CMake: Always CUDA Perf-Neutral Debug

[ax3l]

Summary

Always default-ON for performance-neutral debug info to CUDA builds with CMake, even in Release mode.

Additional background

We used RelWithDebInfo before but switched downstream to Release by default as well to avoid -O2/-O3 complications in flags.

Checklist

The proposed changes:

• fix a bug or incorrect behavior in AMReX
• add new capabilities to AMReX
• changes answers in the test suite to more than roundoff level
• are likely to significantly affect the results of downstream AMReX users
• include documentation in the code and/or rst files, if appropriate

[WeiqunZhang]

@maxpkatz What does --source-in-ptx do? The nvcc documentation on this is simply

Interleave source in PTX.
May only be used in conjunction with --device-debug or --generate-line-info.

[maximumcats]

What does --source-in-ptx do?

The PTX will be annotated with the lines of source it corresponds to. It uses the same underlying functionality as what -lineinfo does, so it doesn't add anything new, but it does allow you to directly inspect the generated PTX (if you use -keep) and see the annotations. There isn't really any reason for an end user to use it that I can think of, since I assume end users don't normally inspect PTX directly but rather would use Nsight Compute for understanding kernels.