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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - PowerPC64: fast isel issue with 16 bit signed constant"
href="https://llvm.org/bugs/show_bug.cgi?id=27721">27721</a>
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<th>Summary</th>
<td>PowerPC64: fast isel issue with 16 bit signed constant
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: PowerPC
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>anton@samba.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>I'm seeing issues with the following test case:
unsigned int k = 1;
unsigned int i;
float h;
float *j = &h;
void foo(void)
{
unsigned short m = 0;
if (k) {
m = 46334;
k = 3;
}
i;
for (;;) {
*j = m;
if (m)
break;
}
}
The constant is created as expected at -O1:
clang -O1 -fno-strict-aliasing
lis 5, 0
ori 3, 5, 46334
mtvsrwz 0, 3
But if we enable fast isel, we end up with a sign extended constant:
clang -O1 -fno-strict-aliasing -mllvm -fast-isel
li 3, -19202
mtvsrwz 0, 3</pre>
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