Align complex types to total size of both components

[wmaxey]

No description provided.

[griwes]

The alignment must be conditional on the abi version. See

libcudacxx/libcxx/include/barrier

Line 200 in 4b1a1df

# if _LIBCUDACXX_CUDA_ABI_VERSION < 3

for prior art.

[griwes]

Wouldn't a simpler change of just slapping alignas(2*sizeof(T)) on complex itself work?

[griwes]

This also needs tests that verify the alignments for both the old abi versions and the new one; there's a barrier v2 abi test in heterogeneous tests that you can use as prior art for how to approach it in general.

[wmaxey]

Wouldn't a simpler change of just slapping alignas(2*sizeof(T)) on complex itself work?

Funny, I hadn't thought of that. Originally I had wrapped the members in anonymous structs, but NVRTC doesn't support that extension.

[wmaxey]

• Simplified implementation
• Added ABI version tests
• Currently passes on GCC, Clang, and NVRTC builds
  • MSVC TBD

[wmaxey]

Closing as #172 will supersede this PR.