[clang] [llvm] [SystemZ] Add support for half (fp16) (PR #109164)

[Jonas Paulsson via cfe-commits]

JonPsson1 wrote:

Patch updated after some progress...

With this version, the fp16 values are passed to conversion functions as integer, which seems to be the default. It is however a bit tricky to do this and at the same time pass half values in FP registers.

At this point I wonder for one thing if it would be better to pass FP16 values to the conversion functions as _Float16 instead? It seems this may be possible to change in the configurations by looking at COMPILER_RT_HAS_FLOAT16 / compiler-rt/lib/builtins/extendhfsf2.c / fp_extend.h...

Not really sure if those conversion functions are supposed to be built and only used for soft-promotion of fp16, or if there are any external implications, for instance gcc compatability.

Any other comments also welcome...



https://github.com/llvm/llvm-project/pull/109164