/* Loop manipulation code for GNU compiler.
- Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
+ Free Software Foundation, Inc.
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 2, or (at your option) any later
+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
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "tm.h"
#include "rtl.h"
#include "hard-reg-set.h"
+#include "obstack.h"
#include "basic-block.h"
#include "cfgloop.h"
#include "cfglayout.h"
+#include "cfghooks.h"
#include "output.h"
+#include "tree-flow.h"
+
+static void copy_loops_to (struct loop **, int,
+ struct loop *);
+static void loop_redirect_edge (edge, basic_block);
+static void remove_bbs (basic_block *, int);
+static bool rpe_enum_p (const_basic_block, const void *);
+static int find_path (edge, basic_block **);
+static void fix_loop_placements (struct loop *, bool *);
+static bool fix_bb_placement (basic_block);
+static void fix_bb_placements (basic_block, bool *);
+static void unloop (struct loop *, bool *);
-static struct loop * duplicate_loop PARAMS ((struct loops *,
- struct loop *, struct loop *));
-static void duplicate_subloops PARAMS ((struct loops *, struct loop *,
- struct loop *));
-static void copy_loops_to PARAMS ((struct loops *, struct loop **,
- int, struct loop *));
-static void loop_redirect_edge PARAMS ((edge, basic_block));
-static bool loop_delete_branch_edge PARAMS ((edge));
-static void copy_bbs PARAMS ((basic_block *, int, edge,
- edge, basic_block **,
- struct loops *, edge *,
- edge *, int));
-static void remove_bbs PARAMS ((dominance_info, basic_block *,
- int));
-static bool rpe_enum_p PARAMS ((basic_block, void *));
-static int find_path PARAMS ((edge, dominance_info,
- basic_block **));
-static bool alp_enum_p PARAMS ((basic_block, void *));
-static void add_loop PARAMS ((struct loops *, struct loop *));
-static void fix_loop_placements PARAMS ((struct loop *));
-static bool fix_bb_placement PARAMS ((struct loops *, basic_block));
-static void fix_bb_placements PARAMS ((struct loops *, basic_block));
-static void place_new_loop PARAMS ((struct loops *, struct loop *));
-static void scale_loop_frequencies PARAMS ((struct loop *, int, int));
-static void scale_bbs_frequencies PARAMS ((basic_block *, int, int, int));
-static void record_exit_edges PARAMS ((edge, basic_block *, int,
- edge *, unsigned *, int));
-static basic_block create_preheader PARAMS ((struct loop *, dominance_info,
- int));
-
-/* Splits basic block BB after INSN, returns created edge. Updates loops
- and dominators. */
-edge
-split_loop_bb (loops, bb, insn)
- struct loops *loops;
- basic_block bb;
- rtx insn;
-{
- edge e;
- basic_block *dom_bbs;
- int n_dom_bbs, i;
-
- /* Split the block. */
- e = split_block (bb, insn);
-
- /* Add dest to loop. */
- add_bb_to_loop (e->dest, e->src->loop_father);
-
- /* Fix dominators. */
- add_to_dominance_info (loops->cfg.dom, e->dest);
- n_dom_bbs = get_dominated_by (loops->cfg.dom, e->src, &dom_bbs);
- for (i = 0; i < n_dom_bbs; i++)
- set_immediate_dominator (loops->cfg.dom, dom_bbs[i], e->dest);
- free (dom_bbs);
- set_immediate_dominator (loops->cfg.dom, e->dest, e->src);
-
- /* Take care of RBI. */
- alloc_aux_for_block (e->dest, sizeof (struct reorder_block_def));
-
- return e;
-}
-
-/* Checks whether basic block BB is dominated by RPE->DOM, where
- RPE is passed through DATA. */
-struct rpe_data
- {
- basic_block dom;
- dominance_info doms;
- };
+#define RDIV(X,Y) (((X) + (Y) / 2) / (Y))
+/* Checks whether basic block BB is dominated by DATA. */
static bool
-rpe_enum_p (bb, data)
- basic_block bb;
- void *data;
+rpe_enum_p (const_basic_block bb, const void *data)
{
- struct rpe_data *rpe = data;
- return dominated_by_p (rpe->doms, bb, rpe->dom);
+ return dominated_by_p (CDI_DOMINATORS, bb, (const_basic_block) data);
}
-/* Remove basic blocks BBS from loop structure and dominance info,
- and delete them afterwards. */
+/* Remove basic blocks BBS. NBBS is the number of the basic blocks. */
+
static void
-remove_bbs (dom, bbs, nbbs)
- dominance_info dom;
- basic_block *bbs;
- int nbbs;
+remove_bbs (basic_block *bbs, int nbbs)
{
int i;
for (i = 0; i < nbbs; i++)
- {
- remove_bb_from_loops (bbs[i]);
- delete_from_dominance_info (dom, bbs[i]);
- flow_delete_block (bbs[i]);
- }
+ delete_basic_block (bbs[i]);
}
/* Find path -- i.e. the basic blocks dominated by edge E and put them
into array BBS, that will be allocated large enough to contain them.
- The number of basic blocks in the path is returned. */
+ E->dest must have exactly one predecessor for this to work (it is
+ easy to achieve and we do not put it here because we do not want to
+ alter anything by this function). The number of basic blocks in the
+ path is returned. */
static int
-find_path (e, doms, bbs)
- edge e;
- dominance_info doms;
- basic_block **bbs;
+find_path (edge e, basic_block **bbs)
{
- edge ae = NULL;
- struct rpe_data rpe;
-
- if (e->dest->pred->pred_next)
- {
- for (ae = e->dest->pred; ae; ae = ae->pred_next)
- if (ae != e && !dominated_by_p (doms, ae->src, e->dest))
- break;
- }
- if (ae)
- {
- /* The path is formed just by the edge. */
- *bbs = NULL;
- return 0;
- }
+ gcc_assert (EDGE_COUNT (e->dest->preds) <= 1);
/* Find bbs in the path. */
- rpe.dom = e->dest;
- rpe.doms = doms;
- *bbs = xcalloc (n_basic_blocks, sizeof (basic_block));
+ *bbs = XCNEWVEC (basic_block, n_basic_blocks);
return dfs_enumerate_from (e->dest, 0, rpe_enum_p, *bbs,
- n_basic_blocks, &rpe);
+ n_basic_blocks, e->dest);
}
-/* Fix placement of basic block BB inside loop hierarchy stored in LOOPS --
+/* Fix placement of basic block BB inside loop hierarchy --
Let L be a loop to that BB belongs. Then every successor of BB must either
1) belong to some superloop of loop L, or
2) be a header of loop K such that K->outer is superloop of L
false if the placement of BB was already correct (provided that placements
of its successors are correct). */
static bool
-fix_bb_placement (loops, bb)
- struct loops *loops;
- basic_block bb;
+fix_bb_placement (basic_block bb)
{
edge e;
- struct loop *loop = loops->tree_root, *act;
+ edge_iterator ei;
+ struct loop *loop = current_loops->tree_root, *act;
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if (e->dest == EXIT_BLOCK_PTR)
continue;
act = e->dest->loop_father;
if (act->header == e->dest)
- act = act->outer;
+ act = loop_outer (act);
if (flow_loop_nested_p (loop, act))
loop = act;
return true;
}
+/* Fix placement of LOOP inside loop tree, i.e. find the innermost superloop
+ of LOOP to that leads at least one exit edge of LOOP, and set it
+ as the immediate superloop of LOOP. Return true if the immediate superloop
+ of LOOP changed. */
+
+static bool
+fix_loop_placement (struct loop *loop)
+{
+ unsigned i;
+ edge e;
+ VEC (edge, heap) *exits = get_loop_exit_edges (loop);
+ struct loop *father = current_loops->tree_root, *act;
+ bool ret = false;
+
+ FOR_EACH_VEC_ELT (edge, exits, i, e)
+ {
+ act = find_common_loop (loop, e->dest->loop_father);
+ if (flow_loop_nested_p (father, act))
+ father = act;
+ }
+
+ if (father != loop_outer (loop))
+ {
+ for (act = loop_outer (loop); act != father; act = loop_outer (act))
+ act->num_nodes -= loop->num_nodes;
+ flow_loop_tree_node_remove (loop);
+ flow_loop_tree_node_add (father, loop);
+
+ /* The exit edges of LOOP no longer exits its original immediate
+ superloops; remove them from the appropriate exit lists. */
+ FOR_EACH_VEC_ELT (edge, exits, i, e)
+ rescan_loop_exit (e, false, false);
+
+ ret = true;
+ }
+
+ VEC_free (edge, heap, exits);
+ return ret;
+}
+
/* Fix placements of basic blocks inside loop hierarchy stored in loops; i.e.
enforce condition condition stated in description of fix_bb_placement. We
start from basic block FROM that had some of its successors removed, so that
his placement no longer has to be correct, and iteratively fix placement of
its predecessors that may change if placement of FROM changed. Also fix
placement of subloops of FROM->loop_father, that might also be altered due
- to this change; the condition for them is simmilar, except that instead of
- successors we consider edges coming out of the loops. */
+ to this change; the condition for them is similar, except that instead of
+ successors we consider edges coming out of the loops.
