Committed with an extra testcase from PR109547
https://gcc.gnu.org/pipermail/gcc-patches/2023-April/616363.html
On Fri, Apr 7, 2023 at 9:34 AM <juzhe.zh...@rivai.ai> wrote:
>
> From: Juzhe-Zhong <juzhe.zh...@rivai.ai>
>
> This patch is to enhance optimization for auto-vectorization.
>
> Before this patch:
>
> Loop:
> vsetvl a5,a2...
> vsetvl zero,a5...
> vle
>
> After this patch:
>
> Loop:
> vsetvl a5,a2
> vle
>
> gcc/ChangeLog:
>
> * config/riscv/riscv-vsetvl.cc (local_eliminate_vsetvl_insn): New
> function.
> (vector_insn_info::skip_avl_compatible_p): Ditto.
> (vector_insn_info::merge): Remove default value.
> (pass_vsetvl::compute_local_backward_infos): Ditto.
> (pass_vsetvl::cleanup_insns): Add local vsetvl elimination.
> * config/riscv/riscv-vsetvl.h: Ditto.
>
> ---
> gcc/config/riscv/riscv-vsetvl.cc | 71 +++++++++++++++++++++++++++++++-
> gcc/config/riscv/riscv-vsetvl.h | 1 +
> 2 files changed, 70 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/config/riscv/riscv-vsetvl.cc
> b/gcc/config/riscv/riscv-vsetvl.cc
> index 7e8a5376705..b402035f7a5 100644
> --- a/gcc/config/riscv/riscv-vsetvl.cc
> +++ b/gcc/config/riscv/riscv-vsetvl.cc
> @@ -1054,6 +1054,51 @@ change_vsetvl_insn (const insn_info *insn, const
> vector_insn_info &info)
> change_insn (rinsn, new_pat);
> }
>
> +static void
> +local_eliminate_vsetvl_insn (const vector_insn_info &dem)
> +{
> + const insn_info *insn = dem.get_insn ();
> + if (!insn || insn->is_artificial ())
> + return;
> + rtx_insn *rinsn = insn->rtl ();
> + const bb_info *bb = insn->bb ();
> + if (vsetvl_insn_p (rinsn))
> + {
> + rtx vl = get_vl (rinsn);
> + for (insn_info *i = insn->next_nondebug_insn ();
> + real_insn_and_same_bb_p (i, bb); i = i->next_nondebug_insn ())
> + {
> + if (i->is_call () || i->is_asm ()
> + || find_access (i->defs (), VL_REGNUM)
> + || find_access (i->defs (), VTYPE_REGNUM))
> + return;
> +
> + if (has_vtype_op (i->rtl ()))
> + {
> + if (!vsetvl_discard_result_insn_p (PREV_INSN (i->rtl ())))
> + return;
> + rtx avl = get_avl (i->rtl ());
> + if (avl != vl)
> + return;
> + set_info *def = find_access (i->uses (), REGNO (avl))->def ();
> + if (def->insn () != insn)
> + return;
> +
> + vector_insn_info new_info;
> + new_info.parse_insn (i);
> + if (!new_info.skip_avl_compatible_p (dem))
> + return;
> +
> + new_info.set_avl_info (dem.get_avl_info ());
> + new_info = dem.merge (new_info, LOCAL_MERGE);
> + change_vsetvl_insn (insn, new_info);
> + eliminate_insn (PREV_INSN (i->rtl ()));
> + return;
> + }
> + }
> + }
> +}
> +
> static bool
> source_equal_p (insn_info *insn1, insn_info *insn2)
> {
> @@ -1984,6 +2029,19 @@ vector_insn_info::compatible_p (const vector_insn_info
> &other) const
> return true;
> }
>
> +bool
> +vector_insn_info::skip_avl_compatible_p (const vector_insn_info &other) const
> +{
> + gcc_assert (valid_or_dirty_p () && other.valid_or_dirty_p ()
> + && "Can't compare invalid demanded infos");
> + unsigned array_size = sizeof (incompatible_conds) / sizeof (demands_cond);
> + /* Bypass AVL incompatible cases. */
> + for (unsigned i = 1; i < array_size; i++)
> + if (incompatible_conds[i].dual_incompatible_p (*this, other))
> + return false;
> + return true;
> +}
> +
> bool
> vector_insn_info::compatible_avl_p (const vl_vtype_info &other) const
> {
> @@ -2178,7 +2236,7 @@ vector_insn_info::fuse_mask_policy (const
> vector_insn_info &info1,
>
> vector_insn_info
> vector_insn_info::merge (const vector_insn_info &merge_info,
> - enum merge_type type = LOCAL_MERGE) const
> + enum merge_type type) const
> {
> if (!vsetvl_insn_p (get_insn ()->rtl ()))
> gcc_assert (this->compatible_p (merge_info)
> @@ -2716,7 +2774,7 @@ pass_vsetvl::compute_local_backward_infos (const
> bb_info *bb)
> && !reg_available_p (insn, change))
> && change.compatible_p (info))
> {
> - info = change.merge (info);
> + info = change.merge (info, LOCAL_MERGE);
> /* Fix PR109399, we should update user vsetvl instruction
> if there is a change in demand fusion. */
> if (vsetvl_insn_p (insn->rtl ()))
> @@ -3998,6 +4056,15 @@ pass_vsetvl::cleanup_insns (void) const
> for (insn_info *insn : bb->real_nondebug_insns ())
> {
> rtx_insn *rinsn = insn->rtl ();
> + const auto &dem = m_vector_manager->vector_insn_infos[insn->uid ()];
> + /* Eliminate local vsetvl:
> + bb 0:
> + vsetvl a5,a6,...
> + vsetvl zero,a5.
> +
> + Eliminate vsetvl in bb2 when a5 is only coming from
> + bb 0. */
> + local_eliminate_vsetvl_insn (dem);
>
> if (vlmax_avl_insn_p (rinsn))
> {
> diff --git a/gcc/config/riscv/riscv-vsetvl.h b/gcc/config/riscv/riscv-vsetvl.h
> index d05472c86a0..d7a6c14e931 100644
> --- a/gcc/config/riscv/riscv-vsetvl.h
> +++ b/gcc/config/riscv/riscv-vsetvl.h
> @@ -380,6 +380,7 @@ public:
> void fuse_mask_policy (const vector_insn_info &, const vector_insn_info &);
>
> bool compatible_p (const vector_insn_info &) const;
> + bool skip_avl_compatible_p (const vector_insn_info &) const;
> bool compatible_avl_p (const vl_vtype_info &) const;
> bool compatible_avl_p (const avl_info &) const;
> bool compatible_vtype_p (const vl_vtype_info &) const;
> --
> 2.36.3
>
