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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Loop vectorizer assertion failure in truncateToMinimalBitwidths"
href="https://bugs.llvm.org/show_bug.cgi?id=38110">38110</a>
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<th>Summary</th>
<td>Loop vectorizer assertion failure in truncateToMinimalBitwidths
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>Other
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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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>Loop Optimizer
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>uweigand@de.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=20543" name="attach_20543" title="Reduced test case">attachment 20543</a> <a href="attachment.cgi?id=20543&action=edit" title="Reduced test case">[details]</a></span>
Reduced test case
Running the attached test case through
opt -loop-vectorize -mcpu=z13
on the s390x-ibm-linux target results in an assertion failure:
Unhandled instruction type!
UNREACHABLE executed at
/home/uweigand/llvm/llvm-head/lib/Transforms/Vectorize/LoopVectorize.cpp:3292!
The unhandled instruction at this point seems to be a phi node.
This is a reduced test case from a real-world application. The corresponding
reduced C source code test case (same assertion failure) is:
void
test (unsigned int width, unsigned char *row,
unsigned short src, unsigned short *dst)
{
unsigned char *sp;
unsigned int i;
sp = row;
for (i = 0; i < width; i++, sp++)
{
if (*sp == src)
*sp = (unsigned char) *dst;
}
}</pre>
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