+
+ If the changes may invalidate the information about irreducible regions,
+ IRRED_INVALIDATED is set to true. */
+
static void
-fix_bb_placements (loops, from)
- struct loops *loops;
- basic_block from;
+fix_bb_placements (basic_block from,
+ bool *irred_invalidated)
{
sbitmap in_queue;
basic_block *queue, *qtop, *qbeg, *qend;
- struct loop *base_loop;
+ struct loop *base_loop, *target_loop;
edge e;
/* We pass through blocks back-reachable from FROM, testing whether some
fix_loop_placement. */
base_loop = from->loop_father;
- if (base_loop == loops->tree_root)
+ /* If we are already in the outermost loop, the basic blocks cannot be moved
+ outside of it. If FROM is the header of the base loop, it cannot be moved
+ outside of it, either. In both cases, we can end now. */
+ if (base_loop == current_loops->tree_root
+ || from == base_loop->header)
return;
in_queue = sbitmap_alloc (last_basic_block);
/* Prevent us from going out of the base_loop. */
SET_BIT (in_queue, base_loop->header->index);
- queue = xcalloc (base_loop->num_nodes + 1, sizeof (basic_block));
+ queue = XNEWVEC (basic_block, base_loop->num_nodes + 1);
qtop = queue + base_loop->num_nodes + 1;
qbeg = queue;
qend = queue + 1;
while (qbeg != qend)
{
+ edge_iterator ei;
from = *qbeg;
qbeg++;
if (qbeg == qtop)
/* Subloop header, maybe move the loop upward. */
if (!fix_loop_placement (from->loop_father))
continue;
+ target_loop = loop_outer (from->loop_father);
}
else
{
/* Ordinary basic block. */
- if (!fix_bb_placement (loops, from))
+ if (!fix_bb_placement (from))
continue;
+ target_loop = from->loop_father;
+ }
+
+ FOR_EACH_EDGE (e, ei, from->succs)
+ {
+ if (e->flags & EDGE_IRREDUCIBLE_LOOP)
+ *irred_invalidated = true;
}
/* Something has changed, insert predecessors into queue. */
- for (e = from->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, from->preds)
{
basic_block pred = e->src;
struct loop *nca;
+ if (e->flags & EDGE_IRREDUCIBLE_LOOP)
+ *irred_invalidated = true;
+
if (TEST_BIT (in_queue, pred->index))
continue;
- /* If it is subloop, then it either was not moved, or
+ /* If it is subloop, then it either was not moved, or
the path up the loop tree from base_loop do not contain
it. */
nca = find_common_loop (pred->loop_father, base_loop);
&& (nca == base_loop
|| nca != pred->loop_father))
pred = pred->loop_father->header;
- else if (!flow_loop_nested_p (from->loop_father, pred->loop_father))
+ else if (!flow_loop_nested_p (target_loop, pred->loop_father))
{
- /* No point in processing it. */
+ /* If PRED is already higher in the loop hierarchy than the
+ TARGET_LOOP to that we moved FROM, the change of the position
+ of FROM does not affect the position of PRED, so there is no
+ point in processing it. */
continue;
}
}
/* Removes path beginning at edge E, i.e. remove basic blocks dominated by E
- and update loop structure stored in LOOPS and dominators. Return true if
- we were able to remove the path, false otherwise (and nothing is affected
- then). */
+ and update loop structures and dominators. Return true if we were able
+ to remove the path, false otherwise (and nothing is affected then). */
bool
-remove_path (loops, e)
- struct loops *loops;
- edge e;
+remove_path (edge e)
{
edge ae;
- basic_block *rem_bbs, *bord_bbs, *dom_bbs, from, bb;
- int i, nrem, n_bord_bbs, n_dom_bbs;
+ basic_block *rem_bbs, *bord_bbs, from, bb;
+ VEC (basic_block, heap) *dom_bbs;
+ int i, nrem, n_bord_bbs;
sbitmap seen;
+ bool irred_invalidated = false;
+
+ if (!can_remove_branch_p (e))
+ return false;
- /* First identify the path. */
- nrem = find_path (e, loops->cfg.dom, &rem_bbs);
+ /* Keep track of whether we need to update information about irreducible
+ regions. This is the case if the removed area is a part of the
+ irreducible region, or if the set of basic blocks that belong to a loop
+ that is inside an irreducible region is changed, or if such a loop is
+ removed. */
+ if (e->flags & EDGE_IRREDUCIBLE_LOOP)
+ irred_invalidated = true;
+
+ /* We need to check whether basic blocks are dominated by the edge
+ e, but we only have basic block dominators. This is easy to
+ fix -- when e->dest has exactly one predecessor, this corresponds
+ to blocks dominated by e->dest, if not, split the edge. */
+ if (!single_pred_p (e->dest))
+ e = single_pred_edge (split_edge (e));
+
+ /* It may happen that by removing path we remove one or more loops
+ we belong to. In this case first unloop the loops, then proceed
+ normally. We may assume that e->dest is not a header of any loop,
+ as it now has exactly one predecessor. */
+ while (loop_outer (e->src->loop_father)
+ && dominated_by_p (CDI_DOMINATORS,
+ e->src->loop_father->latch, e->dest))
+ unloop (e->src->loop_father, &irred_invalidated);
+
+ /* Identify the path. */
+ nrem = find_path (e, &rem_bbs);
n_bord_bbs = 0;
- bord_bbs = xcalloc (n_basic_blocks, sizeof (basic_block));
+ bord_bbs = XCNEWVEC (basic_block, n_basic_blocks);
seen = sbitmap_alloc (last_basic_block);
sbitmap_zero (seen);
/* Find "border" hexes -- i.e. those with predecessor in removed path. */
for (i = 0; i < nrem; i++)
SET_BIT (seen, rem_bbs[i]->index);
- if (nrem)
+ for (i = 0; i < nrem; i++)
{
- for (i = 0; i < nrem; i++)
- {
- bb = rem_bbs[i];
- for (ae = rem_bbs[i]->succ; ae; ae = ae->succ_next)
- if (ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, ae->dest->index))
- {
- SET_BIT (seen, ae->dest->index);
- bord_bbs[n_bord_bbs++] = ae->dest;
- }
- }
+ edge_iterator ei;
+ bb = rem_bbs[i];
+ FOR_EACH_EDGE (ae, ei, rem_bbs[i]->succs)
+ if (ae->dest != EXIT_BLOCK_PTR && !TEST_BIT (seen, ae->dest->index))
+ {
+ SET_BIT (seen, ae->dest->index);
+ bord_bbs[n_bord_bbs++] = ae->dest;
+
+ if (ae->flags & EDGE_IRREDUCIBLE_LOOP)
+ irred_invalidated = true;
+ }
}
- else if (e->dest != EXIT_BLOCK_PTR)
- bord_bbs[n_bord_bbs++] = e->dest;
/* Remove the path. */
from = e->src;
- if (!loop_delete_branch_edge (e))
- {
- free (rem_bbs);
- free (bord_bbs);
- free (seen);
- return false;
- }
- dom_bbs = xcalloc (n_basic_blocks, sizeof (basic_block));
+ remove_branch (e);
+ dom_bbs = NULL;
/* Cancel loops contained in the path. */
for (i = 0; i < nrem; i++)
if (rem_bbs[i]->loop_father->header == rem_bbs[i])
- cancel_loop_tree (loops, rem_bbs[i]->loop_father);
+ cancel_loop_tree (rem_bbs[i]->loop_father);
- remove_bbs (loops->cfg.dom, rem_bbs, nrem);
+ remove_bbs (rem_bbs, nrem);
free (rem_bbs);
- /* Find blocks with whose dominators may be affected. */
- n_dom_bbs = 0;
+ /* Find blocks whose dominators may be affected. */
sbitmap_zero (seen);
for (i = 0; i < n_bord_bbs; i++)
{
- int j, nldom;
- basic_block *ldom;
+ basic_block ldom;
- bb = get_immediate_dominator (loops->cfg.dom, bord_bbs[i]);
+ bb = get_immediate_dominator (CDI_DOMINATORS, bord_bbs[i]);
if (TEST_BIT (seen, bb->index))
continue;
SET_BIT (seen, bb->index);
- nldom = get_dominated_by (loops->cfg.dom, bb, &ldom);
- for (j = 0; j < nldom; j++)
- if (!dominated_by_p (loops->cfg.dom, from, ldom[j]))
- dom_bbs[n_dom_bbs++] = ldom[j];
- free(ldom);
+ for (ldom = first_dom_son (CDI_DOMINATORS, bb);
+ ldom;
+ ldom = next_dom_son (CDI_DOMINATORS, ldom))
+ if (!dominated_by_p (CDI_DOMINATORS, from, ldom))
+ VEC_safe_push (basic_block, heap, dom_bbs, ldom);
}
- free (bord_bbs);
free (seen);
/* Recount dominators. */
- iterate_fix_dominators (loops->cfg.dom, dom_bbs, n_dom_bbs);
- free (dom_bbs);
+ iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, true);
+ VEC_free (basic_block, heap, dom_bbs);
+ free (bord_bbs);
/* Fix placements of basic blocks inside loops and the placement of
loops in the loop tree. */
- fix_bb_placements (loops, from);
- fix_loop_placements (from->loop_father);
+ fix_bb_placements (from, &irred_invalidated);
+ fix_loop_placements (from->loop_father, &irred_invalidated);
+
+ if (irred_invalidated
+ && loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
+ mark_irreducible_loops ();
return true;
}
-/* Predicate for enumeration in add_loop. */
-static bool
-alp_enum_p (bb, alp_header)
- basic_block bb;
- void *alp_header;
+/* Creates place for a new LOOP in loops structure. */
+
+static void
+place_new_loop (struct loop *loop)
{
- return bb != (basic_block) alp_header;
+ loop->num = number_of_loops ();
+ VEC_safe_push (loop_p, gc, current_loops->larray, loop);
}
/* Given LOOP structure with filled header and latch, find the body of the
- corresponding loop and add it to LOOPS tree. */
-static void
-add_loop (loops, loop)
- struct loops *loops;
- struct loop *loop;
+ corresponding loop and add it to loops tree. Insert the LOOP as a son of
+ outer. */
+
+void
+add_loop (struct loop *loop, struct loop *outer)
{
basic_block *bbs;
int i, n;
-
+ struct loop *subloop;
+ edge e;
+ edge_iterator ei;
+
/* Add it to loop structure. */
- place_new_loop (loops, loop);
- loop->level = 1;
+ place_new_loop (loop);
+ flow_loop_tree_node_add (outer, loop);
/* Find its nodes. */
- bbs = xcalloc (n_basic_blocks, sizeof (basic_block));
- n = dfs_enumerate_from (loop->latch, 1, alp_enum_p,
- bbs, n_basic_blocks, loop->header);
+ bbs = XNEWVEC (basic_block, n_basic_blocks);
+ n = get_loop_body_with_size (loop, bbs, n_basic_blocks);
for (i = 0; i < n; i++)
- add_bb_to_loop (bbs[i], loop);
- add_bb_to_loop (loop->header, loop);
+ {
+ if (bbs[i]->loop_father == outer)
+ {
+ remove_bb_from_loops (bbs[i]);
+ add_bb_to_loop (bbs[i], loop);
+ continue;
+ }
- free (bbs);
-}
+ loop->num_nodes++;
-/* Multiply all frequencies of basic blocks in array BBS of lenght NBBS
- by NUM/DEN. */
-static void
-scale_bbs_frequencies (bbs, nbbs, num, den)
- basic_block *bbs;
- int nbbs;
- int num;
- int den;
-{
- int i;
- edge e;
+ /* If we find a direct subloop of OUTER, move it to LOOP. */
+ subloop = bbs[i]->loop_father;
+ if (loop_outer (subloop) == outer
+ && subloop->header == bbs[i])
+ {
+ flow_loop_tree_node_remove (subloop);
+ flow_loop_tree_node_add (loop, subloop);
+ }
+ }
- for (i = 0; i < nbbs; i++)
+ /* Update the information about loop exit edges. */
+ for (i = 0; i < n; i++)
{
- bbs[i]->frequency = (bbs[i]->frequency * num) / den;
- bbs[i]->count = (bbs[i]->count * num) / den;
- for (e = bbs[i]->succ; e; e = e->succ_next)
- e->count = (e->count * num) /den;
+ FOR_EACH_EDGE (e, ei, bbs[i]->succs)
+ {
+ rescan_loop_exit (e, false, false);
+ }
}
+
+ free (bbs);
}
/* Multiply all frequencies in LOOP by NUM/DEN. */
-static void
-scale_loop_frequencies (loop, num, den)
- struct loop *loop;
- int num;
- int den;
+void
+scale_loop_frequencies (struct loop *loop, int num, int den)
{
basic_block *bbs;
bbs = get_loop_body (loop);
- scale_bbs_frequencies (bbs, loop->num_nodes, num, den);
+ scale_bbs_frequencies_int (bbs, loop->num_nodes, num, den);
free (bbs);
}
+/* Recompute dominance information for basic blocks outside LOOP. */
+
+static void
+update_dominators_in_loop (struct loop *loop)
+{
+ VEC (basic_block, heap) *dom_bbs = NULL;
+ sbitmap seen;
+ basic_block *body;
+ unsigned i;
+
+ seen = sbitmap_alloc (last_basic_block);
+ sbitmap_zero (seen);
+ body = get_loop_body (loop);
+
+ for (i = 0; i < loop->num_nodes; i++)
+ SET_BIT (seen, body[i]->index);
+
+ for (i = 0; i < loop->num_nodes; i++)
+ {
+ basic_block ldom;
+
+ for (ldom = first_dom_son (CDI_DOMINATORS, body[i]);
+ ldom;
+ ldom = next_dom_son (CDI_DOMINATORS, ldom))
+ if (!TEST_BIT (seen, ldom->index))
+ {
+ SET_BIT (seen, ldom->index);
+ VEC_safe_push (basic_block, heap, dom_bbs, ldom);
+ }
+ }
+
+ iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, false);
+ free (body);
+ free (seen);
+ VEC_free (basic_block, heap, dom_bbs);
+}
+
+/* Creates an if region as shown above. CONDITION is used to create
+ the test for the if.
