[test-suite] Enable CUDA complex tests with libc++ now that D25403 is resolved.

[tra]

External/CUDA/complex.cu

24

Is this specific to c++14 only, or will we have similar conditions for c++17,20, etc?
Perhaps we could express library version requirements as STDLIB_VERSION >= (__cplusplus / 100) ?
I'm OK with either way.

[jlebar]

External/CUDA/complex.cu

24

I think it's specific to c++14 -- or at least, it's not necessarily a general problem. The other benchmarks work with C++14 compiler plus C++11 stdlib -- it's just <complex> that gives us problems in the particular gcc versions we happen to use.

External/CUDA/complex.cu

 // overload of every function (so that we verify that everything compiles).
 //
 // We do care about the results of complex multiplication / division, since
 // these use code we've written.
 
 #include <stdio.h>
 
 // These tests are pretty annoying to write without C++11, so we require that.
-// In addition, these tests currently don't compile with libc++, because of the
-// issue in https://reviews.llvm.org/D25403.
-//
-// TODO: Once that issue is resolved, take out !defined(_LIBCPP_VERSION) here.
 //
 // In addition, these tests don't work in C++14 mode with pre-C++14 versions of
 // libstdc++ (compile errors in <complex>).
-#if __cplusplus >= 201103L && !defined(_LIBCPP_VERSION) && \
-    (__cplusplus < 201402L || STDLIB_VERSION >= 2014)
+#if __cplusplus >= 201103L && (__cplusplus < 201402L || STDLIB_VERSION >= 2014)
 
 #include <assert.h>
 #include <complex>
 #include <type_traits>
 
 template <class T>
 __device__ double promote(
     T, typename std::enable_if<std::is_integral<T>::value>::type* = 0);