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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [SystemZ] Assertion "Invalid truncate node, src < dst!" failed"
href="https://bugs.llvm.org/show_bug.cgi?id=41780">41780</a>
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<th>Summary</th>
<td>[SystemZ] Assertion "Invalid truncate node, src < dst!" failed
</td>
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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>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Backend: SystemZ
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>paulsson@linux.vnet.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=21901" name="attach_21901" title="reduced test case">attachment 21901</a> <a href="attachment.cgi?id=21901&action=edit" title="reduced test case">[details]</a></span>
reduced test case
llc -mcpu=z13 -O3 -o out.s ./tc_invalidtrunc.ll
SystemZTargetLowering::combineExtract() tries to truncate from i16 to i32.
I am a bit confused about all the implications of extracting a vector element
from a BUILD_VECTOR using possibly another vector type (VecVT) (?), so I have
not attempted a patch yet.
The comment "We're extracting the low part of one operand of the
BUILD_VECTOR.": does this mean we are expecting at this point to truncate the
value always? Or could we make an extension in the integer case, per the
comment:
/// EXTRACT_VECTOR_ELT(VECTOR, IDX) - Returns a single element from VECTOR
/// identified by the (potentially variable) element number IDX. If the
/// return type is an integer type larger than the element type of the
/// vector, the result is extended to the width of the return type. In
/// that case, the high bits are undefined.
If we could do an ANY_EXTEND, this test case would be handled here (although I
am not sure if thats beneficial or not), or if not, I guess it should just
"break" (return without doing anything).</pre>
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