/* Loop manipulation code for GNU compiler.
- Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008, 2009 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, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "cfglayout.h"
#include "cfghooks.h"
#include "output.h"
+#include "tree-flow.h"
static void duplicate_subloops (struct loop *, struct loop *);
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 (basic_block, void *);
+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 basic_block create_preheader (struct loop *, int);
static void unloop (struct loop *, bool *);
#define RDIV(X,Y) (((X) + (Y) / 2) / (Y))
/* Checks whether basic block BB is dominated by DATA. */
static bool
-rpe_enum_p (basic_block bb, void *data)
+rpe_enum_p (const_basic_block bb, const void *data)
{
- return dominated_by_p (CDI_DOMINATORS, bb, data);
+ return dominated_by_p (CDI_DOMINATORS, bb, (const_basic_block) data);
}
/* Remove basic blocks BBS. NBBS is the number of the basic blocks. */
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, nreml;
+ basic_block *rem_bbs, *bord_bbs, from, bb;
+ VEC (basic_block, heap) *dom_bbs;
+ int i, nrem, n_bord_bbs, nreml;
sbitmap seen;
bool irred_invalidated = false;
struct loop **deleted_loop;
/* Remove the path. */
from = e->src;
remove_branch (e);
- dom_bbs = XCNEWVEC (basic_block, n_basic_blocks);
+ dom_bbs = NULL;
/* Cancel loops contained in the path. */
deleted_loop = XNEWVEC (struct loop *, nrem);
if (rem_bbs[i]->loop_father->header == rem_bbs[i])
deleted_loop[nreml++] = rem_bbs[i]->loop_father;
- remove_bbs (rem_bbs, nrem);
- free (rem_bbs);
-
for (i = 0; i < nreml; i++)
cancel_loop_tree (deleted_loop[i]);
free (deleted_loop);
+ remove_bbs (rem_bbs, nrem);
+ free (rem_bbs);
+
/* Find blocks whose dominators may be affected. */
- n_dom_bbs = 0;
sbitmap_zero (seen);
for (i = 0; i < n_bord_bbs; i++)
{
ldom;
ldom = next_dom_son (CDI_DOMINATORS, ldom))
if (!dominated_by_p (CDI_DOMINATORS, from, ldom))
- dom_bbs[n_dom_bbs++] = ldom;
+ VEC_safe_push (basic_block, heap, dom_bbs, ldom);
}
free (seen);
/* Recount dominators. */
- iterate_fix_dominators (CDI_DOMINATORS, 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
fix_loop_placements (from->loop_father, &irred_invalidated);
if (irred_invalidated
- && (current_loops->state & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) != 0)
+ && loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
mark_irreducible_loops ();
return true;
basic_block *bbs;
int i, n;
struct loop *subloop;
+ edge e;
+ edge_iterator ei;
/* Add it to loop structure. */
place_new_loop (loop);
}
}
+ /* Update the information about loop exit edges. */
+ for (i = 0; i < n; i++)
+ {
+ FOR_EACH_EDGE (e, ei, bbs[i]->succs)
+ {
+ rescan_loop_exit (e, false, false);
+ }
+ }
+
free (bbs);
}
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 succ_bb, 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;
+
+ succ_bb = entry_edge->dest;
+ 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 |
+ | ------------- | IV_0 = INITIAL_VALUE |
+ | | ------------------------
+ | | ______ | ENTRY_EDGE
+ | | ENTRY_EDGE / V V
+ | | ====> | -----------------------------
+ | | | | IV_BEFORE = phi (IV_0, IV) |
+ | | | | loop_header |
+ | V | | IV_BEFORE <= UPPER_BOUND |
+ | ------------- | -----------------------\-----
+ | | succ_bb | | | \
+ | ------------- | | \ exit_e
+ | | V V---------
+ | | -------------- | succ_bb |
+ | | | loop_latch | ----------
+ | | |IV = IV_BEFORE + STRIDE
+ | | --------------
+ | \ /
+ | \ ___ /
+
+ 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. */
+
+struct loop *
+create_empty_loop_on_edge (edge entry_edge,
+ tree initial_value,
+ tree stride, tree upper_bound,
+ tree iv,
+ tree *iv_before,
+ struct loop *outer)
+{
+ basic_block loop_header, loop_latch, succ_bb, pred_bb;
+ struct loop *loop;
+ int freq;
+ gcov_type cnt;
+ gimple_stmt_iterator gsi;
+ bool insert_after;
+ gimple_seq stmts;
+ gimple cond_expr;
+ tree exit_test;
+ edge exit_e;
+ int prob;
+ tree upper_bound_gimplified;
+
+ 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. */
+ freq = EDGE_FREQUENCY (entry_edge);
+ cnt = entry_edge->count;
+
+ 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);
+
+ /* 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 ();
+ }
+
+ standard_iv_increment_position (loop, &gsi, &insert_after);
+ create_iv (initial_value, stride, iv, loop, &gsi, insert_after,
+ iv_before, NULL);
+
+ /* 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;
+
+ gsi = gsi_last_bb (exit_e->src);
+
+ upper_bound_gimplified =
+ force_gimple_operand_gsi (&gsi, upper_bound, true, NULL,
+ false, GSI_NEW_STMT);
+ gsi = gsi_last_bb (exit_e->src);
+
+ cond_expr = gimple_build_cond
+ (LE_EXPR, *iv_before, upper_bound_gimplified, 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);
