| /* Vectorizer Specific Loop Manipulations |
| Copyright (C) 2003-2017 Free Software Foundation, Inc. |
| Contributed by Dorit Naishlos <dorit@il.ibm.com> |
| and Ira Rosen <irar@il.ibm.com> |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "cfghooks.h" |
| #include "tree-pass.h" |
| #include "ssa.h" |
| #include "fold-const.h" |
| #include "cfganal.h" |
| #include "gimplify.h" |
| #include "gimple-iterator.h" |
| #include "gimplify-me.h" |
| #include "tree-cfg.h" |
| #include "tree-ssa-loop-manip.h" |
| #include "tree-into-ssa.h" |
| #include "tree-ssa.h" |
| #include "cfgloop.h" |
| #include "tree-scalar-evolution.h" |
| #include "tree-vectorizer.h" |
| #include "tree-ssa-loop-ivopts.h" |
| |
| /************************************************************************* |
| Simple Loop Peeling Utilities |
| |
| Utilities to support loop peeling for vectorization purposes. |
| *************************************************************************/ |
| |
| |
| /* Renames the use *OP_P. */ |
| |
| static void |
| rename_use_op (use_operand_p op_p) |
| { |
| tree new_name; |
| |
| if (TREE_CODE (USE_FROM_PTR (op_p)) != SSA_NAME) |
| return; |
| |
| new_name = get_current_def (USE_FROM_PTR (op_p)); |
| |
| /* Something defined outside of the loop. */ |
| if (!new_name) |
| return; |
| |
| /* An ordinary ssa name defined in the loop. */ |
| |
| SET_USE (op_p, new_name); |
| } |
| |
| |
| /* Renames the variables in basic block BB. Allow renaming of PHI arguments |
| on edges incoming from outer-block header if RENAME_FROM_OUTER_LOOP is |
| true. */ |
| |
| static void |
| rename_variables_in_bb (basic_block bb, bool rename_from_outer_loop) |
| { |
| gimple *stmt; |
| use_operand_p use_p; |
| ssa_op_iter iter; |
| edge e; |
| edge_iterator ei; |
| struct loop *loop = bb->loop_father; |
| struct loop *outer_loop = NULL; |
| |
| if (rename_from_outer_loop) |
| { |
| gcc_assert (loop); |
| outer_loop = loop_outer (loop); |
| } |
| |
| for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
| gsi_next (&gsi)) |
| { |
| stmt = gsi_stmt (gsi); |
| FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
| rename_use_op (use_p); |
| } |
| |
| FOR_EACH_EDGE (e, ei, bb->preds) |
| { |
| if (!flow_bb_inside_loop_p (loop, e->src)) |
| { |
| if (!rename_from_outer_loop) |
| continue; |
| if (e->src != outer_loop->header) |
| { |
| if (outer_loop->inner->next) |
| { |
| /* If outer_loop has 2 inner loops, allow there to |
| be an extra basic block which decides which of the |
| two loops to use using LOOP_VECTORIZED. */ |
| if (!single_pred_p (e->src) |
| || single_pred (e->src) != outer_loop->header) |
| continue; |
| } |
| } |
| } |
| for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
| gsi_next (&gsi)) |
| rename_use_op (PHI_ARG_DEF_PTR_FROM_EDGE (gsi.phi (), e)); |
| } |
| } |
| |
| |
| struct adjust_info |
| { |
| tree from, to; |
| basic_block bb; |
| }; |
| |
| /* A stack of values to be adjusted in debug stmts. We have to |
| process them LIFO, so that the closest substitution applies. If we |
| processed them FIFO, without the stack, we might substitute uses |
| with a PHI DEF that would soon become non-dominant, and when we got |
| to the suitable one, it wouldn't have anything to substitute any |
| more. */ |
| static vec<adjust_info, va_heap> adjust_vec; |
| |
| /* Adjust any debug stmts that referenced AI->from values to use the |
| loop-closed AI->to, if the references are dominated by AI->bb and |
| not by the definition of AI->from. */ |
| |
| static void |
| adjust_debug_stmts_now (adjust_info *ai) |
| { |
| basic_block bbphi = ai->bb; |
| tree orig_def = ai->from; |
| tree new_def = ai->to; |
| imm_use_iterator imm_iter; |
| gimple *stmt; |
| basic_block bbdef = gimple_bb (SSA_NAME_DEF_STMT (orig_def)); |
| |
| gcc_assert (dom_info_available_p (CDI_DOMINATORS)); |
| |
| /* Adjust any debug stmts that held onto non-loop-closed |
| references. */ |
| FOR_EACH_IMM_USE_STMT (stmt, imm_iter, orig_def) |
| { |
| use_operand_p use_p; |
| basic_block bbuse; |
| |
| if (!is_gimple_debug (stmt)) |
| continue; |
| |
| gcc_assert (gimple_debug_bind_p (stmt)); |
| |
| bbuse = gimple_bb (stmt); |
| |
| if ((bbuse == bbphi |
| || dominated_by_p (CDI_DOMINATORS, bbuse, bbphi)) |
| && !(bbuse == bbdef |
| || dominated_by_p (CDI_DOMINATORS, bbuse, bbdef))) |
| { |
| if (new_def) |
| FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) |
| SET_USE (use_p, new_def); |
| else |
| { |
| gimple_debug_bind_reset_value (stmt); |
| update_stmt (stmt); |
| } |
| } |
| } |
| } |
| |
| /* Adjust debug stmts as scheduled before. */ |
| |
| static void |
| adjust_vec_debug_stmts (void) |
| { |
| if (!MAY_HAVE_DEBUG_STMTS) |
| return; |
| |
| gcc_assert (adjust_vec.exists ()); |
| |
| while (!adjust_vec.is_empty ()) |
| { |
| adjust_debug_stmts_now (&adjust_vec.last ()); |
| adjust_vec.pop (); |
| } |
| } |
| |
| /* Adjust any debug stmts that referenced FROM values to use the |
| loop-closed TO, if the references are dominated by BB and not by |
| the definition of FROM. If adjust_vec is non-NULL, adjustments |
| will be postponed until adjust_vec_debug_stmts is called. */ |
| |
| static void |
| adjust_debug_stmts (tree from, tree to, basic_block bb) |
| { |
| adjust_info ai; |
| |
| if (MAY_HAVE_DEBUG_STMTS |
| && TREE_CODE (from) == SSA_NAME |
| && ! SSA_NAME_IS_DEFAULT_DEF (from) |
| && ! virtual_operand_p (from)) |
| { |
| ai.from = from; |
| ai.to = to; |
| ai.bb = bb; |
| |
| if (adjust_vec.exists ()) |
| adjust_vec.safe_push (ai); |
| else |
| adjust_debug_stmts_now (&ai); |
| } |
| } |
| |
| /* Change E's phi arg in UPDATE_PHI to NEW_DEF, and record information |
| to adjust any debug stmts that referenced the old phi arg, |
| presumably non-loop-closed references left over from other |
| transformations. */ |
| |
| static void |
| adjust_phi_and_debug_stmts (gimple *update_phi, edge e, tree new_def) |
| { |
| tree orig_def = PHI_ARG_DEF_FROM_EDGE (update_phi, e); |
| |
| SET_PHI_ARG_DEF (update_phi, e->dest_idx, new_def); |
| |
| if (MAY_HAVE_DEBUG_STMTS) |
| adjust_debug_stmts (orig_def, PHI_RESULT (update_phi), |
| gimple_bb (update_phi)); |
| } |
| |
| /* Make the LOOP iterate NITERS times. This is done by adding a new IV |
| that starts at zero, increases by one and its limit is NITERS. |
| |
| Assumption: the exit-condition of LOOP is the last stmt in the loop. */ |
| |
| void |
| slpeel_make_loop_iterate_ntimes (struct loop *loop, tree niters) |
| { |
| tree indx_before_incr, indx_after_incr; |
| gcond *cond_stmt; |
| gcond *orig_cond; |
| edge exit_edge = single_exit (loop); |
| gimple_stmt_iterator loop_cond_gsi; |
| gimple_stmt_iterator incr_gsi; |
| bool insert_after; |
| tree init = build_int_cst (TREE_TYPE (niters), 0); |
| tree step = build_int_cst (TREE_TYPE (niters), 1); |
| source_location loop_loc; |
| enum tree_code code; |
| |
| orig_cond = get_loop_exit_condition (loop); |
| gcc_assert (orig_cond); |
| loop_cond_gsi = gsi_for_stmt (orig_cond); |
| |
| standard_iv_increment_position (loop, &incr_gsi, &insert_after); |
| create_iv (init, step, NULL_TREE, loop, |
| &incr_gsi, insert_after, &indx_before_incr, &indx_after_incr); |
| |
| indx_after_incr = force_gimple_operand_gsi (&loop_cond_gsi, indx_after_incr, |
| true, NULL_TREE, true, |
| GSI_SAME_STMT); |
| niters = force_gimple_operand_gsi (&loop_cond_gsi, niters, true, NULL_TREE, |
| true, GSI_SAME_STMT); |
| |
| code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GE_EXPR : LT_EXPR; |
| cond_stmt = gimple_build_cond (code, indx_after_incr, niters, NULL_TREE, |
| NULL_TREE); |
| |
| gsi_insert_before (&loop_cond_gsi, cond_stmt, GSI_SAME_STMT); |
| |
| /* Remove old loop exit test: */ |
| gsi_remove (&loop_cond_gsi, true); |
| free_stmt_vec_info (orig_cond); |
| |
| loop_loc = find_loop_location (loop); |
| if (dump_enabled_p ()) |
| { |
| if (LOCATION_LOCUS (loop_loc) != UNKNOWN_LOCATION) |
| dump_printf (MSG_NOTE, "\nloop at %s:%d: ", LOCATION_FILE (loop_loc), |
| LOCATION_LINE (loop_loc)); |
| dump_gimple_stmt (MSG_NOTE, TDF_SLIM, cond_stmt, 0); |
| } |
| |
| /* Record the number of latch iterations. */ |
| loop->nb_iterations = fold_build2 (MINUS_EXPR, TREE_TYPE (niters), niters, |
| build_int_cst (TREE_TYPE (niters), 1)); |
| } |
| |
| /* Helper routine of slpeel_tree_duplicate_loop_to_edge_cfg. |
| For all PHI arguments in FROM->dest and TO->dest from those |
| edges ensure that TO->dest PHI arguments have current_def |
| to that in from. */ |
| |
| static void |
| slpeel_duplicate_current_defs_from_edges (edge from, edge to) |
| { |
| gimple_stmt_iterator gsi_from, gsi_to; |
| |
| for (gsi_from = gsi_start_phis (from->dest), |
| gsi_to = gsi_start_phis (to->dest); |
| !gsi_end_p (gsi_from) && !gsi_end_p (gsi_to);) |
| { |
| gimple *from_phi = gsi_stmt (gsi_from); |
| gimple *to_phi = gsi_stmt (gsi_to); |
| tree from_arg = PHI_ARG_DEF_FROM_EDGE (from_phi, from); |
| tree to_arg = PHI_ARG_DEF_FROM_EDGE (to_phi, to); |
| if (virtual_operand_p (from_arg)) |
| { |
| gsi_next (&gsi_from); |
| continue; |
| } |
| if (virtual_operand_p (to_arg)) |
| { |
| gsi_next (&gsi_to); |
| continue; |
| } |
| if (TREE_CODE (from_arg) != SSA_NAME) |
| gcc_assert (operand_equal_p (from_arg, to_arg, 0)); |
| else |
| { |
| if (get_current_def (to_arg) == NULL_TREE) |
| set_current_def (to_arg, get_current_def (from_arg)); |
| } |
| gsi_next (&gsi_from); |
| gsi_next (&gsi_to); |
| } |
| |
| gphi *from_phi = get_virtual_phi (from->dest); |
| gphi *to_phi = get_virtual_phi (to->dest); |
| if (from_phi) |
| set_current_def (PHI_ARG_DEF_FROM_EDGE (to_phi, to), |
| get_current_def (PHI_ARG_DEF_FROM_EDGE (from_phi, from))); |
| } |
| |
| |
| /* Given LOOP this function generates a new copy of it and puts it |
| on E which is either the entry or exit of LOOP. If SCALAR_LOOP is |
| non-NULL, assume LOOP and SCALAR_LOOP are equivalent and copy the |
