/* Natural loop discovery code for GNU compiler.
- Copyright (C) 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2010
+ 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 "function.h"
#include "basic-block.h"
-#include "toplev.h"
#include "cfgloop.h"
+#include "diagnostic-core.h"
#include "flags.h"
#include "tree.h"
#include "tree-flow.h"
+#include "pointer-set.h"
+#include "output.h"
+#include "ggc.h"
-/* Ratio of frequencies of edges so that one of more latch edges is
- considered to belong to inner loop with same header. */
-#define HEAVY_EDGE_RATIO 8
-
-#define HEADER_BLOCK(B) (* (int *) (B)->aux)
-#define LATCH_EDGE(E) (*(int *) (E)->aux)
-
-static void flow_loops_cfg_dump (const struct loops *, FILE *);
-static void flow_loop_entry_edges_find (struct loop *);
-static void flow_loop_exit_edges_find (struct loop *);
-static int flow_loop_nodes_find (basic_block, struct loop *);
-static void flow_loop_pre_header_scan (struct loop *);
-static basic_block flow_loop_pre_header_find (basic_block);
-static int flow_loop_level_compute (struct loop *);
-static int flow_loops_level_compute (struct loops *);
-static void establish_preds (struct loop *);
-static void canonicalize_loop_headers (void);
-static bool glb_enum_p (basic_block, void *);
+static void flow_loops_cfg_dump (FILE *);
\f
/* Dump loop related CFG information. */
static void
-flow_loops_cfg_dump (const struct loops *loops, FILE *file)
+flow_loops_cfg_dump (FILE *file)
{
- int i;
basic_block bb;
- if (! loops->num || ! file)
+ if (!file)
return;
FOR_EACH_BB (bb)
{
edge succ;
+ edge_iterator ei;
fprintf (file, ";; %d succs { ", bb->index);
- for (succ = bb->succ; succ; succ = succ->succ_next)
+ FOR_EACH_EDGE (succ, ei, bb->succs)
fprintf (file, "%d ", succ->dest->index);
fprintf (file, "}\n");
}
-
- /* Dump the DFS node order. */
- if (loops->cfg.dfs_order)
- {
- fputs (";; DFS order: ", file);
- for (i = 0; i < n_basic_blocks; i++)
- fprintf (file, "%d ", loops->cfg.dfs_order[i]);
-
- fputs ("\n", file);
- }
-
- /* Dump the reverse completion node order. */
- if (loops->cfg.rc_order)
- {
- fputs (";; RC order: ", file);
- for (i = 0; i < n_basic_blocks; i++)
- fprintf (file, "%d ", loops->cfg.rc_order[i]);
-
- fputs ("\n", file);
- }
}
/* Return nonzero if the nodes of LOOP are a subset of OUTER. */
bool
flow_loop_nested_p (const struct loop *outer, const struct loop *loop)
{
- return (loop->depth > outer->depth
- && loop->pred[outer->depth] == outer);
+ unsigned odepth = loop_depth (outer);
+
+ return (loop_depth (loop) > odepth
+ && VEC_index (loop_p, loop->superloops, odepth) == outer);
}
/* Returns the loop such that LOOP is nested DEPTH (indexed from zero)
struct loop *
superloop_at_depth (struct loop *loop, unsigned depth)
{
- if (depth > (unsigned) loop->depth)
- abort ();
+ unsigned ldepth = loop_depth (loop);
+
+ gcc_assert (depth <= ldepth);
- if (depth == (unsigned) loop->depth)
+ if (depth == ldepth)
return loop;
- return loop->pred[depth];
+ return VEC_index (loop_p, loop->superloops, depth);
+}
+
+/* Returns the list of the latch edges of LOOP. */
+
+static VEC (edge, heap) *
+get_loop_latch_edges (const struct loop *loop)
+{
+ edge_iterator ei;
+ edge e;
+ VEC (edge, heap) *ret = NULL;
+
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ {
+ if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header))
+ VEC_safe_push (edge, heap, ret, e);
+ }
+
+ return ret;
}
/* Dump the loop information specified by LOOP to the stream FILE
{
basic_block *bbs;
unsigned i;
+ VEC (edge, heap) *latches;
+ edge e;
if (! loop || ! loop->header)
return;
- fprintf (file, ";;\n;; Loop %d:%s\n", loop->num,
- loop->invalid ? " invalid" : "");
+ fprintf (file, ";;\n;; Loop %d\n", loop->num);