+
+ |
+ | ------------- -------------
+ | | pred_bb | | pred_bb |
+ | ------------- -------------
+ | | |
+ | | | ENTRY_EDGE
+ | | ENTRY_EDGE V
+ | | ====> -------------
+ | | | cond_bb |
+ | | | CONDITION |
+ | | -------------
+ | V / \
+ | ------------- e_false / \ e_true
+ | | succ_bb | V V
+ | ------------- ----------- -----------
+ | | false_bb | | true_bb |
+ | ----------- -----------
+ | \ /
+ | \ /
+ | V V
+ | -------------
+ | | join_bb |
+ | -------------
+ | | exit_edge (result)
+ | V
+ | -----------
+ | | succ_bb |
+ | -----------
+ |
+ */
+
+edge
+create_empty_if_region_on_edge (edge entry_edge, tree condition)
+{
+
+ basic_block cond_bb, true_bb, false_bb, join_bb;
+ edge e_true, e_false, exit_edge;
+ gimple cond_stmt;
+ tree simple_cond;
+ gimple_stmt_iterator gsi;
+
+ cond_bb = split_edge (entry_edge);
+
+ /* Insert condition in cond_bb. */
+ gsi = gsi_last_bb (cond_bb);
+ simple_cond =
+ force_gimple_operand_gsi (&gsi, condition, true, NULL,
+ false, GSI_NEW_STMT);
+ cond_stmt = gimple_build_cond_from_tree (simple_cond, NULL_TREE, NULL_TREE);
+ gsi = gsi_last_bb (cond_bb);
+ gsi_insert_after (&gsi, cond_stmt, GSI_NEW_STMT);
+
+ join_bb = split_edge (single_succ_edge (cond_bb));
+
+ e_true = single_succ_edge (cond_bb);
+ true_bb = split_edge (e_true);
+
+ e_false = make_edge (cond_bb, join_bb, 0);
+ false_bb = split_edge (e_false);
+
+ e_true->flags &= ~EDGE_FALLTHRU;
+ e_true->flags |= EDGE_TRUE_VALUE;
+ e_false->flags &= ~EDGE_FALLTHRU;
+ e_false->flags |= EDGE_FALSE_VALUE;
+
+ set_immediate_dominator (CDI_DOMINATORS, cond_bb, entry_edge->src);
+ set_immediate_dominator (CDI_DOMINATORS, true_bb, cond_bb);
+ set_immediate_dominator (CDI_DOMINATORS, false_bb, cond_bb);
+ set_immediate_dominator (CDI_DOMINATORS, join_bb, cond_bb);
+
+ exit_edge = single_succ_edge (join_bb);
+
+ if (single_pred_p (exit_edge->dest))
+ set_immediate_dominator (CDI_DOMINATORS, exit_edge->dest, join_bb);
+
+ return exit_edge;
+}
+
+/* create_empty_loop_on_edge
+ |
+ | - pred_bb - ------ pred_bb ------
+ | | | | iv0 = initial_value |
+ | -----|----- ---------|-----------
+ | | ______ | entry_edge
+ | | entry_edge / | |
+ | | ====> | -V---V- loop_header -------------
+ | V | | iv_before = phi (iv0, iv_after) |
+ | - succ_bb - | ---|-----------------------------
+ | | | | |
+ | ----------- | ---V--- loop_body ---------------
+ | | | iv_after = iv_before + stride |
+ | | | if (iv_before < upper_bound) |
+ | | ---|--------------\--------------
+ | | | \ exit_e
+ | | V \
+ | | - loop_latch - V- succ_bb -
+ | | | | | |
+ | | /------------- -----------
+ | \ ___ /
+
+ Creates an empty loop as shown above, the IV_BEFORE is the SSA_NAME
+ that is used before the increment of IV. IV_BEFORE should be used for
+ adding code to the body that uses the IV. OUTER is the outer loop in
+ which the new loop should be inserted.
+
+ Both INITIAL_VALUE and UPPER_BOUND expressions are gimplified and
+ inserted on the loop entry edge. This implies that this function
+ should be used only when the UPPER_BOUND expression is a loop
+ invariant. */
+
+struct loop *
+create_empty_loop_on_edge (edge entry_edge,
+ tree initial_value,
+ tree stride, tree upper_bound,
+ tree iv,
+ tree *iv_before,
+ tree *iv_after,
+ struct loop *outer)
+{
+ basic_block loop_header, loop_latch, succ_bb, pred_bb;
+ struct loop *loop;
+ gimple_stmt_iterator gsi;
+ gimple_seq stmts;
+ gimple cond_expr;
+ tree exit_test;
+ edge exit_e;
+ int prob;
+
+ gcc_assert (entry_edge && initial_value && stride && upper_bound && iv);
+
+ /* Create header, latch and wire up the loop. */
+ pred_bb = entry_edge->src;
+ loop_header = split_edge (entry_edge);
+ loop_latch = split_edge (single_succ_edge (loop_header));
+ succ_bb = single_succ (loop_latch);
+ make_edge (loop_header, succ_bb, 0);
+ redirect_edge_succ_nodup (single_succ_edge (loop_latch), loop_header);
+
+ /* Set immediate dominator information. */
+ set_immediate_dominator (CDI_DOMINATORS, loop_header, pred_bb);
+ set_immediate_dominator (CDI_DOMINATORS, loop_latch, loop_header);
+ set_immediate_dominator (CDI_DOMINATORS, succ_bb, loop_header);
+
+ /* Initialize a loop structure and put it in a loop hierarchy. */
+ loop = alloc_loop ();
+ loop->header = loop_header;
+ loop->latch = loop_latch;
+ add_loop (loop, outer);
+
+ /* TODO: Fix frequencies and counts. */
+ prob = REG_BR_PROB_BASE / 2;
+
+ scale_loop_frequencies (loop, REG_BR_PROB_BASE - prob, REG_BR_PROB_BASE);
+
+ /* Update dominators. */
+ update_dominators_in_loop (loop);
+
+ /* Modify edge flags. */
+ exit_e = single_exit (loop);
+ exit_e->flags = EDGE_LOOP_EXIT | EDGE_FALSE_VALUE;
+ single_pred_edge (loop_latch)->flags = EDGE_TRUE_VALUE;
+
+ /* Construct IV code in loop. */
+ initial_value = force_gimple_operand (initial_value, &stmts, true, iv);
+ if (stmts)
+ {
+ gsi_insert_seq_on_edge (loop_preheader_edge (loop), stmts);
+ gsi_commit_edge_inserts ();
+ }
+
+ upper_bound = force_gimple_operand (upper_bound, &stmts, true, NULL);
+ if (stmts)
+ {
+ gsi_insert_seq_on_edge (loop_preheader_edge (loop), stmts);
+ gsi_commit_edge_inserts ();
+ }
+
+ gsi = gsi_last_bb (loop_header);
+ create_iv (initial_value, stride, iv, loop, &gsi, false,
+ iv_before, iv_after);
+
+ /* Insert loop exit condition. */
+ cond_expr = gimple_build_cond
+ (LT_EXPR, *iv_before, upper_bound, NULL_TREE, NULL_TREE);
+
+ exit_test = gimple_cond_lhs (cond_expr);
+ exit_test = force_gimple_operand_gsi (&gsi, exit_test, true, NULL,
+ false, GSI_NEW_STMT);
+ gimple_cond_set_lhs (cond_expr, exit_test);
+ gsi = gsi_last_bb (exit_e->src);
+ gsi_insert_after (&gsi, cond_expr, GSI_NEW_STMT);
+
+ split_block_after_labels (loop_header);
+
+ return loop;
+}
+
/* Make area between HEADER_EDGE and LATCH_EDGE a loop by connecting
- latch to header and update loop tree stored in LOOPS and dominators
+ latch to header and update loop tree and dominators
accordingly. Everything between them plus LATCH_EDGE destination must
be dominated by HEADER_EDGE destination, and back-reachable from
LATCH_EDGE source. HEADER_EDGE is redirected to basic block SWITCH_BB,
- SWITCH_BB->succ to original destination of LATCH_EDGE and
- SWITCH_BB->succ->succ_next to original destination of HEADER_EDGE.
- Returns newly created loop. */
+ FALSE_EDGE of SWITCH_BB to original destination of HEADER_EDGE and
+ TRUE_EDGE of SWITCH_BB to original destination of LATCH_EDGE.