| basic blocks from SCALAR_LOOP instead of LOOP, but to either the |
| entry or exit of LOOP. */ |
| |
| struct loop * |
| slpeel_tree_duplicate_loop_to_edge_cfg (struct loop *loop, |
| struct loop *scalar_loop, edge e) |
| { |
| struct loop *new_loop; |
| basic_block *new_bbs, *bbs, *pbbs; |
| bool at_exit; |
| bool was_imm_dom; |
| basic_block exit_dest; |
| edge exit, new_exit; |
| bool duplicate_outer_loop = false; |
| |
| exit = single_exit (loop); |
| at_exit = (e == exit); |
| if (!at_exit && e != loop_preheader_edge (loop)) |
| return NULL; |
| |
| if (scalar_loop == NULL) |
| scalar_loop = loop; |
| |
| bbs = XNEWVEC (basic_block, scalar_loop->num_nodes + 1); |
| pbbs = bbs + 1; |
| get_loop_body_with_size (scalar_loop, pbbs, scalar_loop->num_nodes); |
| /* Allow duplication of outer loops. */ |
| if (scalar_loop->inner) |
| duplicate_outer_loop = true; |
| /* Check whether duplication is possible. */ |
| if (!can_copy_bbs_p (pbbs, scalar_loop->num_nodes)) |
| { |
| free (bbs); |
| return NULL; |
| } |
| |
| /* Generate new loop structure. */ |
| new_loop = duplicate_loop (scalar_loop, loop_outer (scalar_loop)); |
| duplicate_subloops (scalar_loop, new_loop); |
| |
| exit_dest = exit->dest; |
| was_imm_dom = (get_immediate_dominator (CDI_DOMINATORS, |
| exit_dest) == loop->header ? |
| true : false); |
| |
| /* Also copy the pre-header, this avoids jumping through hoops to |
| duplicate the loop entry PHI arguments. Create an empty |
| pre-header unconditionally for this. */ |
| basic_block preheader = split_edge (loop_preheader_edge (scalar_loop)); |
| edge entry_e = single_pred_edge (preheader); |
| bbs[0] = preheader; |
| new_bbs = XNEWVEC (basic_block, scalar_loop->num_nodes + 1); |
| |
| exit = single_exit (scalar_loop); |
| copy_bbs (bbs, scalar_loop->num_nodes + 1, new_bbs, |
| &exit, 1, &new_exit, NULL, |
| at_exit ? loop->latch : e->src, true); |
| exit = single_exit (loop); |
| basic_block new_preheader = new_bbs[0]; |
| |
| add_phi_args_after_copy (new_bbs, scalar_loop->num_nodes + 1, NULL); |
| |
| if (scalar_loop != loop) |
| { |
| /* If we copied from SCALAR_LOOP rather than LOOP, SSA_NAMEs from |
| SCALAR_LOOP will have current_def set to SSA_NAMEs in the new_loop, |
| but LOOP will not. slpeel_update_phi_nodes_for_guard{1,2} expects |
| the LOOP SSA_NAMEs (on the exit edge and edge from latch to |
| header) to have current_def set, so copy them over. */ |
| slpeel_duplicate_current_defs_from_edges (single_exit (scalar_loop), |
| exit); |
| slpeel_duplicate_current_defs_from_edges (EDGE_SUCC (scalar_loop->latch, |
| 0), |
| EDGE_SUCC (loop->latch, 0)); |
| } |
| |
| if (at_exit) /* Add the loop copy at exit. */ |
| { |
| if (scalar_loop != loop) |
| { |
| gphi_iterator gsi; |
| new_exit = redirect_edge_and_branch (new_exit, exit_dest); |
| |
| for (gsi = gsi_start_phis (exit_dest); !gsi_end_p (gsi); |
| gsi_next (&gsi)) |
| { |
| gphi *phi = gsi.phi (); |
| tree orig_arg = PHI_ARG_DEF_FROM_EDGE (phi, e); |
| location_t orig_locus |
| = gimple_phi_arg_location_from_edge (phi, e); |
| |
| add_phi_arg (phi, orig_arg, new_exit, orig_locus); |
| } |
| } |
| redirect_edge_and_branch_force (e, new_preheader); |
| flush_pending_stmts (e); |
| set_immediate_dominator (CDI_DOMINATORS, new_preheader, e->src); |
| if (was_imm_dom || duplicate_outer_loop) |
| set_immediate_dominator (CDI_DOMINATORS, exit_dest, new_exit->src); |
| |
| /* And remove the non-necessary forwarder again. Keep the other |
| one so we have a proper pre-header for the loop at the exit edge. */ |
| redirect_edge_pred (single_succ_edge (preheader), |
| single_pred (preheader)); |
| delete_basic_block (preheader); |
| set_immediate_dominator (CDI_DOMINATORS, scalar_loop->header, |
| loop_preheader_edge (scalar_loop)->src); |
| } |
| else /* Add the copy at entry. */ |
| { |
| if (scalar_loop != loop) |
| { |
| /* Remove the non-necessary forwarder of scalar_loop again. */ |
| redirect_edge_pred (single_succ_edge (preheader), |
| single_pred (preheader)); |
| delete_basic_block (preheader); |
| set_immediate_dominator (CDI_DOMINATORS, scalar_loop->header, |
| loop_preheader_edge (scalar_loop)->src); |
| preheader = split_edge (loop_preheader_edge (loop)); |
| entry_e = single_pred_edge (preheader); |
| } |
| |
| redirect_edge_and_branch_force (entry_e, new_preheader); |
| flush_pending_stmts (entry_e); |
| set_immediate_dominator (CDI_DOMINATORS, new_preheader, entry_e->src); |
| |
| redirect_edge_and_branch_force (new_exit, preheader); |
| flush_pending_stmts (new_exit); |
| set_immediate_dominator (CDI_DOMINATORS, preheader, new_exit->src); |
| |
| /* And remove the non-necessary forwarder again. Keep the other |
| one so we have a proper pre-header for the loop at the exit edge. */ |
| redirect_edge_pred (single_succ_edge (new_preheader), |
| single_pred (new_preheader)); |
| delete_basic_block (new_preheader); |
| set_immediate_dominator (CDI_DOMINATORS, new_loop->header, |
| loop_preheader_edge (new_loop)->src); |
| } |
| |
| /* Skip new preheader since it's deleted if copy loop is added at entry. */ |
| for (unsigned i = (at_exit ? 0 : 1); i < scalar_loop->num_nodes + 1; i++) |
| rename_variables_in_bb (new_bbs[i], duplicate_outer_loop); |
| |
| if (scalar_loop != loop) |
| { |
| /* Update new_loop->header PHIs, so that on the preheader |
| edge they are the ones from loop rather than scalar_loop. */ |
| gphi_iterator gsi_orig, gsi_new; |
| edge orig_e = loop_preheader_edge (loop); |
| edge new_e = loop_preheader_edge (new_loop); |
| |
| for (gsi_orig = gsi_start_phis (loop->header), |
| gsi_new = gsi_start_phis (new_loop->header); |
| !gsi_end_p (gsi_orig) && !gsi_end_p (gsi_new); |
| gsi_next (&gsi_orig), gsi_next (&gsi_new)) |
| { |
| gphi *orig_phi = gsi_orig.phi (); |
| gphi *new_phi = gsi_new.phi (); |
| tree orig_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, orig_e); |
| location_t orig_locus |
| = gimple_phi_arg_location_from_edge (orig_phi, orig_e); |
| |
| add_phi_arg (new_phi, orig_arg, new_e, orig_locus); |
| } |
| } |
| |
| free (new_bbs); |
| free (bbs); |
| |
| checking_verify_dominators (CDI_DOMINATORS); |
| |
| return new_loop; |
| } |
| |
| |
| /* Given the condition expression COND, put it as the last statement of |
| GUARD_BB; set both edges' probability; set dominator of GUARD_TO to |
| DOM_BB; return the skip edge. GUARD_TO is the target basic block to |
| skip the loop. PROBABILITY is the skip edge's probability. Mark the |
| new edge as irreducible if IRREDUCIBLE_P is true. */ |
| |
| static edge |
| slpeel_add_loop_guard (basic_block guard_bb, tree cond, |
| basic_block guard_to, basic_block dom_bb, |
| profile_probability probability, bool irreducible_p) |
| { |
| gimple_stmt_iterator gsi; |
| edge new_e, enter_e; |
| gcond *cond_stmt; |
| gimple_seq gimplify_stmt_list = NULL; |
| |
| enter_e = EDGE_SUCC (guard_bb, 0); |
| enter_e->flags &= ~EDGE_FALLTHRU; |
| enter_e->flags |= EDGE_FALSE_VALUE; |
| gsi = gsi_last_bb (guard_bb); |
| |
| cond = force_gimple_operand_1 (cond, &gimplify_stmt_list, is_gimple_condexpr, |
| NULL_TREE); |
| if (gimplify_stmt_list) |
| gsi_insert_seq_after (&gsi, gimplify_stmt_list, GSI_NEW_STMT); |
| |
| cond_stmt = gimple_build_cond_from_tree (cond, NULL_TREE, NULL_TREE); |
| gsi = gsi_last_bb (guard_bb); |
| gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT); |
| |
| /* Add new edge to connect guard block to the merge/loop-exit block. */ |
| new_e = make_edge (guard_bb, guard_to, EDGE_TRUE_VALUE); |
| |
| new_e->probability = probability; |
| if (irreducible_p) |
| new_e->flags |= EDGE_IRREDUCIBLE_LOOP; |
| |
| enter_e->probability = probability.invert (); |
| set_immediate_dominator (CDI_DOMINATORS, guard_to, dom_bb); |
| |
| /* Split enter_e to preserve LOOPS_HAVE_PREHEADERS. */ |
| if (enter_e->dest->loop_father->header == enter_e->dest) |
| split_edge (enter_e); |
| |
| return new_e; |
| } |
| |
| |
| /* This function verifies that the following restrictions apply to LOOP: |
| (1) it consists of exactly 2 basic blocks - header, and an empty latch |
| for innermost loop and 5 basic blocks for outer-loop. |
| (2) it is single entry, single exit |
| (3) its exit condition is the last stmt in the header |
| (4) E is the entry/exit edge of LOOP. |
| */ |
| |
| bool |
| slpeel_can_duplicate_loop_p (const struct loop *loop, const_edge e) |
| { |
| edge exit_e = single_exit (loop); |
| edge entry_e = loop_preheader_edge (loop); |
| gcond *orig_cond = get_loop_exit_condition (loop); |
| gimple_stmt_iterator loop_exit_gsi = gsi_last_bb (exit_e->src); |
| unsigned int num_bb = loop->inner? 5 : 2; |
| |
| /* All loops have an outer scope; the only case loop->outer is NULL is for |
| the function itself. */ |
| if (!loop_outer (loop) |
| || loop->num_nodes != num_bb |
| || !empty_block_p (loop->latch) |
| || !single_exit (loop) |
| /* Verify that new loop exit condition can be trivially modified. */ |
| || (!orig_cond || orig_cond != gsi_stmt (loop_exit_gsi)) |
| || (e != exit_e && e != entry_e)) |
| return false; |
| |
| return true; |
| } |
| |
| /* If the loop has a virtual PHI, but exit bb doesn't, create a virtual PHI |
| in the exit bb and rename all the uses after the loop. This simplifies |
| the *guard[12] routines, which assume loop closed SSA form for all PHIs |
| (but normally loop closed SSA form doesn't require virtual PHIs to be |
| in the same form). Doing this early simplifies the checking what |
| uses should be renamed. */ |
| |
| static void |
| create_lcssa_for_virtual_phi (struct loop *loop) |
| { |
| gphi_iterator gsi; |
| edge exit_e = single_exit (loop); |
| |
| for (gsi = gsi_start_phis (loop->header); !gsi_end_p (gsi); gsi_next (&gsi)) |
| if (virtual_operand_p (gimple_phi_result (gsi_stmt (gsi)))) |
| { |
| gphi *phi = gsi.phi (); |
| for (gsi = gsi_start_phis (exit_e->dest); |
| !gsi_end_p (gsi); gsi_next (&gsi)) |
| if (virtual_operand_p (gimple_phi_result (gsi_stmt (gsi)))) |
