From 554fd8c5195424bdbcabf5de30fdc183aba391bd Mon Sep 17 00:00:00 2001 From: upstream source tree Date: Sun, 15 Mar 2015 20:14:05 -0400 Subject: obtained gcc-4.6.4.tar.bz2 from upstream website; verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository. --- gcc/tree-vect-loop-manip.c | 2652 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2652 insertions(+) create mode 100644 gcc/tree-vect-loop-manip.c (limited to 'gcc/tree-vect-loop-manip.c') diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c new file mode 100644 index 000000000..6ab542e9d --- /dev/null +++ b/gcc/tree-vect-loop-manip.c @@ -0,0 +1,2652 @@ +/* Vectorizer Specific Loop Manipulations + Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 + Free Software Foundation, Inc. + Contributed by Dorit Naishlos + and Ira Rosen + +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 +. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "ggc.h" +#include "tree.h" +#include "basic-block.h" +#include "tree-pretty-print.h" +#include "gimple-pretty-print.h" +#include "tree-flow.h" +#include "tree-dump.h" +#include "cfgloop.h" +#include "cfglayout.h" +#include "diagnostic-core.h" +#include "tree-scalar-evolution.h" +#include "tree-vectorizer.h" +#include "langhooks.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. */ + +void +rename_variables_in_bb (basic_block bb) +{ + gimple_stmt_iterator gsi; + gimple stmt; + use_operand_p use_p; + ssa_op_iter iter; + edge e; + edge_iterator ei; + struct loop *loop = bb->loop_father; + + for (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->succs) + { + if (!flow_bb_inside_loop_p (loop, e->dest)) + continue; + for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) + rename_use_op (PHI_ARG_DEF_PTR_FROM_EDGE (gsi_stmt (gsi), e)); + } +} + + +/* Renames variables in new generated LOOP. */ + +void +rename_variables_in_loop (struct loop *loop) +{ + unsigned i; + basic_block *bbs; + + bbs = get_loop_body (loop); + + for (i = 0; i < loop->num_nodes; i++) + rename_variables_in_bb (bbs[i]); + + free (bbs); +} + +typedef struct +{ + tree from, to; + basic_block bb; +} adjust_info; + +DEF_VEC_O(adjust_info); +DEF_VEC_ALLOC_O_STACK(adjust_info); +#define VEC_adjust_info_stack_alloc(alloc) VEC_stack_alloc (adjust_info, alloc) + +/* 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, stack) *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); + + while (!VEC_empty (adjust_info, adjust_vec)) + { + adjust_debug_stmts_now (VEC_last (adjust_info, adjust_vec)); + VEC_pop (adjust_info, adjust_vec); + } + + VEC_free (adjust_info, stack, adjust_vec); +} + +/* 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_VAR (from) != gimple_vop (cfun)) + { + ai.from = from; + ai.to = to; + ai.bb = bb; + + if (adjust_vec) + VEC_safe_push (adjust_info, stack, adjust_vec, &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)); +} + + +/* Update the PHI nodes of NEW_LOOP. + + NEW_LOOP is a duplicate of ORIG_LOOP. + AFTER indicates whether NEW_LOOP executes before or after ORIG_LOOP: + AFTER is true if NEW_LOOP executes after ORIG_LOOP, and false if it + executes before it. */ + +static void +slpeel_update_phis_for_duplicate_loop (struct loop *orig_loop, + struct loop *new_loop, bool after) +{ + tree new_ssa_name; + gimple phi_new, phi_orig; + tree def; + edge orig_loop_latch = loop_latch_edge (orig_loop); + edge orig_entry_e = loop_preheader_edge (orig_loop); + edge new_loop_exit_e = single_exit (new_loop); + edge new_loop_entry_e = loop_preheader_edge (new_loop); + edge entry_arg_e = (after ? orig_loop_latch : orig_entry_e); + gimple_stmt_iterator gsi_new, gsi_orig; + + /* + step 1. For each loop-header-phi: + Add the first phi argument for the phi in NEW_LOOP + (the one associated with the entry of NEW_LOOP) + + step 2. For each loop-header-phi: + Add the second phi argument for the phi in NEW_LOOP + (the one associated with the latch of NEW_LOOP) + + step 3. Update the phis in the successor block of NEW_LOOP. + + case 1: NEW_LOOP was placed before ORIG_LOOP: + The successor block of NEW_LOOP is the header of ORIG_LOOP. + Updating the phis in the successor block can therefore be done + along with the scanning of the loop header phis, because the + header blocks of ORIG_LOOP and NEW_LOOP have exactly the same + phi nodes, organized in the same order. + + case 2: NEW_LOOP was placed after ORIG_LOOP: + The successor block of NEW_LOOP is the original exit block of + ORIG_LOOP - the phis to be updated are the loop-closed-ssa phis. + We postpone updating these phis to a later stage (when + loop guards are added). + */ + + + /* Scan the phis in the headers of the old and new loops + (they are organized in exactly the same order). */ + + for (gsi_new = gsi_start_phis (new_loop->header), + gsi_orig = gsi_start_phis (orig_loop->header); + !gsi_end_p (gsi_new) && !gsi_end_p (gsi_orig); + gsi_next (&gsi_new), gsi_next (&gsi_orig)) + { + source_location locus; + phi_new = gsi_stmt (gsi_new); + phi_orig = gsi_stmt (gsi_orig); + + /* step 1. */ + def = PHI_ARG_DEF_FROM_EDGE (phi_orig, entry_arg_e); + locus = gimple_phi_arg_location_from_edge (phi_orig, entry_arg_e); + add_phi_arg (phi_new, def, new_loop_entry_e, locus); + + /* step 2. */ + def = PHI_ARG_DEF_FROM_EDGE (phi_orig, orig_loop_latch); + locus = gimple_phi_arg_location_from_edge (phi_orig, orig_loop_latch); + if (TREE_CODE (def) != SSA_NAME) + continue; + + new_ssa_name = get_current_def (def); + if (!new_ssa_name) + { + /* This only happens if there are no definitions + inside the loop. use the phi_result in this case. */ + new_ssa_name = PHI_RESULT (phi_new); + } + + /* An ordinary ssa name defined in the loop. */ + add_phi_arg (phi_new, new_ssa_name, loop_latch_edge (new_loop), locus); + + /* Drop any debug references outside the loop, if they would + become ill-formed SSA. */ + adjust_debug_stmts (def, NULL, single_exit (orig_loop)->dest); + + /* step 3 (case 1). */ + if (!after) + { + gcc_assert (new_loop_exit_e == orig_entry_e); + adjust_phi_and_debug_stmts (phi_orig, new_loop_exit_e, new_ssa_name); + } + } +} + + +/* Update PHI nodes for a guard of the LOOP. + + Input: + - LOOP, GUARD_EDGE: LOOP is a loop for which we added guard code that + controls whether LOOP is to be executed. GUARD_EDGE is the edge that + originates from the guard-bb, skips LOOP and reaches the (unique) exit + bb of LOOP. This loop-exit-bb is an empty bb with one successor. + We denote this bb NEW_MERGE_BB because before the guard code was added + it had a single predecessor (the LOOP header), and now it became a merge + point of two paths - the path that ends with the LOOP exit-edge, and + the path that ends with GUARD_EDGE. + - NEW_EXIT_BB: New basic block that is added by this function between LOOP + and NEW_MERGE_BB. It is used to place loop-closed-ssa-form exit-phis. + + ===> The CFG before the guard-code was added: + LOOP_header_bb: + loop_body + if (exit_loop) goto update_bb + else goto LOOP_header_bb + update_bb: + + ==> The CFG after the guard-code was added: + guard_bb: + if (LOOP_guard_condition) goto new_merge_bb + else goto LOOP_header_bb + LOOP_header_bb: + loop_body + if (exit_loop_condition) goto new_merge_bb + else goto LOOP_header_bb + new_merge_bb: + goto update_bb + update_bb: + + ==> The CFG after this function: + guard_bb: + if (LOOP_guard_condition) goto new_merge_bb + else goto LOOP_header_bb + LOOP_header_bb: + loop_body + if (exit_loop_condition) goto new_exit_bb + else goto LOOP_header_bb + new_exit_bb: + new_merge_bb: + goto update_bb + update_bb: + + This function: + 1. creates and updates the relevant phi nodes to account for the new + incoming edge (GUARD_EDGE) into NEW_MERGE_BB. This involves: + 1.1. Create phi nodes at NEW_MERGE_BB. + 1.2. Update the phi nodes at the successor of NEW_MERGE_BB (denoted + UPDATE_BB). UPDATE_BB was the exit-bb of LOOP before NEW_MERGE_BB + 2. preserves loop-closed-ssa-form by creating the required phi nodes + at the exit of LOOP (i.e, in NEW_EXIT_BB). + + There are two flavors to this function: + + slpeel_update_phi_nodes_for_guard1: + Here the guard controls whether we enter or skip LOOP, where LOOP is a + prolog_loop (loop1 below), and the new phis created in NEW_MERGE_BB are + for variables that have phis in the loop header. + + slpeel_update_phi_nodes_for_guard2: + Here the guard controls whether we enter or skip LOOP, where LOOP is an + epilog_loop (loop2 below), and