+ Returns the newly created loop. Frequencies and counts in the new loop
+ are scaled by FALSE_SCALE and in the old one by TRUE_SCALE. */
+
struct loop *
-loopify (loops, latch_edge, header_edge, switch_bb)
- struct loops *loops;
- edge latch_edge;
- edge header_edge;
- basic_block switch_bb;
+loopify (edge latch_edge, edge header_edge,
+ basic_block switch_bb, edge true_edge, edge false_edge,
+ bool redirect_all_edges, unsigned true_scale, unsigned false_scale)
{
basic_block succ_bb = latch_edge->dest;
basic_block pred_bb = header_edge->src;
- basic_block *dom_bbs, *body;
- unsigned n_dom_bbs, i, j;
- sbitmap seen;
- struct loop *loop = xcalloc (1, sizeof (struct loop));
- struct loop *outer = succ_bb->loop_father->outer;
- int freq, prob, tot_prob;
+ struct loop *loop = alloc_loop ();
+ struct loop *outer = loop_outer (succ_bb->loop_father);
+ int freq;
gcov_type cnt;
edge e;
+ edge_iterator ei;
loop->header = header_edge->dest;
loop->latch = latch_edge->src;
freq = EDGE_FREQUENCY (header_edge);
cnt = header_edge->count;
- prob = switch_bb->succ->probability;
- tot_prob = prob + switch_bb->succ->succ_next->probability;
- if (tot_prob == 0)
- tot_prob = 1;
/* Redirect edges. */
loop_redirect_edge (latch_edge, loop->header);
- loop_redirect_edge (header_edge, switch_bb);
- loop_redirect_edge (switch_bb->succ->succ_next, loop->header);
- loop_redirect_edge (switch_bb->succ, succ_bb);
+ loop_redirect_edge (true_edge, succ_bb);
- /* Update dominators. */
- set_immediate_dominator (loops->cfg.dom, switch_bb, pred_bb);
- set_immediate_dominator (loops->cfg.dom, loop->header, switch_bb);
- set_immediate_dominator (loops->cfg.dom, succ_bb, switch_bb);
+ /* During loop versioning, one of the switch_bb edge is already properly
+ set. Do not redirect it again unless redirect_all_edges is true. */
+ if (redirect_all_edges)
+ {
+ loop_redirect_edge (header_edge, switch_bb);
+ loop_redirect_edge (false_edge, loop->header);
+
+ /* Update dominators. */
+ set_immediate_dominator (CDI_DOMINATORS, switch_bb, pred_bb);
+ set_immediate_dominator (CDI_DOMINATORS, loop->header, switch_bb);
+ }
+
+ set_immediate_dominator (CDI_DOMINATORS, succ_bb, switch_bb);
/* Compute new loop. */
- add_loop (loops, loop);
- flow_loop_tree_node_add (outer, loop);
+ add_loop (loop, outer);
/* Add switch_bb to appropriate loop. */
+ if (switch_bb->loop_father)
+ remove_bb_from_loops (switch_bb);
add_bb_to_loop (switch_bb, outer);
/* Fix frequencies. */
- switch_bb->frequency = freq;
- switch_bb->count = cnt;
- for (e = switch_bb->succ; e; e = e->succ_next)
- e->count = (switch_bb->count * e->probability) / REG_BR_PROB_BASE;
- scale_loop_frequencies (loop, prob, tot_prob);
- scale_loop_frequencies (succ_bb->loop_father, tot_prob - prob, tot_prob);
-
- /* Update dominators of blocks outside of LOOP. */
- dom_bbs = xcalloc (n_basic_blocks, sizeof (basic_block));
- n_dom_bbs = 0;
- seen = sbitmap_alloc (last_basic_block);
- sbitmap_zero (seen);
- body = get_loop_body (loop);
-
- for (i = 0; i < loop->num_nodes; i++)
- SET_BIT (seen, body[i]->index);
-
- for (i = 0; i < loop->num_nodes; i++)
+ if (redirect_all_edges)
{
- unsigned nldom;
- basic_block *ldom;
-
- nldom = get_dominated_by (loops->cfg.dom, body[i], &ldom);
- for (j = 0; j < nldom; j++)
- if (!TEST_BIT (seen, ldom[j]->index))
- {
- SET_BIT (seen, ldom[j]->index);
- dom_bbs[n_dom_bbs++] = ldom[j];
- }
- free (ldom);
+ switch_bb->frequency = freq;
+ switch_bb->count = cnt;
+ FOR_EACH_EDGE (e, ei, switch_bb->succs)
+ {
+ e->count = (switch_bb->count * e->probability) / REG_BR_PROB_BASE;
+ }
}
-
- iterate_fix_dominators (loops->cfg.dom, dom_bbs, n_dom_bbs);
-
- free (body);
- free (seen);
- free (dom_bbs);
+ scale_loop_frequencies (loop, false_scale, REG_BR_PROB_BASE);
+ scale_loop_frequencies (succ_bb->loop_father, true_scale, REG_BR_PROB_BASE);
+ update_dominators_in_loop (loop);
return loop;
}
-/* Fix placement of LOOP inside loop tree, i.e. find the innermost superloop
- FATHER of LOOP such that all of the edges comming out of LOOP belong to
- FATHER, and set it as outer loop of LOOP. Return 1 if placement of
- LOOP changed. */
-int
-fix_loop_placement (loop)
- struct loop *loop;
+/* Remove the latch edge of a LOOP and update loops to indicate that
+ the LOOP was removed. After this function, original loop latch will
+ have no successor, which caller is expected to fix somehow.
+
+ If this may cause the information about irreducible regions to become
+ invalid, IRRED_INVALIDATED is set to true. */
+
+static void
+unloop (struct loop *loop, bool *irred_invalidated)
{
basic_block *body;
- unsigned i;
- edge e;
- struct loop *father = loop->pred[0], *act;
+ struct loop *ploop;
+ unsigned i, n;
+ basic_block latch = loop->latch;
+ bool dummy = false;
- body = get_loop_body (loop);
- for (i = 0; i < loop->num_nodes; i++)
- for (e = body[i]->succ; e; e = e->succ_next)
- if (!flow_bb_inside_loop_p (loop, e->dest))
- {
- act = find_common_loop (loop, e->dest->loop_father);
- if (flow_loop_nested_p (father, act))
- father = act;
- }
- free (body);
+ if (loop_preheader_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)
+ *irred_invalidated = true;
- if (father != loop->outer)
+ /* This is relatively straightforward. The dominators are unchanged, as
+ loop header dominates loop latch, so the only thing we have to care of
+ is the placement of loops and basic blocks inside the loop tree. We
+ move them all to the loop->outer, and then let fix_bb_placements do
+ its work. */
+
+ body = get_loop_body (loop);
+ n = loop->num_nodes;
+ for (i = 0; i < n; i++)
+ if (body[i]->loop_father == loop)
+ {
+ remove_bb_from_loops (body[i]);
+ add_bb_to_loop (body[i], loop_outer (loop));
+ }
+ free(body);
+
+ while (loop->inner)
{
- for (act = loop->outer; act != father; act = act->outer)
- act->num_nodes -= loop->num_nodes;
- flow_loop_tree_node_remove (loop);
- flow_loop_tree_node_add (father, loop);
- return 1;
+ ploop = loop->inner;
+ flow_loop_tree_node_remove (ploop);
+ flow_loop_tree_node_add (loop_outer (loop), ploop);
}
- return 0;
+
+ /* Remove the loop and free its data. */
+ delete_loop (loop);
+
+ remove_edge (single_succ_edge (latch));
+
+ /* We do not pass IRRED_INVALIDATED to fix_bb_placements here, as even if
+ there is an irreducible region inside the cancelled loop, the flags will
+ be still correct. */
+ fix_bb_placements (latch, &dummy);
}
/* Fix placement of superloops of LOOP inside loop tree, i.e. ensure that
condition stated in description of fix_loop_placement holds for them.
It is used in case when we removed some edges coming out of LOOP, which
- may cause the right placement of LOOP inside loop tree to change. */
+ may cause the right placement of LOOP inside loop tree to change.
+
+ IRRED_INVALIDATED is set to true if a change in the loop structures might
+ invalidate the information about irreducible regions. */
+
static void
-fix_loop_placements (loop)
- struct loop *loop;
+fix_loop_placements (struct loop *loop, bool *irred_invalidated)
{
struct loop *outer;
- while (loop->outer)
+ while (loop_outer (loop))
{
- outer = loop->outer;
+ outer = loop_outer (loop);
if (!fix_loop_placement (loop))
- break;
+ break;
+
+ /* Changing the placement of a loop in the loop tree may alter the
+ validity of condition 2) of the description of fix_bb_placement
+ for its preheader, because the successor is the header and belongs
+ to the loop. So call fix_bb_placements to fix up the placement
+ of the preheader and (possibly) of its predecessors. */
+ fix_bb_placements (loop_preheader_edge (loop)->src,
+ irred_invalidated);
loop = outer;
}
}
-/* Creates place for a new LOOP in LOOPS structure. */
-static void
-place_new_loop (loops, loop)
- struct loops *loops;
- struct loop *loop;
-{
- loops->parray =
- xrealloc (loops->parray, (loops->num + 1) * sizeof (struct loop *));
- loops->parray[loops->num] = loop;
-
- loop->num = loops->num++;
-}
-
/* Copies copy of LOOP as subloop of TARGET loop, placing newly
- created loop into LOOPS structure. */
-static struct loop *
-duplicate_loop (loops, loop, target)
- struct loops *loops;
- struct loop *loop;
- struct loop *target;
+ created loop into loops structure. */
+struct loop *
+duplicate_loop (struct loop *loop, struct loop *target)
{
struct loop *cloop;
- cloop = xcalloc (1, sizeof (struct loop));
- place_new_loop (loops, cloop);
-
- /* Initialize copied loop. */
- cloop->level = loop->level;
+ cloop = alloc_loop ();
+ place_new_loop (cloop);
- /* Set it as copy of loop. */
- loop->copy = cloop;
+ /* Mark the new loop as copy of LOOP. */
+ set_loop_copy (loop, cloop);
/* Add it to target. */
flow_loop_tree_node_add (target, cloop);
}
/* Copies structure of subloops of LOOP into TARGET loop, placing
- newly created loops into loop tree stored in LOOPS. */
-static void
-duplicate_subloops (loops, loop, target)
- struct loops *loops;
- struct loop *loop;
- struct loop *target;
+ newly created loops into loop tree. */
+void
+duplicate_subloops (struct loop *loop, struct loop *target)
{
struct loop *aloop, *cloop;
for (aloop = loop->inner; aloop; aloop = aloop->next)
{
- cloop = duplicate_loop (loops, aloop, target);
- duplicate_subloops (loops, aloop, cloop);
+ cloop = duplicate_loop (aloop, target);
+ duplicate_subloops (aloop, cloop);
}
}
/* Copies structure of subloops of N loops, stored in array COPIED_LOOPS,
- into TARGET loop, placing newly created loops into loop tree LOOPS. */
-static void
-copy_loops_to (loops, copied_loops, n, target)
- struct loops *loops;
- struct loop **copied_loops;
- int n;
- struct loop *target;
+ into TARGET loop, placing newly created loops into loop tree. */
+static void
+copy_loops_to (struct loop **copied_loops, int n, struct loop *target)
{
struct loop *aloop;
int i;
for (i = 0; i < n; i++)
{
- aloop = duplicate_loop (loops, copied_loops[i], target);
- duplicate_subloops (loops, copied_loops[i], aloop);
+ aloop = duplicate_loop (copied_loops[i], target);
+ duplicate_subloops (copied_loops[i], aloop);
}
}
/* Redirects edge E to basic block DEST. */
static void
-loop_redirect_edge (e, dest)
- edge e;
- basic_block dest;
+loop_redirect_edge (edge e, basic_block dest)
{
if (e->dest == dest)
return;
- cfg_layout_redirect_edge (e, dest);
-}
-
-/* Deletes edge E from a branch if possible. */
-static bool
-loop_delete_branch_edge (e)
- edge e;
-{
- basic_block src = e->src;
-
- if (src->succ->succ_next)
- {
- basic_block newdest;
- /* Cannot handle more than two exit edges. */
- if (src->succ->succ_next->succ_next)
- return false;
- /* And it must be just a simple branch. */
- if (!any_condjump_p (src->end))
- return false;
-
- newdest = (e == src->succ
- ? src->succ->succ_next->dest : src->succ->dest);
- if (newdest == EXIT_BLOCK_PTR)
- return false;
-
- return cfg_layout_redirect_edge (e, newdest);
- }
- else
- {
- /* Cannot happen -- we are using this only to remove an edge
- from branch. */
- abort ();
- }
-
- return false; /* To avoid warning, cannot get here. */
-}
-
-/* Duplicates N basic blocks stored in array BBS (they form a body of
- duplicated loop). Newly created basic blocks are placed into array NEW_BBS
- that we allocate. Edges from basic blocks in BBS are also duplicated and
- copies of those of them that lead into BBS are redirected to appropriate
- newly created block. The function also assigns bbs into loops and updates
- dominators. If ADD_IRREDUCIBLE_FLAG is set, newly created basic blocks that
- are not members of any inner loop are marked irreducible.