| break; |
| if (gsi_end_p (gsi)) |
| { |
| tree new_vop = copy_ssa_name (PHI_RESULT (phi)); |
| gphi *new_phi = create_phi_node (new_vop, exit_e->dest); |
| tree vop = PHI_ARG_DEF_FROM_EDGE (phi, EDGE_SUCC (loop->latch, 0)); |
| imm_use_iterator imm_iter; |
| gimple *stmt; |
| use_operand_p use_p; |
| |
| SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_vop) |
| = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vop); |
| add_phi_arg (new_phi, vop, exit_e, UNKNOWN_LOCATION); |
| gimple_phi_set_result (new_phi, new_vop); |
| FOR_EACH_IMM_USE_STMT (stmt, imm_iter, vop) |
| if (stmt != new_phi |
| && !flow_bb_inside_loop_p (loop, gimple_bb (stmt))) |
| FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) |
| SET_USE (use_p, new_vop); |
| } |
| break; |
| } |
| |
| } |
| |
| /* Function vect_get_loop_location. |
| |
| Extract the location of the loop in the source code. |
| If the loop is not well formed for vectorization, an estimated |
| location is calculated. |
| Return the loop location if succeed and NULL if not. */ |
| |
| source_location |
| find_loop_location (struct loop *loop) |
| { |
| gimple *stmt = NULL; |
| basic_block bb; |
| gimple_stmt_iterator si; |
| |
| if (!loop) |
| return UNKNOWN_LOCATION; |
| |
| stmt = get_loop_exit_condition (loop); |
| |
| if (stmt |
| && LOCATION_LOCUS (gimple_location (stmt)) > BUILTINS_LOCATION) |
| return gimple_location (stmt); |
| |
| /* If we got here the loop is probably not "well formed", |
| try to estimate the loop location */ |
| |
| if (!loop->header) |
| return UNKNOWN_LOCATION; |
| |
| bb = loop->header; |
| |
| for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) |
| { |
| stmt = gsi_stmt (si); |
| if (LOCATION_LOCUS (gimple_location (stmt)) > BUILTINS_LOCATION) |
| return gimple_location (stmt); |
| } |
| |
| return UNKNOWN_LOCATION; |
| } |
| |
| /* Return true if PHI defines an IV of the loop to be vectorized. */ |
| |
| static bool |
| iv_phi_p (gphi *phi) |
| { |
| if (virtual_operand_p (PHI_RESULT (phi))) |
| return false; |
| |
| stmt_vec_info stmt_info = vinfo_for_stmt (phi); |
| gcc_assert (stmt_info != NULL); |
| if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_reduction_def |
| || STMT_VINFO_DEF_TYPE (stmt_info) == vect_double_reduction_def) |
| return false; |
| |
| return true; |
| } |
| |
| /* Function vect_can_advance_ivs_p |
| |
| In case the number of iterations that LOOP iterates is unknown at compile |
| time, an epilog loop will be generated, and the loop induction variables |
| (IVs) will be "advanced" to the value they are supposed to take just before |
| the epilog loop. Here we check that the access function of the loop IVs |
| and the expression that represents the loop bound are simple enough. |
| These restrictions will be relaxed in the future. */ |
| |
| bool |
| vect_can_advance_ivs_p (loop_vec_info loop_vinfo) |
| { |
| struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
| basic_block bb = loop->header; |
| gphi_iterator gsi; |
| |
| /* Analyze phi functions of the loop header. */ |
| |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_NOTE, vect_location, "vect_can_advance_ivs_p:\n"); |
| for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| tree evolution_part; |
| |
| gphi *phi = gsi.phi (); |
| if (dump_enabled_p ()) |
| { |
| dump_printf_loc (MSG_NOTE, vect_location, "Analyze phi: "); |
| dump_gimple_stmt (MSG_NOTE, TDF_SLIM, phi, 0); |
| } |
| |
| /* Skip virtual phi's. The data dependences that are associated with |
| virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. |
| |
| Skip reduction phis. */ |
| if (!iv_phi_p (phi)) |
| { |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "reduc or virtual phi. skip.\n"); |
| continue; |
| } |
| |
| /* Analyze the evolution function. */ |
| |
| evolution_part |
| = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (vinfo_for_stmt (phi)); |
| if (evolution_part == NULL_TREE) |
| { |
| if (dump_enabled_p ()) |
| dump_printf (MSG_MISSED_OPTIMIZATION, |
| "No access function or evolution.\n"); |
| return false; |
| } |
| |
| /* FORNOW: We do not transform initial conditions of IVs |
| which evolution functions are not invariants in the loop. */ |
| |
| if (!expr_invariant_in_loop_p (loop, evolution_part)) |
| { |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, |
| "evolution not invariant in loop.\n"); |
| return false; |
| } |
| |
| /* FORNOW: We do not transform initial conditions of IVs |
| which evolution functions are a polynomial of degree >= 2. */ |
| |
| if (tree_is_chrec (evolution_part)) |
| { |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, |
| "evolution is chrec.\n"); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| |
| /* Function vect_update_ivs_after_vectorizer. |
| |
| "Advance" the induction variables of LOOP to the value they should take |
| after the execution of LOOP. This is currently necessary because the |
| vectorizer does not handle induction variables that are used after the |
| loop. Such a situation occurs when the last iterations of LOOP are |
| peeled, because: |
| 1. We introduced new uses after LOOP for IVs that were not originally used |
| after LOOP: the IVs of LOOP are now used by an epilog loop. |
| 2. LOOP is going to be vectorized; this means that it will iterate N/VF |
| times, whereas the loop IVs should be bumped N times. |
| |
| Input: |
| - LOOP - a loop that is going to be vectorized. The last few iterations |
| of LOOP were peeled. |
| - NITERS - the number of iterations that LOOP executes (before it is |
| vectorized). i.e, the number of times the ivs should be bumped. |
| - UPDATE_E - a successor edge of LOOP->exit that is on the (only) path |
| coming out from LOOP on which there are uses of the LOOP ivs |
| (this is the path from LOOP->exit to epilog_loop->preheader). |
| |
| The new definitions of the ivs are placed in LOOP->exit. |
| The phi args associated with the edge UPDATE_E in the bb |
| UPDATE_E->dest are updated accordingly. |
| |
| Assumption 1: Like the rest of the vectorizer, this function assumes |
| a single loop exit that has a single predecessor. |
| |
| Assumption 2: The phi nodes in the LOOP header and in update_bb are |
| organized in the same order. |
| |
| Assumption 3: The access function of the ivs is simple enough (see |
| vect_can_advance_ivs_p). This assumption will be relaxed in the future. |
| |
| Assumption 4: Exactly one of the successors of LOOP exit-bb is on a path |
| coming out of LOOP on which the ivs of LOOP are used (this is the path |
| that leads to the epilog loop; other paths skip the epilog loop). This |
| path starts with the edge UPDATE_E, and its destination (denoted update_bb) |
| needs to have its phis updated. |
| */ |
| |
| static void |
| vect_update_ivs_after_vectorizer (loop_vec_info loop_vinfo, |
| tree niters, edge update_e) |
| { |
| gphi_iterator gsi, gsi1; |
| struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
| basic_block update_bb = update_e->dest; |
| basic_block exit_bb = single_exit (loop)->dest; |
| |
| /* Make sure there exists a single-predecessor exit bb: */ |
| gcc_assert (single_pred_p (exit_bb)); |
| gcc_assert (single_succ_edge (exit_bb) == update_e); |
| |
| for (gsi = gsi_start_phis (loop->header), gsi1 = gsi_start_phis (update_bb); |
| !gsi_end_p (gsi) && !gsi_end_p (gsi1); |
| gsi_next (&gsi), gsi_next (&gsi1)) |
| { |
| tree init_expr; |
| tree step_expr, off; |
| tree type; |
| tree var, ni, ni_name; |
| gimple_stmt_iterator last_gsi; |
| |
| gphi *phi = gsi.phi (); |
| gphi *phi1 = gsi1.phi (); |
| if (dump_enabled_p ()) |
| { |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "vect_update_ivs_after_vectorizer: phi: "); |
| dump_gimple_stmt (MSG_NOTE, TDF_SLIM, phi, 0); |
| } |
| |
| /* Skip reduction and virtual phis. */ |
| if (!iv_phi_p (phi)) |
| { |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "reduc or virtual phi. skip.\n"); |
| continue; |
| } |
| |
| type = TREE_TYPE (gimple_phi_result (phi)); |
| step_expr = STMT_VINFO_LOOP_PHI_EVOLUTION_PART (vinfo_for_stmt (phi)); |
| step_expr = unshare_expr (step_expr); |
| |
| /* FORNOW: We do not support IVs whose evolution function is a polynomial |
| of degree >= 2 or exponential. */ |
| gcc_assert (!tree_is_chrec (step_expr)); |
| |
| init_expr = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop)); |
| |
| off = fold_build2 (MULT_EXPR, TREE_TYPE (step_expr), |
| fold_convert (TREE_TYPE (step_expr), niters), |
| step_expr); |
| if (POINTER_TYPE_P (type)) |
| ni = fold_build_pointer_plus (init_expr, off); |
| else |
| ni = fold_build2 (PLUS_EXPR, type, |
| init_expr, fold_convert (type, off)); |
| |
| var = create_tmp_var (type, "tmp"); |
| |
| last_gsi = gsi_last_bb (exit_bb); |
| gimple_seq new_stmts = NULL; |
| ni_name = force_gimple_operand (ni, &new_stmts, false, var); |
| /* Exit_bb shouldn't be empty. */ |
| if (!gsi_end_p (last_gsi)) |
| gsi_insert_seq_after (&last_gsi, new_stmts, GSI_SAME_STMT); |
| else |
| gsi_insert_seq_before (&last_gsi, new_stmts, GSI_SAME_STMT); |
| |
| /* Fix phi expressions in the successor bb. */ |
| adjust_phi_and_debug_stmts (phi1, update_e, ni_name); |
| } |
| } |
| |
| /* Function vect_gen_prolog_loop_niters |
| |
| Generate the number of iterations which should be peeled as prolog for the |
| loop represented by LOOP_VINFO. It is calculated as the misalignment of |
| DR - the data reference recorded in LOOP_VINFO_UNALIGNED_DR (LOOP_VINFO). |
| As a result, after the execution of this loop, the data reference DR will |
| refer to an aligned location. The following computation is generated: |
| |
| If the misalignment of DR is known at compile time: |
| addr_mis = int mis = DR_MISALIGNMENT (dr); |
| Else, compute address misalignment in bytes: |
| addr_mis = addr & (vectype_align - 1) |
| |
| prolog_niters = ((VF - addr_mis/elem_size)&(VF-1))/step |