- fprintf (file, ";; header %d, latch %d, pre-header %d\n",
- loop->header->index, loop->latch->index,
- loop->pre_header ? loop->pre_header->index : -1);
- fprintf (file, ";; depth %d, level %d, outer %ld\n",
- loop->depth, loop->level,
- (long) (loop->outer ? loop->outer->num : -1));
+ fprintf (file, ";; header %d, ", loop->header->index);
+ if (loop->latch)
+ fprintf (file, "latch %d\n", loop->latch->index);
+ else
+ {
+ fprintf (file, "multiple latches:");
+ latches = get_loop_latch_edges (loop);
+ FOR_EACH_VEC_ELT (edge, latches, i, e)
+ fprintf (file, " %d", e->src->index);
+ VEC_free (edge, heap, latches);
+ fprintf (file, "\n");
+ }
- if (loop->pre_header_edges)
- flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
- loop->num_pre_header_edges, file);
+ fprintf (file, ";; depth %d, outer %ld\n",
+ loop_depth (loop), (long) (loop_outer (loop)
+ ? loop_outer (loop)->num : -1));
- flow_edge_list_print (";; entry edges", loop->entry_edges,
- loop->num_entries, file);
fprintf (file, ";; nodes:");
bbs = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
fprintf (file, " %d", bbs[i]->index);
free (bbs);
fprintf (file, "\n");
- flow_edge_list_print (";; exit edges", loop->exit_edges,
- loop->num_exits, file);
if (loop_dump_aux)
loop_dump_aux (loop, file, verbose);
}
-/* Dump the loop information specified by LOOPS to the stream FILE,
+/* Dump the loop information about loops to the stream FILE,
using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
void
-flow_loops_dump (const struct loops *loops, FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose)
+flow_loops_dump (FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose)
{
- int i;
- int num_loops;
+ loop_iterator li;
+ struct loop *loop;
- num_loops = loops->num;
- if (! num_loops || ! file)
+ if (!current_loops || ! file)
return;
- fprintf (file, ";; %d loops found, %d levels\n",
- num_loops, loops->levels);
+ fprintf (file, ";; %d loops found\n", number_of_loops ());
- for (i = 0; i < num_loops; i++)
+ FOR_EACH_LOOP (li, loop, LI_INCLUDE_ROOT)
{
- struct loop *loop = loops->parray[i];
-
- if (!loop)
- continue;
-
flow_loop_dump (loop, file, loop_dump_aux, verbose);
}
if (verbose)
- flow_loops_cfg_dump (loops, file);
+ flow_loops_cfg_dump (file);
}
/* Free data allocated for LOOP. */
+
void
flow_loop_free (struct loop *loop)
{
- if (loop->pre_header_edges)
- free (loop->pre_header_edges);
- if (loop->entry_edges)
- free (loop->entry_edges);
- if (loop->exit_edges)
- free (loop->exit_edges);
- if (loop->pred)
- free (loop->pred);
- free (loop);
+ struct loop_exit *exit, *next;
+
+ VEC_free (loop_p, gc, loop->superloops);
+
+ /* Break the list of the loop exit records. They will be freed when the
+ corresponding edge is rescanned or removed, and this avoids
+ accessing the (already released) head of the list stored in the
+ loop structure. */
+ for (exit = loop->exits->next; exit != loop->exits; exit = next)
+ {
+ next = exit->next;
+ exit->next = exit;
+ exit->prev = exit;
+ }
+
+ ggc_free (loop->exits);
+ ggc_free (loop);
}
/* Free all the memory allocated for LOOPS. */
void
flow_loops_free (struct loops *loops)
{
- if (loops->parray)
+ if (loops->larray)
{
unsigned i;
-
- if (! loops->num)
- abort ();
+ loop_p loop;
/* Free the loop descriptors. */
- for (i = 0; i < loops->num; i++)
+ FOR_EACH_VEC_ELT (loop_p, loops->larray, i, loop)
{
- struct loop *loop = loops->parray[i];
-
if (!loop)
continue;
flow_loop_free (loop);
}
- free (loops->parray);
- loops->parray = NULL;
-
- if (loops->cfg.dfs_order)
- free (loops->cfg.dfs_order);
- if (loops->cfg.rc_order)
- free (loops->cfg.rc_order);
-
+ VEC_free (loop_p, gc, loops->larray);
}
}
-/* Find the entry edges into the LOOP. */
+/* Find the nodes contained within the LOOP with header HEADER.