-
- Additionally, we perform following manipulation with edges:
- We have two special edges given. LATCH_EDGE is the latch edge of the
- duplicated loop and leads into its header (one of blocks in BBS);
- it does not have neccessarily lead from one of the blocks, because
- we may be copying the loop body several times in unrolling.
- Edge ENTRY leads also leads to header, and it is either latch or entry
- edge. Copy of LATCH_EDGE is redirected to header and is stored in
- HEADER_EDGE, the ENTRY edge is redirected into copy of header and
- returned as COPY_HEADER_EDGE. The effect is following:
- if LATCH_EDGE == ENTRY, then the loop is unrolled by one copy,
- HEADER_EDGE is latch of a new loop, COPY_HEADER_EDGE leads from original
- latch source to first block in copy.
- if LATCH_EDGE != ENTRY, then the loop is peeled by one copy,
- HEADER_EDGE is entry edge of the loop, COPY_HEADER_EDGE leads from
- original entry block to first block in peeled copy.
- */
-static void
-copy_bbs (bbs, n, entry, latch_edge, new_bbs, loops, header_edge, copy_header_edge, add_irreducible_flag)
- basic_block *bbs;
- int n;
- edge entry;
- edge latch_edge;
- basic_block **new_bbs;
- struct loops *loops;
- edge *header_edge;
- edge *copy_header_edge;
- int add_irreducible_flag;
-{
- int i;
- basic_block bb, new_bb, header = entry->dest, dom_bb;
- edge e;
-
- /* Duplicate bbs, update dominators, assign bbs to loops. */
- (*new_bbs) = xcalloc (n, sizeof (basic_block));
- for (i = 0; i < n; i++)
- {
- /* Duplicate. */
- bb = bbs[i];
- new_bb = (*new_bbs)[i] = cfg_layout_duplicate_bb (bb, NULL);
- RBI (new_bb)->duplicated = 1;
- /* Add to loop. */
- add_bb_to_loop (new_bb, bb->loop_father->copy);
- add_to_dominance_info (loops->cfg.dom, new_bb);
- /* Possibly set header. */
- if (bb->loop_father->header == bb && bb != header)
- new_bb->loop_father->header = new_bb;
- /* Or latch. */
- if (bb->loop_father->latch == bb &&
- bb->loop_father != header->loop_father)
- new_bb->loop_father->latch = new_bb;
- /* Take care of irreducible loops. */
- if (add_irreducible_flag
- && bb->loop_father == header->loop_father)
- new_bb->flags |= BB_IRREDUCIBLE_LOOP;
- }
-
- /* Set dominators. */
- for (i = 0; i < n; i++)
- {
- bb = bbs[i];
- new_bb = (*new_bbs)[i];
- if (bb != header)
- {
- /* For anything else than loop header, just copy it. */
- dom_bb = get_immediate_dominator (loops->cfg.dom, bb);
- dom_bb = RBI (dom_bb)->copy;
- }
- else
- {
- /* Copy of header is dominated by entry source. */
- dom_bb = entry->src;
- }
- if (!dom_bb)
- abort ();
- set_immediate_dominator (loops->cfg.dom, new_bb, dom_bb);
- }
-
- /* Redirect edges. */
- for (i = 0; i < n; i++)
- {
- edge e_pred;
- new_bb = (*new_bbs)[i];
- bb = bbs[i];
- for (e = bb->pred; e; e = e_pred)
- {
- basic_block src = e->src;
-
- e_pred = e->pred_next;
-
- if (!RBI (src)->duplicated)
- continue;
-
- /* Leads to copied loop and it is not latch edge, redirect it. */
- if (bb != header)
- loop_redirect_edge (e, new_bb);
- }
- }
-
- /* Redirect header edge. */
- bb = RBI (latch_edge->src)->copy;
- for (e = bb->succ; e->dest != latch_edge->dest; e = e->succ_next);
- *header_edge = e;
- loop_redirect_edge (*header_edge, header);
-
- /* Redirect entry to copy of header. */
- loop_redirect_edge (entry, RBI (header)->copy);
- *copy_header_edge = entry;
-
- /* Clear information about duplicates. */
- for (i = 0; i < n; i++)
- RBI ((*new_bbs)[i])->duplicated = 0;
+ redirect_edge_and_branch_force (e, dest);
}
/* Check whether LOOP's body can be duplicated. */
bool
-can_duplicate_loop_p (loop)
- struct loop *loop;
+can_duplicate_loop_p (const struct loop *loop)
{
- basic_block *bbs;
- unsigned i;
-
- bbs = get_loop_body (loop);
-
- for (i = 0; i < loop->num_nodes; i++)
- {
- edge e;
-
- /* In case loop contains abnormal edge we can not redirect,
- we can't perform duplication. */
-
- for (e = bbs[i]->succ; e; e = e->succ_next)
- if ((e->flags & EDGE_ABNORMAL)
- && flow_bb_inside_loop_p (loop, e->dest))
- {
- free (bbs);
- return false;
- }
+ int ret;
+ basic_block *bbs = get_loop_body (loop);
- if (!cfg_layout_can_duplicate_bb_p (bbs[i]))
- {
- free (bbs);
- return false;
- }
- }
+ ret = can_copy_bbs_p (bbs, loop->num_nodes);
free (bbs);
- return true;
+ return ret;
}
-/* Record edges, leading from NBBS basic blocks stored in BBS, that were created
- by copying ORIG edge (or just ORIG edge if IS_ORIG is set).
- If ORIG is NULL, then record all edges coming outside of BBS. Store them
- into TO_REMOVE array that must be large enough to hold them all; their
- number is returned in N_TO_REMOVE. */
+/* Sets probability and count of edge E to zero. The probability and count
+ is redistributed evenly to the remaining edges coming from E->src. */
+
static void
-record_exit_edges (orig, bbs, nbbs, to_remove, n_to_remove, is_orig)
- edge orig;
- basic_block *bbs;
- int nbbs;
- edge *to_remove;
- unsigned *n_to_remove;
- int is_orig;
+set_zero_probability (edge e)
{
- sbitmap my_blocks;
- int i;
- edge e;
-
- if (orig)
+ basic_block bb = e->src;
+ edge_iterator ei;
+ edge ae, last = NULL;
+ unsigned n = EDGE_COUNT (bb->succs);
+ gcov_type cnt = e->count, cnt1;
+ unsigned prob = e->probability, prob1;
+
+ gcc_assert (n > 1);
+ cnt1 = cnt / (n - 1);
+ prob1 = prob / (n - 1);
+
+ FOR_EACH_EDGE (ae, ei, bb->succs)
{
- if (is_orig)
- {
- to_remove[(*n_to_remove)++] = orig;
- return;
- }
-
- for (e = RBI (orig->src)->copy->succ; e; e = e->succ_next)
- if (e->dest == orig->dest)
- break;
- if (!e)
- abort ();
+ if (ae == e)
+ continue;
- to_remove[(*n_to_remove)++] = e;
+ ae->probability += prob1;
+ ae->count += cnt1;
+ last = ae;
}
- else
- {
- my_blocks = sbitmap_alloc (last_basic_block);
- sbitmap_zero (my_blocks);
- for (i = 0; i < nbbs; i++)
- SET_BIT (my_blocks, bbs[i]->index);
-
- for (i = 0; i < nbbs; i++)
- for (e = bbs[i]->succ; e; e = e->succ_next)
- if (e->dest == EXIT_BLOCK_PTR ||
- !TEST_BIT (my_blocks, e->dest->index))
- to_remove[(*n_to_remove)++] = e;
-
- free (my_blocks);
- }
-}
+ /* Move the rest to one of the edges. */
+ last->probability += prob % (n - 1);
+ last->count += cnt % (n - 1);
-#define RDIV(X,Y) (((X) + (Y) / 2) / (Y))
+ e->probability = 0;
+ e->count = 0;
+}
-/* Duplicates body of LOOP to given edge E NDUPL times. Takes care of
- updating LOOPS structure and dominators. E's destination must be LOOP
- header for this to work, i.e. it must be entry or latch edge of this loop;
- these are unique, as the loops must have preheaders for this function to
- work correctly (in case E is latch, the function unrolls the loop, if E is
- entry edge, it peels the loop). Store edges created by copying ORIG edge
- (if NULL, then all edges leaving loop) from copies corresponding to set
- bits in WONT_EXIT bitmap (bit 0 corresponds to original LOOP body, the
- other copies are numbered in order given by control flow through them)
- into TO_REMOVE array. Returns false if duplication is impossible. */
-int
-duplicate_loop_to_header_edge (loop, e, loops, ndupl, wont_exit, orig,
- to_remove, n_to_remove, flags)
- struct loop *loop;
- edge e;
- struct loops *loops;
- unsigned ndupl;
- sbitmap wont_exit;
- edge orig;
- edge *to_remove;
- unsigned *n_to_remove;
- int flags;
+/* Duplicates body of LOOP to given edge E NDUPL times. Takes care of updating
+ loop structure and dominators. E's destination must be LOOP header for
+ this to work, i.e. it must be entry or latch edge of this loop; these are
+ unique, as the loops must have preheaders for this function to work
+ correctly (in case E is latch, the function unrolls the loop, if E is entry
+ edge, it peels the loop). Store edges created by copying ORIG edge from
+ copies corresponding to set bits in WONT_EXIT bitmap (bit 0 corresponds to
+ original LOOP body, the other copies are numbered in order given by control
+ flow through them) into TO_REMOVE array. Returns false if duplication is
+ impossible. */
+
+bool
+duplicate_loop_to_header_edge (struct loop *loop, edge e,
+ unsigned int ndupl, sbitmap wont_exit,
+ edge orig, VEC (edge, heap) **to_remove,
+ int flags)
{
struct loop *target, *aloop;
struct loop **orig_loops;
basic_block header = loop->header, latch = loop->latch;
basic_block *new_bbs, *bbs, *first_active;
basic_block new_bb, bb, first_active_latch = NULL;
- edge ae, latch_edge, he;
+ edge ae, latch_edge;
+ edge spec_edges[2], new_spec_edges[2];
+#define SE_LATCH 0
+#define SE_ORIG 1
unsigned i, j, n;
int is_latch = (latch == e->src);
int scale_act = 0, *scale_step = NULL, scale_main = 0;
+ int scale_after_exit = 0;
int p, freq_in, freq_le, freq_out_orig;
int prob_pass_thru, prob_pass_wont_exit, prob_pass_main;
int add_irreducible_flag;
+ basic_block place_after;
+ bitmap bbs_to_scale = NULL;
+ bitmap_iterator bi;
- if (e->dest != loop->header)
- abort ();
- if (ndupl <= 0)
- abort ();
+ gcc_assert (e->dest == loop->header);
+ gcc_assert (ndupl > 0);
if (orig)
{
/* Orig must be edge out of the loop. */
- if (!flow_bb_inside_loop_p (loop, orig->src))
