commit 2a6addb4f931eb4256804486aa679fd007cb2fff
author Deven Desai <deven.desai.amd@gmail.com> Fri Jan 08 18:04:40 2021 +0000
committer Deven Desai <deven.desai.amd@gmail.com> Fri Jan 08 18:04:40 2021 +0000
tree 25e637978cc71124334bfad1d2ba8538942f24c5
parent f149e0ebc3d3d5ca63234e58ca72690caf07e3b5

Fix for breakage in ROCm support - 210108

The following commit breaks ROCm support for Eigen
https://gitlab.com/libeigen/eigen/-/commit/f149e0ebc3d3d5ca63234e58ca72690caf07e3b5

All unit tests fail with the following error

```
Building HIPCC object test/CMakeFiles/gpu_basic.dir/gpu_basic_generated_gpu_basic.cu.o
In file included from /home/rocm-user/eigen/test/gpu_basic.cu:19:
In file included from /home/rocm-user/eigen/test/main.h:356:
In file included from /home/rocm-user/eigen/Eigen/QR:11:
In file included from /home/rocm-user/eigen/Eigen/Core:166:
/home/rocm-user/eigen/Eigen/src/Core/MathFunctionsImpl.h:105:35: error: __host__ __device__ function 'complex_sqrt' cannot overload __host__ function 'complex_sqrt'
EIGEN_DEVICE_FUNC std::complex<T> complex_sqrt(const std::complex<T>& z) {
                                  ^
/home/rocm-user/eigen/Eigen/src/Core/MathFunctions.h:342:38: note: previous declaration is here
template<typename T> std::complex<T> complex_sqrt(const std::complex<T>& a_x);
                                     ^
1 error generated when compiling for gfx900.
CMake Error at gpu_basic_generated_gpu_basic.cu.o.cmake:192 (message):
  Error generating file
  /home/rocm-user/eigen/build/test/CMakeFiles/gpu_basic.dir//./gpu_basic_generated_gpu_basic.cu.o

test/CMakeFiles/gpu_basic.dir/build.make:63: recipe for target 'test/CMakeFiles/gpu_basic.dir/gpu_basic_generated_gpu_basic.cu.o' failed
make[3]: *** [test/CMakeFiles/gpu_basic.dir/gpu_basic_generated_gpu_basic.cu.o] Error 1
CMakeFiles/Makefile2:16618: recipe for target 'test/CMakeFiles/gpu_basic.dir/all' failed
make[2]: *** [test/CMakeFiles/gpu_basic.dir/all] Error 2
CMakeFiles/Makefile2:16625: recipe for target 'test/CMakeFiles/gpu_basic.dir/rule' failed
make[1]: *** [test/CMakeFiles/gpu_basic.dir/rule] Error 2
Makefile:5401: recipe for target 'gpu_basic' failed
make: *** [gpu_basic] Error 2

```

The error message is accurate, and the fix (provided in thsi commit) is trivial.