[PATCH v2 1/1] [RISC-V] Add support for _Bfloat16

[Jeff Law]

On 4/2/24 3:22 AM, Xiao Zeng wrote:
> 1 At point <https://github.com/riscv/riscv-bfloat16>,
>    BF16 has already been completed "post public review".
> 
> 2 LLVM has also added support for RISCV BF16 in
>    <https://reviews.llvm.org/D151313> and
>    <https://reviews.llvm.org/D150929>.
> 
> 3 According to the discussion <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/367>,
>    this use __bf16 and use DF16b in riscv_mangle_type like x86.
> 
> Below test are passed for this patch
>      * The riscv fully regression test.
> 
> gcc/ChangeLog:
> 
> 	* config/riscv/iterators.md: New mode iterator HFBF.
> 	* config/riscv/riscv-builtins.cc (riscv_init_builtin_types):
> 	Initialize data type _Bfloat16.
> 	* config/riscv/riscv-modes.def (FLOAT_MODE): New.
> 	(ADJUST_FLOAT_FORMAT): New.
> 	* config/riscv/riscv.cc (riscv_mangle_type): Support for BFmode.
> 	(riscv_scalar_mode_supported_p): Ditto.
> 	(riscv_libgcc_floating_mode_supported_p): Ditto.
> 	(riscv_init_libfuncs): Set the conversion method for BFmode and
> 	HFmode.
> 	(riscv_block_arith_comp_libfuncs_for_mode): Set the arithmetic
> 	and comparison libfuncs for the mode.
> 	* config/riscv/riscv.md (mode" ): Add BF.
> 	(movhf): Support for BFmode.
> 	(mov<mode>): Ditto.
> 	(*movhf_softfloat): Ditto.
> 	(*mov<mode>_softfloat): Ditto.
> 
> libgcc/ChangeLog:
> 
> 	* config/riscv/sfp-machine.h (_FP_NANFRAC_B): New.
> 	(_FP_NANSIGN_B): Ditto.
> 	* config/riscv/t-softfp32: Add support for BF16 libfuncs.
> 	* config/riscv/t-softfp64: Ditto.
> 	* soft-fp/floatsibf.c: For si -> bf16.
> 	* soft-fp/floatunsibf.c: For unsi -> bf16.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/riscv/bf16_arithmetic.c: New test.
> 	* gcc.target/riscv/bf16_call.c: New test.
> 	* gcc.target/riscv/bf16_comparison.c: New test.
> 	* gcc.target/riscv/bf16_float_libcall_convert.c: New test.
> 	* gcc.target/riscv/bf16_integer_libcall_convert.c: New test.
Just some nits.  In t-softfp32 and t-softfp64 the code you've added 
should be using tabs, not 8 spaces, as noted by the CI "Lint Status":

https://github.com/ewlu/gcc-precommit-ci/issues/1412#issuecomment-2031568644

With that fixed, this is fine for the trunk.  No need to repost, go 
ahead and commit.

Thanks for your patience,
Jeff