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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Alignment specifier not applied to anonymous structure or union"
href="https://bugs.llvm.org/show_bug.cgi?id=43983">43983</a>
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<th>Summary</th>
<td>Alignment specifier not applied to anonymous structure or union
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>9.0
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<th>Hardware</th>
<td>Macintosh
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<th>OS</th>
<td>MacOS X
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>omrimor2@illinois.edu
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>Created <span class=""><a href="attachment.cgi?id=22802" name="attach_22802" title="minimal example">attachment 22802</a> <a href="attachment.cgi?id=22802&action=edit" title="minimal example">[details]</a></span>
minimal example
The _Alignas specifier is not being applied to anonymous structures or unions.
If the structure or union is given a declarator then the alignment specifier is
correctly applied. This is a useful construct in that it allows for alignment
of portions of a structure.
#include <stdio.h>
struct A { struct { int a; }; };
struct B { _Alignas(64) struct { int b; }; };
struct C { _Alignas(64) struct { int c; } x; };
int main(int argc, char *argv[])
{
printf("%zu %zu %zu\n",
sizeof(struct A), sizeof(struct B), sizeof(struct C));
return 0;
}
Should output "4 64 64" on an LP64 platform; instead outputs "4 4 64". GCC 9
compiles correctly. I haven't yet tested on platforms other than macOS.</pre>
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