llvm-project

104f3c18 - Reland "[flang][runtime] Use cuda::std::complex in F18 runtime CUDA build. (#109078)" (#109207)

Reland "[flang][runtime] Use cuda::std::complex in F18 runtime CUDA build. (#109078)" (#109207) `std::complex` operators do not work for the CUDA device compilation of F18 runtime. This change makes use of `cuda::std::complex` from `libcudacxx`. `cuda::std::complex` does not have specializations for `long double`, so the change is accompanied with a clean-up for `long double` usage. Additional change on top of #109078 is to use `cuda::std::complex` only for the device compilation, otherwise the host compilation fails because `libcudacxx` may not support `long double` specialization at all (depending on the compiler).