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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 --- - ARM inline asm - cp10/cp11 rejected under armv7a" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D23998&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=qkwtrJYmCLIFfhc6OmTIQ21lQ7996WNd70i1-k1zWv8&s=EJ7NYXWPteXCsfvSYgFsy7njPK5cNFRIjFbmWvJqqGs&e=">23998</a>
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<th>Summary</th>
<td>ARM inline asm - cp10/cp11 rejected under armv7a
</td>
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<th>Product</th>
<td>clang
</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>Linux
</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>-New Bugs
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>shenhan@google.com
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>glibc macro FPU_GETCW, FPU_SETCP (see below) is rejected by clang because
ARMAsmParser thinks that cp10, cp11 is not accessible under armv7/armv8. That's
not correct for armv7a with neon/vfp feature.
According to ARMv7a Architecture Reference manual - A2.9
Any implementation that includes either or both of the Advanced SIMD extension
and the VFP extension must enable access to both CP10 and CP11.
Code reference -
<span class="quote">> sysdeps/arm/fpu__control.h</span >
#define _FPU_GETCW(cw) \
__asm__ __volatile__ ("mrc p10, 7, %0, cr1, cr0, 0" : "=r" (cw))
#define _FPU_SETCW(cw) \
__asm__ __volatile__ ("mcr p10, 7, %0, cr1, cr0, 0" : : "r" (cw))
<span class="quote">> ARMAsmParser.cpp - </span >
ARMAsmParser::OperandMatchResultTy
... ...
// ARMv7 and v8 don't allow cp10/cp11 due to VFP/NEON specific instructions
if ((hasV7Ops() || hasV8Ops()) && (Num == 10 || Num == 11))
return MatchOperand_NoMatch;</pre>
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