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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [ARM64] Inefficient range check sequence"
href="http://llvm.org/bugs/show_bug.cgi?id=20927">20927</a>
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<th>Summary</th>
<td>[ARM64] Inefficient range check sequence
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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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>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: AArch64
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>grosbach@apple.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
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</tr></table>
<p>
<div>
<pre>Consider:
long foo(long a, long b, long v1, long v2) {
if (a >= v1 && a < v2)
return b;
return 0;
}
We generate:
cmp x0, x2
csinc w8, wzr, wzr, lt
cmp x0, x3
csinc w9, wzr, wzr, ge
and w8, w8, w9
cmp w8, #0
csel x0, x1, xzr, ne
ret
This seems like it should have generated something like:
mov x4, #0
cmp x0, x2
ccmp x0, x3, #imm, lt
csel x0, x1, x4, ge
ret</pre>
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</p>
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