| |
| (elem_size = element type size; an element is the scalar element whose type |
| is the inner type of the vectype) |
| |
| The computations will be emitted at the end of BB. We also compute and |
| store upper bound (included) of the result in BOUND. |
| |
| When the step of the data-ref in the loop is not 1 (as in interleaved data |
| and SLP), the number of iterations of the prolog must be divided by the step |
| (which is equal to the size of interleaved group). |
| |
| The above formulas assume that VF == number of elements in the vector. This |
| may not hold when there are multiple-types in the loop. |
| In this case, for some data-references in the loop the VF does not represent |
| the number of elements that fit in the vector. Therefore, instead of VF we |
| use TYPE_VECTOR_SUBPARTS. */ |
| |
| static tree |
| vect_gen_prolog_loop_niters (loop_vec_info loop_vinfo, |
| basic_block bb, int *bound) |
| { |
| struct data_reference *dr = LOOP_VINFO_UNALIGNED_DR (loop_vinfo); |
| tree var; |
| tree niters_type = TREE_TYPE (LOOP_VINFO_NITERS (loop_vinfo)); |
| gimple_seq stmts = NULL, new_stmts = NULL; |
| tree iters, iters_name; |
| gimple *dr_stmt = DR_STMT (dr); |
| stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt); |
| tree vectype = STMT_VINFO_VECTYPE (stmt_info); |
| unsigned int target_align = DR_TARGET_ALIGNMENT (dr); |
| |
| if (LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0) |
| { |
| int npeel = LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo); |
| |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "known peeling = %d.\n", npeel); |
| |
| iters = build_int_cst (niters_type, npeel); |
| *bound = LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo); |
| } |
| else |
| { |
| bool negative = tree_int_cst_compare (DR_STEP (dr), size_zero_node) < 0; |
| tree offset = negative |
| ? size_int (-TYPE_VECTOR_SUBPARTS (vectype) + 1) : size_zero_node; |
| tree start_addr = vect_create_addr_base_for_vector_ref (dr_stmt, |
| &stmts, offset); |
| tree type = unsigned_type_for (TREE_TYPE (start_addr)); |
| tree target_align_minus_1 = build_int_cst (type, target_align - 1); |
| HOST_WIDE_INT elem_size |
| = int_cst_value (TYPE_SIZE_UNIT (TREE_TYPE (vectype))); |
| tree elem_size_log = build_int_cst (type, exact_log2 (elem_size)); |
| HOST_WIDE_INT align_in_elems = target_align / elem_size; |
| tree align_in_elems_minus_1 = build_int_cst (type, align_in_elems - 1); |
| tree align_in_elems_tree = build_int_cst (type, align_in_elems); |
| tree misalign_in_bytes; |
| tree misalign_in_elems; |
| |
| /* Create: misalign_in_bytes = addr & (target_align - 1). */ |
| misalign_in_bytes |
| = fold_build2 (BIT_AND_EXPR, type, fold_convert (type, start_addr), |
| target_align_minus_1); |
| |
| /* Create: misalign_in_elems = misalign_in_bytes / element_size. */ |
| misalign_in_elems |
| = fold_build2 (RSHIFT_EXPR, type, misalign_in_bytes, elem_size_log); |
| |
| /* Create: (niters_type) ((align_in_elems - misalign_in_elems) |
| & (align_in_elems - 1)). */ |
| if (negative) |
| iters = fold_build2 (MINUS_EXPR, type, misalign_in_elems, |
| align_in_elems_tree); |
| else |
| iters = fold_build2 (MINUS_EXPR, type, align_in_elems_tree, |
| misalign_in_elems); |
| iters = fold_build2 (BIT_AND_EXPR, type, iters, align_in_elems_minus_1); |
| iters = fold_convert (niters_type, iters); |
| *bound = align_in_elems - 1; |
| } |
| |
| if (dump_enabled_p ()) |
| { |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "niters for prolog loop: "); |
| dump_generic_expr (MSG_NOTE, TDF_SLIM, iters); |
| dump_printf (MSG_NOTE, "\n"); |
| } |
| |
| var = create_tmp_var (niters_type, "prolog_loop_niters"); |
| iters_name = force_gimple_operand (iters, &new_stmts, false, var); |
| |
| if (new_stmts) |
| gimple_seq_add_seq (&stmts, new_stmts); |
| if (stmts) |
| { |
| gcc_assert (single_succ_p (bb)); |
| gimple_stmt_iterator gsi = gsi_last_bb (bb); |
| if (gsi_end_p (gsi)) |
| gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT); |
| else |
| gsi_insert_seq_after (&gsi, stmts, GSI_SAME_STMT); |
| } |
| return iters_name; |
| } |
| |
| |
| /* Function vect_update_init_of_dr |
| |
| NITERS iterations were peeled from LOOP. DR represents a data reference |
| in LOOP. This function updates the information recorded in DR to |
| account for the fact that the first NITERS iterations had already been |
| executed. Specifically, it updates the OFFSET field of DR. */ |
| |
| static void |
| vect_update_init_of_dr (struct data_reference *dr, tree niters) |
| { |
| tree offset = DR_OFFSET (dr); |
| |
| niters = fold_build2 (MULT_EXPR, sizetype, |
| fold_convert (sizetype, niters), |
| fold_convert (sizetype, DR_STEP (dr))); |
| offset = fold_build2 (PLUS_EXPR, sizetype, |
| fold_convert (sizetype, offset), niters); |
| DR_OFFSET (dr) = offset; |
| } |
| |
| |
| /* Function vect_update_inits_of_drs |
| |
| NITERS iterations were peeled from the loop represented by LOOP_VINFO. |
| This function updates the information recorded for the data references in |
| the loop to account for the fact that the first NITERS iterations had |
| already been executed. Specifically, it updates the initial_condition of |
| the access_function of all the data_references in the loop. */ |
| |
| static void |
| vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters) |
| { |
| unsigned int i; |
| vec<data_reference_p> datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); |
| struct data_reference *dr; |
| |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "=== vect_update_inits_of_dr ===\n"); |
| |
| /* Adjust niters to sizetype and insert stmts on loop preheader edge. */ |
| if (!types_compatible_p (sizetype, TREE_TYPE (niters))) |
| { |
| gimple_seq seq; |
| edge pe = loop_preheader_edge (LOOP_VINFO_LOOP (loop_vinfo)); |
| tree var = create_tmp_var (sizetype, "prolog_loop_adjusted_niters"); |
| |
| niters = fold_convert (sizetype, niters); |
| niters = force_gimple_operand (niters, &seq, false, var); |
| if (seq) |
| { |
| basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, seq); |
| gcc_assert (!new_bb); |
| } |
| } |
| |
| FOR_EACH_VEC_ELT (datarefs, i, dr) |
| vect_update_init_of_dr (dr, niters); |
| } |
| |
| |
| /* This function builds ni_name = number of iterations. Statements |
| are emitted on the loop preheader edge. If NEW_VAR_P is not NULL, set |
| it to TRUE if new ssa_var is generated. */ |
| |
| tree |
| vect_build_loop_niters (loop_vec_info loop_vinfo, bool *new_var_p) |
| { |
| tree ni = unshare_expr (LOOP_VINFO_NITERS (loop_vinfo)); |
| if (TREE_CODE (ni) == INTEGER_CST) |
| return ni; |
| else |
| { |
| tree ni_name, var; |
| gimple_seq stmts = NULL; |
| edge pe = loop_preheader_edge (LOOP_VINFO_LOOP (loop_vinfo)); |
| |
| var = create_tmp_var (TREE_TYPE (ni), "niters"); |
| ni_name = force_gimple_operand (ni, &stmts, false, var); |
| if (stmts) |
| { |
| gsi_insert_seq_on_edge_immediate (pe, stmts); |
| if (new_var_p != NULL) |
| *new_var_p = true; |
| } |
| |
| return ni_name; |
| } |
| } |
| |
| /* Calculate the number of iterations above which vectorized loop will be |
| preferred than scalar loop. NITERS_PROLOG is the number of iterations |
| of prolog loop. If it's integer const, the integer number is also passed |
| in INT_NITERS_PROLOG. BOUND_PROLOG is the upper bound (included) of |
| number of iterations of prolog loop. VFM1 is vector factor minus one. |
| If CHECK_PROFITABILITY is true, TH is the threshold below which scalar |
| (rather than vectorized) loop will be executed. This function stores |
| upper bound (included) of the result in BOUND_SCALAR. */ |
| |
| static tree |
| vect_gen_scalar_loop_niters (tree niters_prolog, int int_niters_prolog, |
| int bound_prolog, int vfm1, int th, |
| int *bound_scalar, bool check_profitability) |
| { |
| tree type = TREE_TYPE (niters_prolog); |
| tree niters = fold_build2 (PLUS_EXPR, type, niters_prolog, |
| build_int_cst (type, vfm1)); |
| |
| *bound_scalar = vfm1 + bound_prolog; |
| if (check_profitability) |
| { |
| /* TH indicates the minimum niters of vectorized loop, while we |
| compute the maximum niters of scalar loop. */ |
| th--; |
| /* Peeling for constant times. */ |
| if (int_niters_prolog >= 0) |
| { |
| *bound_scalar = (int_niters_prolog + vfm1 < th |
| ? th |
| : vfm1 + int_niters_prolog); |
| return build_int_cst (type, *bound_scalar); |
| } |
| /* Peeling for unknown times. Note BOUND_PROLOG is the upper |
| bound (inlcuded) of niters of prolog loop. */ |
| if (th >= vfm1 + bound_prolog) |
| { |
| *bound_scalar = th; |
| return build_int_cst (type, th); |
| } |
| /* Need to do runtime comparison, but BOUND_SCALAR remains the same. */ |
| else if (th > vfm1) |
| return fold_build2 (MAX_EXPR, type, build_int_cst (type, th), niters); |
| } |
| return niters; |
| } |
| |
| /* This function generates the following statements: |
| |
| niters = number of iterations loop executes (after peeling) |
| niters_vector = niters / vf |
| |
| and places them on the loop preheader edge. NITERS_NO_OVERFLOW is |
| true if NITERS doesn't overflow. */ |
| |
| void |
| vect_gen_vector_loop_niters (loop_vec_info loop_vinfo, tree niters, |
| tree *niters_vector_ptr, bool niters_no_overflow) |
| { |
| tree ni_minus_gap, var; |
| tree niters_vector, type = TREE_TYPE (niters); |
| int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); |
| edge pe = loop_preheader_edge (LOOP_VINFO_LOOP (loop_vinfo)); |
| tree log_vf = build_int_cst (type, exact_log2 (vf)); |
| |
| /* If epilogue loop is required because of data accesses with gaps, we |
| subtract one iteration from the total number of iterations here for |
| correct calculation of RATIO. */ |
| if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)) |
| { |
| ni_minus_gap = fold_build2 (MINUS_EXPR, type, niters, |
| build_one_cst (type)); |
| if (!is_gimple_val (ni_minus_gap)) |
| { |
| var = create_tmp_var (type, "ni_gap"); |
