<html>
<head>
<base href="http://llvm.org/bugs/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - AsmPrinter::isBlockOnlyReachableByFallthrough() only checks register operands of a bundle instruction"
href="http://llvm.org/bugs/show_bug.cgi?id=17894">17894</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>AsmPrinter::isBlockOnlyReachableByFallthrough() only checks register operands of a bundle instruction
</td>
</tr>
<tr>
<th>Product</th>
<td>tools
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>llc
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>triple.yang@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Since llvm::finalizeBundle() only collect register operands in
lib/CodeGen/MachineInstrBundle.cpp,
AsmPrinter::isBlockOnlyReachableByFallthrough() can only check its collected
register operands, and thus miss MachineOperand like MO_MachineBasicBlock,
which will lead to to errors.
For example, instruction sequence:
########## s1 start #######
...
insn1
...
jump LBB0
...
LBB0:
...
########## s1 end ########
is packetized, insn1 and "jump LBB0" is bundled, we expect:
########### s2 start #######
...
{ insn1; jump LBB0 }
...
LBB0:
...
########### s2 end ########
Instead, lcc will generate:
########### s2' start ########
...
{ insn1; jump LBB0 }
...
#LBB0:
...
########### s2' end ########
which results in linking error saying undefined reference to LBB0 if LBB0 has
no other predecessors.
This is because AsmPrinter::isBlockOnlyReachableByFallthrough() forgets to
check MachineOperand LBB0.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>