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

[Trevor Gross via cfe-commits]

tgross35 wrote:

To clarify, the code is calling `__extendhfdf2` then `__truncdfhf2` from either libgcc or from compiler-rt with your patches, and the compiler-rt version is incorrect? Could you have it print the intermediate results as u16 hex (`Op0 + Op1`, `Res2`, `Res`)?

Not sure if you are testing only on s390x but there should probably be a unit test at https://github.com/llvm/llvm-project/tree/d90423e310482bdbc731242fa25dcb3dd44e69de/compiler-rt/test/builtins/Unit to see if things work on other platforms.

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