committed with few tweaks, thanks.
On Wed, Jan 4, 2023 at 9:46 PM <juzhe.zh...@rivai.ai> wrote:
> From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
>
> gcc/ChangeLog:
>
> * config/riscv/riscv-vsetvl.cc (can_backward_propagate_p): Fix for
> null iter_bb.
> (vector_insn_info::set_demand_info): New function.
> (pass_vsetvl::emit_local_forward_vsetvls): Adjust for refinement
> of Phase 3.
> (pass_vsetvl::merge_successors): Ditto.
> (pass_vsetvl::compute_global_backward_infos): Ditto.
> (pass_vsetvl::backward_demand_fusion): Ditto.
> (pass_vsetvl::forward_demand_fusion): Ditto.
> (pass_vsetvl::demand_fusion): New function.
> (pass_vsetvl::lazy_vsetvl): Adjust for refinement of phase 3.
> * config/riscv/riscv-vsetvl.h: New function declaration.
>
> ---
> gcc/config/riscv/riscv-vsetvl.cc | 138 ++++++++++++++++++++++++++++---
> gcc/config/riscv/riscv-vsetvl.h | 1 +
> 2 files changed, 128 insertions(+), 11 deletions(-)
>
> diff --git a/gcc/config/riscv/riscv-vsetvl.cc
> b/gcc/config/riscv/riscv-vsetvl.cc
> index 52f0195980a..d42cfa91d63 100644
> --- a/gcc/config/riscv/riscv-vsetvl.cc
> +++ b/gcc/config/riscv/riscv-vsetvl.cc
> @@ -43,7 +43,7 @@ along with GCC; see the file COPYING3. If not see
> - Phase 2 - Emit vsetvl instructions within each basic block
> according to
> demand, compute and save ANTLOC && AVLOC of each block.
>
> - - Phase 3 - Backward demanded info propagation and fusion across
> blocks.
> + - Phase 3 - Backward && forward demanded info propagation and fusion
> across blocks.
>
> - Phase 4 - Lazy code motion including: compute local properties,
> pre_edge_lcm and vsetvl insertion && delete edges for LCM results.
> @@ -434,8 +434,12 @@ can_backward_propagate_p (const function_info *ssa,
> const basic_block cfg_bb,
> set_info *ultimate_def = look_through_degenerate_phi (set);
> const basic_block ultimate_bb = ultimate_def->bb ()->cfg_bb ();
> FOR_BB_BETWEEN (iter_bb, ultimate_bb, def->bb ()->cfg_bb (),
> next_bb)
> - if (iter_bb->index == cfg_bb->index)
> - return true;
> + {
> + if (!iter_bb)
> + break;
> + if (iter_bb->index == cfg_bb->index)
> + return true;
> + }
>
> return false;
> };
> @@ -1172,6 +1176,19 @@ vector_insn_info::parse_insn (insn_info *insn)
> m_demands[DEMAND_MASK_POLICY] = true;
> }
>
> +void
> +vector_insn_info::set_demand_info (const vector_insn_info &other)
> +{
> + set_sew (other.get_sew ());
> + set_vlmul (other.get_vlmul ());
> + set_ratio (other.get_ratio ());
> + set_ta (other.get_ta ());
> + set_ma (other.get_ma ());
> + set_avl_info (other.get_avl_info ());
> + for (size_t i = 0; i < NUM_DEMAND; i++)
> + m_demands[i] = other.demand_p ((enum demand_type) i);
> +}
> +
> void
> vector_insn_info::demand_vl_vtype ()
> {
> @@ -1691,8 +1708,10 @@ private:
> void emit_local_forward_vsetvls (const bb_info *);
>
> /* Phase 3. */
> - void merge_successors (const basic_block, const basic_block);
> - void compute_global_backward_infos (void);
> + bool merge_successors (const basic_block, const basic_block);
> + bool backward_demand_fusion (void);
> + bool forward_demand_fusion (void);
> + void demand_fusion (void);
>
> /* Phase 4. */
> void prune_expressions (void);
> @@ -1866,7 +1885,7 @@ pass_vsetvl::emit_local_forward_vsetvls (const
> bb_info *bb)
> }
>
> /* Merge all successors of Father except child node. */
> -void
> +bool
> pass_vsetvl::merge_successors (const basic_block father,
> const basic_block child)
> {
> @@ -1877,7 +1896,8 @@ pass_vsetvl::merge_successors (const basic_block
> father,
> || father_info.local_dem.empty_p ());
> gcc_assert (father_info.reaching_out.dirty_p ()
> || father_info.reaching_out.empty_p ());
> -
> +
> + bool changed_p = false;
> FOR_EACH_EDGE (e, ei, father->succs)
> {
> const basic_block succ = e->dest;
> @@ -1907,12 +1927,15 @@ pass_vsetvl::merge_successors (const basic_block
> father,
>
> father_info.local_dem = new_info;
> father_info.reaching_out = new_info;
> + changed_p = true;
> }
> +
> + return changed_p;
> }
>
> /* Compute global backward demanded info. */
> -void
> -pass_vsetvl::compute_global_backward_infos (void)
> +bool
> +pass_vsetvl::backward_demand_fusion (void)
> {
> /* We compute global infos by backward propagation.