- abort ();
- if (flow_bb_inside_loop_p (loop, orig->dest))
- abort ();
+ gcc_assert (flow_bb_inside_loop_p (loop, orig->src));
+ gcc_assert (!flow_bb_inside_loop_p (loop, orig->dest));
}
- bbs = get_loop_body (loop);
+ n = loop->num_nodes;
+ bbs = get_loop_body_in_dom_order (loop);
+ gcc_assert (bbs[0] == loop->header);
+ gcc_assert (bbs[n - 1] == loop->latch);
/* Check whether duplication is possible. */
-
- for (i = 0; i < loop->num_nodes; i++)
+ if (!can_copy_bbs_p (bbs, loop->num_nodes))
{
- if (!cfg_layout_can_duplicate_bb_p (bbs[i]))
- {
- free (bbs);
- return false;
- }
+ free (bbs);
+ return false;
}
+ new_bbs = XNEWVEC (basic_block, loop->num_nodes);
- add_irreducible_flag = !is_latch && (e->src->flags & BB_IRREDUCIBLE_LOOP);
+ /* In case we are doing loop peeling and the loop is in the middle of
+ irreducible region, the peeled copies will be inside it too. */
+ add_irreducible_flag = e->flags & EDGE_IRREDUCIBLE_LOOP;
+ gcc_assert (!is_latch || !add_irreducible_flag);
/* Find edge from latch. */
latch_edge = loop_latch_edge (loop);
prob_pass_wont_exit =
RDIV (REG_BR_PROB_BASE * (freq_le + freq_out_orig), freq_in);
- scale_step = xmalloc (ndupl * sizeof (int));
+ if (orig
+ && REG_BR_PROB_BASE - orig->probability != 0)
+ {
+ /* The blocks that are dominated by a removed exit edge ORIG have
+ frequencies scaled by this. */
+ scale_after_exit = RDIV (REG_BR_PROB_BASE * REG_BR_PROB_BASE,
+ REG_BR_PROB_BASE - orig->probability);
+ bbs_to_scale = BITMAP_ALLOC (NULL);
+ for (i = 0; i < n; i++)
+ {
+ if (bbs[i] != orig->src
+ && dominated_by_p (CDI_DOMINATORS, bbs[i], orig->src))
+ bitmap_set_bit (bbs_to_scale, i);
+ }
+ }
+
+ scale_step = XNEWVEC (int, ndupl);
- for (i = 1; i <= ndupl; i++)
- scale_step[i - 1] = TEST_BIT (wont_exit, i)
+ for (i = 1; i <= ndupl; i++)
+ scale_step[i - 1] = TEST_BIT (wont_exit, i)
? prob_pass_wont_exit
: prob_pass_thru;
- if (is_latch)
+ /* Complete peeling is special as the probability of exit in last
+ copy becomes 1. */
+ if (flags & DLTHE_FLAG_COMPLETTE_PEEL)
+ {
+ int wanted_freq = EDGE_FREQUENCY (e);
+
+ if (wanted_freq > freq_in)
+ wanted_freq = freq_in;
+
+ gcc_assert (!is_latch);
+ /* First copy has frequency of incoming edge. Each subsequent
+ frequency should be reduced by prob_pass_wont_exit. Caller
+ should've managed the flags so all except for original loop
+ has won't exist set. */
+ scale_act = RDIV (wanted_freq * REG_BR_PROB_BASE, freq_in);
+ /* Now simulate the duplication adjustments and compute header
+ frequency of the last copy. */
+ for (i = 0; i < ndupl; i++)
+ wanted_freq = RDIV (wanted_freq * scale_step[i], REG_BR_PROB_BASE);
+ scale_main = RDIV (wanted_freq * REG_BR_PROB_BASE, freq_in);
+ }
+ else if (is_latch)
{
prob_pass_main = TEST_BIT (wont_exit, 0)
? prob_pass_wont_exit
scale_act = REG_BR_PROB_BASE - prob_pass_thru;
}
for (i = 0; i < ndupl; i++)
- if (scale_step[i] < 0 || scale_step[i] > REG_BR_PROB_BASE)
- abort ();
- if (scale_main < 0 || scale_main > REG_BR_PROB_BASE
- || scale_act < 0 || scale_act > REG_BR_PROB_BASE)
- abort ();
+ gcc_assert (scale_step[i] >= 0 && scale_step[i] <= REG_BR_PROB_BASE);
+ gcc_assert (scale_main >= 0 && scale_main <= REG_BR_PROB_BASE
+ && scale_act >= 0 && scale_act <= REG_BR_PROB_BASE);
}
/* Loop the new bbs will belong to. */
- target = find_common_loop (e->src->loop_father, e->dest->loop_father);
+ target = e->src->loop_father;
/* Original loops. */
n_orig_loops = 0;
for (aloop = loop->inner; aloop; aloop = aloop->next)
n_orig_loops++;
- orig_loops = xcalloc (n_orig_loops, sizeof (struct loop *));
+ orig_loops = XCNEWVEC (struct loop *, n_orig_loops);
for (aloop = loop->inner, i = 0; aloop; aloop = aloop->next, i++)
orig_loops[i] = aloop;
- loop->copy = target;
-
- /* Original basic blocks. */
- n = loop->num_nodes;
+ set_loop_copy (loop, target);
- first_active = xcalloc(n, sizeof (basic_block));
+ first_active = XNEWVEC (basic_block, n);
if (is_latch)
{
memcpy (first_active, bbs, n * sizeof (basic_block));
first_active_latch = latch;
}
- /* Record exit edges in original loop body. */
- if (TEST_BIT (wont_exit, 0))
- record_exit_edges (orig, bbs, n, to_remove, n_to_remove, true);
-
+ spec_edges[SE_ORIG] = orig;
+ spec_edges[SE_LATCH] = latch_edge;
+
+ place_after = e->src;
for (j = 0; j < ndupl; j++)
{
/* Copy loops. */
- copy_loops_to (loops, orig_loops, n_orig_loops, target);
+ copy_loops_to (orig_loops, n_orig_loops, target);
/* Copy bbs. */
- copy_bbs (bbs, n, e, latch_edge, &new_bbs, loops,
- &e, &he, add_irreducible_flag);
- if (is_latch)
- loop->latch = RBI (latch)->copy;
+ copy_bbs (bbs, n, new_bbs, spec_edges, 2, new_spec_edges, loop,
+ place_after);
+ place_after = new_spec_edges[SE_LATCH]->src;
- /* Record exit edges in this copy. */
- if (TEST_BIT (wont_exit, j + 1))
- record_exit_edges (orig, new_bbs, n, to_remove, n_to_remove, false);
-
- /* Set counts and frequencies. */
- for (i = 0; i < n; i++)
- {
- new_bb = new_bbs[i];
- bb = bbs[i];
+ if (flags & DLTHE_RECORD_COPY_NUMBER)
+ for (i = 0; i < n; i++)
+ {
+ gcc_assert (!new_bbs[i]->aux);
+ new_bbs[i]->aux = (void *)(size_t)(j + 1);
+ }
- if (flags & DLTHE_FLAG_UPDATE_FREQ)
+ /* Note whether the blocks and edges belong to an irreducible loop. */
+ if (add_irreducible_flag)
+ {
+ for (i = 0; i < n; i++)
+ new_bbs[i]->flags |= BB_DUPLICATED;
+ for (i = 0; i < n; i++)
{
- new_bb->count = RDIV (scale_act * bb->count, REG_BR_PROB_BASE);
- new_bb->frequency = RDIV (scale_act * bb->frequency,
- REG_BR_PROB_BASE);
+ edge_iterator ei;
+ new_bb = new_bbs[i];
+ if (new_bb->loop_father == target)
+ new_bb->flags |= BB_IRREDUCIBLE_LOOP;
+
+ FOR_EACH_EDGE (ae, ei, new_bb->succs)
+ if ((ae->dest->flags & BB_DUPLICATED)
+ && (ae->src->loop_father == target
+ || ae->dest->loop_father == target))
+ ae->flags |= EDGE_IRREDUCIBLE_LOOP;
}
- else
+ for (i = 0; i < n; i++)
+ new_bbs[i]->flags &= ~BB_DUPLICATED;
+ }
+
+ /* Redirect the special edges. */
+ if (is_latch)
+ {
+ redirect_edge_and_branch_force (latch_edge, new_bbs[0]);
+ redirect_edge_and_branch_force (new_spec_edges[SE_LATCH],
+ loop->header);
+ set_immediate_dominator (CDI_DOMINATORS, new_bbs[0], latch);
+ latch = loop->latch = new_bbs[n - 1];
+ e = latch_edge = new_spec_edges[SE_LATCH];
+ }
+ else
+ {
+ redirect_edge_and_branch_force (new_spec_edges[SE_LATCH],
+ loop->header);
+ redirect_edge_and_branch_force (e, new_bbs[0]);
+ set_immediate_dominator (CDI_DOMINATORS, new_bbs[0], e->src);
+ e = new_spec_edges[SE_LATCH];
+ }
+
+ /* Record exit edge in this copy. */
+ if (orig && TEST_BIT (wont_exit, j + 1))
+ {
+ if (to_remove)
+ VEC_safe_push (edge, heap, *to_remove, new_spec_edges[SE_ORIG]);
+ set_zero_probability (new_spec_edges[SE_ORIG]);
+
+ /* Scale the frequencies of the blocks dominated by the exit. */
+ if (bbs_to_scale)
{
- new_bb->count = bb->count;
- new_bb->frequency = bb->frequency;
+ EXECUTE_IF_SET_IN_BITMAP (bbs_to_scale, 0, i, bi)
+ {
+ scale_bbs_frequencies_int (new_bbs + i, 1, scale_after_exit,
+ REG_BR_PROB_BASE);
+ }
}
-
- for (ae = new_bb->succ; ae; ae = ae->succ_next)
- ae->count = RDIV (new_bb->count * ae->probability,
- REG_BR_PROB_BASE);
}
- if (flags & DLTHE_FLAG_UPDATE_FREQ)
- scale_act = RDIV (scale_act * scale_step[j], REG_BR_PROB_BASE);
+ /* Record the first copy in the control flow order if it is not
+ the original loop (i.e. in case of peeling). */
if (!first_active_latch)
{
memcpy (first_active, new_bbs, n * sizeof (basic_block));
- first_active_latch = RBI (latch)->copy;
+ first_active_latch = new_bbs[n - 1];
}
-
- free (new_bbs);
-
- /* Original loop header is dominated by latch copy
- if we duplicated on its only entry edge. */
- if (!is_latch && !header->pred->pred_next->pred_next)
- set_immediate_dominator (loops->cfg.dom, header, RBI (latch)->copy);
- if (is_latch && j == 0)
+
+ /* Set counts and frequencies. */
+ if (flags & DLTHE_FLAG_UPDATE_FREQ)
{
- /* Update edge from latch. */
- for (latch_edge = RBI (header)->copy->pred;
- latch_edge->src != latch;
- latch_edge = latch_edge->pred_next);
+ scale_bbs_frequencies_int (new_bbs, n, scale_act, REG_BR_PROB_BASE);
+ scale_act = RDIV (scale_act * scale_step[j], REG_BR_PROB_BASE);
}
}
- /* Now handle original loop. */
-
- /* Update edge counts. */
- if (flags & DLTHE_FLAG_UPDATE_FREQ)
+ free (new_bbs);
+ free (orig_loops);
+
+ /* Record the exit edge in the original loop body, and update the frequencies. */
+ if (orig && TEST_BIT (wont_exit, 0))
{
- for (i = 0; i < n; i++)
+ if (to_remove)
+ VEC_safe_push (edge, heap, *to_remove, orig);
+ set_zero_probability (orig);
+
+ /* Scale the frequencies of the blocks dominated by the exit. */
+ if (bbs_to_scale)
{
- bb = bbs[i];
- bb->count = RDIV (scale_main * bb->count, REG_BR_PROB_BASE);
- bb->frequency = RDIV (scale_main * bb->frequency, REG_BR_PROB_BASE);
- for (ae = bb->succ; ae; ae = ae->succ_next)
- ae->count = RDIV (bb->count * ae->probability, REG_BR_PROB_BASE);
+ EXECUTE_IF_SET_IN_BITMAP (bbs_to_scale, 0, i, bi)
+ {
