RISC-V: Fix riscv_vector_chunks configuration according to TARGET_MIN_VLEN

  From: zhongjuzhe <juzhe.zhong@rivai.ai>

gcc/ChangeLog:

        * config/riscv/riscv.cc (riscv_convert_vector_bits): Change configuration according to TARGET_MIN_VLEN.
        * config/riscv/riscv.h (UNITS_PER_FP_REG): Fix annotation.

---
 gcc/config/riscv/riscv.cc | 11 ++++++-----
 gcc/config/riscv/riscv.h  |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)
  

Thanks, pushed with a few minor style fixes.

On Tue, Aug 30, 2022 at 9:51 AM <juzhe.zhong@rivai.ai> wrote:
>
> From: zhongjuzhe <juzhe.zhong@rivai.ai>
>
> gcc/ChangeLog:
>
>         * config/riscv/riscv.cc (riscv_convert_vector_bits): Change configuration according to TARGET_MIN_VLEN.
>         * config/riscv/riscv.h (UNITS_PER_FP_REG): Fix annotation.
>
> ---
>  gcc/config/riscv/riscv.cc | 11 ++++++-----
>  gcc/config/riscv/riscv.h  |  2 +-
>  2 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> index 4d439e15392..ef606f33983 100644
> --- a/gcc/config/riscv/riscv.cc
> +++ b/gcc/config/riscv/riscv.cc
> @@ -5219,14 +5219,15 @@ riscv_init_machine_status (void)
>  static poly_uint16
>  riscv_convert_vector_bits (void)
>  {
> -  /* The runtime invariant is only meaningful when vector is enabled. */
> +  /* The runtime invariant is only meaningful when TARGET_VECTOR is enabled. */
>    if (!TARGET_VECTOR)
>      return 0;
>
> -  if (TARGET_VECTOR_ELEN_64 || TARGET_VECTOR_ELEN_FP_64)
> +  if (TARGET_MIN_VLEN > 32)
>      {
> -      /* When targetting Zve64* (ELEN = 64) extensions, we should use 64-bit
> -        chunk size. Runtime invariant: The single indeterminate represent the
> +      /* When targetting minimum VLEN > 32, we should use 64-bit chunk size.
> +         Otherwise we can not include sew = 64bits.
> +        Runtime invariant: The single indeterminate represent the
>          number of 64-bit chunks in a vector beyond minimum length of 64 bits.
>          Thus the number of bytes in a vector is 8 + 8 * x1 which is
>          riscv_vector_chunks * 8 = poly_int (8, 8). */
> @@ -5234,7 +5235,7 @@ riscv_convert_vector_bits (void)
>      }
>    else
>      {
> -      /* When targetting Zve32* (ELEN = 32) extensions, we should use 32-bit
> +      /* When targetting minimum VLEN = 32, we should use 32-bit
>          chunk size. Runtime invariant: The single indeterminate represent the
>          number of 32-bit chunks in a vector beyond minimum length of 32 bits.
>          Thus the number of bytes in a vector is 4 + 4 * x1 which is
> diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
> index 1d8139c2c9b..29582f7c545 100644
> --- a/gcc/config/riscv/riscv.h
> +++ b/gcc/config/riscv/riscv.h
> @@ -160,7 +160,7 @@ ASM_MISA_SPEC
>
>  /* The `Q' extension is not yet supported.  */
>  #define UNITS_PER_FP_REG (TARGET_DOUBLE_FLOAT ? 8 : 4)
> -/* Size per vector register. For zve32*, size = poly (4, 4). Otherwise, size = poly (8, 8). */
> +/* Size per vector register. For VLEN = 32, size = poly (4, 4). Otherwise, size = poly (8, 8). */
>  #define UNITS_PER_V_REG (riscv_vector_chunks * riscv_bytes_per_vector_chunk)
>
>  /* The largest type that can be passed in floating-point registers.  */
> --
> 2.36.1
>