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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Declaration conflict between __clang_cuda_math_forward_declares.h and libstdc++"
href="https://bugs.llvm.org/show_bug.cgi?id=42972">42972</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Declaration conflict between __clang_cuda_math_forward_declares.h and libstdc++
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>CUDA
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jonathanchesterfield@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Tagged as cuda, but the problem may only reproduce from openmp.
The abs definition introduced in <a href="https://reviews.llvm.org/D62046">https://reviews.llvm.org/D62046</a> breaks
<iostream> and <algorithm> when mixed with libstdc++ 7.4 and openmp, e.g.
test.cpp:
`#include <iostream>`
~/llvm-install/bin/clang++ -std=c++11 -fopenmp
-fopenmp-targets=nvptx64-nvidia-cuda -Xopenmp-target=nvptx64-nvidia-cuda
-march=sm_50 -nocudalib -o test.x test.cpp
abs returning a const value seems a bit weird, I don't follow the reasoning in
the diff that makes this necessary.
```
In file included from
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/algorithm:62:
In file included from
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/bits/stl_algo.h:59:
In file included from
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/cstdlib:77:
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/bits/std_abs.h:70:3:
error:
declaration conflicts with target of using declaration already in scope
abs(double __x)
^
/home/jon/llvm-install/lib/clang/10.0.0/include/__clang_cuda_math_forward_declares.h:50:25:
note:
target of using declaration
__DEVICE__ const double abs(const double);
^
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/bits/std_abs.h:52:11:
note: using
declaration
using ::abs;
^
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/bits/std_abs.h:74:3:
error:
declaration conflicts with target of using declaration already in scope
abs(float __x)
^
/home/jon/llvm-install/lib/clang/10.0.0/include/__clang_cuda_math_forward_declares.h:51:24:
note:
target of using declaration
__DEVICE__ const float abs(const float);
^
/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/bits/std_abs.h:52:11:
note: using
declaration
using ::abs;
^
2 errors generated.
```</pre>
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