the new phis created in NEW_MERGE_BB are + for variables that have phis in the loop exit. + + I.E., the overall structure is: + + loop1_preheader_bb: + guard1 (goto loop1/merge1_bb) + loop1 + loop1_exit_bb: + guard2 (goto merge1_bb/merge2_bb) + merge1_bb + loop2 + loop2_exit_bb + merge2_bb + next_bb + + slpeel_update_phi_nodes_for_guard1 takes care of creating phis in + loop1_exit_bb and merge1_bb. These are entry phis (phis for the vars + that have phis in loop1->header). + + slpeel_update_phi_nodes_for_guard2 takes care of creating phis in + loop2_exit_bb and merge2_bb. These are exit phis (phis for the vars + that have phis in next_bb). It also adds some of these phis to + loop1_exit_bb. + + slpeel_update_phi_nodes_for_guard1 is always called before + slpeel_update_phi_nodes_for_guard2. They are both needed in order + to create correct data-flow and loop-closed-ssa-form. + + Generally slpeel_update_phi_nodes_for_guard1 creates phis for variables + that change between iterations of a loop (and therefore have a phi-node + at the loop entry), whereas slpeel_update_phi_nodes_for_guard2 creates + phis for variables that are used out of the loop (and therefore have + loop-closed exit phis). Some variables may be both updated between + iterations and used after the loop. This is why in loop1_exit_bb we + may need both entry_phis (created by slpeel_update_phi_nodes_for_guard1) + and exit phis (created by slpeel_update_phi_nodes_for_guard2). + + - IS_NEW_LOOP: if IS_NEW_LOOP is true, then LOOP is a newly created copy of + an original loop. i.e., we have: + + orig_loop + guard_bb (goto LOOP/new_merge) + new_loop <-- LOOP + new_exit + new_merge + next_bb + + If IS_NEW_LOOP is false, then LOOP is an original loop, in which case we + have: + + new_loop + guard_bb (goto LOOP/new_merge) + orig_loop <-- LOOP + new_exit + new_merge + next_bb + + The SSA names defined in the original loop have a current + reaching definition that that records the corresponding new + ssa-name used in the new duplicated loop copy. + */ + +/* Function slpeel_update_phi_nodes_for_guard1 + + Input: + - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above. + - DEFS - a bitmap of ssa names to mark new names for which we recorded + information. + + In the context of the overall structure, we have: + + loop1_preheader_bb: + guard1 (goto loop1/merge1_bb) +LOOP-> loop1 + loop1_exit_bb: + guard2 (goto merge1_bb/merge2_bb) + merge1_bb + loop2 + loop2_exit_bb + merge2_bb + next_bb + + For each name updated between loop iterations (i.e - for each name that has + an entry (loop-header) phi in LOOP) we create a new phi in: + 1. merge1_bb (to account for the edge from guard1) + 2. loop1_exit_bb (an exit-phi to keep LOOP in loop-closed form) +*/ + +static void +slpeel_update_phi_nodes_for_guard1 (edge guard_edge, struct loop *loop, + bool is_new_loop, basic_block *new_exit_bb, + bitmap *defs) +{ + gimple orig_phi, new_phi; + gimple update_phi, update_phi2; + tree guard_arg, loop_arg; + basic_block new_merge_bb = guard_edge->dest; + edge e = EDGE_SUCC (new_merge_bb, 0); + basic_block update_bb = e->dest; + basic_block orig_bb = loop->header; + edge new_exit_e; + tree current_new_name; + gimple_stmt_iterator gsi_orig, gsi_update; + + /* Create new bb between loop and new_merge_bb. */ + *new_exit_bb = split_edge (single_exit (loop)); + + new_exit_e = EDGE_SUCC (*new_exit_bb, 0); + + for (gsi_orig = gsi_start_phis (orig_bb), + gsi_update = gsi_start_phis (update_bb); + !gsi_end_p (gsi_orig) && !gsi_end_p (gsi_update); + gsi_next (&gsi_orig), gsi_next (&gsi_update)) + { + source_location loop_locus, guard_locus;; + orig_phi = gsi_stmt (gsi_orig); + update_phi = gsi_stmt (gsi_update); + + /** 1. Handle new-merge-point phis **/ + + /* 1.1. Generate new phi node in NEW_MERGE_BB: */ + new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), + new_merge_bb); + + /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge + of LOOP. Set the two phi args in NEW_PHI for these edges: */ + loop_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, EDGE_SUCC (loop->latch, 0)); + loop_locus = gimple_phi_arg_location_from_edge (orig_phi, + EDGE_SUCC (loop->latch, + 0)); + guard_arg = PHI_ARG_DEF_FROM_EDGE (orig_phi, loop_preheader_edge (loop)); + guard_locus + = gimple_phi_arg_location_from_edge (orig_phi, + loop_preheader_edge (loop)); + + add_phi_arg (new_phi, loop_arg, new_exit_e, loop_locus); + add_phi_arg (new_phi, guard_arg, guard_edge, guard_locus); + + /* 1.3. Update phi in successor block. */ + gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == loop_arg + || PHI_ARG_DEF_FROM_EDGE (update_phi, e) == guard_arg); + adjust_phi_and_debug_stmts (update_phi, e, PHI_RESULT (new_phi)); + update_phi2 = new_phi; + + + /** 2. Handle loop-closed-ssa-form phis **/ + + if (!is_gimple_reg (PHI_RESULT (orig_phi))) + continue; + + /* 2.1. Generate new phi node in NEW_EXIT_BB: */ + new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), + *new_exit_bb); + + /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop. */ + add_phi_arg (new_phi, loop_arg, single_exit (loop), loop_locus); + + /* 2.3. Update phi in successor of NEW_EXIT_BB: */ + gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg); + adjust_phi_and_debug_stmts (update_phi2, new_exit_e, + PHI_RESULT (new_phi)); + + /* 2.4. Record the newly created name with set_current_def. + We want to find a name such that + name = get_current_def (orig_loop_name) + and to set its current definition as follows: + set_current_def (name, new_phi_name) + + If LOOP is a new loop then loop_arg is already the name we're + looking for. If LOOP is the original loop, then loop_arg is + the orig_loop_name and the relevant name is recorded in its + current reaching definition. */ + if (is_new_loop) + current_new_name = loop_arg; + else + { + current_new_name = get_current_def (loop_arg); + /* current_def is not available only if the variable does not + change inside the loop, in which case we also don't care + about recording a current_def for it because we won't be + trying to create loop-exit-phis for it. */ + if (!current_new_name) + continue; + } + gcc_assert (get_current_def (current_new_name) == NULL_TREE); + + set_current_def (current_new_name, PHI_RESULT (new_phi)); + bitmap_set_bit (*defs, SSA_NAME_VERSION (current_new_name)); + } +} + + +/* Function slpeel_update_phi_nodes_for_guard2 + + Input: + - GUARD_EDGE, LOOP, IS_NEW_LOOP, NEW_EXIT_BB - as explained above. + + In the context of the overall structure, we have: + + loop1_preheader_bb: + guard1 (goto loop1/merge1_bb) + loop1 + loop1_exit_bb: + guard2 (goto merge1_bb/merge2_bb) + merge1_bb +LOOP-> loop2 + loop2_exit_bb + merge2_bb + next_bb + + For each name used out side the loop (i.e - for each name that has an exit + phi in next_bb) we create a new phi in: + 1. merge2_bb (to account for the edge from guard_bb) + 2. loop2_exit_bb (an exit-phi to keep LOOP in loop-closed form) + 3. guard2 bb (an exit phi to keep the preceding loop in loop-closed form), + if needed (if it wasn't handled by slpeel_update_phis_nodes_for_phi1). +*/ + +static void +slpeel_update_phi_nodes_for_guard2 (edge guard_edge, struct loop *loop, + bool is_new_loop, basic_block *new_exit_bb) +{ + gimple orig_phi, new_phi; + gimple update_phi, update_phi2; + tree guard_arg, loop_arg; + basic_block new_merge_bb = guard_edge->dest; + edge e = EDGE_SUCC (new_merge_bb, 0); + basic_block update_bb = e->dest; + edge new_exit_e; + tree orig_def, orig_def_new_name; + tree new_name, new_name2; + tree arg; + gimple_stmt_iterator gsi; + + /* Create new bb between loop and new_merge_bb. */ + *new_exit_bb = split_edge (single_exit (loop)); + + new_exit_e = EDGE_SUCC (*new_exit_bb, 0); + + for (gsi = gsi_start_phis (update_bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + update_phi = gsi_stmt (gsi); + orig_phi = update_phi; + orig_def = PHI_ARG_DEF_FROM_EDGE (orig_phi, e); + /* This loop-closed-phi actually doesn't represent a use + out of the loop - the phi arg is a constant. */ + if (TREE_CODE (orig_def) != SSA_NAME) + continue; + orig_def_new_name = get_current_def (orig_def); + arg = NULL_TREE; + + /** 1. Handle new-merge-point phis **/ + + /* 1.1. Generate new phi node in NEW_MERGE_BB: */ + new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), + new_merge_bb); + + /* 1.2. NEW_MERGE_BB has two incoming edges: GUARD_EDGE and the exit-edge + of LOOP. Set the two PHI args in NEW_PHI for these edges: */ + new_name = orig_def; + new_name2 = NULL_TREE; + if (orig_def_new_name) + { + new_name = orig_def_new_name; + /* Some variables have both loop-entry-phis and loop-exit-phis. + Such variables were given yet newer names by phis placed in + guard_bb by slpeel_update_phi_nodes_for_guard1. I.e: + new_name2 = get_current_def (get_current_def (orig_name)). */ + new_name2 = get_current_def (new_name); + } + + if (is_new_loop) + { + guard_arg = orig_def; + loop_arg = new_name; + } + else + { + guard_arg = new_name; + loop_arg = orig_def; + } + if (new_name2) + guard_arg = new_name2; + + add_phi_arg (new_phi, loop_arg, new_exit_e, UNKNOWN_LOCATION); + add_phi_arg (new_phi, guard_arg, guard_edge, UNKNOWN_LOCATION); + + /* 1.3. Update phi in successor block. */ + gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi, e) == orig_def); + adjust_phi_and_debug_stmts (update_phi, e, PHI_RESULT (new_phi)); + update_phi2 = new_phi; + + + /** 2. Handle loop-closed-ssa-form phis **/ + + /* 2.1. Generate new phi node in NEW_EXIT_BB: */ + new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), + *new_exit_bb); + + /* 2.2. NEW_EXIT_BB has one incoming edge: the exit-edge of the loop. */ + add_phi_arg (new_phi, loop_arg, single_exit (loop), UNKNOWN_LOCATION); + + /* 2.3. Update phi in successor of NEW_EXIT_BB: */ + gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, new_exit_e) == loop_arg); + adjust_phi_and_debug_stmts (update_phi2, new_exit_e, + PHI_RESULT (new_phi)); + + + /** 3. Handle loop-closed-ssa-form phis for first loop **/ + + /* 3.1. Find the relevant names that need an exit-phi in + GUARD_BB, i.e. names for which + slpeel_update_phi_nodes_for_guard1 had not already created a + phi node. This is the case for names that are used outside + the loop (and therefore need an exit phi) but are not updated + across loop iterations (and therefore don't have a + loop-header-phi). + + slpeel_update_phi_nodes_for_guard1 is responsible for + creating loop-exit phis in GUARD_BB for names that have a + loop-header-phi. When such a phi is created we also record + the new name in its current definition. If this new name + exists, then guard_arg was set to this new name (see 1.2 + above). Therefore, if guard_arg is not this new name, this + is an indication that an exit-phi in GUARD_BB was not yet + created, so we take care of it here. */ + if (guard_arg == new_name2) + continue; + arg = guard_arg; + + /* 3.2. Generate new phi node in GUARD_BB: */ + new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), + guard_edge->src); + + /* 3.3. GUARD_BB has one incoming edge: */ + gcc_assert (EDGE_COUNT (guard_edge->src->preds) == 1); + add_phi_arg (new_phi, arg, EDGE_PRED (guard_edge->src, 0), + UNKNOWN_LOCATION); + + /* 3.4. Update phi in successor of GUARD_BB: */ + gcc_assert (PHI_ARG_DEF_FROM_EDGE (update_phi2, guard_edge) + == guard_arg); + adjust_phi_and_debug_stmts (update_phi2, guard_edge, + PHI_RESULT (new_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; + gimple cond_stmt; + gimple 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); + LOC 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); + + loop_loc = find_loop_location (loop); + if (dump_file && (dump_flags & TDF_DETAILS)) + { + if (loop_loc != UNKNOWN_LOC) + fprintf (dump_file, "\nloop at %s:%d: ", + LOC_FILE (loop_loc), LOC_LINE (loop_loc)); + print_gimple_stmt (dump_file, cond_stmt, 0, TDF_SLIM); + } + + loop->nb_iterations = niters; +} + + +/* Given LOOP this function generates a new copy of it and puts it + on E which is either the entry or exit of LOOP. */ + +struct loop * +slpeel_tree_duplicate_loop_to_edge_cfg (struct loop *loop, edge e) +{ + struct loop *new_loop; + basic_block *new_bbs, *bbs; + bool at_exit; + bool was_imm_dom; + basic_block exit_dest; + gimple phi; + tree phi_arg; + edge exit, new_exit; + gimple_stmt_iterator gsi; + + at_exit = (e == single_exit (loop)); + if (!at_exit && e != loop_preheader_edge (loop)) + return NULL; + + bbs = get_loop_body (loop); + + /* Check whether duplication is possible. */ + if (!can_copy_bbs_p (bbs, loop->num_nodes)) + { + free (bbs); + return NULL; + } + + /* Generate new loop structure. */ + new_loop = duplicate_loop (loop, loop_outer (loop)); + if (!new_loop) + { + free (bbs); + return NULL; + } + + exit_dest = single_exit (loop)->dest; + was_imm_dom = (get_immediate_dominator (CDI_DOMINATORS, + exit_dest) == loop->header ? + true : false); + + new_bbs = XNEWVEC (basic_block, loop->num_nodes); + + exit = single_exit (loop); + copy_bbs (bbs, loop->num_nodes, new_bbs, + &exit, 1, &new_exit, NULL, + e->src); + + /* Duplicating phi args at exit bbs as coming + also from exit of duplicated loop. */ + for (gsi = gsi_start_phis (exit_dest); !gsi_end_p (gsi); gsi_next (&gsi)) + { + phi = gsi_stmt (gsi); + phi_arg = PHI_ARG_DEF_FROM_EDGE (phi, single_exit (loop)); + if (phi_arg) + { + edge new_loop_exit_edge; + source_location locus; + + locus = gimple_phi_arg_location_from_edge (phi, single_exit (loop)); + if (EDGE_SUCC (new_loop->header, 0)->dest == new_loop->latch) + new_loop_exit_edge = EDGE_SUCC (new_loop->header, 1); + else + new_loop_exit_edge = EDGE_SUCC (new_loop->header, 0); + + add_phi_arg (phi, phi_arg, new_loop_exit_edge, locus); + } + } + + if (at_exit) /* Add the loop copy at exit. */ + { + redirect_edge_and_branch_force (e, new_loop->header); + PENDING_STMT (e) = NULL; + set_immediate_dominator (CDI_DOMINATORS, new_loop->header, e->src); + if (was_imm_dom) + set_immediate_dominator (CDI_DOMINATORS, exit_dest, new_loop->header); + } + else /* Add the copy at entry. */ + { + edge new_exit_e; + edge entry_e = loop_preheader_edge (loop); + basic_block preheader = entry_e->src; + + if (!flow_bb_inside_loop_p (new_loop, + EDGE_SUCC (new_loop->header, 0)->dest)) + new_exit_e = EDGE_SUCC (new_loop->header, 0); + else + new_exit_e = EDGE_SUCC (new_loop->header, 1); + + redirect_edge_and_branch_force (new_exit_e, loop->header); + PENDING_STMT (new_exit_e) = NULL; + set_immediate_dominator (CDI_DOMINATORS, loop->header, + new_exit_e->src); + + /* We have to add phi args to the loop->header here as coming + from new_exit_e edge. */ + for (gsi = gsi_start_phis (loop->header); + !gsi_end_p (gsi); + gsi_next (&gsi)) + { + phi = gsi_stmt (gsi); + phi_arg = PHI_ARG_DEF_FROM_EDGE (phi, entry_e); + if (phi_arg) + add_phi_arg (phi, phi_arg, new_exit_e, + gimple_phi_arg_location_from_edge (phi, entry_e)); + } + + redirect_edge_and_branch_force (entry_e, new_loop->header); + PENDING_STMT (entry_e) = NULL; + set_immediate_dominator (CDI_DOMINATORS, new_loop->header, preheader); + } + + free (new_bbs); + free (bbs); + + return new_loop; +} + + +/* Given the condition statement COND, put it as the last statement + of GUARD_BB; EXIT_BB is the basic block to skip the loop; + Assumes that this is the single exit of the guarded loop. + Returns the skip edge, inserts new stmts on the COND_EXPR_STMT_LIST. */ + +static edge +slpeel_add_loop_guard (basic_block guard_bb, tree cond, + gimple_seq cond_expr_stmt_list, + basic_block exit_bb, basic_block dom_bb) +{ + gimple_stmt_iterator gsi; + edge new_e, enter_e; + gimple 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 (cond, &gimplify_stmt_list, true, NULL_TREE); + if (gimplify_stmt_list) + gimple_seq_add_seq (&cond_expr_stmt_list, gimplify_stmt_list); + cond_stmt = gimple_build_cond (NE_EXPR, + cond, build_int_cst (TREE_TYPE (cond), 0), + NULL_TREE, NULL_TREE); + if (cond_expr_stmt_list) + gsi_insert_seq_after (&gsi, cond_expr_stmt_list, GSI_NEW_STMT); + + 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, exit_bb, EDGE_TRUE_VALUE); + set_immediate_dominator (CDI_DOMINATORS, exit_bb, dom_bb); + return new_e; +} + + +/* This function verifies that the following restrictions apply to LOOP: + (1) it is innermost + (2) it consists of exactly 2 basic blocks - header, and an empty latch. + (3) it is single entry, single exit + (4) its exit condition is the last stmt in the header + (5) 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); + gimple orig_cond = get_loop_exit_condition (loop); + gimple_stmt_iterator loop_exit_gsi = gsi_last_bb (exit_e->src); + + if (need_ssa_update_p (cfun)) + return false; + + if (loop->inner + /* All loops have an outer scope; the only case loop->outer is NULL is for + the function itself. */ + || !loop_outer (loop) + || loop->num_nodes != 2 + || !