Re: [PATCH] RISC-V: Add function comment for cleanup_insns.

[Kito Cheng <kito.cheng@gmail.com>]

Pushed

On Sun, Apr 23, 2023 at 7:34 PM <juzhe.zhong@rivai.ai> wrote:
>
> From: Juzhe-Zhong <juzhe.zhong@rivai.ai>
>
> Address Jeff's comment: https://patchwork.sourceware.org/project/gcc/patch/20230330012804.110539-1-juzhe.zhong@rivai.ai/
> Add a function comment.
>
> gcc/ChangeLog:
>
>         * config/riscv/riscv-vsetvl.cc (pass_vsetvl::pre_vsetvl): Add function comment for cleanup_insns.
>
> ---
>  gcc/config/riscv/riscv-vsetvl.cc | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/gcc/config/riscv/riscv-vsetvl.cc b/gcc/config/riscv/riscv-vsetvl.cc
> index ac99028df43..fa68b8a0462 100644
> --- a/gcc/config/riscv/riscv-vsetvl.cc
> +++ b/gcc/config/riscv/riscv-vsetvl.cc
> @@ -3998,6 +3998,21 @@ pass_vsetvl::pre_vsetvl (void)
>      commit_edge_insertions ();
>  }
>
> +/* Before VSETVL PASS, RVV instructions pattern is depending on AVL operand
> +   implicitly. Since we will emit VSETVL instruction and make RVV instructions
> +   depending on VL/VTYPE global status registers, we remove the such AVL operand
> +   in the RVV instructions pattern here in order to remove AVL dependencies when
> +   AVL operand is a register operand.
> +
> +   Before the VSETVL PASS:
> +     li a5,32
> +     ...
> +     vadd.vv (..., a5)
> +   After the VSETVL PASS:
> +     li a5,32
> +     vsetvli zero, a5, ...
> +     ...
> +     vadd.vv (..., const_int 0).  */
>  void
>  pass_vsetvl::cleanup_insns (void) const
>  {
> --
> 2.36.1
>