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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 --- - flex scanner results in "Bad machine code: Using an undefined physical register" after r188766"
href="http://llvm.org/bugs/show_bug.cgi?id=17315">17315</a>
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<th>Summary</th>
<td>flex scanner results in "Bad machine code: Using an undefined physical register" after r188766
</td>
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<th>Product</th>
<td>new-bugs
</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>FreeBSD
</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>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>dimitry@andric.com
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=11254" name="attach_11254" title="Testcase for flex scanner "Bad machine code" bug">attachment 11254</a> <a href="attachment.cgi?id=11254&action=edit" title="Testcase for flex scanner "Bad machine code" bug">[details]</a></span>
Testcase for flex scanner "Bad machine code" bug
While attempting to build a recent version of FreeBSD with clang trunk r191105,
I got a few "Bad machine code" errors, in a flex scanner that is generated
during the build process:
*** Bad machine code: Using an undefined physical register ***
- function: yylex
- basic block: BB#8 sw.bb (0x2a5b0f10)
- instruction: TCRETURNri %vreg32, 0, <regmask>, %ESP<imp-use>,
%ECX<imp-use,kill>; GR32_TC:%vreg32
- operand 4: %ECX<imp-use,kill>
*** Bad machine code: Using an undefined physical register ***
- function: yylex
- basic block: BB#11 sw.bb10 (0x2a5ad3ac)
- instruction: TCRETURNri %vreg26, 0, <regmask>, %ESP<imp-use>, %ECX<imp-use>;
GR32_TC:%vreg26
- operand 4: %ECX<imp-use>
fatal error: error in backend: Found 2 machine code errors.
This error does not occur with the 3.3 release version of clang we are using in
FreeBSD itself. After reducing the test case to the attached file, I was able
to bisect where the problem started appearing:
<a href="http://llvm.org/viewvc/llvm-project?view=revision&revision=188766">http://llvm.org/viewvc/llvm-project?view=revision&revision=188766</a>
To reproduce, compile the attached testcase with:
clang -O2 -fPIC -fstack-protector -c flexbug.c</pre>
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