[RISCV] [1/2] Add intrinsic for Zbc extension

[LevyHsu]

Summary

Head files are included in the second patch in case the name needs to be changed.

RV32 / 64:
clmul
clmulh
clmulr

[craig.topper]

clang/include/clang/Basic/BuiltinsRISCV.def

22

I think we should drop the underscore in clmul_h and clmul_r. The mnemonic doesn't have a period between them. So that's different than orc.b and crc32.w.

llvm/include/llvm/IR/IntrinsicsRISCV.td

82

clmul_h -> clmulh
clmul_r -> clmulr

[LevyHsu]

1. clang/include/clang/Basic/BuiltinsRISCV.def clang/lib/CodeGen/CGBuiltin.cpp llvm/include/llvm/IR/IntrinsicsRISCV.td clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbc.c clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbc.c
   • Renaming clmul_h clmul_r to clmulh clmulr

2. llvm/test/CodeGen/RISCV/rv32zbc-intrinsic.ll llvm/test/CodeGen/RISCV/rv64zbc-intrinsic.ll
   • Renaming clmul.h clmul.r to clmulh clmulr

[craig.topper]

LGTM. We can adjust the builtin names in the future if we need to do something different to match gcc.