[PATCH] D61949: [OpenMP][bugfix] Fix issues with C++ 17 compilation when handling math functions

[Artem Belevich via Phabricator via cfe-commits]

tra added inline comments.


================
Comment at: lib/Headers/__clang_cuda_device_functions.h:1477
 #endif // CUDA_VERSION >= 9020
+#if __cplusplus >= 201703L
+__DEVICE__ int abs(int __a) noexcept { return __nv_abs(__a); }
----------------
jdoerfert wrote:
> Hahnfeld wrote:
> > If I recall correctly, `__cplusplus` is not defined in C mode, so both GCC and Clang will issue a warning with `-Wundef`.
> > 
> > Maybe this can be solved with something similar to:
> > ```lang=c
> > #ifdef __cplusplus
> > #define cpp_version __cplusplus
> > #else
> > #define cpp_version 0
> > #endif
> > ```
> > (to avoid repetition of `#if defined(__cplusplus) && __cplusplus >= 201703L`)
> I dislike defining the version and advice to repeating `#if defined(__cplusplus) && __cplusplus >= 201703L)`
> 
I agree with @jdoerfert.
If that's needed too often, we can move c++-only functions under one global `#if defined(__cplusplus)`.



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Comment at: lib/Headers/__clang_cuda_device_functions.h:1579-1586
+#if __cplusplus >= 201703L
+__DEVICE__ long labs(long __a) noexcept { return __nv_llabs(__a); };
+#else
 __DEVICE__ long labs(long __a) { return __nv_llabs(__a); };
+#endif
+#else
+#if __cplusplus >= 201703L
----------------
This is typically dealt with by defining and using a macro which would expand to `noexcept` or to nothing.
E.g. something like [[ https://github.com/llvm-mirror/libcxx/blob/dbd4f51025003a7c869c4e5267ab8780e91367d5/include/__config#L848 | what libcxx does ]].

This should reduce the number of needed `#if`.


Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D61949/new/

https://reviews.llvm.org/D61949