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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Thread safety analysis very slow in long functions because of LocalVariableMap"
href="https://bugs.llvm.org/show_bug.cgi?id=43311">43311</a>
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<th>Summary</th>
<td>Thread safety analysis very slow in long functions because of LocalVariableMap
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>trunk
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<th>Hardware</th>
<td>All
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Frontend
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>aaronpuchert@alice-dsl.net
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<p>
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<pre>The LocalVariableMap data structure keeps a set of life values for every
program point, which can be prohibitively expensive for very long functions.
Since the entire state is copied over for every modification, the complexity is
O(n^2) in the worst case. Of course long functions are not good programming
style, but they occur.
Currently the map is only used to find out if branch expressions are related to
the result of a try-acquire function call. That doesn't require tracking all
values in the program though.</pre>
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