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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - X86FlagsCopyLowering.cpp fails to remove killed $eflags from successor live-ins"
href="https://bugs.llvm.org/show_bug.cgi?id=44462">44462</a>
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<th>Summary</th>
<td>X86FlagsCopyLowering.cpp fails to remove killed $eflags from successor live-ins
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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>
</tr>
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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: X86
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
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<th>Reporter</th>
<td>paulsson@linux.vnet.ibm.com
</td>
</tr>
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<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
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<p>
<div>
<pre>test/CodeGen/X86/copy-eflags.ll contains a function PR37100 which results in
this bug.
This was exposed by the (temporarily reverted) machine verifier improvement for
live-in lists (see <a href="https://reviews.llvm.org/D68267">https://reviews.llvm.org/D68267</a> which also has some
discussion about this test case).
<a href="https://reviews.llvm.org/D71375">https://reviews.llvm.org/D71375</a> is a suggested patch for
X86FlagsCopyLowering.cpp.
# After X86 EFLAGS copy lowering
bb.1.bb1:
...
TEST8rr %23:gr8, %23:gr8, implicit-def $eflags
JCC_1 %bb.3, 5, implicit killed $eflags
bb.2.bb1:
; predecessors: %bb.1
successors: %bb.3(0x80000000); %bb.3(100.00%)
liveins: $eflags</pre>
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