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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - O(n^2) behavior building debug info for large structs"
href="https://bugs.llvm.org/show_bug.cgi?id=34562">34562</a>
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<th>Summary</th>
<td>O(n^2) behavior building debug info for large structs
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<th>Product</th>
<td>libraries
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<th>Version</th>
<td>5.0
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>DebugInfo
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>djones@xtreme-eda.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
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<pre>My application can at times create structs with 100,000+ members. It appears
that generating debug info for these structs has quadratic-ish behavior.
The attached IR file contains no code, however, it takes several minutes to
load into opt/llc due to the large amount of debug info.
It appears that uniquing metadata is O(N), and when you have N items of
metadata, the whole process is O(N^2) which is noticeable for large N.
I found this originally with LLVM 3.9, but it is also present in 5.0 rc2, and
likely in the 5.0 release.</pre>
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