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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang does not fully grok 'register asm("x")' declarations for powerpc"
href="https://bugs.llvm.org/show_bug.cgi?id=44435">44435</a>
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<th>Summary</th>
<td>clang does not fully grok 'register asm("x")' declarations for powerpc
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>9.0
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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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>LLVM Codegen
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>chmeeedalf@gmail.com
</td>
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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>
<div>
<pre>This may be a general bug, but I've only tested on powerpc64.
libreoffice uses asm register allocations a'la:
register long r3 asm("r3");
With gcc, it allocates register r3 to the variable, but clang ignores the asm
bit, and treats it as an uninitialized variable, leading to crashes in
libreoffice.
A trivial example program:
#include <stdio.h>
int main(int argc, char **argv)
{
register long x asm("r3");
printf("%ld, %d\n", x, argc);
return (0);
}
Built with clang:
[chmeee@ralga:pts/12]:~> ./test_regasm
4611686018427378136, 1
Built with gcc9:
[chmeee@ralga:pts/12]:~> ./test_regasm
1, 1
r3 on entry is argc, so it should print 1 for both arguments.</pre>
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