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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [x86, SSE] no optimization for move mask instructions"
href="https://llvm.org/bugs/show_bug.cgi?id=27982">27982</a>
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<th>Summary</th>
<td>[x86, SSE] no optimization for move mask instructions
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: X86
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>spatel+llvm@rotateright.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>Similar to <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [x86, SSE] failed to eliminate unused instruction"
href="show_bug.cgi?id=27924">bug 27924</a>, I noticed this problem in a checker program that I used
for <a href="http://reviews.llvm.org/D20774">http://reviews.llvm.org/D20774</a> :
$ cat movmsk.ll
declare i32 @llvm.x86.sse2.pmovmskb.128(<16 x i8>)
define i1 @movmsk() {
%movmsk = tail call i32 @llvm.x86.sse2.pmovmskb.128(<16 x i8>
zeroinitializer)
%cmp = icmp eq i32 %movmsk, 65535
ret i1 %cmp
}
$ ./llc -o - movmsk.ll
...
pxor %xmm0, %xmm0
pmovmskb %xmm0, %eax
cmpl $65535, %eax ## imm = 0xFFFF
sete %al
retq
There doesn't seem to be any analysis for an X86ISD::MOVMSK node in the DAG.</pre>
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