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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - "Virtual register def doesn't dominate all uses" assert from PHI elimination"
href="http://llvm.org/bugs/show_bug.cgi?id=16508">16508</a>
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<th>Summary</th>
<td>"Virtual register def doesn't dominate all uses" assert from PHI elimination
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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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>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Common Code Generator Code
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>hfinkel@anl.gov
</td>
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<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>Created <span class=""><a href="attachment.cgi?id=10799" name="attach_10799" title="bugpoint reduced test case">attachment 10799</a> <a href="attachment.cgi?id=10799&action=edit" title="bugpoint reduced test case">[details]</a></span>
bugpoint reduced test case
When compiling the attached (bugpoint reduced) test case using llc, phi
elimination creates the following block:
BB#7: derived from LLVM BB %for.cond940
Predecessors according to CFG: BB#7 BB#6
%vreg1<def> = COPY %vreg21<kill>; G8RC:%vreg1,%vreg21
%vreg21<def> = COPY %vreg2; G8RC:%vreg21,%vreg2
%vreg2<def> = COPY %vreg22<kill>; G8RC:%vreg2,%vreg22
%vreg22<def> = IMPLICIT_DEF; G8RC:%vreg22
BCC 68, %vreg16, <BB#7>; CRRC:%vreg16
B <BB#8>
Successors according to CFG: BB#8(4) BB#7(124)
which latter asserts as:
*** Bad machine code: Virtual register def doesn't dominate all uses. ***
- function: func_7
- basic block: BB#7 for.cond940 (0x10027f1d0f0)
- instruction: %vreg2<def> = COPY %vreg22<kill>; G8RC:%vreg2,%vreg22
LLVM ERROR: Found 1 machine code errors.
Credit for finding the (unreduced) failing case goes to csmith
(<a href="https://github.com/csmith-project/csmith">https://github.com/csmith-project/csmith</a>).</pre>
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