/* Loop manipulation code for GNU compiler.
- Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2003, 2004, 2005, 2007 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"
static void copy_loops_to (struct loop **, int,
struct loop *);
static void loop_redirect_edge (edge, basic_block);
-static bool loop_delete_branch_edge (edge, int);
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 bool alp_enum_p (basic_block, void *);
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 place_new_loop (struct loop *);
-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. */
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;
father = act;
}
- if (father != loop->outer)
+ if (father != loop_outer (loop))
{
- for (act = loop->outer; act != father; act = act->outer)
+ 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);
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 deleted, irred_invalidated = false;
+ bool irred_invalidated = false;
struct loop **deleted_loop;
- if (!loop_delete_branch_edge (e, 0))
+ if (!can_remove_branch_p (e))
return false;
/* Keep track of whether we need to update information about irreducible
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 (e->src->loop_father->outer
+ 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);
/* Remove the path. */
from = e->src;
- deleted = loop_delete_branch_edge (e, 1);
- gcc_assert (deleted);
- dom_bbs = XCNEWVEC (basic_block, n_basic_blocks);
+ remove_branch (e);
+ dom_bbs = NULL;
/* Cancel loops contained in the path. */
deleted_loop = XNEWVEC (struct loop *, nrem);
free (deleted_loop);
/* 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;
}
-/* Predicate for enumeration in add_loop. */
-static bool
-alp_enum_p (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. Insert the LOOP as a son of
outer. */
-static void
+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 (loop);
flow_loop_tree_node_add (outer, loop);
/* Find its nodes. */
- bbs = XCNEWVEC (basic_block, n_basic_blocks);
- 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++)
+ {
+ if (bbs[i]->loop_father == outer)
+ {
+ remove_bb_from_loops (bbs[i]);
+ add_bb_to_loop (bbs[i], loop);
+ continue;
+ }
+
+ loop->num_nodes++;
+
+ /* 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);
+ }
+ }
+ /* Update the information about loop exit edges. */
for (i = 0; i < n; i++)
{
- remove_bb_from_loops (bbs[i]);
- add_bb_to_loop (bbs[i], loop);
+ FOR_EACH_EDGE (e, ei, bbs[i]->succs)
+ {
+ rescan_loop_exit (e, false, false);
+ }
}
- remove_bb_from_loops (loop->header);
- add_bb_to_loop (loop->header, loop);
free (bbs);
}
{
basic_block succ_bb = latch_edge->dest;
basic_block pred_bb = header_edge->src;
- basic_block *dom_bbs, *body;
- unsigned n_dom_bbs, i;
+ basic_block *body;
+ VEC (basic_block, heap) *dom_bbs;
+ unsigned i;
sbitmap seen;
struct loop *loop = alloc_loop ();
- struct loop *outer = succ_bb->loop_father->outer;
+ struct loop *outer = loop_outer (succ_bb->loop_father);
int freq;
gcov_type cnt;
edge e;
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;
+ dom_bbs = NULL;
seen = sbitmap_alloc (last_basic_block);
sbitmap_zero (seen);
body = get_loop_body (loop);
if (!TEST_BIT (seen, ldom->index))
{
SET_BIT (seen, ldom->index);
- dom_bbs[n_dom_bbs++] = ldom;
+ VEC_safe_push (basic_block, heap, dom_bbs, ldom);
}
}
- iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, n_dom_bbs);
+ iterate_fix_dominators (CDI_DOMINATORS, dom_bbs, false);
free (body);
free (seen);
- free (dom_bbs);
+ VEC_free (basic_block, heap, dom_bbs);
return loop;
}
if (body[i]->loop_father == loop)
{
remove_bb_from_loops (body[i]);
- add_bb_to_loop (body[i], loop->outer);
+ add_bb_to_loop (body[i], loop_outer (loop));
}
free(body);
{
ploop = loop->inner;
flow_loop_tree_node_remove (ploop);
- flow_loop_tree_node_add (loop->outer, ploop);
+ flow_loop_tree_node_add (loop_outer (loop), ploop);
}
/* Remove the loop and free its data. */
{
struct loop *outer;
- while (loop->outer)
+ while (loop_outer (loop))
{
- outer = loop->outer;
+ outer = loop_outer (loop);
if (!fix_loop_placement (loop))
break;
}
}
-/* Creates place for a new LOOP in loops structure. */
-static void
-place_new_loop (struct loop *loop)
-{
- loop->num = number_of_loops ();
- VEC_safe_push (loop_p, heap, current_loops->larray, loop);
-}
-