+ scale_bbs_frequencies_int (bbs + i, 1, scale_after_exit,
+ REG_BR_PROB_BASE);
+ }
}
+ }
+
+ /* Update the original loop. */
+ if (!is_latch)
+ set_immediate_dominator (CDI_DOMINATORS, e->dest, e->src);
+ if (flags & DLTHE_FLAG_UPDATE_FREQ)
+ {
+ scale_bbs_frequencies_int (bbs, n, scale_main, REG_BR_PROB_BASE);
free (scale_step);
}
- free (orig_loops);
- /* Update dominators of other blocks if affected. */
+ /* Update dominators of outer blocks if affected. */
for (i = 0; i < n; i++)
{
- basic_block dominated, dom_bb, *dom_bbs;
- int n_dom_bbs,j;
+ basic_block dominated, dom_bb;
+ VEC (basic_block, heap) *dom_bbs;
+ unsigned j;
bb = bbs[i];
- n_dom_bbs = get_dominated_by (loops->cfg.dom, bb, &dom_bbs);
- for (j = 0; j < n_dom_bbs; j++)
+ bb->aux = 0;
+
+ dom_bbs = get_dominated_by (CDI_DOMINATORS, bb);
+ FOR_EACH_VEC_ELT (basic_block, dom_bbs, j, dominated)
{
- dominated = dom_bbs[j];
if (flow_bb_inside_loop_p (loop, dominated))
continue;
dom_bb = nearest_common_dominator (
- loops->cfg.dom, first_active[i], first_active_latch);
- set_immediate_dominator (loops->cfg.dom, dominated, dom_bb);
+ CDI_DOMINATORS, first_active[i], first_active_latch);
+ set_immediate_dominator (CDI_DOMINATORS, dominated, dom_bb);
}
- free (dom_bbs);
+ VEC_free (basic_block, heap, dom_bbs);
}
free (first_active);
free (bbs);
+ BITMAP_FREE (bbs_to_scale);
return true;
}
+/* A callback for make_forwarder block, to redirect all edges except for
+ MFB_KJ_EDGE to the entry part. E is the edge for that we should decide
+ whether to redirect it. */
+
+edge mfb_kj_edge;
+bool
+mfb_keep_just (edge e)
+{
+ return e != mfb_kj_edge;
+}
+
+/* True when a candidate preheader BLOCK has predecessors from LOOP. */
+
+static bool
+has_preds_from_loop (basic_block block, struct loop *loop)
+{
+ edge e;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, block->preds)
+ if (e->src->loop_father == loop)
+ return true;
+ return false;
+}
+
/* Creates a pre-header for a LOOP. Returns newly created block. Unless
CP_SIMPLE_PREHEADERS is set in FLAGS, we only force LOOP to have single
entry; otherwise we also force preheader block to have only one successor.
- The function also updates dominators stored in DOM. */
-static basic_block
-create_preheader (loop, dom, flags)
- struct loop *loop;
- dominance_info dom;
- int flags;
+ When CP_FALLTHRU_PREHEADERS is set in FLAGS, we force the preheader block
+ to be a fallthru predecessor to the loop header and to have only
+ predecessors from outside of the loop.
+ The function also updates dominators. */
+
+basic_block
+create_preheader (struct loop *loop, int flags)
{
edge e, fallthru;
basic_block dummy;
- basic_block jump, src = 0;
- struct loop *cloop, *ploop;
int nentry = 0;
- rtx insn;
-
- cloop = loop->outer;
+ bool irred = false;
+ bool latch_edge_was_fallthru;
+ edge one_succ_pred = NULL, single_entry = NULL;
+ edge_iterator ei;
- for (e = loop->header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
{
if (e->src == loop->latch)
continue;
+ irred |= (e->flags & EDGE_IRREDUCIBLE_LOOP) != 0;
nentry++;
+ single_entry = e;
+ if (single_succ_p (e->src))
+ one_succ_pred = e;
}
- if (!nentry)
- abort ();
+ gcc_assert (nentry);
if (nentry == 1)
{
- for (e = loop->header->pred; e->src == loop->latch; e = e->pred_next);
- if (!(flags & CP_SIMPLE_PREHEADERS)
- || !e->src->succ->succ_next)
+ bool need_forwarder_block = false;
+
+ /* We do not allow entry block to be the loop preheader, since we
+ cannot emit code there. */
+ if (single_entry->src == ENTRY_BLOCK_PTR)
+ need_forwarder_block = true;
+ else
+ {
+ /* If we want simple preheaders, also force the preheader to have
+ just a single successor. */
+ if ((flags & CP_SIMPLE_PREHEADERS)
+ && !single_succ_p (single_entry->src))
+ need_forwarder_block = true;
+ /* If we want fallthru preheaders, also create forwarder block when
+ preheader ends with a jump or has predecessors from loop. */
+ else if ((flags & CP_FALLTHRU_PREHEADERS)
+ && (JUMP_P (BB_END (single_entry->src))
+ || has_preds_from_loop (single_entry->src, loop)))
+ need_forwarder_block = true;
+ }
+ if (! need_forwarder_block)
return NULL;
}
- insn = first_insn_after_basic_block_note (loop->header);
- if (insn)
- insn = PREV_INSN (insn);
- else
- insn = get_last_insn ();
- if (insn == loop->header->end)
- {
- /* Split_block would not split block after its end. */
- emit_note_after (NOTE_INSN_DELETED, insn);
- }
- if (flags & CP_INSIDE_CFGLAYOUT)
- fallthru = cfg_layout_split_block (loop->header, insn);
- else
- fallthru = split_block (loop->header, insn);
+ mfb_kj_edge = loop_latch_edge (loop);
+ latch_edge_was_fallthru = (mfb_kj_edge->flags & EDGE_FALLTHRU) != 0;
+ fallthru = make_forwarder_block (loop->header, mfb_keep_just, NULL);
dummy = fallthru->src;
loop->header = fallthru->dest;
- /* The header could be a latch of some superloop(s); due to design of
- split_block, it would now move to fallthru->dest. */
- for (ploop = loop; ploop; ploop = ploop->outer)
- if (ploop->latch == dummy)
- ploop->latch = fallthru->dest;
+ /* Try to be clever in placing the newly created preheader. The idea is to
+ avoid breaking any "fallthruness" relationship between blocks.
- add_to_dominance_info (dom, fallthru->dest);
-
- /* Redirect edges. */
- for (e = dummy->pred; e; e = e->pred_next)
+ The preheader was created just before the header and all incoming edges
+ to the header were redirected to the preheader, except the latch edge.
+ So the only problematic case is when this latch edge was a fallthru
+ edge: it is not anymore after the preheader creation so we have broken
+ the fallthruness. We're therefore going to look for a better place. */
+ if (latch_edge_was_fallthru)
{
- src = e->src;
- if (src == loop->latch)
- break;
+ if (one_succ_pred)
+ e = one_succ_pred;
+ else
+ e = EDGE_PRED (dummy, 0);
+
+ move_block_after (dummy, e->src);
}
- if (!e)
- abort ();
-
- dummy->frequency -= EDGE_FREQUENCY (e);
- dummy->count -= e->count;
- fallthru->count -= e->count;
- if (flags & CP_INSIDE_CFGLAYOUT)
- cfg_layout_redirect_edge (e, loop->header);
- else
+
+ if (irred)
{
- jump = redirect_edge_and_branch_force (e, loop->header);
- if (jump)
- {
- add_to_dominance_info (dom, jump);
- set_immediate_dominator (dom, jump, src);
- add_bb_to_loop (jump, loop);
- loop->latch = jump;
- }
+ dummy->flags |= BB_IRREDUCIBLE_LOOP;
+ single_succ_edge (dummy)->flags |= EDGE_IRREDUCIBLE_LOOP;
}
- /* Update structures. */
- redirect_immediate_dominators (dom, dummy, loop->header);
- set_immediate_dominator (dom, loop->header, dummy);
- loop->header->loop_father = loop;
- add_bb_to_loop (dummy, cloop);
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Created preheader block for loop %i\n",
+ if (dump_file)
+ fprintf (dump_file, "Created preheader block for loop %i\n",
loop->num);
+ if (flags & CP_FALLTHRU_PREHEADERS)
+ gcc_assert ((single_succ_edge (dummy)->flags & EDGE_FALLTHRU)
+ && !JUMP_P (BB_END (dummy)));
+
return dummy;
}
-/* Create preheaders for each loop from loop tree stored in LOOPS; for meaning
- of FLAGS see create_preheader. */
+/* Create preheaders for each loop; for meaning of FLAGS see create_preheader. */
+
void
-create_preheaders (loops, flags)
- struct loops *loops;
- int flags;
+create_preheaders (int flags)
{
- unsigned i;
- for (i = 1; i < loops->num; i++)
- create_preheader (loops->parray[i], loops->cfg.dom, flags);
- loops->state |= LOOPS_HAVE_PREHEADERS;
+ loop_iterator li;
+ struct loop *loop;
+
+ if (!current_loops)
+ return;
+
+ FOR_EACH_LOOP (li, loop, 0)
+ create_preheader (loop, flags);
+ loops_state_set (LOOPS_HAVE_PREHEADERS);
}
-/* Forces all loop latches of loops from loop tree LOOPS to have only single
- successor. */
+/* Forces all loop latches to have only single successor. */
+
void
-force_single_succ_latches (loops)
- struct loops *loops;
+force_single_succ_latches (void)
{
- unsigned i;
+ loop_iterator li;
struct loop *loop;
edge e;
- for (i = 1; i < loops->num; i++)
+ FOR_EACH_LOOP (li, loop, 0)
{
- loop = loops->parray[i];
- if (!loop->latch->succ->succ_next)
- continue;
-
- for (e = loop->header->pred; e->src != loop->latch; e = e->pred_next)
+ if (loop->latch != loop->header && single_succ_p (loop->latch))
continue;
- loop_split_edge_with (e, NULL_RTX, loops);
+ e = find_edge (loop->latch, loop->header);
+
+ split_edge (e);
}
- loops->state |= LOOPS_HAVE_SIMPLE_LATCHES;
+ loops_state_set (LOOPS_HAVE_SIMPLE_LATCHES);
}
-/* A quite stupid function to put INSNS on edge E. They are supposed to form
- just one basic block. Jumps in INSNS are not handled, so cfg do not have to
- be ok after this function. The created block is placed on correct place
- in LOOPS structure and its dominator is set. */
-basic_block
-loop_split_edge_with (e, insns, loops)
- edge e;
- rtx insns;
- struct loops *loops;
+/* This function is called from loop_version. It splits the entry edge
+ of the loop we want to version, adds the versioning condition, and
+ adjust the edges to the two versions of the loop appropriately.
