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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - Upper 8 registers are no longer available to asm statement" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D23955&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=ZvNRW0MpOrhrj1TxuoQ50nadsctVMOMFro52-HNLVdk&s=u_W9QXF8yh4BXtYE7l7X5YuD2pcR0MYel9WLd2alTn0&e=">23955</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Upper 8 registers are no longer available to asm statement
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>hjl.tools@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, matze@braunis.de
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Before r239309, this works:
[hjl@gnu-32 bin]$ cat x.c
void
foo (int p)
{
register int reg __asm__("r8") = p;
__asm__ __volatile__("# %0" : : "r" (reg));
}
[hjl@gnu-32 bin]$ ./clang -S -O2 x.c
[hjl@gnu-32 bin]$ cat x.s
.text
.file "x.c"
.globl foo
.align 16, 0x90
.type foo,@function
foo: # @foo
.cfi_startproc
# BB#0:
movl %edi, %r8d
#APP
#NO_APP
retq
.Lfunc_end0:
.size foo, .Lfunc_end0-foo
.cfi_endproc
Now, I got
[hjl@gnu-6 bin]$ ./clang -S -O2 x.c
x.c:5:24: error: couldn't allocate input reg for constraint '{r8}'
__asm__ __volatile__("# %0" : : "r" (reg));
^
1 error generated.
[hjl@gnu-6 bin]$
If I use "r8d", I get
[hjl@gnu-6 bin]$ cat x.c
void
foo (int p)
{
register int reg __asm__("r8d") = p;
__asm__ __volatile__("# %0" : : "r" (reg));
}
[hjl@gnu-6 bin]$ ./clang -S -O2 x.c
x.c:4:28: error: unknown register name 'r8d' in asm
register int reg __asm__("r8d") = p;
^
1 error generated.
[hjl@gnu-6 bin]$</pre>
</div>
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