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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [AArch64] missed opportunity to use conditional select invert (csinv)"
href="https://llvm.org/bugs/show_bug.cgi?id=28965">28965</a>
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<th>Summary</th>
<td>[AArch64] missed opportunity to use conditional select invert (csinv)
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<th>Product</th>
<td>libraries
</td>
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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
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Backend: AArch64
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>spatel+llvm@rotateright.com
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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>Forking this off of <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [SimplifyCFG] failure to sink common function call below if/else"
href="show_bug.cgi?id=28964">bug 28964</a>:
define i32 @goo(i32 %x) {
%cmp = icmp eq i32 %x, 1
%sel = select i1 %cmp, i32 1, i32 -1
%call = tail call i32 @bar(i32 %sel)
ret i32 %call
}
declare i32 @bar(i32)
$ ./llc -o - selcall.ll -mtriple=aarch64
...
cmp w0, #1 // =1
orr w8, wzr, #0x1
cneg w0, w8, ne
b bar
gcc 4.8 on godbolt ( <a href="https://godbolt.org/g/BW5RJu">https://godbolt.org/g/BW5RJu</a> ) shows:
foo(int):
cmp w0, 1
csinv w0, w0, wzr, eq
b bar(int)</pre>
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