/* Copies copy of LOOP as subloop of TARGET loop, placing newly
created loop into loops structure. */
struct 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);
redirect_edge_and_branch_force (e, dest);
}
-/* Deletes edge E from a branch if possible. Unless REALLY_DELETE is set,
- just test whether it is possible to remove the edge. */
-static bool
-loop_delete_branch_edge (edge e, int really_delete)
-{
- basic_block src = e->src;
- basic_block newdest;
- int irr;
- edge snd;
-
- gcc_assert (EDGE_COUNT (src->succs) > 1);
-
- /* Cannot handle more than two exit edges. */
- if (EDGE_COUNT (src->succs) > 2)
- return false;
- /* And it must be just a simple branch. */
- if (!any_condjump_p (BB_END (src)))
- return false;
-
- snd = e == EDGE_SUCC (src, 0) ? EDGE_SUCC (src, 1) : EDGE_SUCC (src, 0);
- newdest = snd->dest;
- if (newdest == EXIT_BLOCK_PTR)
- return false;
-
- /* Hopefully the above conditions should suffice. */
- if (!really_delete)
- return true;
-
- /* Redirecting behaves wrongly wrto this flag. */
- irr = snd->flags & EDGE_IRREDUCIBLE_LOOP;
-
- if (!redirect_edge_and_branch (e, newdest))
- return false;
- single_succ_edge (src)->flags &= ~EDGE_IRREDUCIBLE_LOOP;
- single_succ_edge (src)->flags |= irr;
-
- return true;
-}
-
/* 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;
entry; otherwise we also force preheader block to have only one successor.
The function also updates dominators. */
-static basic_block
+basic_block
create_preheader (struct loop *loop, int flags)
{
edge e, fallthru;
int nentry = 0;
bool irred = false;
bool latch_edge_was_fallthru;
- edge one_succ_pred = 0;
+ edge one_succ_pred = NULL, single_entry = NULL;
edge_iterator ei;
FOR_EACH_EDGE (e, ei, loop->header->preds)
continue;
irred |= (e->flags & EDGE_IRREDUCIBLE_LOOP) != 0;
nentry++;
+ single_entry = e;
if (single_succ_p (e->src))
one_succ_pred = e;
}
gcc_assert (nentry);
if (nentry == 1)
{
- /* Get an edge that is different from the one from loop->latch
- to loop->header. */
- e = EDGE_PRED (loop->header,
- EDGE_PRED (loop->header, 0)->src == loop->latch);
-
- if (!(flags & CP_SIMPLE_PREHEADERS) || single_succ_p (e->src))
+ if (/* 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)))
return NULL;
}
loop_iterator li;
struct loop *loop;
+ if (!current_loops)
+ return;
+
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;
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. */
+ /* 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)
{
- bb->aux = (void *) (size_t) bb->loop_father->depth;
+ if (changed_bbs)
+ bb->aux = (void *) (size_t) loop_depth (bb->loop_father);
bb->loop_father = current_loops->tree_root;
}
- /* Remove the dead loops from structures. */
- current_loops->tree_root->num_nodes = n_basic_blocks;
- FOR_EACH_LOOP (li, loop, 0)
+ 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)
{
- loop->num_nodes = 0;
if (loop->header)
continue;
{
ploop = loop->inner;
flow_loop_tree_node_remove (ploop);
- flow_loop_tree_node_add (loop->outer, ploop);
+ flow_loop_tree_node_add (loop_outer (loop), ploop);
}
/* Remove the loop and free its data. */
delete_loop (loop);
}
- /* Rescan the bodies of loops, starting from the outermost. */
+ /* 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);
}
/* Now fix the loop nesting. */
FOR_EACH_LOOP (li, loop, 0)
{
- bb = loop_preheader_edge (loop)->src;
- if (bb->loop_father != loop->outer)
+ ploop = superloop[loop->num];
+ if (ploop != loop_outer (loop))
{
flow_loop_tree_node_remove (loop);
- flow_loop_tree_node_add (bb->loop_father, loop);
+ flow_loop_tree_node_add (ploop, loop);
}
}
+ free (superloop);
/* Mark the blocks whose loop has changed. */
- FOR_EACH_BB (bb)
+ if (changed_bbs)
{
- if (changed_bbs
- && (void *) (size_t) bb->loop_father->depth != bb->aux)
- bitmap_set_bit (changed_bbs, bb->index);
+ 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;
+ bb->aux = NULL;
+ }
}
- if (current_loops->state & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
+ 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 (current_loops->state & LOOPS_HAVE_RECORDED_EXITS)
- {
- release_recorded_exits ();
- record_loop_exits ();
- }
+ if (record_exits)
+ record_loop_exits ();
+
+#ifdef ENABLE_CHECKING
+ verify_loop_structure ();
+#endif
}
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