> We want to have better performance in these following cases:
> @@ -1939,6 +1962,7 @@ pass_vsetvl::compute_global_backward_infos (void)
> We backward propagate the first VSETVL into e32,mf2 so that we
> could be able to eliminate the second VSETVL in LCM. */
>
> + bool changed_p = false;
> for (const bb_info *bb : crtl->ssa->reverse_bbs ())
> {
> basic_block cfg_bb = bb->cfg_bb ();
> @@ -1982,9 +2006,10 @@ pass_vsetvl::compute_global_backward_infos (void)
> block_info.reaching_out.set_dirty ();
> block_info.reaching_out.set_dirty_pat (new_pat);
> block_info.local_dem = block_info.reaching_out;
> + changed_p = true;
> }
>
> - merge_successors (e->src, cfg_bb);
> + changed_p |= merge_successors (e->src, cfg_bb);
> }
> else if (block_info.reaching_out.dirty_p ())
> {
> @@ -2011,6 +2036,7 @@ pass_vsetvl::compute_global_backward_infos (void)
> new_info.set_dirty_pat (new_pat);
> block_info.local_dem = new_info;
> block_info.reaching_out = new_info;
> + changed_p = true;
> }
> else
> {
> @@ -2031,9 +2057,99 @@ pass_vsetvl::compute_global_backward_infos (void)
> if (block_info.local_dem == block_info.reaching_out)
> block_info.local_dem = new_info;
> block_info.reaching_out = new_info;
> + changed_p = true;
> + }
> + }
> + }
> + return changed_p;
> +}
> +
> +/* Compute global forward demanded info. */
> +bool
> +pass_vsetvl::forward_demand_fusion (void)
> +{
> + /* Enhance the global information propagation especially
> + backward propagation miss the propagation.
> + Consider such case:
> +
> + bb0
> + (TU)
> + / \
> + bb1 bb2
> + (TU) (ANY)
> + existing edge -----> \ / (TU) <----- LCM create this edge.
> + bb3
> + (TU)
> +
> + Base on the situation, LCM fails to eliminate the VSETVL instruction
> and
> + insert an edge from bb2 to bb3 since we can't backward propagate bb3
> into
> + bb2. To avoid this confusing LCM result and non-optimal codegen, we
> should
> + forward propagate information from bb0 to bb2 which is friendly to
> LCM. */
> + bool changed_p = false;
> + for (const bb_info *bb : crtl->ssa->bbs ())
> + {
> + basic_block cfg_bb = bb->cfg_bb ();
> + const auto &prop
> + = m_vector_manager->vector_block_infos[cfg_bb->index].reaching_out;
> +
> + /* If there is nothing to propagate, just skip it. */
> + if (!prop.valid_or_dirty_p ())
> + continue;
> +
> + edge e;
> + edge_iterator ei;
> + /* Forward propagate to each successor. */
> + FOR_EACH_EDGE (e, ei, cfg_bb->succs)
> + {
> + auto &local_dem
> + =
> m_vector_manager->vector_block_infos[e->dest->index].local_dem;
> + auto &reaching_out
> + =
> m_vector_manager->vector_block_infos[e->dest->index].reaching_out;
> +
> + /* It's quite obvious, we don't need to propagate itself. */
> + if (e->dest->index == cfg_bb->index)
> + continue;
> +
> + /* If there is nothing to propagate, just skip it. */
> + if (!local_dem.valid_or_dirty_p ())
> + continue;
> +
> + if (prop > local_dem)
> + {
> + if (local_dem.dirty_p ())
> + {
> + gcc_assert (local_dem == reaching_out);
> + rtx dirty_pat
> + = gen_vsetvl_pat (prop.get_insn ()->rtl (), prop);
> + local_dem = prop;
> + local_dem.set_dirty ();
> + local_dem.set_dirty_pat (dirty_pat);
> + reaching_out = local_dem;
> + }
> + else
> + {
> + if (reaching_out == local_dem)
> + reaching_out.set_demand_info (prop);
> + local_dem.set_demand_info (prop);
> + change_vsetvl_insn (local_dem.get_insn (), prop);
> + }
> + changed_p = true;
> }
> }
> }
> + return changed_p;
> +}
> +
> +void
> +pass_vsetvl::demand_fusion (void)
> +{
> + bool changed_p = true;
> + while (changed_p)
> + {
> + changed_p = false;
> + changed_p |= backward_demand_fusion ();
> + changed_p |= forward_demand_fusion ();
> + }
>
> if (dump_file)
> {
> @@ -2519,7 +2635,7 @@ pass_vsetvl::lazy_vsetvl (void)
> /* Phase 3 - Propagate demanded info across blocks. */
> if (dump_file)
> fprintf (dump_file, "\nPhase 3: Demands propagation across blocks\n");
> - compute_global_backward_infos ();
> + demand_fusion ();
> if (dump_file)
> m_vector_manager->dump (dump_file);
>
> diff --git a/gcc/config/riscv/riscv-vsetvl.h
> b/gcc/config/riscv/riscv-vsetvl.h
> index c8218a6ff00..33481a87163 100644
> --- a/gcc/config/riscv/riscv-vsetvl.h
> +++ b/gcc/config/riscv/riscv-vsetvl.h
> @@ -273,6 +273,7 @@ public:
> void set_dirty () { m_state = DIRTY; }
> void set_dirty_pat (rtx pat) { m_dirty_pat = pat; }
> void set_insn (rtl_ssa::insn_info *insn) { m_insn = insn; }
> + void set_demand_info (const vector_insn_info &);
>
> bool demand_p (enum demand_type type) const { return m_demands[type]; }
> void demand (enum demand_type type) { m_demands[type] = true; }
> --
> 2.36.3
>
>
