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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - NVPTX: Bad machine code: Reading virtual register without a def" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24300&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=XxLmIe417Nhbk0Q10jjF6UJz_9d9rQR6xuU4xAxUw_Q&s=JQMf75DN_kBmfzoPkMrzi_JucI2M3K2ornCprH1jEio&e=">24300</a>
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<th>Summary</th>
<td>NVPTX: Bad machine code: Reading virtual register without a def
</td>
</tr>
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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>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: PTX
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>tobias@grosser.es
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=14662" name="attach_14662" title="Test case to reproduce the bug">attachment 14662</a> <a href="attachment.cgi?id=14662&action=edit" title="Test case to reproduce the bug">[details]</a></span>
Test case to reproduce the bug
The attached test case fails when running it through llc (243247).
The following error is printed:
----------------------------------------------------------------------
# Machine code for function hoge: Post SSA
BB#0: derived from LLVM BB %bb
%vreg2<def> = IMOV64i 0; Int64Regs:%vreg2
CBranch %vreg3<undef>, <BB#6>; Int1Regs:%vreg3
GOTO <BB#1>
Successors according to CFG: BB#1(16) BB#6(16)
BB#6:
Predecessors according to CFG: BB#0
%vreg9<def> = COPY %vreg2; Int64Regs:%vreg9,%vreg2
GOTO <BB#5>
Successors according to CFG: BB#5
BB#1: derived from LLVM BB %bb1
Predecessors according to CFG: BB#0
CBranch %vreg4<undef>, <BB#3>; Int1Regs:%vreg4
GOTO <BB#2>
Successors according to CFG: BB#3(16) BB#2(16)
BB#2: derived from LLVM BB %bb2
Predecessors according to CFG: BB#1 BB#3
CBranch %vreg7, <BB#4>; Int1Regs:%vreg7
Successors according to CFG: BB#4(16) BB#7(16)
BB#7:
Predecessors according to CFG: BB#2
%vreg9<def> = COPY %vreg2; Int64Regs:%vreg9,%vreg2
GOTO <BB#5>
Successors according to CFG: BB#5
BB#3: derived from LLVM BB %bb3
Predecessors according to CFG: BB#1
GOTO <BB#2>
Successors according to CFG: BB#2(16)
BB#4: derived from LLVM BB %bb5
Predecessors according to CFG: BB#2
%vreg9<def> = COPY %vreg2; Int64Regs:%vreg9,%vreg2
Successors according to CFG: BB#5
BB#5: derived from LLVM BB %bb7
Predecessors according to CFG: BB#4 BB#5 BB#6 BB#7
%vreg0<def> = COPY %vreg9<kill>; Int64Regs:%vreg0,%vreg9
%vreg1<def> = ADDi64ri %vreg0, 1; Int64Regs:%vreg1,%vreg0
%vreg9<def> = COPY %vreg1; Int64Regs:%vreg9,%vreg1
GOTO <BB#5>
Successors according to CFG: BB#5
# End machine code for function hoge.
*** Bad machine code: Reading virtual register without a def ***
- function: hoge
- basic block: BB#2 bb2 (0x621000005648)
- instruction: CBranch- operand 0: %vreg7
LLVM ERROR: Found 1 machine code errors.
----------------------------------------------------------------------
The test case has been found by bugpoint while reducing another issue. It would
be great if we could _not_ crash, as this would allow allow me to reduce the
original bug.</pre>
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