+ Return the number of nodes within the loop. */
-static void
-flow_loop_entry_edges_find (struct loop *loop)
+int
+flow_loop_nodes_find (basic_block header, struct loop *loop)
{
- edge e;
- int num_entries;
+ VEC (basic_block, heap) *stack = NULL;
+ int num_nodes = 1;
+ edge latch;
+ edge_iterator latch_ei;
+ unsigned depth = loop_depth (loop);
- num_entries = 0;
- for (e = loop->header->pred; e; e = e->pred_next)
+ header->loop_father = loop;
+ header->loop_depth = depth;
+
+ FOR_EACH_EDGE (latch, latch_ei, loop->header->preds)
{
- if (flow_loop_outside_edge_p (loop, e))
- num_entries++;
- }
+ if (latch->src->loop_father == loop
+ || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header))
+ continue;
- if (! num_entries)
- abort ();
+ num_nodes++;
+ VEC_safe_push (basic_block, heap, stack, latch->src);
+ latch->src->loop_father = loop;
+ latch->src->loop_depth = depth;
- loop->entry_edges = xmalloc (num_entries * sizeof (edge *));
+ while (!VEC_empty (basic_block, stack))
+ {
+ basic_block node;
+ edge e;
+ edge_iterator ei;
- num_entries = 0;
- for (e = loop->header->pred; e; e = e->pred_next)
- {
- if (flow_loop_outside_edge_p (loop, e))
- loop->entry_edges[num_entries++] = e;
+ node = VEC_pop (basic_block, stack);
+
+ FOR_EACH_EDGE (e, ei, node->preds)
+ {
+ basic_block ancestor = e->src;
+
+ if (ancestor->loop_father != loop)
+ {
+ ancestor->loop_father = loop;
+ ancestor->loop_depth = depth;
+ num_nodes++;
+ VEC_safe_push (basic_block, heap, stack, ancestor);
+ }
+ }
+ }
}
+ VEC_free (basic_block, heap, stack);
- loop->num_entries = num_entries;
+ return num_nodes;
}
-/* Find the exit edges from the LOOP. */
+/* Records the vector of superloops of the loop LOOP, whose immediate
+ superloop is FATHER. */
static void
-flow_loop_exit_edges_find (struct loop *loop)
+establish_preds (struct loop *loop, struct loop *father)
{
- edge e;
- basic_block node, *bbs;
- unsigned num_exits, i;
+ loop_p ploop;
+ unsigned depth = loop_depth (father) + 1;
+ unsigned i;
- loop->exit_edges = NULL;
- loop->num_exits = 0;
+ VEC_truncate (loop_p, loop->superloops, 0);
+ VEC_reserve (loop_p, gc, loop->superloops, depth);
+ FOR_EACH_VEC_ELT (loop_p, father->superloops, i, ploop)
+ VEC_quick_push (loop_p, loop->superloops, ploop);
+ VEC_quick_push (loop_p, loop->superloops, father);
- /* Check all nodes within the loop to see if there are any
- successors not in the loop. Note that a node may have multiple
- exiting edges. */
- num_exits = 0;
- bbs = get_loop_body (loop);
- for (i = 0; i < loop->num_nodes; i++)
- {
- node = bbs[i];
- for (e = node->succ; e; e = e->succ_next)
- {
- basic_block dest = e->dest;
+ for (ploop = loop->inner; ploop; ploop = ploop->next)
+ establish_preds (ploop, loop);
+}
- if (!flow_bb_inside_loop_p (loop, dest))
- num_exits++;
- }
- }
+/* Add LOOP to the loop hierarchy tree where FATHER is father of the
+ added loop. If LOOP has some children, take care of that their
+ pred field will be initialized correctly. */
- if (! num_exits)
- {
- free (bbs);
- return;
- }
+void
