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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - [X86] Inline assembly operands don't work with .intel_syntax" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24232&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=dBwRkzZlLeE1jFd19BXC0PI9QCkLdPyxptNc0JUnqNY&s=-UlNN8MtYgnuV61WEj0aI-sNrdght43VqUFfrqC6jWo&e=">24232</a>
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<th>Summary</th>
<td>[X86] Inline assembly operands don't work with .intel_syntax
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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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>Backend: X86
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>rnk@google.com
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, noloader@gmail.com, rafael.espindola@gmail.com, yuri@tsoft.com
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<th>Classification</th>
<td>Unclassified
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</tr></table>
<p>
<div>
<pre>Consider this C code:
int mynegation(int r) {
__asm(".intel_syntax\n"
"negl %0\n"
: "=r"(r)
: "0"(r));
return r;
}
It gives this IR:
define i32 @mynegation(i32 %r) {
entry:
%0 = tail call i32 asm ".intel_syntax\0Anegl $0\0A",
"=r,0,~{dirflag},~{fpsr},~{flags}"(i32 %r)
ret i32 %0
}
Our inline asm operand support expands the $0 operand as '%ecx' and then
attempts to re-parse the inline assembly. This fails, because '%ecx' should not
have the percent in intel style assembly. We get this error:
<inline asm>:2:6: error: unknown token in expression
negl %ecx
^
Our current inline assembly support works by running the operands through the
old AsmPrinter infrastructure and then re-parsing with MC. If instead we could
teach the MC asm parser how to tolerate symbolic operands, we could fix this
problem without worrying about .intel_syntax directives.
Alternatively, we could hack the intel syntax parser to be OK with %. GCC
probably does this.</pre>
</div>
</p>
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