| gimple *stmts = NULL; |
| ni_minus_gap = force_gimple_operand (ni_minus_gap, &stmts, |
| true, var); |
| gsi_insert_seq_on_edge_immediate (pe, stmts); |
| } |
| } |
| else |
| ni_minus_gap = niters; |
| |
| /* Create: niters >> log2(vf) */ |
| /* If it's known that niters == number of latch executions + 1 doesn't |
| overflow, we can generate niters >> log2(vf); otherwise we generate |
| (niters - vf) >> log2(vf) + 1 by using the fact that we know ratio |
| will be at least one. */ |
| if (niters_no_overflow) |
| niters_vector = fold_build2 (RSHIFT_EXPR, type, ni_minus_gap, log_vf); |
| else |
| niters_vector |
| = fold_build2 (PLUS_EXPR, type, |
| fold_build2 (RSHIFT_EXPR, type, |
| fold_build2 (MINUS_EXPR, type, ni_minus_gap, |
| build_int_cst (type, vf)), |
| log_vf), |
| build_int_cst (type, 1)); |
| |
| if (!is_gimple_val (niters_vector)) |
| { |
| var = create_tmp_var (type, "bnd"); |
| gimple_seq stmts = NULL; |
| niters_vector = force_gimple_operand (niters_vector, &stmts, true, var); |
| gsi_insert_seq_on_edge_immediate (pe, stmts); |
| /* Peeling algorithm guarantees that vector loop bound is at least ONE, |
| we set range information to make niters analyzer's life easier. */ |
| if (stmts != NULL) |
| set_range_info (niters_vector, VR_RANGE, |
| wi::to_wide (build_int_cst (type, 1)), |
| wi::to_wide (fold_build2 (RSHIFT_EXPR, type, |
| TYPE_MAX_VALUE (type), |
| log_vf))); |
| } |
| *niters_vector_ptr = niters_vector; |
| |
| return; |
| } |
| |
| /* Given NITERS_VECTOR which is the number of iterations for vectorized |
| loop specified by LOOP_VINFO after vectorization, compute the number |
| of iterations before vectorization (niters_vector * vf) and store it |
| to NITERS_VECTOR_MULT_VF_PTR. */ |
| |
| static void |
| vect_gen_vector_loop_niters_mult_vf (loop_vec_info loop_vinfo, |
| tree niters_vector, |
| tree *niters_vector_mult_vf_ptr) |
| { |
| int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); |
| struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
| tree type = TREE_TYPE (niters_vector); |
| tree log_vf = build_int_cst (type, exact_log2 (vf)); |
| basic_block exit_bb = single_exit (loop)->dest; |
| |
| gcc_assert (niters_vector_mult_vf_ptr != NULL); |
| tree niters_vector_mult_vf = fold_build2 (LSHIFT_EXPR, type, |
| niters_vector, log_vf); |
| if (!is_gimple_val (niters_vector_mult_vf)) |
| { |
| tree var = create_tmp_var (type, "niters_vector_mult_vf"); |
| gimple_seq stmts = NULL; |
| niters_vector_mult_vf = force_gimple_operand (niters_vector_mult_vf, |
| &stmts, true, var); |
| gimple_stmt_iterator gsi = gsi_start_bb (exit_bb); |
| gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT); |
| } |
| *niters_vector_mult_vf_ptr = niters_vector_mult_vf; |
| } |
| |
| /* Function slpeel_tree_duplicate_loop_to_edge_cfg duplciates FIRST/SECOND |
| from SECOND/FIRST and puts it at the original loop's preheader/exit |
| edge, the two loops are arranged as below: |
| |
| preheader_a: |
| first_loop: |
| header_a: |
| i_1 = PHI<i_0, i_2>; |
| ... |
| i_2 = i_1 + 1; |
| if (cond_a) |
| goto latch_a; |
| else |
| goto between_bb; |
| latch_a: |
| goto header_a; |
| |
| between_bb: |
| ;; i_x = PHI<i_2>; ;; LCSSA phi node to be created for FIRST, |
| |
| second_loop: |
| header_b: |
| i_3 = PHI<i_0, i_4>; ;; Use of i_0 to be replaced with i_x, |
| or with i_2 if no LCSSA phi is created |
| under condition of CREATE_LCSSA_FOR_IV_PHIS. |
| ... |
| i_4 = i_3 + 1; |
| if (cond_b) |
| goto latch_b; |
| else |
| goto exit_bb; |
| latch_b: |
| goto header_b; |
| |
| exit_bb: |
| |
| This function creates loop closed SSA for the first loop; update the |
| second loop's PHI nodes by replacing argument on incoming edge with the |
| result of newly created lcssa PHI nodes. IF CREATE_LCSSA_FOR_IV_PHIS |
| is false, Loop closed ssa phis will only be created for non-iv phis for |
| the first loop. |
| |
| This function assumes exit bb of the first loop is preheader bb of the |
| second loop, i.e, between_bb in the example code. With PHIs updated, |
| the second loop will execute rest iterations of the first. */ |
| |
| static void |
| slpeel_update_phi_nodes_for_loops (loop_vec_info loop_vinfo, |
| struct loop *first, struct loop *second, |
| bool create_lcssa_for_iv_phis) |
| { |
| gphi_iterator gsi_update, gsi_orig; |
| struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); |
| |
| edge first_latch_e = EDGE_SUCC (first->latch, 0); |
| edge second_preheader_e = loop_preheader_edge (second); |
| basic_block between_bb = single_exit (first)->dest; |
| |
| gcc_assert (between_bb == second_preheader_e->src); |
| gcc_assert (single_pred_p (between_bb) && single_succ_p (between_bb)); |
| /* Either the first loop or the second is the loop to be vectorized. */ |
| gcc_assert (loop == first || loop == second); |
| |
| for (gsi_orig = gsi_start_phis (first->header), |
| gsi_update = gsi_start_phis (second->header); |
| !gsi_end_p (gsi_orig) && !gsi_end_p (gsi_update); |
| gsi_next (&gsi_orig), gsi_next (&gsi_update)) |
| { |
| gphi *orig_phi = gsi_orig.phi (); |
| gphi *update_phi = gsi_update.phi (); |
| |
| tree arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, first_latch_e); |
| /* Generate lcssa PHI node for the first loop. */ |
| gphi *vect_phi = (loop == first) ? orig_phi : update_phi; |
| if (create_lcssa_for_iv_phis || !iv_phi_p (vect_phi)) |
| { |
| tree new_res = copy_ssa_name (PHI_RESULT (orig_phi)); |
| gphi *lcssa_phi = create_phi_node (new_res, between_bb); |
| add_phi_arg (lcssa_phi, arg, single_exit (first), UNKNOWN_LOCATION); |
| arg = new_res; |
| } |
| |
| /* Update PHI node in the second loop by replacing arg on the loop's |
| incoming edge. */ |
| adjust_phi_and_debug_stmts (update_phi, second_preheader_e, arg); |
| } |
| } |
| |
| /* Function slpeel_add_loop_guard adds guard skipping from the beginning |
| of SKIP_LOOP to the beginning of UPDATE_LOOP. GUARD_EDGE and MERGE_EDGE |
| are two pred edges of the merge point before UPDATE_LOOP. The two loops |
| appear like below: |
| |
| guard_bb: |
| if (cond) |
| goto merge_bb; |
| else |
| goto skip_loop; |
| |
| skip_loop: |
| header_a: |
| i_1 = PHI<i_0, i_2>; |
| ... |
| i_2 = i_1 + 1; |
| if (cond_a) |
| goto latch_a; |
| else |
| goto exit_a; |
| latch_a: |
| goto header_a; |
| |
| exit_a: |
| i_5 = PHI<i_2>; |
| |
| merge_bb: |
| ;; PHI (i_x = PHI<i_0, i_5>) to be created at merge point. |
| |
| update_loop: |
| header_b: |
| i_3 = PHI<i_5, i_4>; ;; Use of i_5 to be replaced with i_x. |
| ... |
| i_4 = i_3 + 1; |
| if (cond_b) |
| goto latch_b; |
| else |
| goto exit_bb; |
| latch_b: |
| goto header_b; |
| |
| exit_bb: |
| |
| This function creates PHI nodes at merge_bb and replaces the use of i_5 |
| in the update_loop's PHI node with the result of new PHI result. */ |
| |
| static void |
| slpeel_update_phi_nodes_for_guard1 (struct loop *skip_loop, |
| struct loop *update_loop, |
| edge guard_edge, edge merge_edge) |
| { |
| source_location merge_loc, guard_loc; |
| edge orig_e = loop_preheader_edge (skip_loop); |
| edge update_e = loop_preheader_edge (update_loop); |
| gphi_iterator gsi_orig, gsi_update; |
| |
| for ((gsi_orig = gsi_start_phis (skip_loop->header), |
| gsi_update = gsi_start_phis (update_loop->header)); |
| !gsi_end_p (gsi_orig) && !gsi_end_p (gsi_update); |
| gsi_next (&gsi_orig), gsi_next (&gsi_update)) |
| { |
| gphi *orig_phi = gsi_orig.phi (); |
| gphi *update_phi = gsi_update.phi (); |
| |
| /* Generate new phi node at merge bb of the guard. */ |
| tree new_res = copy_ssa_name (PHI_RESULT (orig_phi)); |
| gphi *new_phi = create_phi_node (new_res, guard_edge->dest); |
| |
| /* Merge bb has two incoming edges: GUARD_EDGE and MERGE_EDGE. Set the |
| args in NEW_PHI for these edges. */ |
| tree merge_arg = PHI_ARG_DEF_FROM_EDGE (update_phi, update_e); |
| tree guard_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, orig_e); |
| merge_loc = gimple_phi_arg_location_from_edge (update_phi, update_e); |
| guard_loc = gimple_phi_arg_location_from_edge (orig_phi, orig_e); |
| add_phi_arg (new_phi, merge_arg, merge_edge, merge_loc); |
| add_phi_arg (new_phi, guard_arg, guard_edge, guard_loc); |
| |
| /* Update phi in UPDATE_PHI. */ |
| adjust_phi_and_debug_stmts (update_phi, update_e, new_res); |
| } |
| } |
| |
| /* LCSSA_PHI is a lcssa phi of EPILOG loop which is copied from LOOP, |
| this function searches for the corresponding lcssa phi node in exit |
| bb of LOOP. If it is found, return the phi result; otherwise return |
| NULL. */ |
| |
| static tree |
| find_guard_arg (struct loop *loop, struct loop *epilog ATTRIBUTE_UNUSED, |
| gphi *lcssa_phi) |
| { |
| gphi_iterator gsi; |
| edge e = single_exit (loop); |
| |
| gcc_assert (single_pred_p (e->dest)); |
| for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| gphi *phi = gsi.phi (); |
| if (operand_equal_p (PHI_ARG_DEF (phi, 0), |
| PHI_ARG_DEF (lcssa_phi, 0), 0)) |
| return PHI_RESULT (phi); |
| } |
| return NULL_TREE; |
| } |
| |
| /* LOOP and EPILOG are two consecutive loops in CFG and EPILOG is copied |
| from LOOP. Function slpeel_add_loop_guard adds guard skipping from a |
| point between the two loops to the end of EPILOG. Edges GUARD_EDGE |
| and MERGE_EDGE are the two pred edges of merge_bb at the end of EPILOG. |
| The CFG looks like: |
| |
| loop: |
| header_a: |
| i_1 = PHI<i_0, i_2>; |
| ... |
| i_2 = i_1 + 1; |
| if (cond_a) |
| goto latch_a; |
| else |
| goto exit_a; |
| latch_a: |
| goto header_a; |
| |
| exit_a: |
| |
| guard_bb: |
| if (cond) |
| goto merge_bb; |
| else |
| goto epilog_loop; |
| |
| ;; fall_through_bb |
| |
| epilog_loop: |
| header_b: |
| i_3 = PHI<i_2, i_4>; |
| ... |
| i_4 = i_3 + 1; |
| if (cond_b) |
| goto latch_b; |
| else |
| goto merge_bb; |
| latch_b: |
| goto header_b; |
| |
| merge_bb: |
| ; PHI node (i_y = PHI<i_2, i_4>) to be created at merge point. |
| |
| exit_bb: |