+flow_loop_tree_node_add (struct loop *father, struct loop *loop)
+{
+ loop->next = father->inner;
+ father->inner = loop;
- loop->exit_edges = xmalloc (num_exits * sizeof (edge *));
+ establish_preds (loop, father);
+}
- /* Store all exiting edges into an array. */
- num_exits = 0;
- for (i = 0; i < loop->num_nodes; i++)
- {
- node = bbs[i];
- for (e = node->succ; e; e = e->succ_next)
- {
- basic_block dest = e->dest;
+/* Remove LOOP from the loop hierarchy tree. */
+
+void
+flow_loop_tree_node_remove (struct loop *loop)
+{
+ struct loop *prev, *father;
+
+ father = loop_outer (loop);
- if (!flow_bb_inside_loop_p (loop, dest))
- loop->exit_edges[num_exits++] = e;
- }
+ /* Remove loop from the list of sons. */
+ if (father->inner == loop)
+ father->inner = loop->next;
+ else
+ {
+ for (prev = father->inner; prev->next != loop; prev = prev->next)
+ continue;
+ prev->next = loop->next;
}
- free (bbs);
- loop->num_exits = num_exits;
+
+ VEC_truncate (loop_p, loop->superloops, 0);
}
-/* Find the nodes contained within the LOOP with header HEADER.
- Return the number of nodes within the loop. */
+/* Allocates and returns new loop structure. */
-static int
-flow_loop_nodes_find (basic_block header, struct loop *loop)
+struct loop *
+alloc_loop (void)
{
- basic_block *stack;
- int sp;
- int num_nodes = 1;
+ struct loop *loop = ggc_alloc_cleared_loop ();
- header->loop_father = loop;
- header->loop_depth = loop->depth;
+ loop->exits = ggc_alloc_cleared_loop_exit ();
+ loop->exits->next = loop->exits->prev = loop->exits;
+ loop->can_be_parallel = false;
- if (loop->latch->loop_father != loop)
- {
- stack = xmalloc (n_basic_blocks * sizeof (basic_block));
- sp = 0;
- num_nodes++;
- stack[sp++] = loop->latch;
- loop->latch->loop_father = loop;
- loop->latch->loop_depth = loop->depth;
+ return loop;
+}
- while (sp)
- {
- basic_block node;
- edge e;
+/* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops
+ (including the root of the loop tree). */
- node = stack[--sp];
+static void
+init_loops_structure (struct loops *loops, unsigned num_loops)
+{
+ struct loop *root;
- for (e = node->pred; e; e = e->pred_next)
- {
- basic_block ancestor = e->src;
+ memset (loops, 0, sizeof *loops);
+ loops->larray = VEC_alloc (loop_p, gc, num_loops);
- if (ancestor != ENTRY_BLOCK_PTR
- && ancestor->loop_father != loop)
- {
- ancestor->loop_father = loop;
- ancestor->loop_depth = loop->depth;
- num_nodes++;
- stack[sp++] = ancestor;
- }
- }
- }
- free (stack);
- }
- return num_nodes;
+ /* Dummy loop containing whole function. */
+ root = alloc_loop ();
+ root->num_nodes = n_basic_blocks;
+ root->latch = EXIT_BLOCK_PTR;
+ root->header = ENTRY_BLOCK_PTR;
+ ENTRY_BLOCK_PTR->loop_father = root;
+ EXIT_BLOCK_PTR->loop_father = root;
+
+ VEC_quick_push (loop_p, loops->larray, root);
+ loops->tree_root = root;
}
-/* For each loop in the lOOPS tree that has just a single exit
- record the exit edge. */
+/* Find all the natural loops in the function and save in LOOPS structure and
+ recalculate loop_depth information in basic block structures.
