CbC/CbC_gcc: gcc/tree-vect-loop-manip.c comparison

comparison gcc/tree-vect-loop-manip.c @ 55:77e2b8dfacca gcc-4.4.5

update it from 4.4.3 to 4.5.0

author	ryoma <e075725@ie.u-ryukyu.ac.jp>
date	Fri, 12 Feb 2010 23:39:51 +0900
parents
children	b7f97abdc517

comparison

equal deleted inserted replaced

-:c156f1bd5cd9
+:77e2b8dfacca
+/* Vectorizer Specific Loop Manipulations
+Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 "tm.h"
+#include "ggc.h"
+#include "tree.h"
+#include "basic-block.h"
+#include "diagnostic.h"
+#include "tree-flow.h"
+#include "tree-dump.h"
+#include "cfgloop.h"
+#include "cfglayout.h"
+#include "expr.h"
+#include "toplev.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);
+}
+/* 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);
+/* step 3 (case 1).  */
+if (!after)
+{
+gcc_assert (new_loop_exit_e == orig_entry_e);
+SET_PHI_ARG_DEF (phi_orig,
+new_loop_exit_e->dest_idx,
+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);
+SET_PHI_ARG_DEF (update_phi, e->dest_idx, 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);
+SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, 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);
+SET_PHI_ARG_DEF (update_phi, e->dest_idx, 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);
+SET_PHI_ARG_DEF (update_phi2, new_exit_e->dest_idx, 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);
+SET_PHI_ARG_DEF (update_phi2, guard_edge->dest_idx, 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);
+}
+/* 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 (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 ();
+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;
+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));
+/* Create: ratio = ni >> log2(vf) */
+ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_name), ni_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.  */
+SET_PHI_ARG_DEF (phi1, update_e->dest_idx, 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_size - 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)
+{
+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 step = 1;
+int element_size = GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (DR_REF (dr))));
+int nelements = TYPE_VECTOR_SUBPARTS (vectype);
+if (STMT_VINFO_STRIDED_ACCESS (stmt_info))
+step = DR_GROUP_SIZE (vinfo_for_stmt (DR_GROUP_FIRST_DR (stmt_info)));
+pe = loop_preheader_edge (loop);
+if (LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo) > 0)
+{
+int byte_misalign = LOOP_PEELING_FOR_ALIGNMENT (loop_vinfo);
+int elem_misalign = byte_misalign / element_size;
+if (vect_print_dump_info (REPORT_DETAILS))
+fprintf (vect_dump, "known alignment = %d.", byte_misalign);
+iters = build_int_cst (niters_type,
+(((nelements - elem_misalign) & (nelements - 1)) / step));
+}
+else
+{
+gimple_seq new_stmts = NULL;
+tree start_addr = vect_create_addr_base_for_vector_ref (dr_stmt,
+						&new_stmts, NULL_TREE, 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_size_minus_1 = build_int_cst (type, vectype_align - 1);
+tree elem_size_log =
+build_int_cst (type, exact_log2 (vectype_align/nelements));
+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_size - 1)  */
+byte_misalign =
+fold_build2 (BIT_AND_EXPR, type, fold_convert (type, start_addr), vectype_size_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)  */
+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);
+/* 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 (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
+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;
+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);
+/* 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, niters_of_prolog_loop);
+/* 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 (i = 0; VEC_iterate (gimple, may_misalign_stmts, i, ref_stmt); i++)
+{
+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;
+/* create: addr_tmp = (int)(address_of_first_vector) */
+addr_base =
+	vect_create_addr_base_for_vector_ref (ref_stmt, &new_stmt_list,
+					      NULL_TREE, 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.
+VECT_FACTOR: vectorization factor.
+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 vect_factor)
+{
+tree segment_length = fold_build2 (MULT_EXPR, integer_type_node,
+			             DR_STEP (dr), vect_factor);
+if (vect_supportable_dr_alignment (dr) == dr_explicit_realign_optimized)
+{
+tree vector_size = TYPE_SIZE_UNIT
+			  (STMT_VINFO_VECTYPE (vinfo_for_stmt (DR_STMT (dr))));
+segment_length = fold_build2 (PLUS_EXPR, integer_type_node,
+				    segment_length, vector_size);
+}
+return fold_convert (sizetype, 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);
+tree vect_factor =
+build_int_cst (integer_type_node, LOOP_VINFO_VECT_FACTOR (loop_vinfo));
+ddr_p ddr;
+unsigned int i;
+tree part_cond_expr;
+/* 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 (i = 0; VEC_iterate (ddr_p, may_alias_ddrs, i, ddr); i++)
+{
+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;
+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);
+segment_length_a = vect_vfa_segment_size (dr_a, vect_factor);
+segment_length_b = vect_vfa_segment_size (dr_b, vect_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);
+	}
+part_cond_expr =
+	fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
+	  fold_build2 (LT_EXPR, boolean_type_node,
+	    fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_a),
+	      addr_base_a,
+	      segment_length_a),
+	    addr_base_b),
+	  fold_build2 (LT_EXPR, boolean_type_node,
+	    fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (addr_base_b),
+	      addr_base_b,
+	      segment_length_b),
+	    addr_base_a));
+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));
+SET_PHI_ARG_DEF (orig_phi, e->dest_idx, 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;
+}

Mercurial > hg > CbC > CbC_gcc

comparison gcc/tree-vect-loop-manip.c @ 55:77e2b8dfacca gcc-4.4.5