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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] fp16 neon intrinsics are available even the target doesn't support fp16"
href="https://llvm.org/bugs/show_bug.cgi?id=27550">27550</a>
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<th>Summary</th>
<td>[ARM] fp16 neon intrinsics are available even the target doesn't support fp16
</td>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>-New Bugs
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>silviu.baranga@arm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<th>Classification</th>
<td>Unclassified
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</tr></table>
<p>
<div>
<pre>The following code:
#include <arm_neon.h>
float16x4_t f(float32x4_t x) {
return vcvt_f16_f32(x);
}
compiled with:
clang -target armv7-linux-gnueabi -mfpu=neon rep.c
-I/usr/include/arm-linux-gnueabihf -mfloat-abi=hard
triggers an assert in instruction selection:
fatal error: error in backend: Cannot select: intrinsic
%llvm.arm.neon.vcvtfp2hf
This is because we're using the vcvt_f16_f32 intrinsic and defined the fpu to
be neon (not neon-fp16), and therefore the target doesn't support the f16 vcvt
instruction.
We should be emitting an error in the frontend instead.</pre>
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