From ae947d973778dcd7d5ddf8d3e772a136aed5a2f4 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Tue, 24 Aug 2021 12:25:25 +0200 Subject: [PATCH] tree-optimization/100089 - avoid leaving scalar if-converted code around To: gcc-patches@gcc.gnu.org This avoids leaving scalar if-converted code around for the case of BB vectorizing an if-converted loop body when using the very-cheap cost model. In this case we scan not vectorized scalar stmts in the basic-block vectorized for COND_EXPRs and force the vectorization to be marked as not profitable. The patch also makes sure to always consider all BB vectorization subgraphs together for costing purposes when vectorizing an if-converted loop body. 2021-08-24 Richard Biener PR tree-optimization/100089 * tree-vectorizer.h (vect_slp_bb): Rename to ... (vect_slp_if_converted_bb): ... this and get the original loop as new argument. * tree-vectorizer.c (try_vectorize_loop_1): Revert previous fix, pass original loop to vect_slp_if_converted_bb. * tree-vect-slp.c (vect_bb_vectorization_profitable_p): If orig_loop was passed scan the not vectorized stmts for COND_EXPRs and force not profitable if found. (vect_slp_region): Pass down all SLP instances to costing if orig_loop was specified. (vect_slp_bbs): Pass through orig_loop. (vect_slp_bb): Rename to ... (vect_slp_if_converted_bb): ... this and get the original loop as new argument. (vect_slp_function): Adjust. --- gcc/tree-vect-slp.c | 70 ++++++++++++++++++++++++++++++++++--------- gcc/tree-vectorizer.c | 20 +++++++------ gcc/tree-vectorizer.h | 2 +- 3 files changed, 68 insertions(+), 24 deletions(-) diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c index 3ed5bc1989a..8bfa45772d3 100644 --- a/gcc/tree-vect-slp.c +++ b/gcc/tree-vect-slp.c @@ -5287,7 +5287,8 @@ li_cost_vec_cmp (const void *a_, const void *b_) static bool vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo, - vec slp_instances) + vec slp_instances, + loop_p orig_loop) { slp_instance instance; int i; @@ -5324,6 +5325,30 @@ vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo, vector_costs.safe_splice (instance->cost_vec); instance->cost_vec.release (); } + /* When we're vectorizing an if-converted loop body with the + very-cheap cost model make sure we vectorized all if-converted + code. */ + bool force_not_profitable = false; + if (orig_loop && flag_vect_cost_model == VECT_COST_MODEL_VERY_CHEAP) + { + gcc_assert (bb_vinfo->bbs.length () == 1); + for (gimple_stmt_iterator gsi = gsi_start_bb (bb_vinfo->bbs[0]); + !gsi_end_p (gsi); gsi_next (&gsi)) + { + /* The costing above left us with DCEable vectorized scalar + stmts having the visited flag set. */ + if (gimple_visited_p (gsi_stmt (gsi))) + continue; + + if (gassign *ass = dyn_cast (gsi_stmt (gsi))) + if (gimple_assign_rhs_code (ass) == COND_EXPR) + { + force_not_profitable = true; + break; + } + } + } + /* Unset visited flag. */ stmt_info_for_cost *cost; FOR_EACH_VEC_ELT (scalar_costs, i, cost) @@ -5448,9 +5473,14 @@ vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo, return false; } + if (dump_enabled_p () && force_not_profitable) + dump_printf_loc (MSG_NOTE, vect_location, + "not profitable because of unprofitable if-converted " + "scalar code\n"); + scalar_costs.release (); vector_costs.release (); - return true; + return !force_not_profitable; } /* qsort comparator for lane defs. */ @@ -5895,7 +5925,8 @@ vect_slp_analyze_bb_1 (bb_vec_info bb_vinfo, int n_stmts, bool &fatal, static bool vect_slp_region (vec bbs, vec datarefs, - vec *dataref_groups, unsigned int n_stmts) + vec *dataref_groups, unsigned int n_stmts, + loop_p orig_loop) { bb_vec_info bb_vinfo; auto_vector_modes vector_modes; @@ -5944,7 +5975,9 @@ vect_slp_region (vec bbs, vec datarefs, vect_location = instance->location (); if (!unlimited_cost_model (NULL) && !vect_bb_vectorization_profitable_p - (bb_vinfo, instance->subgraph_entries)) + (bb_vinfo, + orig_loop ? BB_VINFO_SLP_INSTANCES (bb_vinfo) + : instance->subgraph_entries, orig_loop)) { for (slp_instance inst : instance->subgraph_entries) if (inst->kind == slp_inst_kind_bb_reduc) @@ -5965,7 +5998,9 @@ vect_slp_region (vec bbs, vec datarefs, "using SLP\n"); vectorized = true; - vect_schedule_slp (bb_vinfo, instance->subgraph_entries); + vect_schedule_slp (bb_vinfo, + orig_loop ? BB_VINFO_SLP_INSTANCES (bb_vinfo) + : instance->subgraph_entries); unsigned HOST_WIDE_INT bytes; if (dump_enabled_p ()) @@ -5980,6 +6015,11 @@ vect_slp_region (vec bbs, vec datarefs, "basic block part vectorized using " "variable length vectors\n"); } + + /* When we're called from loop vectorization we're considering + all subgraphs at once. */ + if (orig_loop) + break; } } else @@ -6047,7 +6087,7 @@ vect_slp_region (vec bbs, vec datarefs, true if anything in the basic-block was vectorized. */ static bool -vect_slp_bbs (const vec &bbs) +vect_slp_bbs (const vec &bbs, loop_p orig_loop) { vec datarefs = vNULL; auto_vec dataref_groups; @@ -6077,18 +6117,20 @@ vect_slp_bbs (const vec &bbs) ++current_group; } - return vect_slp_region (bbs, datarefs, &dataref_groups, insns); + return vect_slp_region (bbs, datarefs, &dataref_groups, insns, orig_loop); } -/* Main entry for the BB vectorizer. Analyze and transform BB, returns - true if anything in the basic-block was vectorized. */ +/* Special entry for the BB vectorizer. Analyze and transform a single + if-converted BB with ORIG_LOOPs body being the not if-converted + representation. Returns true if anything in the basic-block was + vectorized. */ bool -vect_slp_bb (basic_block bb) +vect_slp_if_converted_bb (basic_block bb, loop_p orig_loop) { auto_vec bbs; bbs.safe_push (bb); - return vect_slp_bbs (bbs); + return vect_slp_bbs (bbs, orig_loop); } /* Main entry for the BB vectorizer. Analyze and transform BB, returns @@ -6139,7 +6181,7 @@ vect_slp_function (function *fun) if (split && !bbs.is_empty ()) { - r |= vect_slp_bbs (bbs); + r |= vect_slp_bbs (bbs, NULL); bbs.truncate (0); bbs.quick_push (bb); } @@ -6157,13 +6199,13 @@ vect_slp_function (function *fun) dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, "splitting region at control altering " "definition %G", last); - r |= vect_slp_bbs (bbs); + r |= vect_slp_bbs (bbs, NULL); bbs.truncate (0); } } if (!bbs.is_empty ()) - r |= vect_slp_bbs (bbs); + r |= vect_slp_bbs (bbs, NULL); free (rpo); diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c index 813f4683d1e..3aa3e2a6783 100644 --- a/gcc/tree-vectorizer.c +++ b/gcc/tree-vectorizer.c @@ -1033,10 +1033,7 @@ try_vectorize_loop_1 (hash_table *&simduid_to_vf_htab, only non-if-converted parts took part in BB vectorization. */ if (flag_tree_slp_vectorize != 0 && loop_vectorized_call - && ! loop->inner - /* This would purely be a workaround and should be removed - once PR100089 is fixed. */ - && flag_vect_cost_model != VECT_COST_MODEL_VERY_CHEAP) + && ! loop->inner) { basic_block bb = loop->header; bool require_loop_vectorize = false; @@ -1062,12 +1059,17 @@ try_vectorize_loop_1 (hash_table *&simduid_to_vf_htab, gimple_set_uid (stmt, -1); gimple_set_visited (stmt, false); } - if (!require_loop_vectorize && vect_slp_bb (bb)) + if (!require_loop_vectorize) { - fold_loop_internal_call (loop_vectorized_call, - boolean_true_node); - loop_vectorized_call = NULL; - ret |= TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; + tree arg = gimple_call_arg (loop_vectorized_call, 1); + class loop *scalar_loop = get_loop (cfun, tree_to_shwi (arg)); + if (vect_slp_if_converted_bb (bb, scalar_loop)) + { + fold_loop_internal_call (loop_vectorized_call, + boolean_true_node); + loop_vectorized_call = NULL; + ret |= TODO_cleanup_cfg | TODO_update_ssa_only_virtuals; + } } } /* If outer loop vectorization fails for LOOP_VECTORIZED guarded diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h index 0ccbaafd50d..6e90217373f 100644 --- a/gcc/tree-vectorizer.h +++ b/gcc/tree-vectorizer.h @@ -2087,7 +2087,7 @@ extern void vect_gather_slp_loads (vec_info *); extern void vect_get_slp_defs (slp_tree, vec *); extern void vect_get_slp_defs (vec_info *, slp_tree, vec > *, unsigned n = -1U); -extern bool vect_slp_bb (basic_block); +extern bool vect_slp_if_converted_bb (basic_block bb, loop_p orig_loop); extern bool vect_slp_function (function *); extern stmt_vec_info vect_find_last_scalar_stmt_in_slp (slp_tree); extern stmt_vec_info vect_find_first_scalar_stmt_in_slp (slp_tree); -- 2.31.1