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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Aggregates containing elements with constexpr constructors are not statically initalized"
href="https://bugs.llvm.org/show_bug.cgi?id=45367">45367</a>
</td>
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<th>Summary</th>
<td>Aggregates containing elements with constexpr constructors are not statically initalized
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>10.0
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++2a
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>billy.oneal@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>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=23295" name="attach_23295" title="repro.cpp">attachment 23295</a> <a href="attachment.cgi?id=23295&action=edit" title="repro.cpp">[details]</a></span>
repro.cpp
Previously reported as <a href="https://github.com/microsoft/STL/issues/661">https://github.com/microsoft/STL/issues/661</a>
In the following example, should_be_statically_initalized should be eligible
for static initialization, then the dynamic initializer for foo that calls
bar() should run, resulting in the asserts in main(). However, clang only seems
to give these static initializers if the varaible is {}'d.
C:\Users\billy\Desktop>type repro.cpp
#include <assert.h>
struct FakeAtomic {
int example;
constexpr FakeAtomic() noexcept : example{} {}
int operator++() { return ++example; }
int operator++(int) { return example++; }
int load() const { return example; }
};
struct Meow {
FakeAtomic data[2];
char padding[64];
};
int bar();
int foo = bar();
#ifdef WORKAROUND
Meow should_be_statically_initalized[256]{};
#else
Meow should_be_statically_initalized[256];
#endif
int bar() { return should_be_statically_initalized[0].data[0]++; }
int main() {
assert(foo == 0);
assert(should_be_statically_initalized[0].data[0].load() == 1);
}
C:\Users\billy\Desktop>clang-cl /EHsc /W4 /WX .\repro.cpp
C:\Users\billy\Desktop>.\repro.exe
Assertion failed: should_be_statically_initalized[0].data[0].load() == 1, file
.\repro.cpp, line 30
C:\Users\billy\Desktop>clang-cl /DWORKAROUND /EHsc /W4 /WX .\repro.cpp
C:\Users\billy\Desktop>.\repro.exe
C:\Users\billy\Desktop></pre>
</div>
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