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