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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 - PPC vector fails to optimize shift (used bits)"
href="https://bugs.llvm.org/show_bug.cgi?id=45628">45628</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>PPC vector fails to optimize shift (used bits)
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Macintosh
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</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>slandden@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre><a href="https://godbolt.org/z/KZwVRg">https://godbolt.org/z/KZwVRg</a>
// Type your code here, or load an example.
#include <altivec.h>
typedef vector unsigned __int128 block;
typedef vector unsigned long long vector2_u64;
block swap_with_shift(block num) {
return num << 64 | num >> 64;
}
block swap_without_shift(block num) {
vector unsigned long long ret;
ret[0] = ((vector2_u64)num)[1];
ret[1] = ((vector2_u64)num)[0];
return (block)ret;
}
typedef unsigned __int128 u128;
u128 swap_scalar(u128 in) {
return in << 64 | in >> 64;
}
swap_with_shift: # @swap_with_shift
xxspltd 35, 34, 1
xxswapd 34, 34
xxlxor 0, 0, 0
xxpermdi 35, 35, 0, 1
xxpermdi 34, 0, 34, 1
xxlor 34, 35, 34
blr
.long 0
.quad 0
swap_without_shift: # @swap_without_shift
xxswapd 34, 34
blr
.long 0
.quad 0
swap_scalar: # @swap_scalar
mr 5, 3
mr 3, 4
mr 4, 5
blr
.long 0
.quad 0</pre>
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