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; +} + +#ifdef ENABLE_CHECKING +static void +slpeel_verify_cfg_after_peeling (struct loop *first_loop, + struct loop *second_loop) +{ + basic_block loop1_exit_bb = single_exit (first_loop)->dest; + basic_block loop2_entry_bb = loop_preheader_edge (second_loop)->src; + basic_block loop1_entry_bb = loop_preheader_edge (first_loop)->src; + + /* A guard that controls whether the second_loop is to be executed or skipped + is placed in first_loop->exit. first_loop->exit therefore has two + successors - one is the preheader of second_loop, and the other is a bb + after second_loop. + */ + gcc_assert (EDGE_COUNT (loop1_exit_bb->succs) == 2); + + /* 1. Verify that one of the successors of first_loop->exit is the preheader + of second_loop. */ + + /* The preheader of new_loop is expected to have two predecessors: + first_loop->exit and the block that precedes first_loop. */ + + gcc_assert (EDGE_COUNT (loop2_entry_bb->preds) == 2 + && ((EDGE_PRED (loop2_entry_bb, 0)->src == loop1_exit_bb + && EDGE_PRED (loop2_entry_bb, 1)->src == loop1_entry_bb) + || (EDGE_PRED (loop2_entry_bb, 1)->src == loop1_exit_bb + && EDGE_PRED (loop2_entry_bb, 0)->src == loop1_entry_bb))); + + /* Verify that the other successor of first_loop->exit is after the + second_loop. */ + /* TODO */ +} +#endif + +/* If the run time cost model check determines that vectorization is + not profitable and hence scalar loop should be generated then set + FIRST_NITERS to prologue peeled iterations. This will allow all the + iterations to be executed in the prologue peeled scalar loop. */ + +static void +set_prologue_iterations (basic_block bb_before_first_loop, + tree first_niters, + struct loop *loop, + unsigned int th) +{ + edge e; + basic_block cond_bb, then_bb; + tree var, prologue_after_cost_adjust_name; + gimple_stmt_iterator gsi; + gimple newphi; + edge e_true, e_false, e_fallthru; + gimple cond_stmt; + gimple_seq gimplify_stmt_list = NULL, stmts = NULL; + tree cost_pre_condition = NULL_TREE; + tree scalar_loop_iters = + unshare_expr (LOOP_VINFO_NITERS_UNCHANGED (loop_vec_info_for_loop (loop))); + + e = single_pred_edge (bb_before_first_loop); + cond_bb = split_edge(e); + + e = single_pred_edge (bb_before_first_loop); + then_bb = split_edge(e); + set_immediate_dominator (CDI_DOMINATORS, then_bb, cond_bb); + + e_false = make_single_succ_edge (cond_bb, bb_before_first_loop, + EDGE_FALSE_VALUE); + set_immediate_dominator (CDI_DOMINATORS, bb_before_first_loop, cond_bb); + + e_true = EDGE_PRED (then_bb, 0); + e_true->flags &= ~EDGE_FALLTHRU; + e_true->flags |= EDGE_TRUE_VALUE; + + e_fallthru = EDGE_SUCC (then_bb, 0); + + cost_pre_condition = + fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters, + build_int_cst (TREE_TYPE (scalar_loop_iters), th)); + cost_pre_condition = + force_gimple_operand (cost_pre_condition, &gimplify_stmt_list, + true, NULL_TREE); + cond_stmt = gimple_build_cond (NE_EXPR, cost_pre_condition, + build_int_cst (TREE_TYPE (cost_pre_condition), + 0), NULL_TREE, NULL_TREE); + + gsi = gsi_last_bb (cond_bb); + if (gimplify_stmt_list) + gsi_insert_seq_after (&gsi, gimplify_stmt_list, GSI_NEW_STMT); + + gsi = gsi_last_bb (cond_bb); + gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT); + + var = create_tmp_var (TREE_TYPE (scalar_loop_iters), + "prologue_after_cost_adjust"); + add_referenced_var (var); + prologue_after_cost_adjust_name = + force_gimple_operand (scalar_loop_iters, &stmts, false, var); + + gsi = gsi_last_bb (then_bb); + if (stmts) + gsi_insert_seq_after (&gsi, stmts, GSI_NEW_STMT); + + newphi = create_phi_node (var, bb_before_first_loop); + add_phi_arg (newphi, prologue_after_cost_adjust_name, e_fallthru, + UNKNOWN_LOCATION); + add_phi_arg (newphi, first_niters, e_false, UNKNOWN_LOCATION); + + first_niters = PHI_RESULT (newphi); +} + + +/* Remove dead assignments from loop NEW_LOOP. */ + +static void +remove_dead_stmts_from_loop (struct loop *new_loop) +{ + basic_block *bbs = get_loop_body (new_loop); + unsigned i; + for (i = 0; i < new_loop->num_nodes; ++i) + { + gimple_stmt_iterator gsi; + for (gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi);) + { + gimple stmt = gsi_stmt (gsi); + if (is_gimple_assign (stmt) + && TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME + && has_zero_uses (gimple_assign_lhs (stmt))) + { + gsi_remove (&gsi, true); + release_defs (stmt); + } + else + gsi_next (&gsi); + } + } + free (bbs); +} + + +/* Function slpeel_tree_peel_loop_to_edge. + + Peel the first (last) iterations of LOOP into a new prolog (epilog) loop + that is placed on the entry (exit) edge E of LOOP. After this transformation + we have two loops one after the other - first-loop iterates FIRST_NITERS + times, and second-loop iterates the remainder NITERS - FIRST_NITERS times. + If the cost model indicates that it is profitable to emit a scalar + loop instead of the vector one, then the prolog (epilog) loop will iterate + for the entire unchanged scalar iterations of the loop. + + Input: + - LOOP: the loop to be peeled. + - E: the exit or entry edge of LOOP. + If it is the entry edge, we peel the first iterations of LOOP. In this + case first-loop is LOOP, and second-loop is the newly created loop. + If it is the exit edge, we peel the last iterations of LOOP. In this + case, first-loop is the newly created loop, and second-loop is LOOP. + - NITERS: the number of iterations that LOOP iterates. + - FIRST_NITERS: the number of iterations that the first-loop should iterate. + - UPDATE_FIRST_LOOP_COUNT: specified whether this function is responsible + for updating the loop bound of the first-loop to FIRST_NITERS. If it + is false, the caller of this function may want to take care of this + (this can be useful if we don't want new stmts added to first-loop). + - TH: cost model profitability threshold of iterations for vectorization. + - CHECK_PROFITABILITY: specify whether cost model check has not occurred + during versioning and hence needs to occur during + prologue generation or whether cost model check + has not occurred during prologue generation and hence + needs to occur during epilogue generation. + + + Output: + The function returns a pointer to the new loop-copy, or NULL if it failed + to perform the transformation. + + The function generates two if-then-else guards: one before the first loop, + and the other before the second loop: + The first guard is: + if (FIRST_NITERS == 0) then skip the first loop, + and go directly to the second loop. + The second guard is: + if (FIRST_NITERS == NITERS) then skip the second loop. + + If the optional COND_EXPR and COND_EXPR_STMT_LIST arguments are given + then the generated condition is combined with COND_EXPR and the + statements in COND_EXPR_STMT_LIST are emitted together with it. + + FORNOW only simple loops are supported (see slpeel_can_duplicate_loop_p). + FORNOW the resulting code will not be in loop-closed-ssa form. +*/ + +static struct loop* +slpeel_tree_peel_loop_to_edge (struct loop *loop, + edge e, tree first_niters, + tree niters, bool update_first_loop_count, + unsigned int th, bool check_profitability, + tree cond_expr, gimple_seq cond_expr_stmt_list) +{ + struct loop *new_loop = NULL, *first_loop, *second_loop; + edge skip_e; + tree pre_condition = NULL_TREE; + bitmap definitions; + basic_block bb_before_second_loop, bb_after_second_loop; + basic_block bb_before_first_loop; + basic_block bb_between_loops; + basic_block new_exit_bb; + edge exit_e = single_exit (loop); + LOC loop_loc; + tree cost_pre_condition = NULL_TREE; + + if (!slpeel_can_duplicate_loop_p (loop, e)) + return NULL; + + /* We have to initialize cfg_hooks. Then, when calling + cfg_hooks->split_edge, the function tree_split_edge + is actually called and, when calling cfg_hooks->duplicate_block, + the function tree_duplicate_bb is called. */ + gimple_register_cfg_hooks (); + + + /* 1. Generate a copy of LOOP and put it on E (E is the entry/exit of LOOP). + Resulting CFG would be: + + first_loop: + do { + } while ... + + second_loop: + do { + } while ... + + orig_exit_bb: + */ + + if (!(new_loop = slpeel_tree_duplicate_loop_to_edge_cfg (loop, e))) + { + loop_loc = find_loop_location (loop); + if (dump_file && (dump_flags & TDF_DETAILS)) + { + if (loop_loc != UNKNOWN_LOC) + fprintf (dump_file, "\n%s:%d: note: ", + LOC_FILE (loop_loc), LOC_LINE (loop_loc)); + fprintf (dump_file, "tree_duplicate_loop_to_edge_cfg failed.