should be bitcasted to integer type
before feeding it to zero-extend.
<span class="quote">> ../../build/bin/llc -mattr=+avx2 test.ll -o test.s</span >
LLVM ERROR: Cannot select: t502: v4i64 = X86ISD::VZEXT t501
t501: v4f32 = bitcast t500
t500: v2f64 = extract_subvector t466, Constant:i64<0>
t466: v4f64 = X86ISD::VPERMI t428, Constant:i8<-58>
t428: v4f64 = bitcast t433
t433: v8f32 = X86ISD::VPERMILPI t27, Constant:i8<108>
t27: v8f32,ch = load<LD32[FixedStack-5]> t0, FrameIndex:i64<-5>,
undef:i64
t26: i64 = FrameIndex<-5>
t18: i64 = undef
t432: i8 = Constant<108>
t465: i8 = Constant<-58>
t411: i64 = Constant<0>
In function: test</pre>
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