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<head>
<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - LICM segafaults on simple generated file (a lot of empty loops)"
href="https://bugs.llvm.org/show_bug.cgi?id=34066">34066</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>LICM segafaults on simple generated file (a lot of empty loops)
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>3.9
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Windows NT
</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>Loop Optimizer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>konstantin.vladimirov@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Use clang 3.9.0
clang++ -v
clang version 3.9.0 (tags/RELEASE_390/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Compile attached file with
clang++ -S -O2 out.c
You will see:
0 clang-4.0 0x00000000011c44d0
llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 32
1 clang-4.0 0x00000000011c2285 llvm::sys::RunSignalHandlers() + 69
2 clang-4.0 0x00000000011c23bc
3 libpthread.so.0 0x00007ffff7bcf850
4 clang-4.0 0x000000000104d983
llvm::sinkRegion(llvm::DomTreeNodeBase<llvm::BasicBlock>*, llvm::AAResults*,
llvm::LoopInfo*, llvm::DominatorTree*, llvm::TargetLibraryInfo*, llvm::Loop*,
llvm::AliasSetTracker*, llvm::LoopSafetyInfo*,
llvm::OptimizationRemarkEmitter*) + 35
5 clang-4.0 0x000000000104da53
llvm::sinkRegion(llvm::DomTreeNodeBase<llvm::BasicBlock>*, llvm::AAResults*,
llvm::LoopInfo*, llvm::DominatorTree*, llvm::TargetLibraryInfo*, llvm::Loop*,
llvm::AliasSetTracker*, llvm::LoopSafetyInfo*,
llvm::OptimizationRemarkEmitter*) + 243
6 clang-4.0 0x000000000104da53
llvm::sinkRegion(llvm::DomTreeNodeBase<llvm::BasicBlock>*, llvm::AAResults*,
llvm::LoopInfo*, llvm::DominatorTree*, llvm::TargetLibraryInfo*, llvm::Loop*,
llvm::AliasSetTracker*, llvm::LoopSafetyInfo*,
llvm::OptimizationRemarkEmitter*) + 243
7 clang-4.0 0x000000000104da53
llvm::sinkRegion(llvm::DomTreeNodeBase<llvm::BasicBlock>*, llvm::AAResults*,
llvm::LoopInfo*, llvm::DominatorTree*, llvm::TargetLibraryInfo*, llvm::Loop*,
llvm::AliasSetTracker*, llvm::LoopSafetyInfo*,
llvm::OptimizationRemarkEmitter*) + 243
File is generated with following ruby script:
class IfNode
end
class ForNode
end
class LeafNode
end
class Node
attr_reader :value
attr_reader :childs
def initialize(value, childs)
@value = value
@childs = childs
end
end
def create_node(nlev)
ret = nil
if nlev > 0
value = (rand(2) == 1 ? IfNode.new : ForNode.new)
nchilds = rand(10) + 1
childs = Array.new(nchilds) {create_node(nlev-1)}
ret = Node.new(value, childs)
end
ret = Node.new(LeafNode.new, nil) if ret.nil?
ret
end
def print_node(n)
unless n.value.is_a?(LeafNode)
puts "if (true) {" if n.value.is_a?(IfNode)
puts "for (int i = 1; i < 1000; ++i) {" if n.value.is_a?(ForNode)
n.childs.map { |c| print_node c }
puts "}"
end
end
top = create_node(8)
puts "void foo() {"
print_node top
puts "}"
i.e. it is guaranteed to be 8 levels of nesting with no more then 11 childs for
each node.
GCC eats such output just fine.</pre>
</div>
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