\n"); + } + return NULL; + } + + if (MAY_HAVE_DEBUG_STMTS) + { + gcc_assert (!adjust_vec); + adjust_vec = VEC_alloc (adjust_info, stack, 32); + } + + if (e == exit_e) + { + /* NEW_LOOP was placed after LOOP. */ + first_loop = loop; + second_loop = new_loop; + } + else + { + /* NEW_LOOP was placed before LOOP. */ + first_loop = new_loop; + second_loop = loop; + } + + definitions = ssa_names_to_replace (); + slpeel_update_phis_for_duplicate_loop (loop, new_loop, e == exit_e); + rename_variables_in_loop (new_loop); + + + /* 2. Add the guard code in one of the following ways: + + 2.a Add the guard that controls whether the first loop is executed. + This occurs when this function is invoked for prologue or epilogue + generation and when the cost model check can be done at compile time. + + Resulting CFG would be: + + bb_before_first_loop: + if (FIRST_NITERS == 0) GOTO bb_before_second_loop + GOTO first-loop + + first_loop: + do { + } while ... + + bb_before_second_loop: + + second_loop: + do { + } while ... + + orig_exit_bb: + + 2.b Add the cost model check that allows the prologue + to iterate for the entire unchanged scalar + iterations of the loop in the event that the cost + model indicates that the scalar loop is more + profitable than the vector one. This occurs when + this function is invoked for prologue generation + and the cost model check needs to be done at run + time. + + Resulting CFG after prologue peeling would be: + + if (scalar_loop_iterations <= th) + FIRST_NITERS = scalar_loop_iterations + + bb_before_first_loop: + if (FIRST_NITERS == 0) GOTO bb_before_second_loop + GOTO first-loop + + first_loop: + do { + } while ... + + bb_before_second_loop: + + second_loop: + do { + } while ... + + orig_exit_bb: + + 2.c Add the cost model check that allows the epilogue + to iterate for the entire unchanged scalar + iterations of the loop in the event that the cost + model indicates that the scalar loop is more + profitable than the vector one. This occurs when + this function is invoked for epilogue generation + and the cost model check needs to be done at run + time. This check is combined with any pre-existing + check in COND_EXPR to avoid versioning. + + Resulting CFG after prologue peeling would be: + + bb_before_first_loop: + if ((scalar_loop_iterations <= th) + || + FIRST_NITERS == 0) GOTO bb_before_second_loop + GOTO first-loop + + first_loop: + do { + } while ... + + bb_before_second_loop: + + second_loop: + do { + } while ... + + orig_exit_bb: + */ + + bb_before_first_loop = split_edge (loop_preheader_edge (first_loop)); + bb_before_second_loop = split_edge (single_exit (first_loop)); + + /* Epilogue peeling. */ + if (!update_first_loop_count) + { + pre_condition = + fold_build2 (LE_EXPR, boolean_type_node, first_niters, + build_int_cst (TREE_TYPE (first_niters), 0)); + if (check_profitability) + { + tree scalar_loop_iters + = unshare_expr (LOOP_VINFO_NITERS_UNCHANGED + (loop_vec_info_for_loop (loop))); + cost_pre_condition = + fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters, + build_int_cst (TREE_TYPE (scalar_loop_iters), th)); + + pre_condition = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, + cost_pre_condition, pre_condition); + } + if (cond_expr) + { + pre_condition = + fold_build2 (TRUTH_OR_EXPR, boolean_type_node, + pre_condition, + fold_build1 (TRUTH_NOT_EXPR, boolean_type_node, + cond_expr)); + } + } + + /* Prologue peeling. */ + else + { + if (check_profitability) + set_prologue_iterations (bb_before_first_loop, first_niters, + loop, th); + + pre_condition = + fold_build2 (LE_EXPR, boolean_type_node, first_niters, + build_int_cst (TREE_TYPE (first_niters), 0)); + } + + skip_e = slpeel_add_loop_guard (bb_before_first_loop, pre_condition, + cond_expr_stmt_list, + bb_before_second_loop, bb_before_first_loop); + slpeel_update_phi_nodes_for_guard1 (skip_e, first_loop, + first_loop == new_loop, + &new_exit_bb, &definitions); + + + /* 3. Add the guard that controls whether the second loop is executed. + Resulting CFG would be: + + bb_before_first_loop: + if (FIRST_NITERS == 0) GOTO bb_before_second_loop (skip first loop) + GOTO first-loop + + first_loop: + do { + } while ... + + bb_between_loops: + if (FIRST_NITERS == NITERS) GOTO bb_after_second_loop (skip second loop) + GOTO bb_before_second_loop + + bb_before_second_loop: + + second_loop: + do { + } while ... + + bb_after_second_loop: + + orig_exit_bb: + */ + + bb_between_loops = new_exit_bb; + bb_after_second_loop = split_edge (single_exit (second_loop)); + + pre_condition = + fold_build2 (EQ_EXPR, boolean_type_node, first_niters, niters); + skip_e = slpeel_add_loop_guard (bb_between_loops, pre_condition, NULL, + bb_after_second_loop, bb_before_first_loop); + slpeel_update_phi_nodes_for_guard2 (skip_e, second_loop, + second_loop == new_loop, &new_exit_bb); + + /* 4. Make first-loop iterate FIRST_NITERS times, if requested. + */ + if (update_first_loop_count) + slpeel_make_loop_iterate_ntimes (first_loop, first_niters); + + BITMAP_FREE (definitions); + delete_update_ssa (); + + /* Remove all pattern statements from the loop copy. They will confuse + the expander if DCE is disabled. + ??? The pattern recognizer should be split into an analysis and + a transformation phase that is then run only on the loop that is + going to be transformed. */ + remove_dead_stmts_from_loop (new_loop); + + adjust_vec_debug_stmts (); + + return new_loop; +} + +/* 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. */ + +LOC +find_loop_location (struct loop *loop) +{ + gimple stmt = NULL; + basic_block bb; + gimple_stmt_iterator si; + + if (!loop) + return UNKNOWN_LOC; + + stmt = get_loop_exit_condition (loop); + + if (stmt && gimple_location (stmt) != UNKNOWN_LOC) + 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_LOC; + + bb = loop->header; + + for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) + { + stmt = gsi_stmt (si); + if (gimple_location (stmt) != UNKNOWN_LOC) + return gimple_location (stmt); + } + + return UNKNOWN_LOC; +} + + +/* This function builds ni_name = number of iterations loop executes + on the loop preheader. If SEQ is given the stmt is instead emitted + there. */ + +static tree +vect_build_loop_niters (loop_vec_info loop_vinfo, gimple_seq seq) +{ + tree ni_name, var; + gimple_seq stmts = NULL; + edge pe; + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + tree ni = unshare_expr (LOOP_VINFO_NITERS (loop_vinfo)); + + var = create_tmp_var (TREE_TYPE (ni), "niters"); + add_referenced_var (var); + ni_name = force_gimple_operand (ni, &stmts, false, var); + + pe = loop_preheader_edge (loop); + if (stmts) + { + if (seq) + gimple_seq_add_seq (&seq, stmts); + else + { + basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + } + + return ni_name; +} + + +/* This function generates the following statements: + + ni_name = number of iterations loop executes + ratio = ni_name / vf + ratio_mult_vf_name = ratio * vf + + and places them at the loop preheader edge or in COND_EXPR_STMT_LIST + if that is non-NULL. */ + +static void +vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo, + tree *ni_name_ptr, + tree *ratio_mult_vf_name_ptr, + tree *ratio_name_ptr, + gimple_seq cond_expr_stmt_list) +{ + + edge pe; + basic_block new_bb; + gimple_seq stmts; + tree ni_name, ni_minus_gap_name; + tree var; + tree ratio_name; + tree ratio_mult_vf_name; + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + tree ni = LOOP_VINFO_NITERS (loop_vinfo); + int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo); + tree log_vf; + + pe = loop_preheader_edge (loop); + + /* Generate temporary variable that contains + number of iterations loop executes. */ + + ni_name = vect_build_loop_niters (loop_vinfo, cond_expr_stmt_list); + log_vf = build_int_cst (TREE_TYPE (ni), 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_name = fold_build2 (MINUS_EXPR, TREE_TYPE (ni_name), + ni_name, + build_one_cst (TREE_TYPE (ni_name))); + if (!is_gimple_val (ni_minus_gap_name)) + { + var = create_tmp_var (TREE_TYPE (ni), "ni_gap"); + add_referenced_var (var); + + stmts = NULL; + ni_minus_gap_name = force_gimple_operand (ni_minus_gap_name, &stmts, + true, var); + if (cond_expr_stmt_list) + gimple_seq_add_seq (&cond_expr_stmt_list, stmts); + else + { + pe = loop_preheader_edge (loop); + new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + } + } + else + ni_minus_gap_name = ni_name; + + /* Create: ratio = ni >> log2(vf) */ + + ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_minus_gap_name), + ni_minus_gap_name, log_vf); + if (!is_gimple_val (ratio_name)) + { + var = create_tmp_var (TREE_TYPE (ni), "bnd"); + add_referenced_var (var); + + stmts = NULL; + ratio_name = force_gimple_operand (ratio_name, &stmts, true, var); + if (cond_expr_stmt_list) + gimple_seq_add_seq (&cond_expr_stmt_list, stmts); + else + { + pe = loop_preheader_edge (loop); + new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + } + + /* Create: ratio_mult_vf = ratio << log2 (vf). */ + + ratio_mult_vf_name = fold_build2 (LSHIFT_EXPR, TREE_TYPE (ratio_name), + ratio_name, log_vf); + if (!is_gimple_val (ratio_mult_vf_name)) + { + var = create_tmp_var (TREE_TYPE (ni), "ratio_mult_vf"); + add_referenced_var (var); + + stmts = NULL; + ratio_mult_vf_name = force_gimple_operand (ratio_mult_vf_name, &stmts, + true, var); + if (cond_expr_stmt_list) + gimple_seq_add_seq (&cond_expr_stmt_list, stmts); + else + { + pe = loop_preheader_edge (loop); + new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + } + + *ni_name_ptr = ni_name; + *ratio_mult_vf_name_ptr = ratio_mult_vf_name; + *ratio_name_ptr = ratio_name; + + return; +} + +/* 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; + gimple phi; + gimple_stmt_iterator gsi; + + /* Analyze phi functions of the loop header. */ + + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "vect_can_advance_ivs_p:"); + + for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + tree access_fn = NULL; + tree evolution_part; + + phi = gsi_stmt (gsi); + if (vect_print_dump_info (REPORT_DETAILS)) + { + fprintf (vect_dump, "Analyze phi: "); + print_gimple_stmt (vect_dump, phi, 0, TDF_SLIM); + } + + /* Skip virtual phi's. The data dependences that are associated with + virtual defs/uses (i.e., memory accesses) are analyzed elsewhere. */ + + if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "virtual phi. skip."); + continue; + } + + /* Skip reduction phis. */ + + if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "reduc phi. skip."); + continue; + } + + /* Analyze the evolution function. */ + + access_fn = instantiate_parameters + (loop, analyze_scalar_evolution (loop, PHI_RESULT (phi))); + + if (!access_fn) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "No Access function."); + return false; + } + + if (vect_print_dump_info (REPORT_DETAILS)) + { + fprintf (vect_dump, "Access function of PHI: "); + print_generic_expr (vect_dump, access_fn, TDF_SLIM); + } + + evolution_part = evolution_part_in_loop_num (access_fn, loop->num); + + if (evolution_part == NULL_TREE) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "No evolution."); + 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)) + 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) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + basic_block exit_bb = single_exit (loop)->dest; + gimple phi, phi1; + gimple_stmt_iterator gsi, gsi1; + basic_block update_bb = update_e->dest; + + /* gcc_assert (vect_can_advance_ivs_p (loop_vinfo)); */ + + /* Make sure there exists a single-predecessor exit bb: */ + gcc_assert (single_pred_p (exit_bb)); + + 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 access_fn = NULL; + tree evolution_part; + tree init_expr; + tree step_expr, off; + tree type; + tree var, ni, ni_name; + gimple_stmt_iterator last_gsi; + + phi = gsi_stmt (gsi); + phi1 = gsi_stmt (gsi1); + if (vect_print_dump_info (REPORT_DETAILS)) + { + fprintf (vect_dump, "vect_update_ivs_after_vectorizer: phi: "); + print_gimple_stmt (vect_dump, phi, 0, TDF_SLIM); + } + + /* Skip virtual phi's. */ + if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "virtual phi. skip."); + continue; + } + + /* Skip reduction phis. */ + if (STMT_VINFO_DEF_TYPE (vinfo_for_stmt (phi)) == vect_reduction_def) + { + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "reduc phi. skip."); + continue; + } + + access_fn = analyze_scalar_evolution (loop, PHI_RESULT (phi)); + gcc_assert (access_fn); + /* We can end up with an access_fn like + (short int) {(short unsigned int) i_49, +, 1}_1 + for further analysis we need to strip the outer cast but we + need to preserve the original type. */ + type = TREE_TYPE (access_fn); + STRIP_NOPS (access_fn); + evolution_part = + unshare_expr (evolution_part_in_loop_num (access_fn, loop->num)); + gcc_assert (evolution_part != NULL_TREE); + + /* FORNOW: We do not support IVs whose evolution function is a polynomial + of degree >= 2 or exponential. */ + gcc_assert (!tree_is_chrec (evolution_part)); + + step_expr = evolution_part; + init_expr = unshare_expr (initial_condition_in_loop_num (access_fn, + loop->num)); + init_expr = fold_convert (type, init_expr); + + off = fold_build2 (MULT_EXPR, TREE_TYPE (step_expr), + fold_convert (TREE_TYPE (step_expr), niters), + step_expr); + if (POINTER_TYPE_P (TREE_TYPE (init_expr))) + ni = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (init_expr), + init_expr, + fold_convert (sizetype, off)); + else + ni = fold_build2 (PLUS_EXPR, TREE_TYPE (init_expr), + init_expr, + fold_convert (TREE_TYPE (init_expr), off)); + + var = create_tmp_var (TREE_TYPE (init_expr), "tmp"); + add_referenced_var (var); + + last_gsi = gsi_last_bb (exit_bb); + ni_name = force_gimple_operand_gsi (&last_gsi, ni, false, var, + true, GSI_SAME_STMT); + + /* Fix phi expressions in the successor bb. */ + adjust_phi_and_debug_stmts (phi1, update_e, ni_name); + } +} + +/* Return the more conservative threshold between the + min_profitable_iters returned by the cost model and the user + specified threshold, if provided. */ + +static unsigned int +conservative_cost_threshold (loop_vec_info loop_vinfo, + int min_profitable_iters) +{ + unsigned int th; + int min_scalar_loop_bound; + + min_scalar_loop_bound = ((PARAM_VALUE (PARAM_MIN_VECT_LOOP_BOUND) + * LOOP_VINFO_VECT_FACTOR (loop_vinfo)) - 1); + + /* Use the cost model only if it is more conservative than user specified + threshold. */ + th = (unsigned) min_scalar_loop_bound; + if (min_profitable_iters + && (!min_scalar_loop_bound + || min_profitable_iters > min_scalar_loop_bound)) + th = (unsigned) min_profitable_iters; + + if (th && vect_print_dump_info (REPORT_COST)) + fprintf (vect_dump, "Profitability threshold is %u loop iterations.", th); + + return th; +} + +/* Function vect_do_peeling_for_loop_bound + + Peel the last iterations of the loop represented by LOOP_VINFO. + The peeled iterations form a new epilog loop. Given that the loop now + iterates NITERS times, the new epilog loop iterates + NITERS % VECTORIZATION_FACTOR times. + + The original loop will later be made to iterate + NITERS / VECTORIZATION_FACTOR times (this value is placed into RATIO). + + COND_EXPR and COND_EXPR_STMT_LIST are combined with a new generated + test. */ + +void +vect_do_peeling_for_loop_bound (loop_vec_info loop_vinfo, tree *ratio, + tree cond_expr, gimple_seq cond_expr_stmt_list) +{ + tree ni_name, ratio_mult_vf_name; + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + struct loop *new_loop; + edge update_e; + basic_block preheader; + int loop_num; + bool check_profitability = false; + unsigned int th = 0; + int min_profitable_iters; + + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "=== vect_do_peeling_for_loop_bound ==="); + + initialize_original_copy_tables (); + + /* Generate the following variables on the preheader of original loop: + + ni_name = number of iteration the original loop executes + ratio = ni_name / vf + ratio_mult_vf_name = ratio * vf */ + vect_generate_tmps_on_preheader (loop_vinfo, &ni_name, + &ratio_mult_vf_name, ratio, + cond_expr_stmt_list); + + loop_num = loop->num; + + /* If cost model check not done during versioning and + peeling for alignment. */ + if (!LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT (loop_vinfo) + && !LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo) + && !LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) + && !cond_expr) + { + check_profitability = true; + + /* Get profitability threshold for vectorized loop. */ + min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo); + + th = conservative_cost_threshold (loop_vinfo, + min_profitable_iters); + } + + new_loop = slpeel_tree_peel_loop_to_edge (loop, single_exit (loop), + ratio_mult_vf_name, ni_name, false, + th, check_profitability, + cond_expr, cond_expr_stmt_list); + gcc_assert (new_loop); + gcc_assert (loop_num == loop->num); +#ifdef ENABLE_CHECKING + slpeel_verify_cfg_after_peeling (loop, new_loop); +#endif + + /* A guard that controls whether the new_loop is to be executed or skipped + is placed in LOOP->exit. LOOP->exit therefore has two successors - one + is the preheader of NEW_LOOP, where the IVs from LOOP are used. The other + is a bb after NEW_LOOP, where these IVs are not used. Find the edge that + is on the path where the LOOP IVs are used and need to be updated. */ + + preheader = loop_preheader_edge (new_loop)->src; + if (EDGE_PRED (preheader, 0)->src == single_exit (loop)->dest) + update_e = EDGE_PRED (preheader, 0); + else + update_e = EDGE_PRED (preheader, 1); + + /* Update IVs of original loop as if they were advanced + by ratio_mult_vf_name steps. */ + vect_update_ivs_after_vectorizer (loop_vinfo, ratio_mult_vf_name, update_e); + + /* After peeling we have to reset scalar evolution analyzer. */ + scev_reset (); + + free_original_copy_tables (); +} + + +/* Function vect_gen_niters_for_prolog_loop + + Set the number of iterations for the loop represented by LOOP_VINFO + to the minimum between LOOP_NITERS (the original iteration count of the loop) + and 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 = min (LOOP_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) + + 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_niters_for_prolog_loop (loop_vec_info loop_vinfo, tree loop_niters, + tree *wide_prolog_niters) +{ + struct data_reference *dr = LOOP_VINFO_UNALIGNED_DR (loop_vinfo); + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + tree var; + gimple_seq stmts; + tree iters, iters_name; + edge pe; + basic_block new_bb; + gimple dr_stmt = DR_STMT (dr); + stmt_vec_info stmt_info = vinfo_for_stmt (dr_stmt); + tree vectype = STMT_VINFO_VECTYPE (stmt_info); + int vectype_align = TYPE_ALIGN (vectype) / BITS_PER_UNIT; + tree niters_type = TREE_TYPE (loop_niters); + int nelements = TYPE_VECTOR_SUBPARTS (vectype); + + pe = loop_preheader_edge (loop); + + if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0) + { + int npeel = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo); + + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "known peeling = %d.", npeel); + + iters = build_int_cst (niters_type, npeel); + } + else + { + gimple_seq new_stmts = NULL; + bool negative = tree_int_cst_compare (DR_STEP (dr), size_zero_node) < 0; + tree offset = negative + ? size_int (-TYPE_VECTOR_SUBPARTS (vectype) + 1) : NULL_TREE; + tree start_addr = vect_create_addr_base_for_vector_ref (dr_stmt, + &new_stmts, offset, loop); + tree ptr_type = TREE_TYPE (start_addr); + tree size = TYPE_SIZE (ptr_type); + tree type = lang_hooks.types.type_for_size (tree_low_cst (size, 1), 1); + tree vectype_align_minus_1 = build_int_cst (type, vectype_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)); + tree nelements_minus_1 = build_int_cst (type, nelements - 1); + tree nelements_tree = build_int_cst (type, nelements); + tree byte_misalign; + tree elem_misalign; + + new_bb = gsi_insert_seq_on_edge_immediate (pe, new_stmts); + gcc_assert (!new_bb); + + /* Create: byte_misalign = addr & (vectype_align - 1) */ + byte_misalign = + fold_build2 (BIT_AND_EXPR, type, fold_convert (type, start_addr), + vectype_align_minus_1); + + /* Create: elem_misalign = byte_misalign / element_size */ + elem_misalign = + fold_build2 (RSHIFT_EXPR, type, byte_misalign, elem_size_log); + + /* Create: (niters_type) (nelements - elem_misalign)&(nelements - 1) */ + if (negative) + iters = fold_build2 (MINUS_EXPR, type, elem_misalign, nelements_tree); + else + iters = fold_build2 (MINUS_EXPR, type, nelements_tree, elem_misalign); + iters = fold_build2 (BIT_AND_EXPR, type, iters, nelements_minus_1); + iters = fold_convert (niters_type, iters); + } + + /* Create: prolog_loop_niters = min (iters, loop_niters) */ + /* If the loop bound is known at compile time we already verified that it is + greater than vf; since the misalignment ('iters') is at most vf, there's + no need to generate the MIN_EXPR in this case. */ + if (TREE_CODE (loop_niters) != INTEGER_CST) + iters = fold_build2 (MIN_EXPR, niters_type, iters, loop_niters); + + if (vect_print_dump_info (REPORT_DETAILS)) + { + fprintf (vect_dump, "niters for prolog loop: "); + print_generic_expr (vect_dump, iters, TDF_SLIM); + } + + var = create_tmp_var (niters_type, "prolog_loop_niters"); + add_referenced_var (var); + stmts = NULL; + iters_name = force_gimple_operand (iters, &stmts, false, var); + if (types_compatible_p (sizetype, niters_type)) + *wide_prolog_niters = iters_name; + else + { + gimple_seq seq = NULL; + tree wide_iters = fold_convert (sizetype, iters); + var = create_tmp_var (sizetype, "prolog_loop_niters"); + add_referenced_var (var); + *wide_prolog_niters = force_gimple_operand (wide_iters, &seq, false, + var); + if (seq) + gimple_seq_add_seq (&stmts, seq); + } + + /* Insert stmt on loop preheader edge. */ + if (stmts) + { + basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, stmts); + gcc_assert (!new_bb); + } + + 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, heap) *datarefs = LOOP_VINFO_DATAREFS (loop_vinfo); + struct data_reference *dr; + + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "=== vect_update_inits_of_dr ==="); + + FOR_EACH_VEC_ELT (data_reference_p, datarefs, i, dr) + vect_update_init_of_dr (dr, niters); +} + + +/* Function vect_do_peeling_for_alignment + + Peel the first 'niters' iterations of the loop represented by LOOP_VINFO. + 'niters' is set to the misalignment of one of the data references in the + loop, thereby forcing it to refer to an aligned location at the beginning + of the execution of this loop. The data reference for which we are + peeling is recorded in LOOP_VINFO_UNALIGNED_DR. */ + +void +vect_do_peeling_for_alignment (loop_vec_info loop_vinfo) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + tree niters_of_prolog_loop, ni_name; + tree n_iters; + tree wide_prolog_niters; + struct loop *new_loop; + unsigned int th = 0; + int min_profitable_iters; + + if (vect_print_dump_info (REPORT_DETAILS)) + fprintf (vect_dump, "=== vect_do_peeling_for_alignment ==="); + + initialize_original_copy_tables (); + + ni_name = vect_build_loop_niters (loop_vinfo, NULL); + niters_of_prolog_loop = vect_gen_niters_for_prolog_loop (loop_vinfo, ni_name, + &wide_prolog_niters); + + + /* Get profitability threshold for vectorized loop. */ + min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo); + th = conservative_cost_threshold (loop_vinfo, + min_profitable_iters); + + /* Peel the prolog loop and iterate it niters_of_prolog_loop. */ + new_loop = + slpeel_tree_peel_loop_to_edge (loop, loop_preheader_edge (loop), + niters_of_prolog_loop, ni_name, true, + th, true, NULL_TREE, NULL); + + gcc_assert (new_loop); +#ifdef ENABLE_CHECKING + slpeel_verify_cfg_after_peeling (new_loop, loop); +#endif + + /* Update number of times loop executes. */ + n_iters = LOOP_VINFO_NITERS (loop_vinfo); + LOOP_VINFO_NITERS (loop_vinfo) = fold_build2 (MINUS_EXPR, + TREE_TYPE (n_iters), n_iters, niters_of_prolog_loop); + + /* Update the init conditions of the access functions of all data refs. */ + vect_update_inits_of_drs (loop_vinfo, wide_prolog_niters); + + /* After peeling we have to reset scalar evolution analyzer. */ + scev_reset (); + + free_original_copy_tables (); +} + + +/* 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) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + VEC(gimple,heap) *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 psize; + tree int_ptrsize_type; + char tmp_name[20]; + tree or_tmp_name = NULL_TREE; + tree and_tmp, 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)); + + /* CHECKME: what is the best integer or unsigned type to use to hold a + cast from a pointer value? */ + psize = TYPE_SIZE (ptr_type_node); + int_ptrsize_type + = lang_hooks.types.type_for_size (tree_low_cst (psize, 1), 0); + + /* 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 (gimple, may_misalign_stmts, i, ref_stmt) + { + gimple_seq new_stmt_list = NULL; + tree addr_base; + tree addr_tmp, addr_tmp_name; + tree or_tmp, 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) : NULL_TREE; + + /* create: addr_tmp = (int)(address_of_first_vector) */ + addr_base = + vect_create_addr_base_for_vector_ref (ref_stmt, &new_stmt_list, + offset, loop); + if (new_stmt_list != NULL) + gimple_seq_add_seq (cond_expr_stmt_list, new_stmt_list); + + sprintf (tmp_name, "%s%d", "addr2int", i); + addr_tmp = create_tmp_var (int_ptrsize_type, tmp_name); + add_referenced_var (addr_tmp); + addr_tmp_name = make_ssa_name (addr_tmp, NULL); + addr_stmt = gimple_build_assign_with_ops (NOP_EXPR, addr_tmp_name, + addr_base, NULL_TREE); + SSA_NAME_DEF_STMT (addr_tmp_name) = addr_stmt; + 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, "%s%d", "orptrs", i); + or_tmp = create_tmp_var (int_ptrsize_type, tmp_name); + add_referenced_var (or_tmp); + new_or_tmp_name = make_ssa_name (or_tmp, NULL); + or_stmt = gimple_build_assign_with_ops (BIT_IOR_EXPR, + new_or_tmp_name, + or_tmp_name, addr_tmp_name); + SSA_NAME_DEF_STMT (new_or_tmp_name) = or_stmt; + 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 = create_tmp_var (int_ptrsize_type, "andmask" ); + add_referenced_var (and_tmp); + and_tmp_name = make_ssa_name (and_tmp, NULL); + + and_stmt = gimple_build_assign_with_ops (BIT_AND_EXPR, and_tmp_name, + or_tmp_name, mask_cst); + SSA_NAME_DEF_STMT (and_tmp_name) = and_stmt; + 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); + 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_vfa_segment_size. + + Create an expression that computes the size of segment + that will be accessed for a data reference. The functions takes into + account that realignment loads may access one more vector. + + Input: + DR: The data reference. + LENGTH_FACTOR: segment length to consider. + + Return an expression whose value is the size of segment which will be + accessed by DR. */ + +static tree +vect_vfa_segment_size (struct data_reference *dr, tree length_factor) +{ + tree segment_length; + segment_length = size_binop (MULT_EXPR, + fold_convert (sizetype, DR_STEP (dr)), + fold_convert (sizetype, length_factor)); + if (vect_supportable_dr_alignment (dr, false) + == dr_explicit_realign_optimized) + { + tree vector_size = TYPE_SIZE_UNIT + (STMT_VINFO_VECTYPE (vinfo_for_stmt (DR_STMT (dr)))); + + segment_length = size_binop (PLUS_EXPR, segment_length, vector_size); + } + return segment_length; +} + + +/* 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. + LOOP_VINFO - field LOOP_VINFO_MAY_ALIAS_STMTS contains the list of ddrs + to be checked. + + Output: + COND_EXPR - conditional expression. + 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. +*/ + +static void +vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo, + tree * cond_expr, + gimple_seq * cond_expr_stmt_list) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + VEC (ddr_p, heap) * may_alias_ddrs = + LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo); + int vect_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo); + tree scalar_loop_iters = LOOP_VINFO_NITERS (loop_vinfo); + + ddr_p ddr; + unsigned int i; + tree part_cond_expr, length_factor; + + /* Create expression + ((store_ptr_0 + store_segment_length_0) < load_ptr_0) + || (load_ptr_0 + load_segment_length_0) < store_ptr_0)) + && + ... + && + ((store_ptr_n + store_segment_length_n) < load_ptr_n) + || (load_ptr_n + load_segment_length_n) < store_ptr_n)) */ + + if (VEC_empty (ddr_p, may_alias_ddrs)) + return; + + FOR_EACH_VEC_ELT (ddr_p, may_alias_ddrs, i, ddr) + { + struct data_reference *dr_a, *dr_b; + gimple dr_group_first_a, dr_group_first_b; + tree addr_base_a, addr_base_b; + tree segment_length_a, segment_length_b; + gimple stmt_a, stmt_b; + tree seg_a_min, seg_a_max, seg_b_min, seg_b_max; + + dr_a = DDR_A (ddr); + stmt_a = DR_STMT (DDR_A (ddr)); + dr_group_first_a = DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_a)); + if (dr_group_first_a) + { + stmt_a = dr_group_first_a; + dr_a = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt_a)); + } + + dr_b = DDR_B (ddr); + stmt_b = DR_STMT (DDR_B (ddr)); + dr_group_first_b = DR_GROUP_FIRST_DR (vinfo_for_stmt (stmt_b)); + if (dr_group_first_b) + { + stmt_b = dr_group_first_b; + dr_b = STMT_VINFO_DATA_REF (vinfo_for_stmt (stmt_b)); + } + + addr_base_a = + vect_create_addr_base_for_vector_ref (stmt_a, cond_expr_stmt_list, + NULL_TREE, loop); + addr_base_b = + vect_create_addr_base_for_vector_ref (stmt_b, cond_expr_stmt_list, + NULL_TREE, loop); + + if (!operand_equal_p (DR_STEP (dr_a), DR_STEP (dr_b), 0)) + length_factor = scalar_loop_iters; + else + length_factor = size_int (vect_factor); + segment_length_a = vect_vfa_segment_size (dr_a, length_factor); + segment_length_b = vect_vfa_segment_size (dr_b, length_factor); + + if (vect_print_dump_info (REPORT_DR_DETAILS)) + { + fprintf (vect_dump, + "create runtime check for data references "); + print_generic_expr (vect_dump, DR_REF (dr_a), TDF_SLIM); + fprintf (vect_dump, " and "); + print_generic_expr (vect_dump, DR_REF (dr_b), TDF_SLIM); + } + + seg_a_min = addr_base_a; + seg_a_max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_a), + addr_base_a, segment_length_a); + if (tree_int_cst_compare (DR_STEP (dr_a), size_zero_node) < 0) + seg_a_min = seg_a_max, seg_a_max = addr_base_a; + + seg_b_min = addr_base_b; + seg_b_max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_b), + addr_base_b, segment_length_b); + if (tree_int_cst_compare (DR_STEP (dr_b), size_zero_node) < 0) + seg_b_min = seg_b_max, seg_b_max = addr_base_b; + + part_cond_expr = + fold_build2 (TRUTH_OR_EXPR, boolean_type_node, + fold_build2 (LT_EXPR, boolean_type_node, seg_a_max, seg_b_min), + fold_build2 (LT_EXPR, boolean_type_node, seg_b_max, seg_a_min)); + + if (*cond_expr) + *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, + *cond_expr, part_cond_expr); + else + *cond_expr = part_cond_expr; + } + + if (vect_print_dump_info (REPORT_VECTORIZED_LOCATIONS)) + fprintf (vect_dump, "created %u versioning for alias checks.\n", + VEC_length (ddr_p, may_alias_ddrs)); +} + + +/* 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 initially. + + The versioning precondition(s) are placed in *COND_EXPR and + *COND_EXPR_STMT_LIST. If DO_VERSIONING is true versioning is + also performed, otherwise only the conditions are generated. */ + +void +vect_loop_versioning (loop_vec_info loop_vinfo, bool do_versioning, + tree *cond_expr, gimple_seq *cond_expr_stmt_list) +{ + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + basic_block condition_bb; + gimple_stmt_iterator gsi, cond_exp_gsi; + basic_block merge_bb; + basic_block new_exit_bb; + edge new_exit_e, e; + gimple orig_phi, new_phi; + tree arg; + unsigned prob = 4 * REG_BR_PROB_BASE / 5; + gimple_seq gimplify_stmt_list = NULL; + tree scalar_loop_iters = LOOP_VINFO_NITERS (loop_vinfo); + int min_profitable_iters = 0; + unsigned int th; + + /* Get profitability threshold for vectorized loop. */ + min_profitable_iters = LOOP_VINFO_COST_MODEL_MIN_ITERS (loop_vinfo); + + th = conservative_cost_threshold (loop_vinfo, + min_profitable_iters); + + *cond_expr = + fold_build2 (GT_EXPR, boolean_type_node, scalar_loop_iters, + build_int_cst (TREE_TYPE (scalar_loop_iters), th)); + + *cond_expr = force_gimple_operand (*cond_expr, cond_expr_stmt_list, + false, NULL_TREE); + + if (LOOP_REQUIRES_VERSIONING_FOR_ALIGNMENT (loop_vinfo)) + vect_create_cond_for_align_checks (loop_vinfo, cond_expr, + cond_expr_stmt_list); + + if (LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo)) + vect_create_cond_for_alias_checks (loop_vinfo, cond_expr, + cond_expr_stmt_list); + + *cond_expr = + fold_build2 (NE_EXPR, boolean_type_node, *cond_expr, integer_zero_node); + *cond_expr = + force_gimple_operand (*cond_expr, &gimplify_stmt_list, true, NULL_TREE); + gimple_seq_add_seq (cond_expr_stmt_list, gimplify_stmt_list); + + /* If we only needed the extra conditions and a new loop copy + bail out here. */ + if (!do_versioning) + return; + + initialize_original_copy_tables (); + loop_version (loop, *cond_expr, &condition_bb, + prob, prob, REG_BR_PROB_BASE - prob, true); + 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. */ + + merge_bb = single_exit (loop)->dest; + 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)) + { + orig_phi = gsi_stmt (gsi); + new_phi = create_phi_node (SSA_NAME_VAR (PHI_RESULT (orig_phi)), + 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. */ + + update_ssa (TODO_update_ssa); + 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); + *cond_expr_stmt_list = NULL; + } + *cond_expr = NULL_TREE; +} + -- cgit v1.2.3