+ e is an incoming edge. Returns the basic block containing the
+ condition.
+
+ --- edge e ---- > [second_head]
+
+ Split it and insert new conditional expression and adjust edges.
+
+ --- edge e ---> [cond expr] ---> [first_head]
+ |
+ +---------> [second_head]
+
+ THEN_PROB is the probability of then branch of the condition. */
+
+static basic_block
+lv_adjust_loop_entry_edge (basic_block first_head, basic_block second_head,
+ edge e, void *cond_expr, unsigned then_prob)
+{
+ basic_block new_head = NULL;
+ edge e1;
+
+ gcc_assert (e->dest == second_head);
+
+ /* Split edge 'e'. This will create a new basic block, where we can
+ insert conditional expr. */
+ new_head = split_edge (e);
+
+ lv_add_condition_to_bb (first_head, second_head, new_head,
+ cond_expr);
+
+ /* Don't set EDGE_TRUE_VALUE in RTL mode, as it's invalid there. */
+ e = single_succ_edge (new_head);
+ e1 = make_edge (new_head, first_head,
+ current_ir_type () == IR_GIMPLE ? EDGE_TRUE_VALUE : 0);
+ e1->probability = then_prob;
+ e->probability = REG_BR_PROB_BASE - then_prob;
+ e1->count = RDIV (e->count * e1->probability, REG_BR_PROB_BASE);
+ e->count = RDIV (e->count * e->probability, REG_BR_PROB_BASE);
+
+ set_immediate_dominator (CDI_DOMINATORS, first_head, new_head);
+ set_immediate_dominator (CDI_DOMINATORS, second_head, new_head);
+
+ /* Adjust loop header phi nodes. */
+ lv_adjust_loop_header_phi (first_head, second_head, new_head, e1);
+
+ return new_head;
+}
+
+/* Main entry point for Loop Versioning transformation.
+
+ This transformation given a condition and a loop, creates
+ -if (condition) { loop_copy1 } else { loop_copy2 },
+ where loop_copy1 is the loop transformed in one way, and loop_copy2
+ is the loop transformed in another way (or unchanged). 'condition'
+ may be a run time test for things that were not resolved by static
+ analysis (overlapping ranges (anti-aliasing), alignment, etc.).
+
+ THEN_PROB is the probability of the then edge of the if. THEN_SCALE
+ is the ratio by that the frequencies in the original loop should
+ be scaled. ELSE_SCALE is the ratio by that the frequencies in the
+ new loop should be scaled.
+
+ If PLACE_AFTER is true, we place the new loop after LOOP in the
+ instruction stream, otherwise it is placed before LOOP. */
+
+struct loop *
+loop_version (struct loop *loop,
+ void *cond_expr, basic_block *condition_bb,
+ unsigned then_prob, unsigned then_scale, unsigned else_scale,
+ bool place_after)
+{
+ basic_block first_head, second_head;
+ edge entry, latch_edge, true_edge, false_edge;
+ int irred_flag;
+ struct loop *nloop;
+ basic_block cond_bb;
+
+ /* Record entry and latch edges for the loop */
+ entry = loop_preheader_edge (loop);
+ irred_flag = entry->flags & EDGE_IRREDUCIBLE_LOOP;
+ entry->flags &= ~EDGE_IRREDUCIBLE_LOOP;
+
+ /* Note down head of loop as first_head. */
+ first_head = entry->dest;
+
+ /* Duplicate loop. */
+ if (!cfg_hook_duplicate_loop_to_header_edge (loop, entry, 1,
+ NULL, NULL, NULL, 0))
+ {
+ entry->flags |= irred_flag;
+ return NULL;
+ }
+
+ /* After duplication entry edge now points to new loop head block.
+ Note down new head as second_head. */
+ second_head = entry->dest;
+
+ /* Split loop entry edge and insert new block with cond expr. */
+ cond_bb = lv_adjust_loop_entry_edge (first_head, second_head,
+ entry, cond_expr, then_prob);
+ if (condition_bb)
+ *condition_bb = cond_bb;
+
+ if (!cond_bb)
+ {
+ entry->flags |= irred_flag;
+ return NULL;
+ }
+
+ latch_edge = single_succ_edge (get_bb_copy (loop->latch));
+
+ extract_cond_bb_edges (cond_bb, &true_edge, &false_edge);
+ nloop = loopify (latch_edge,
+ single_pred_edge (get_bb_copy (loop->header)),
+ cond_bb, true_edge, false_edge,
+ false /* Do not redirect all edges. */,
+ then_scale, else_scale);
+
+ /* loopify redirected latch_edge. Update its PENDING_STMTS. */
+ lv_flush_pending_stmts (latch_edge);
+
+ /* loopify redirected condition_bb's succ edge. Update its PENDING_STMTS. */
+ extract_cond_bb_edges (cond_bb, &true_edge, &false_edge);
+ lv_flush_pending_stmts (false_edge);
+ /* Adjust irreducible flag. */
+ if (irred_flag)
+ {
+ cond_bb->flags |= BB_IRREDUCIBLE_LOOP;
+ loop_preheader_edge (loop)->flags |= EDGE_IRREDUCIBLE_LOOP;
+ loop_preheader_edge (nloop)->flags |= EDGE_IRREDUCIBLE_LOOP;
+ single_pred_edge (cond_bb)->flags |= EDGE_IRREDUCIBLE_LOOP;
+ }
+
+ if (place_after)
+ {
+ basic_block *bbs = get_loop_body_in_dom_order (nloop), after;
+ unsigned i;
+
+ after = loop->latch;
+
+ for (i = 0; i < nloop->num_nodes; i++)
+ {
+ move_block_after (bbs[i], after);
+ after = bbs[i];
+ }
+ free (bbs);
+ }
+
+ /* At this point condition_bb is loop preheader with two successors,
+ first_head and second_head. Make sure that loop preheader has only
+ one successor. */
+ split_edge (loop_preheader_edge (loop));
+ split_edge (loop_preheader_edge (nloop));
+
+ return nloop;
+}
+
+/* The structure of loops might have changed. Some loops might get removed
+ (and their headers and latches were set to NULL), loop exists might get
+ removed (thus the loop nesting may be wrong), and some blocks and edges
+ were changed (so the information about bb --> loop mapping does not have
+ to be correct). But still for the remaining loops the header dominates
+ the latch, and loops did not get new subloops (new loops might possibly
+ get created, but we are not interested in them). Fix up the mess.
+
+ If CHANGED_BBS is not NULL, basic blocks whose loop has changed are
+ marked in it. */
+
+void
+fix_loop_structure (bitmap changed_bbs)
{
- basic_block src, dest, new_bb;
- struct loop *loop_c;
- edge new_e;
-
- src = e->src;
- dest = e->dest;
-
- loop_c = find_common_loop (src->loop_father, dest->loop_father);
-
- /* Create basic block for it. */
-
- new_bb = create_basic_block (NULL_RTX, NULL_RTX, EXIT_BLOCK_PTR->prev_bb);
- add_to_dominance_info (loops->cfg.dom, new_bb);
- add_bb_to_loop (new_bb, loop_c);
- new_bb->flags = insns ? BB_SUPERBLOCK : 0;
- if (src->flags & BB_IRREDUCIBLE_LOOP)
+ basic_block bb;
+ struct loop *loop, *ploop;
+ loop_iterator li;
+ bool record_exits = false;
+ struct loop **superloop = XNEWVEC (struct loop *, number_of_loops ());
+
+ /* Remove the old bb -> loop mapping. Remember the depth of the blocks in
+ the loop hierarchy, so that we can recognize blocks whose loop nesting
+ relationship has changed. */
+ FOR_EACH_BB (bb)
+ {
+ if (changed_bbs)
+ bb->aux = (void *) (size_t) loop_depth (bb->loop_father);
+ bb->loop_father = current_loops->tree_root;
+ }
+
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ {
+ release_recorded_exits ();
+ record_exits = true;
+ }
+
+ /* Remove the dead loops from structures. We start from the innermost
+ loops, so that when we remove the loops, we know that the loops inside
+ are preserved, and do not waste time relinking loops that will be
+ removed later. */
+ FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST)
{
- /* We expect simple preheaders here. */
- if ((dest->flags & BB_IRREDUCIBLE_LOOP)
- || dest->loop_father->header == dest)
- new_bb->flags |= BB_IRREDUCIBLE_LOOP;
+ if (loop->header)
+ continue;
+
+ while (loop->inner)
+ {
+ ploop = loop->inner;
+ flow_loop_tree_node_remove (ploop);
+ flow_loop_tree_node_add (loop_outer (loop), ploop);
+ }
+
+ /* Remove the loop and free its data. */
+ delete_loop (loop);
}
- new_e = make_edge (new_bb, dest, EDGE_FALLTHRU);
- new_e->probability = REG_BR_PROB_BASE;
- new_e->count = e->count;
+ /* Rescan the bodies of loops, starting from the outermost ones. We assume
+ that no optimization interchanges the order of the loops, i.e., it cannot
+ happen that L1 was superloop of L2 before and it is subloop of L2 now
+ (without explicitly updating loop information). At the same time, we also
+ determine the new loop structure. */
+ current_loops->tree_root->num_nodes = n_basic_blocks;
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ superloop[loop->num] = loop->header->loop_father;
+ loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
+ }
- new_bb->count = e->count;
- new_bb->frequency = EDGE_FREQUENCY (e);
- cfg_layout_redirect_edge (e, new_bb);
+ /* Now fix the loop nesting. */
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ ploop = superloop[loop->num];
+ if (ploop != loop_outer (loop))
+ {
+ flow_loop_tree_node_remove (loop);
+ flow_loop_tree_node_add (ploop, loop);
+ }
+ }
+ free (superloop);
- alloc_aux_for_block (new_bb, sizeof (struct reorder_block_def));
- if (insns)
+ /* Mark the blocks whose loop has changed. */
+ if (changed_bbs)
{
- start_sequence ();
- emit_insn (insns);
- insns = get_insns ();
- end_sequence ();
- emit_insn_after (insns, new_bb->end);
+ FOR_EACH_BB (bb)
+ {
+ if ((void *) (size_t) loop_depth (bb->loop_father) != bb->aux)
+ bitmap_set_bit (changed_bbs, bb->index);
+
+ bb->aux = NULL;
+ }
}
- set_immediate_dominator (loops->cfg.dom, new_bb, src);
- set_immediate_dominator (loops->cfg.dom, dest,
- recount_dominator (loops->cfg.dom, dest));
+ if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS))
+ create_preheaders (CP_SIMPLE_PREHEADERS);
+
+ if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
+ force_single_succ_latches ();
+
+ if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
+ mark_irreducible_loops ();
+
+ if (record_exits)
+ record_loop_exits ();
- if (dest->loop_father->latch == src)
- dest->loop_father->latch = new_bb;
-
- return new_bb;
+#ifdef ENABLE_CHECKING
+ verify_loop_structure ();
+#endif
}