| i_x = PHI<i_4>; ;Use of i_4 to be replaced with i_y in merge_bb. |
| |
| For each name used out side EPILOG (i.e - for each name that has a lcssa |
| phi in exit_bb) we create a new PHI in merge_bb. The new PHI has two |
| args corresponding to GUARD_EDGE and MERGE_EDGE. Arg for MERGE_EDGE is |
| the arg of the original PHI in exit_bb, arg for GUARD_EDGE is defined |
| by LOOP and is found in the exit bb of LOOP. Arg of the original PHI |
| in exit_bb will also be updated. */ |
| |
| static void |
| slpeel_update_phi_nodes_for_guard2 (struct loop *loop, struct loop *epilog, |
| edge guard_edge, edge merge_edge) |
| { |
| gphi_iterator gsi; |
| basic_block merge_bb = guard_edge->dest; |
| |
| gcc_assert (single_succ_p (merge_bb)); |
| edge e = single_succ_edge (merge_bb); |
| basic_block exit_bb = e->dest; |
| gcc_assert (single_pred_p (exit_bb)); |
| gcc_assert (single_pred (exit_bb) == single_exit (epilog)->dest); |
| |
| for (gsi = gsi_start_phis (exit_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| gphi *update_phi = gsi.phi (); |
| tree old_arg = PHI_ARG_DEF (update_phi, 0); |
| /* This loop-closed-phi actually doesn't represent a use out of the |
| loop - the phi arg is a constant. */ |
| if (TREE_CODE (old_arg) != SSA_NAME) |
| continue; |
| |
| tree merge_arg = get_current_def (old_arg); |
| if (!merge_arg) |
| merge_arg = old_arg; |
| |
| tree guard_arg = find_guard_arg (loop, epilog, update_phi); |
| /* If the var is live after loop but not a reduction, we simply |
| use the old arg. */ |
| if (!guard_arg) |
| guard_arg = old_arg; |
| |
| /* Create new phi node in MERGE_BB: */ |
| tree new_res = copy_ssa_name (PHI_RESULT (update_phi)); |
| gphi *merge_phi = create_phi_node (new_res, merge_bb); |
| |
| /* MERGE_BB has two incoming edges: GUARD_EDGE and MERGE_EDGE, Set |
| the two PHI args in merge_phi for these edges. */ |
| add_phi_arg (merge_phi, merge_arg, merge_edge, UNKNOWN_LOCATION); |
| add_phi_arg (merge_phi, guard_arg, guard_edge, UNKNOWN_LOCATION); |
| |
| /* Update the original phi in exit_bb. */ |
| adjust_phi_and_debug_stmts (update_phi, e, new_res); |
| } |
| } |
| |
| /* EPILOG loop is duplicated from the original loop for vectorizing, |
| the arg of its loop closed ssa PHI needs to be updated. */ |
| |
| static void |
| slpeel_update_phi_nodes_for_lcssa (struct loop *epilog) |
| { |
| gphi_iterator gsi; |
| basic_block exit_bb = single_exit (epilog)->dest; |
| |
| gcc_assert (single_pred_p (exit_bb)); |
| edge e = EDGE_PRED (exit_bb, 0); |
| for (gsi = gsi_start_phis (exit_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| rename_use_op (PHI_ARG_DEF_PTR_FROM_EDGE (gsi.phi (), e)); |
| } |
| |
| /* Function vect_do_peeling. |
| |
| Input: |
| - LOOP_VINFO: Represent a loop to be vectorized, which looks like: |
| |
| preheader: |
| LOOP: |
| header_bb: |
| loop_body |
| if (exit_loop_cond) goto exit_bb |
| else goto header_bb |
| exit_bb: |
| |
| - NITERS: The number of iterations of the loop. |
| - NITERSM1: The number of iterations of the loop's latch. |
| - NITERS_NO_OVERFLOW: No overflow in computing NITERS. |
| - TH, CHECK_PROFITABILITY: Threshold of niters to vectorize loop if |
| CHECK_PROFITABILITY is true. |
| Output: |
| - NITERS_VECTOR: The number of iterations of loop after vectorization. |
| |
| This function peels prolog and epilog from the loop, adds guards skipping |
| PROLOG and EPILOG for various conditions. As a result, the changed CFG |
| would look like: |
| |
| guard_bb_1: |
| if (prefer_scalar_loop) goto merge_bb_1 |
| else goto guard_bb_2 |
| |
| guard_bb_2: |
| if (skip_prolog) goto merge_bb_2 |
| else goto prolog_preheader |
| |
| prolog_preheader: |
| PROLOG: |
| prolog_header_bb: |
| prolog_body |
| if (exit_prolog_cond) goto prolog_exit_bb |
| else goto prolog_header_bb |
| prolog_exit_bb: |
| |
| merge_bb_2: |
| |
| vector_preheader: |
| VECTOR LOOP: |
| vector_header_bb: |
| vector_body |
| if (exit_vector_cond) goto vector_exit_bb |
| else goto vector_header_bb |
| vector_exit_bb: |
| |
| guard_bb_3: |
| if (skip_epilog) goto merge_bb_3 |
| else goto epilog_preheader |
| |
| merge_bb_1: |
| |
| epilog_preheader: |
| EPILOG: |
| epilog_header_bb: |
| epilog_body |
| if (exit_epilog_cond) goto merge_bb_3 |
| else goto epilog_header_bb |
| |
| merge_bb_3: |
| |
| Note this function peels prolog and epilog only if it's necessary, |
| as well as guards. |
| Returns created epilogue or NULL. |
| |
| TODO: Guard for prefer_scalar_loop should be emitted along with |
| versioning conditions if loop versioning is needed. */ |
| |
| |
| struct loop * |
| vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1, |
| tree *niters_vector, int th, bool check_profitability, |
| bool niters_no_overflow) |
| { |
| edge e, guard_e; |
| tree type = TREE_TYPE (niters), guard_cond; |
| basic_block guard_bb, guard_to; |
| profile_probability prob_prolog, prob_vector, prob_epilog; |
| int bound_prolog = 0, bound_scalar = 0, bound = 0; |
| int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); |
| int prolog_peeling = LOOP_VINFO_PEELING_FOR_ALIGNMENT (loop_vinfo); |
| bool epilog_peeling = (LOOP_VINFO_PEELING_FOR_NITER (loop_vinfo) |
| || LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)); |
| |
| if (!prolog_peeling && !epilog_peeling) |
| return NULL; |
| |
| prob_vector = profile_probability::guessed_always ().apply_scale (9, 10); |
| if ((vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo)) == 2) |
| vf = 3; |
| prob_prolog = prob_epilog = profile_probability::guessed_always () |
| .apply_scale (vf - 1, vf); |
| vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); |
| |
| struct loop *prolog, *epilog = NULL, *loop = LOOP_VINFO_LOOP (loop_vinfo); |
| struct loop *first_loop = loop; |
| bool irred_flag = loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP; |
| create_lcssa_for_virtual_phi (loop); |
| update_ssa (TODO_update_ssa_only_virtuals); |
| |
| if (MAY_HAVE_DEBUG_STMTS) |
| { |
| gcc_assert (!adjust_vec.exists ()); |
| adjust_vec.create (32); |
| } |
| initialize_original_copy_tables (); |
| |
| /* Prolog loop may be skipped. */ |
| bool skip_prolog = (prolog_peeling != 0); |
| /* Skip to epilog if scalar loop may be preferred. It's only needed |
| when we peel for epilog loop and when it hasn't been checked with |
| loop versioning. */ |
| bool skip_vector = (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo) |
| && !LOOP_REQUIRES_VERSIONING (loop_vinfo)); |
| /* Epilog loop must be executed if the number of iterations for epilog |
| loop is known at compile time, otherwise we need to add a check at |
| the end of vector loop and skip to the end of epilog loop. */ |
| bool skip_epilog = (prolog_peeling < 0 |
| || !LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)); |
| /* PEELING_FOR_GAPS is special because epilog loop must be executed. */ |
| if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)) |
| skip_epilog = false; |
| |
| /* Record the anchor bb at which guard should be placed if scalar loop |
| may be preferred. */ |
| basic_block anchor = loop_preheader_edge (loop)->src; |
| if (skip_vector) |
| { |
| split_edge (loop_preheader_edge (loop)); |
| |
| /* Due to the order in which we peel prolog and epilog, we first |
| propagate probability to the whole loop. The purpose is to |
| avoid adjusting probabilities of both prolog and vector loops |
| separately. Note in this case, the probability of epilog loop |
| needs to be scaled back later. */ |
| basic_block bb_before_loop = loop_preheader_edge (loop)->src; |
| if (prob_vector.initialized_p ()) |
| scale_bbs_frequencies (&bb_before_loop, 1, prob_vector); |
| scale_loop_profile (loop, prob_vector, bound); |
| } |
| |
| tree niters_prolog = build_int_cst (type, 0); |
| source_location loop_loc = find_loop_location (loop); |
| struct loop *scalar_loop = LOOP_VINFO_SCALAR_LOOP (loop_vinfo); |
| if (prolog_peeling) |
| { |
| e = loop_preheader_edge (loop); |
| if (!slpeel_can_duplicate_loop_p (loop, e)) |
| { |
| dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc, |
| "loop can't be duplicated to preheader edge.\n"); |
| gcc_unreachable (); |
| } |
| /* Peel prolog and put it on preheader edge of loop. */ |
| prolog = slpeel_tree_duplicate_loop_to_edge_cfg (loop, scalar_loop, e); |
| if (!prolog) |
| { |
| dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc, |
| "slpeel_tree_duplicate_loop_to_edge_cfg failed.\n"); |
| gcc_unreachable (); |
| } |
| slpeel_update_phi_nodes_for_loops (loop_vinfo, prolog, loop, true); |
| first_loop = prolog; |
| reset_original_copy_tables (); |
| |
| /* Generate and update the number of iterations for prolog loop. */ |
| niters_prolog = vect_gen_prolog_loop_niters (loop_vinfo, anchor, |
| &bound_prolog); |
| slpeel_make_loop_iterate_ntimes (prolog, niters_prolog); |
| |
| /* Skip the prolog loop. */ |
| if (skip_prolog) |
| { |
| guard_cond = fold_build2 (EQ_EXPR, boolean_type_node, |
| niters_prolog, build_int_cst (type, 0)); |
| guard_bb = loop_preheader_edge (prolog)->src; |
| basic_block bb_after_prolog = loop_preheader_edge (loop)->src; |
| guard_to = split_edge (loop_preheader_edge (loop)); |
| guard_e = slpeel_add_loop_guard (guard_bb, guard_cond, |
| guard_to, guard_bb, |
| prob_prolog.invert (), |
| irred_flag); |
| e = EDGE_PRED (guard_to, 0); |
| e = (e != guard_e ? e : EDGE_PRED (guard_to, 1)); |
| slpeel_update_phi_nodes_for_guard1 (prolog, loop, guard_e, e); |
| |
| scale_bbs_frequencies (&bb_after_prolog, 1, prob_prolog); |
| scale_loop_profile (prolog, prob_prolog, bound_prolog); |
| } |
| /* Update init address of DRs. */ |
| vect_update_inits_of_drs (loop_vinfo, niters_prolog); |
| /* Update niters for vector loop. */ |
| LOOP_VINFO_NITERS (loop_vinfo) |
| = fold_build2 (MINUS_EXPR, type, niters, niters_prolog); |
| LOOP_VINFO_NITERSM1 (loop_vinfo) |
| = fold_build2 (MINUS_EXPR, type, |
| LOOP_VINFO_NITERSM1 (loop_vinfo), niters_prolog); |
