RISC-V: Simplify codes of changing vsetvl instruction

From: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>

This patch is NFC patch. I move these code as a function since we will
reuse it in the following patch (Refine phase 3 of VSETVL PASS)

gcc/ChangeLog:

        * config/riscv/riscv-vsetvl.cc (change_vsetvl_insn): New function.
        (pass_vsetvl::compute_global_backward_infos): Simplify codes.

---
 gcc/config/riscv/riscv-vsetvl.cc | 36 ++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 16 deletions(-)

committed, thanks.

On Tue, Jan 3, 2023 at 3:25 PM <juzhe.zhong@rivai.ai> wrote:

> From: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>
>
> This patch is NFC patch. I move these code as a function since we will
> reuse it in the following patch (Refine phase 3 of VSETVL PASS)
>
> gcc/ChangeLog:
>
>         * config/riscv/riscv-vsetvl.cc (change_vsetvl_insn): New function.
>         (pass_vsetvl::compute_global_backward_infos): Simplify codes.
>
> ---
>  gcc/config/riscv/riscv-vsetvl.cc | 36 ++++++++++++++++++--------------
>  1 file changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/gcc/config/riscv/riscv-vsetvl.cc
> b/gcc/config/riscv/riscv-vsetvl.cc
> index fe76bea297e..6dbaea32b03 100644
> --- a/gcc/config/riscv/riscv-vsetvl.cc
> +++ b/gcc/config/riscv/riscv-vsetvl.cc
> @@ -880,6 +880,25 @@ change_insn (function_info *ssa, insn_change change,
> insn_info *insn,
>    return true;
>  }
>
> +static void
> +change_vsetvl_insn (const insn_info *insn, const vector_insn_info &info)
> +{
> +  rtx_insn *rinsn;
> +  if (vector_config_insn_p (insn->rtl ()))
> +    {
> +      rinsn = insn->rtl ();
> +      gcc_assert (vsetvl_insn_p (rinsn) && "Can't handle X0, rs1 vsetvli
> yet");
> +    }
> +  else
> +    {
> +      gcc_assert (has_vtype_op (insn->rtl ()));
> +      rinsn = PREV_INSN (insn->rtl ());
> +      gcc_assert (vector_config_insn_p (rinsn));
> +    }
> +  rtx new_pat = gen_vsetvl_pat (rinsn, info);
> +  change_insn (rinsn, new_pat);
> +}
> +
>  avl_info::avl_info (const avl_info &other)
>  {
>    m_value = other.get_value ();
> @@ -1941,7 +1960,6 @@ pass_vsetvl::compute_global_backward_infos (void)
>        /* Backward propagate to each predecessor.  */
>        FOR_EACH_EDGE (e, ei, cfg_bb->preds)
>         {
> -         rtx new_pat;
>           auto &block_info
>             = m_vector_manager->vector_block_infos[e->src->index];
>
> @@ -2011,21 +2029,7 @@ pass_vsetvl::compute_global_backward_infos (void)
>                 be_merged = block_info.local_dem;
>               vector_insn_info new_info = be_merged.merge (prop, true);
>
> -             rtx_insn *rinsn;
> -             if (vector_config_insn_p (new_info.get_insn ()->rtl ()))
> -               {
> -                 rinsn = new_info.get_insn ()->rtl ();
> -                 gcc_assert (vsetvl_insn_p (rinsn)
> -                             && "Can't handle X0, rs1 vsetvli yet");
> -               }
> -             else
> -               {
> -                 gcc_assert (has_vtype_op (new_info.get_insn ()->rtl ()));
> -                 rinsn = PREV_INSN (new_info.get_insn ()->rtl ());
> -                 gcc_assert (vector_config_insn_p (rinsn));
> -               }
> -             new_pat = gen_vsetvl_pat (rinsn, new_info);
> -             change_insn (rinsn, new_pat);
> +             change_vsetvl_insn (new_info.get_insn (), new_info);
>               if (block_info.local_dem == block_info.reaching_out)
>                 block_info.local_dem = new_info;
>               block_info.reaching_out = new_info;
> --
> 2.36.3
>
>