+
+ return loop;
+}
+
/* Make area between HEADER_EDGE and LATCH_EDGE a loop by connecting
latch to header and update loop tree and dominators
accordingly. Everything between them plus LATCH_EDGE destination must
{
basic_block succ_bb = latch_edge->dest;
basic_block pred_bb = header_edge->src;
- basic_block *dom_bbs, *body;
- unsigned n_dom_bbs, i;
- sbitmap seen;
struct loop *loop = alloc_loop ();
struct loop *outer = loop_outer (succ_bb->loop_father);
int freq;
}
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 of blocks outside of LOOP. */
- dom_bbs = XCNEWVEC (basic_block, n_basic_blocks);
- 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++)
- {
- 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);
- dom_bbs[n_dom_bbs++] = ldom;
- }
- }
-
- iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, n_dom_bbs);
-
- free (body);
- free (seen);
- free (dom_bbs);
+ update_dominators_in_loop (loop);
return loop;
}
place_new_loop (cloop);
/* Mark the new loop as copy of LOOP. */
- loop->copy = cloop;
+ set_loop_copy (loop, cloop);
/* Add it to target. */
flow_loop_tree_node_add (target, cloop);
/* Check whether LOOP's body can be duplicated. */
bool
-can_duplicate_loop_p (struct loop *loop)
+can_duplicate_loop_p (const struct loop *loop)
{
int ret;
basic_block *bbs = get_loop_body (loop);
for (aloop = loop->inner, i = 0; aloop; aloop = aloop->next, i++)
orig_loops[i] = aloop;
- loop->copy = target;
+ set_loop_copy (loop, target);
first_active = XNEWVEC (basic_block, n);
if (is_latch)
/* 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];
bb->aux = 0;
- n_dom_bbs = get_dominated_by (CDI_DOMINATORS, bb, &dom_bbs);
- for (j = 0; j < n_dom_bbs; j++)
+ dom_bbs = get_dominated_by (CDI_DOMINATORS, bb);
+ for (j = 0; VEC_iterate (basic_block, dom_bbs, j, dominated); j++)
{
- dominated = dom_bbs[j];
if (flow_bb_inside_loop_p (loop, dominated))
continue;
dom_bb = nearest_common_dominator (
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);
MFB_KJ_EDGE to the entry part. E is the edge for that we should decide
whether to redirect it. */
-static edge mfb_kj_edge;
-static bool
+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.
+ 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. */
-static basic_block
+basic_block
create_preheader (struct loop *loop, int flags)
{
edge e, fallthru;
gcc_assert (nentry);
if (nentry == 1)
{
- if (/* We do not allow entry block to be the loop preheader, since we
+ bool need_forwarder_block = false;
+
+ /* We do not allow entry block to be the loop preheader, since we
cannot emit code there. */
- single_entry->src != ENTRY_BLOCK_PTR
- /* If we want simple preheaders, also force the preheader to have
- just a single successor. */
- && !((flags & CP_SIMPLE_PREHEADERS)
- && !single_succ_p (single_entry->src)))
+ 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;
}
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;
}
FOR_EACH_LOOP (li, loop, 0)
create_preheader (loop, flags);
- current_loops->state |= LOOPS_HAVE_PREHEADERS;
+ loops_state_set (LOOPS_HAVE_PREHEADERS);
}
/* Forces all loop latches to have only single successor. */
split_edge (e);
}
- current_loops->state |= LOOPS_HAVE_SIMPLE_LATCHES;
+ loops_state_set (LOOPS_HAVE_SIMPLE_LATCHES);
}
/* This function is called from loop_version. It splits the entry edge
struct loop *nloop;
basic_block cond_bb;
- /* CHECKME: Loop versioning does not handle nested loop at this point. */
- if (loop->inner)
- return NULL;
-
/* Record entry and latch edges for the loop */
entry = loop_preheader_edge (loop);
irred_flag = entry->flags & EDGE_IRREDUCIBLE_LOOP;
free (bbs);
}
- /* At this point condition_bb is loop predheader with two successors,
- first_head and second_head. Make sure that loop predheader has only
+ /* 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));
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 subloobs (new loops might possibly
+ 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
bool record_exits = false;
struct loop **superloop = XNEWVEC (struct loop *, number_of_loops ());
- gcc_assert (current_loops->state & LOOPS_HAVE_SIMPLE_LATCHES);
-
/* 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. */
bb->loop_father = current_loops->tree_root;
}
- if (current_loops->state & LOOPS_HAVE_RECORDED_EXITS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
{
release_recorded_exits ();
record_exits = true;
}
}
- if (current_loops->state & LOOPS_HAVE_PREHEADERS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS))
create_preheaders (CP_SIMPLE_PREHEADERS);
- if (current_loops->state & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
+ 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)
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