| bool new_var_p = false; |
| niters = vect_build_loop_niters (loop_vinfo, &new_var_p); |
| /* It's guaranteed that vector loop bound before vectorization is at |
| least VF, so set range information for newly generated var. */ |
| if (new_var_p) |
| set_range_info (niters, VR_RANGE, |
| wi::to_wide (build_int_cst (type, vf)), |
| wi::to_wide (TYPE_MAX_VALUE (type))); |
| |
| /* Prolog iterates at most bound_prolog times, latch iterates at |
| most bound_prolog - 1 times. */ |
| record_niter_bound (prolog, bound_prolog - 1, false, true); |
| delete_update_ssa (); |
| adjust_vec_debug_stmts (); |
| scev_reset (); |
| } |
| |
| if (epilog_peeling) |
| { |
| e = single_exit (loop); |
| if (!slpeel_can_duplicate_loop_p (loop, e)) |
| { |
| dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc, |
| "loop can't be duplicated to exit edge.\n"); |
| gcc_unreachable (); |
| } |
| /* Peel epilog and put it on exit edge of loop. */ |
| epilog = slpeel_tree_duplicate_loop_to_edge_cfg (loop, scalar_loop, e); |
| if (!epilog) |
| { |
| dump_printf_loc (MSG_MISSED_OPTIMIZATION, loop_loc, |
| "slpeel_tree_duplicate_loop_to_edge_cfg failed.\n"); |
| gcc_unreachable (); |
| } |
| slpeel_update_phi_nodes_for_loops (loop_vinfo, loop, epilog, false); |
| |
| /* Scalar version loop may be preferred. In this case, add guard |
| and skip to epilog. Note this only happens when the number of |
| iterations of loop is unknown at compile time, otherwise this |
| won't be vectorized. */ |
| if (skip_vector) |
| { |
| /* Additional epilogue iteration is peeled if gap exists. */ |
| bool peel_for_gaps = LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo); |
| tree t = vect_gen_scalar_loop_niters (niters_prolog, prolog_peeling, |
| bound_prolog, |
| peel_for_gaps ? vf : vf - 1, |
| th, &bound_scalar, |
| check_profitability); |
| /* Build guard against NITERSM1 since NITERS may overflow. */ |
| guard_cond = fold_build2 (LT_EXPR, boolean_type_node, nitersm1, t); |
| guard_bb = anchor; |
| guard_to = split_edge (loop_preheader_edge (epilog)); |
| guard_e = slpeel_add_loop_guard (guard_bb, guard_cond, |
| guard_to, guard_bb, |
| prob_vector.invert (), |
| irred_flag); |
| e = EDGE_PRED (guard_to, 0); |
| e = (e != guard_e ? e : EDGE_PRED (guard_to, 1)); |
| slpeel_update_phi_nodes_for_guard1 (first_loop, epilog, guard_e, e); |
| |
| /* Simply propagate profile info from guard_bb to guard_to which is |
| a merge point of control flow. */ |
| guard_to->count = guard_bb->count; |
| |
| /* Scale probability of epilog loop back. |
| FIXME: We should avoid scaling down and back up. Profile may |
| get lost if we scale down to 0. */ |
| basic_block *bbs = get_loop_body (epilog); |
| for (unsigned int i = 0; i < epilog->num_nodes; i++) |
| bbs[i]->count = bbs[i]->count.apply_scale |
| (bbs[i]->count, |
| bbs[i]->count.apply_probability |
| (prob_vector)); |
| free (bbs); |
| } |
| |
| basic_block bb_before_epilog = loop_preheader_edge (epilog)->src; |
| tree niters_vector_mult_vf; |
| /* If loop is peeled for non-zero constant times, now niters refers to |
| orig_niters - prolog_peeling, it won't overflow even the orig_niters |
| overflows. */ |
| niters_no_overflow |= (prolog_peeling > 0); |
| vect_gen_vector_loop_niters (loop_vinfo, niters, |
| niters_vector, niters_no_overflow); |
| vect_gen_vector_loop_niters_mult_vf (loop_vinfo, *niters_vector, |
| &niters_vector_mult_vf); |
| /* Update IVs of original loop as if they were advanced by |
| niters_vector_mult_vf steps. */ |
| gcc_checking_assert (vect_can_advance_ivs_p (loop_vinfo)); |
| edge update_e = skip_vector ? e : loop_preheader_edge (epilog); |
| vect_update_ivs_after_vectorizer (loop_vinfo, niters_vector_mult_vf, |
| update_e); |
| |
| if (skip_epilog) |
| { |
| guard_cond = fold_build2 (EQ_EXPR, boolean_type_node, |
| niters, niters_vector_mult_vf); |
| guard_bb = single_exit (loop)->dest; |
| guard_to = split_edge (single_exit (epilog)); |
| guard_e = slpeel_add_loop_guard (guard_bb, guard_cond, guard_to, |
| skip_vector ? anchor : guard_bb, |
| prob_epilog.invert (), |
| irred_flag); |
| slpeel_update_phi_nodes_for_guard2 (loop, epilog, guard_e, |
| single_exit (epilog)); |
| /* Only need to handle basic block before epilog loop if it's not |
| the guard_bb, which is the case when skip_vector is true. */ |
| if (guard_bb != bb_before_epilog) |
| { |
| prob_epilog = prob_vector * prob_epilog + prob_vector.invert (); |
| |
| scale_bbs_frequencies (&bb_before_epilog, 1, prob_epilog); |
| } |
| scale_loop_profile (epilog, prob_epilog, bound); |
| } |
| else |
| slpeel_update_phi_nodes_for_lcssa (epilog); |
| |
| bound = LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo) ? vf - 1 : vf - 2; |
| /* We share epilog loop with scalar version loop. */ |
| bound = MAX (bound, bound_scalar - 1); |
| record_niter_bound (epilog, bound, false, true); |
| |
| delete_update_ssa (); |
| adjust_vec_debug_stmts (); |
| scev_reset (); |
| } |
| adjust_vec.release (); |
| free_original_copy_tables (); |
| |
| return epilog; |
| } |
| |
| /* Function vect_create_cond_for_niters_checks. |
| |
| Create a conditional expression that represents the run-time checks for |
| loop's niter. The loop is guaranteed to to terminate if the run-time |
| checks hold. |
| |
| Input: |
| COND_EXPR - input conditional expression. New conditions will be chained |
| with logical AND operation. If it is NULL, then the function |
| is used to return the number of alias checks. |
| LOOP_VINFO - field LOOP_VINFO_MAY_ALIAS_STMTS contains the list of ddrs |
| to be checked. |
| |
| Output: |
| COND_EXPR - conditional expression. |
| |
| The returned COND_EXPR is the conditional expression to be used in the |
| if statement that controls which version of the loop gets executed at |
| runtime. */ |
| |
| static void |
| vect_create_cond_for_niters_checks (loop_vec_info loop_vinfo, tree *cond_expr) |
| { |
| tree part_cond_expr = LOOP_VINFO_NITERS_ASSUMPTIONS (loop_vinfo); |
| |
| if (*cond_expr) |
| *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, |
| *cond_expr, part_cond_expr); |
| else |
| *cond_expr = part_cond_expr; |
| } |
| |
| /* Set *COND_EXPR to a tree that is true when both the original *COND_EXPR |
| and PART_COND_EXPR are true. Treat a null *COND_EXPR as "true". */ |
| |
| static void |
| chain_cond_expr (tree *cond_expr, tree part_cond_expr) |
| { |
| if (*cond_expr) |
| *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, |
| *cond_expr, part_cond_expr); |
| else |
| *cond_expr = part_cond_expr; |
| } |
| |
| /* Function vect_create_cond_for_align_checks. |
| |
| Create a conditional expression that represents the alignment checks for |
| all of data references (array element references) whose alignment must be |
| checked at runtime. |
| |
| Input: |
| COND_EXPR - input conditional expression. New conditions will be chained |
| with logical AND operation. |
| LOOP_VINFO - two fields of the loop information are used. |
| LOOP_VINFO_PTR_MASK is the mask used to check the alignment. |
| LOOP_VINFO_MAY_MISALIGN_STMTS contains the refs to be checked. |
| |
| Output: |
| COND_EXPR_STMT_LIST - statements needed to construct the conditional |
| expression. |
| The returned value is the conditional expression to be used in the if |
| statement that controls which version of the loop gets executed at runtime. |
| |
| The algorithm makes two assumptions: |
| 1) The number of bytes "n" in a vector is a power of 2. |
| 2) An address "a" is aligned if a%n is zero and that this |
| test can be done as a&(n-1) == 0. For example, for 16 |
| byte vectors the test is a&0xf == 0. */ |
| |
| static void |
| vect_create_cond_for_align_checks (loop_vec_info loop_vinfo, |
| tree *cond_expr, |
| gimple_seq *cond_expr_stmt_list) |
| { |
| vec<gimple *> may_misalign_stmts |
| = LOOP_VINFO_MAY_MISALIGN_STMTS (loop_vinfo); |
| gimple *ref_stmt; |
| int mask = LOOP_VINFO_PTR_MASK (loop_vinfo); |
| tree mask_cst; |
| unsigned int i; |
| tree int_ptrsize_type; |
| char tmp_name[20]; |
| tree or_tmp_name = NULL_TREE; |
| tree and_tmp_name; |
| gimple *and_stmt; |
| tree ptrsize_zero; |
| tree part_cond_expr; |
| |
| /* Check that mask is one less than a power of 2, i.e., mask is |
| all zeros followed by all ones. */ |
| gcc_assert ((mask != 0) && ((mask & (mask+1)) == 0)); |
| |
| int_ptrsize_type = signed_type_for (ptr_type_node); |
| |
| /* Create expression (mask & (dr_1 || ... || dr_n)) where dr_i is the address |
| of the first vector of the i'th data reference. */ |
| |
| FOR_EACH_VEC_ELT (may_misalign_stmts, i, ref_stmt) |
| { |
| gimple_seq new_stmt_list = NULL; |
| tree addr_base; |
| tree addr_tmp_name; |
| tree new_or_tmp_name; |
| gimple *addr_stmt, *or_stmt; |
| stmt_vec_info stmt_vinfo = vinfo_for_stmt (ref_stmt); |
| tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo); |
| bool negative = tree_int_cst_compare |
| (DR_STEP (STMT_VINFO_DATA_REF (stmt_vinfo)), size_zero_node) < 0; |
| tree offset = negative |
| ? size_int (-TYPE_VECTOR_SUBPARTS (vectype) + 1) : size_zero_node; |
| |
| /* create: addr_tmp = (int)(address_of_first_vector) */ |
| addr_base = |
| vect_create_addr_base_for_vector_ref (ref_stmt, &new_stmt_list, |
| offset); |
| if (new_stmt_list != NULL) |
| gimple_seq_add_seq (cond_expr_stmt_list, new_stmt_list); |
| |
| sprintf (tmp_name, "addr2int%d", i); |
| addr_tmp_name = make_temp_ssa_name (int_ptrsize_type, NULL, tmp_name); |
| addr_stmt = gimple_build_assign (addr_tmp_name, NOP_EXPR, addr_base); |
| gimple_seq_add_stmt (cond_expr_stmt_list, addr_stmt); |
| |
| /* The addresses are OR together. */ |
| |
| if (or_tmp_name != NULL_TREE) |
| { |
| /* create: or_tmp = or_tmp | addr_tmp */ |
| sprintf (tmp_name, "orptrs%d", i); |
| new_or_tmp_name = make_temp_ssa_name (int_ptrsize_type, NULL, tmp_name); |
| or_stmt = gimple_build_assign (new_or_tmp_name, BIT_IOR_EXPR, |
