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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [[no_unique_address]] on array of class takes compilation time and memory linear in size of array"
href="https://bugs.llvm.org/show_bug.cgi?id=49809">49809</a>
</td>
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<th>Summary</th>
<td>[[no_unique_address]] on array of class takes compilation time and memory linear in size of array
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
</td>
</tr>
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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>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++17
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>davidfromonline@gmail.com
</td>
</tr>
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<th>CC</th>
<td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
</td>
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<p>
<div>
<pre>The following translation unit
```
struct s {
// Doesn't have to be empty
};
struct array {
[[no_unique_address]] s m_value[1'000'000'000ULL];
};
void f() {
array a;
}
```
eventually crashes with out of memory, but if it were to compile it would have
taken approximately 45 seconds on my machine with `clang++ -std=c++17 -c
test.cpp`. Based on the progression from smaller array sizes, making the array
10x larger would make it take about 450 seconds.
Just reproduced with latest commit
```
<span class="quote">> clang++ --version</span >
clang version 13.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
0f7e3a55463d2ed9abc60c6fd0126bcb19fc6d69)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/david/llvm/build/bin
```</pre>
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