[RFC][OpenCL] Testing all OpenCL builtin function declarations in clang

We would like to ask for feedback regarding testing strategies for the large

amount of OpenCL builtin function declarations.

I would like to summarise the offline discussion among OpenCL developers
regarding the testing strategies that we have chosen to implement:

  • We will go ahead with option (2) i.e. automatic generation of tests and use
    of clang invocation originally proposed in reviews.llvm.org/D97869 for the fast
    header mechanism based on the Tablegen definitions.

  • We will enhance the testing with test files added and maintained manually
    that will be checking the statistical information as explained in (2) or also
    the comparison between opencl-c.h and Tablegen description (3). The latter one
    (originally proposed in reviews.llvm.org/D99577) could also be useful to obtain
    additional coverage for opencl-c.h testing if there is enough interest while it
    is still in maintenance.

Let me know if there is any feedback on the proposed plan.