| or_tmp_name, addr_tmp_name); |
| gimple_seq_add_stmt (cond_expr_stmt_list, or_stmt); |
| or_tmp_name = new_or_tmp_name; |
| } |
| else |
| or_tmp_name = addr_tmp_name; |
| |
| } /* end for i */ |
| |
| mask_cst = build_int_cst (int_ptrsize_type, mask); |
| |
| /* create: and_tmp = or_tmp & mask */ |
| and_tmp_name = make_temp_ssa_name (int_ptrsize_type, NULL, "andmask"); |
| |
| and_stmt = gimple_build_assign (and_tmp_name, BIT_AND_EXPR, |
| or_tmp_name, mask_cst); |
| gimple_seq_add_stmt (cond_expr_stmt_list, and_stmt); |
| |
| /* Make and_tmp the left operand of the conditional test against zero. |
| if and_tmp has a nonzero bit then some address is unaligned. */ |
| ptrsize_zero = build_int_cst (int_ptrsize_type, 0); |
| part_cond_expr = fold_build2 (EQ_EXPR, boolean_type_node, |
| and_tmp_name, ptrsize_zero); |
| chain_cond_expr (cond_expr, part_cond_expr); |
| } |
| |
| /* If LOOP_VINFO_CHECK_UNEQUAL_ADDRS contains <A1, B1>, ..., <An, Bn>, |
| create a tree representation of: (&A1 != &B1) && ... && (&An != &Bn). |
| Set *COND_EXPR to a tree that is true when both the original *COND_EXPR |
| and this new condition are true. Treat a null *COND_EXPR as "true". */ |
| |
| static void |
| vect_create_cond_for_unequal_addrs (loop_vec_info loop_vinfo, tree *cond_expr) |
| { |
| vec<vec_object_pair> pairs = LOOP_VINFO_CHECK_UNEQUAL_ADDRS (loop_vinfo); |
| unsigned int i; |
| vec_object_pair *pair; |
| FOR_EACH_VEC_ELT (pairs, i, pair) |
| { |
| tree addr1 = build_fold_addr_expr (pair->first); |
| tree addr2 = build_fold_addr_expr (pair->second); |
| tree part_cond_expr = fold_build2 (NE_EXPR, boolean_type_node, |
| addr1, addr2); |
| chain_cond_expr (cond_expr, part_cond_expr); |
| } |
| } |
| |
| /* Function vect_create_cond_for_alias_checks. |
| |
| Create a conditional expression that represents the run-time checks for |
| overlapping of address ranges represented by a list of data references |
| relations passed as input. |
| |
| Input: |
| COND_EXPR - input conditional expression. New conditions will be chained |
| with logical AND operation. If it is NULL, then the function |
| is used to return the number of alias checks. |
| LOOP_VINFO - field LOOP_VINFO_MAY_ALIAS_STMTS contains the list of ddrs |
| to be checked. |
| |
| Output: |
| COND_EXPR - conditional expression. |
| |
| The returned COND_EXPR is the conditional expression to be used in the if |
| statement that controls which version of the loop gets executed at runtime. |
| */ |
| |
| void |
| vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo, tree * cond_expr) |
| { |
| vec<dr_with_seg_len_pair_t> comp_alias_ddrs = |
| LOOP_VINFO_COMP_ALIAS_DDRS (loop_vinfo); |
| |
| if (comp_alias_ddrs.is_empty ()) |
| return; |
| |
| create_runtime_alias_checks (LOOP_VINFO_LOOP (loop_vinfo), |
| &comp_alias_ddrs, cond_expr); |
| if (dump_enabled_p ()) |
| dump_printf_loc (MSG_NOTE, vect_location, |
| "created %u versioning for alias checks.\n", |
| comp_alias_ddrs.length ()); |
| } |
| |
| |
| /* Function vect_loop_versioning. |
| |
| If the loop has data references that may or may not be aligned or/and |
| has data reference relations whose independence was not proven then |
| two versions of the loop need to be generated, one which is vectorized |
| and one which isn't. A test is then generated to control which of the |
| loops is executed. The test checks for the alignment of all of the |
| data references that may or may not be aligned. An additional |
| sequence of runtime tests is generated for each pairs of DDRs whose |
| independence was not proven. The vectorized version of loop is |
| executed only if both alias and alignment tests are passed. |
| |
| The test generated to check which version of loop is executed |
| is modified to also check for profitability as indicated by the |
| cost model threshold TH. |
| |
| The versioning precondition(s) are placed in *COND_EXPR and |
| *COND_EXPR_STMT_LIST. */ |
| |
| void |
| vect_loop_versioning (loop_vec_info loop_vinfo, |
| unsigned int th, bool check_profitability) |
| { |
| struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo), *nloop; |
| struct loop *scalar_loop = LOOP_VINFO_SCALAR_LOOP (loop_vinfo); |
| basic_block condition_bb; |
| gphi_iterator gsi; |
| gimple_stmt_iterator cond_exp_gsi; |
| basic_block merge_bb; |
| basic_block new_exit_bb; |
| edge new_exit_e, e; |
| gphi *orig_phi, *new_phi; |
| tree cond_expr = NULL_TREE; |
| gimple_seq cond_expr_stmt_list = NULL; |
| tree arg; |
| profile_probability prob = profile_probability::likely (); |
| gimple_seq gimplify_stmt_list = NULL; |
| tree scalar_loop_iters = LOOP_VINFO_NITERSM1 (loop_vinfo); |
| bool version_align = LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT (loop_vinfo); |
| bool version_alias = LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo); |
| bool version_niter = LOOP_REQUIRES_VERSIONING_FOR_NITERS (loop_vinfo); |
| |
| if (check_profitability) |
| cond_expr = fold_build2 (GE_EXPR, boolean_type_node, scalar_loop_iters, |
| build_int_cst (TREE_TYPE (scalar_loop_iters), |
| th - 1)); |
| |
| if (version_niter) |
| vect_create_cond_for_niters_checks (loop_vinfo, &cond_expr); |
| |
| if (cond_expr) |
| cond_expr = force_gimple_operand_1 (cond_expr, &cond_expr_stmt_list, |
| is_gimple_condexpr, NULL_TREE); |
| |
| if (version_align) |
| vect_create_cond_for_align_checks (loop_vinfo, &cond_expr, |
| &cond_expr_stmt_list); |
| |
| if (version_alias) |
| { |
| vect_create_cond_for_unequal_addrs (loop_vinfo, &cond_expr); |
| vect_create_cond_for_alias_checks (loop_vinfo, &cond_expr); |
| } |
| |
| cond_expr = force_gimple_operand_1 (cond_expr, &gimplify_stmt_list, |
| is_gimple_condexpr, NULL_TREE); |
| gimple_seq_add_seq (&cond_expr_stmt_list, gimplify_stmt_list); |
| |
| initialize_original_copy_tables (); |
| if (scalar_loop) |
| { |
| edge scalar_e; |
| basic_block preheader, scalar_preheader; |
| |
| /* We don't want to scale SCALAR_LOOP's frequencies, we need to |
| scale LOOP's frequencies instead. */ |
| nloop = loop_version (scalar_loop, cond_expr, &condition_bb, |
| prob, prob.invert (), prob, prob.invert (), true); |
| scale_loop_frequencies (loop, prob); |
| /* CONDITION_BB was created above SCALAR_LOOP's preheader, |
| while we need to move it above LOOP's preheader. */ |
| e = loop_preheader_edge (loop); |
| scalar_e = loop_preheader_edge (scalar_loop); |
| gcc_assert (empty_block_p (e->src) |
| && single_pred_p (e->src)); |
| gcc_assert (empty_block_p (scalar_e->src) |
| && single_pred_p (scalar_e->src)); |
| gcc_assert (single_pred_p (condition_bb)); |
| preheader = e->src; |
| scalar_preheader = scalar_e->src; |
| scalar_e = find_edge (condition_bb, scalar_preheader); |
| e = single_pred_edge (preheader); |
| redirect_edge_and_branch_force (single_pred_edge (condition_bb), |
| scalar_preheader); |
| redirect_edge_and_branch_force (scalar_e, preheader); |
| redirect_edge_and_branch_force (e, condition_bb); |
| set_immediate_dominator (CDI_DOMINATORS, condition_bb, |
| single_pred (condition_bb)); |
| set_immediate_dominator (CDI_DOMINATORS, scalar_preheader, |
| single_pred (scalar_preheader)); |
| set_immediate_dominator (CDI_DOMINATORS, preheader, |
| condition_bb); |
| } |
| else |
| nloop = loop_version (loop, cond_expr, &condition_bb, |
| prob, prob.invert (), prob, prob.invert (), true); |
| |
| if (version_niter) |
| { |
| /* The versioned loop could be infinite, we need to clear existing |
| niter information which is copied from the original loop. */ |
| gcc_assert (loop_constraint_set_p (loop, LOOP_C_FINITE)); |
| vect_free_loop_info_assumptions (nloop); |
| /* And set constraint LOOP_C_INFINITE for niter analyzer. */ |
| loop_constraint_set (loop, LOOP_C_INFINITE); |
| } |
| |
| if (LOCATION_LOCUS (vect_location) != UNKNOWN_LOCATION |
| && dump_enabled_p ()) |
| { |
| if (version_alias) |
| dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, vect_location, |
| "loop versioned for vectorization because of " |
| "possible aliasing\n"); |
| if (version_align) |
| dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, vect_location, |
| "loop versioned for vectorization to enhance " |
| "alignment\n"); |
| |
| } |
| free_original_copy_tables (); |
| |
| /* Loop versioning violates an assumption we try to maintain during |
| vectorization - that the loop exit block has a single predecessor. |
| After versioning, the exit block of both loop versions is the same |
| basic block (i.e. it has two predecessors). Just in order to simplify |
| following transformations in the vectorizer, we fix this situation |
| here by adding a new (empty) block on the exit-edge of the loop, |
| with the proper loop-exit phis to maintain loop-closed-form. |
| If loop versioning wasn't done from loop, but scalar_loop instead, |
| merge_bb will have already just a single successor. */ |
| |
| merge_bb = single_exit (loop)->dest; |
| if (scalar_loop == NULL || EDGE_COUNT (merge_bb->preds) >= 2) |
| { |
| gcc_assert (EDGE_COUNT (merge_bb->preds) >= 2); |
| new_exit_bb = split_edge (single_exit (loop)); |
| new_exit_e = single_exit (loop); |
| e = EDGE_SUCC (new_exit_bb, 0); |
| |
| for (gsi = gsi_start_phis (merge_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| { |
| tree new_res; |
| orig_phi = gsi.phi (); |
| new_res = copy_ssa_name (PHI_RESULT (orig_phi)); |
| new_phi = create_phi_node (new_res, new_exit_bb); |
| arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, e); |
| add_phi_arg (new_phi, arg, new_exit_e, |
| gimple_phi_arg_location_from_edge (orig_phi, e)); |
| adjust_phi_and_debug_stmts (orig_phi, e, PHI_RESULT (new_phi)); |
| } |
| } |
| |
| /* End loop-exit-fixes after versioning. */ |
| |
| if (cond_expr_stmt_list) |
| { |
| cond_exp_gsi = gsi_last_bb (condition_bb); |
| gsi_insert_seq_before (&cond_exp_gsi, cond_expr_stmt_list, |
| GSI_SAME_STMT); |
| } |
| update_ssa (TODO_update_ssa); |
| } |