LGTM, it's always good to improve some debug for vsetvli insertion
pass, it's really non-trivial optimization.
On Thu, Jan 25, 2024 at 4:59 PM Juzhe-Zhong <juzhe.zh...@rivai.ai> wrote:
>
> While looking into PR113469, I notice the LCM delete a vsetvl incorrectly.
>
> This patch add dump information of all predecessors for LCM delete vsetvl
> block
> for better debugging.
>
> Tested no regression.
>
> gcc/ChangeLog:
>
> * config/riscv/riscv-vsetvl.cc (get_all_predecessors): New function.
> (pre_vsetvl::pre_global_vsetvl_info): Add LCM delete block all
> predecessors dump information.
>
> ---
> gcc/config/riscv/riscv-vsetvl.cc | 42 ++++++++++++++++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/gcc/config/riscv/riscv-vsetvl.cc
> b/gcc/config/riscv/riscv-vsetvl.cc
> index 72c5a127d9e..da258b964fc 100644
> --- a/gcc/config/riscv/riscv-vsetvl.cc
> +++ b/gcc/config/riscv/riscv-vsetvl.cc
> @@ -654,6 +654,31 @@ invalid_opt_bb_p (basic_block cfg_bb)
> return false;
> }
>
> +/* Get all predecessors of BB. */
> +static hash_set<basic_block>
> +get_all_predecessors (basic_block bb)
> +{
> + hash_set<basic_block> blocks;
> + auto_vec<basic_block> work_list;
> + hash_set<basic_block> visited_list;
> + work_list.safe_push (bb);
> +
> + while (!work_list.is_empty ())
> + {
> + basic_block new_bb = work_list.pop ();
> + visited_list.add (new_bb);
> + edge e;
> + edge_iterator ei;
> + FOR_EACH_EDGE (e, ei, new_bb->preds)
> + {
> + if (!visited_list.contains (e->src))
> + work_list.safe_push (e->src);
> + blocks.add (e->src);
> + }
> + }
> + return blocks;
> +}
> +
> /* This flags indicates the minimum demand of the vl and vtype values by the
> RVV instruction. For example, DEMAND_RATIO_P indicates that this RVV
> instruction only needs the SEW/LMUL ratio to remain the same, and does not
> @@ -3142,6 +3167,23 @@ pre_vsetvl::pre_global_vsetvl_info ()
> const vsetvl_block_info &block_info = get_block_info (info.get_bb ());
> gcc_assert (block_info.get_entry_info () == info);
> info.set_delete ();
> + if (dump_file && (dump_flags & TDF_DETAILS))
> + {
> + fprintf (dump_file,
> + "\nLCM deleting vsetvl of block %d, it has predecessors:
> \n",
> + bb->index ());
> + hash_set<basic_block> all_preds
> + = get_all_predecessors (bb->cfg_bb ());
> + int i = 0;
> + for (const auto pred : all_preds)
> + {
> + fprintf (dump_file, "%d ", pred->index);
> + i++;
> + if (i % 32 == 0)
> + fprintf (dump_file, "\n");
> + }
> + fprintf (dump_file, "\n");
> + }
> }
>
> /* Remove vsetvl infos if all precessors are available to the block. */
> --
> 2.36.3
>