+ Return the number of natural loops found. */
-void
-mark_single_exit_loops (struct loops *loops)
+int
+flow_loops_find (struct loops *loops)
{
- basic_block bb;
+ int b;
+ int num_loops;
edge e;
- struct loop *loop;
- unsigned i;
+ sbitmap headers;
+ int *dfs_order;
+ int *rc_order;
+ basic_block header;
+ basic_block bb;
+
+ /* Ensure that the dominators are computed. */
+ calculate_dominance_info (CDI_DOMINATORS);
- for (i = 1; i < loops->num; i++)
+ /* Taking care of this degenerate case makes the rest of
+ this code simpler. */
+ if (n_basic_blocks == NUM_FIXED_BLOCKS)
{
- loop = loops->parray[i];
- if (loop)
- loop->single_exit = NULL;
+ init_loops_structure (loops, 1);
+ return 1;
}
- FOR_EACH_BB (bb)
+ dfs_order = NULL;
+ rc_order = NULL;
+
+ /* Count the number of loop headers. This should be the
+ same as the number of natural loops. */
+ headers = sbitmap_alloc (last_basic_block);
+ sbitmap_zero (headers);
+
+ num_loops = 0;
+ FOR_EACH_BB (header)
{
- if (bb->loop_father == loops->tree_root)
+ edge_iterator ei;
+
+ header->loop_depth = 0;
+
+ /* If we have an abnormal predecessor, do not consider the
+ loop (not worth the problems). */
+ if (bb_has_abnormal_pred (header))
continue;
- for (e = bb->succ; e; e = e->succ_next)
+
+ FOR_EACH_EDGE (e, ei, header->preds)
{
- if (e->dest == EXIT_BLOCK_PTR)
- continue;
+ basic_block latch = e->src;
- if (flow_bb_inside_loop_p (bb->loop_father, e->dest))
- continue;
+ gcc_assert (!(e->flags & EDGE_ABNORMAL));
- for (loop = bb->loop_father;
- loop != e->dest->loop_father;
- loop = loop->outer)
+ /* Look for back edges where a predecessor is dominated
+ by this block. A natural loop has a single entry
+ node (header) that dominates all the nodes in the
+ loop. It also has single back edge to the header
+ from a latch node. */
+ if (latch != ENTRY_BLOCK_PTR
+ && dominated_by_p (CDI_DOMINATORS, latch, header))
{
- /* If we have already seen an exit, mark this by the edge that
- surely does not occur as any exit. */
- if (loop->single_exit)
- loop->single_exit = ENTRY_BLOCK_PTR->succ;
- else
- loop->single_exit = e;
+ /* Shared headers should be eliminated by now. */
+ SET_BIT (headers, header->index);
+ num_loops++;
}
}
}
- for (i = 1; i < loops->num; i++)
- {
- loop = loops->parray[i];
- if (!loop)
- continue;
-
- if (loop->single_exit == ENTRY_BLOCK_PTR->succ)
- loop->single_exit = NULL;
- }
+ /* Allocate loop structures. */
+ init_loops_structure (loops, num_loops + 1);
- loops->state |= LOOPS_HAVE_MARKED_SINGLE_EXITS;
-}
+ /* Find and record information about all the natural loops
+ in the CFG. */
+ FOR_EACH_BB (bb)
+ bb->loop_father = loops->tree_root;
-/* Find the root node of the loop pre-header extended basic block and
- the edges along the trace from the root node to the loop header. */
+ if (num_loops)
+ {
+ /* Compute depth first search order of the CFG so that outer
+ natural loops will be found before inner natural loops. */
+ dfs_order = XNEWVEC (int, n_basic_blocks);
+ rc_order = XNEWVEC (int, n_basic_blocks);
+ pre_and_rev_post_order_compute (dfs_order, rc_order, false);
-static void
-flow_loop_pre_header_scan (struct loop *loop)
-{
- int num;
- basic_block ebb;
- edge e;
+ num_loops = 1;
- loop->num_pre_header_edges = 0;
- if (loop->num_entries != 1)
- return;
+ for (b = 0; b < n_basic_blocks - NUM_FIXED_BLOCKS; b++)
+ {
+ struct loop *loop;
+ edge_iterator ei;
- ebb = loop->entry_edges[0]->src;
- if (ebb == ENTRY_BLOCK_PTR)
- return;
+ /* Search the nodes of the CFG in reverse completion order
+ so that we can find outer loops first. */
+ if (!TEST_BIT (headers, rc_order[b]))
+ continue;
- /* Count number of edges along trace from loop header to
- root of pre-header extended basic block. Usually this is
- only one or two edges. */
- for (num = 1; ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next;
- num++)
- ebb = ebb->pred->src;
-
- loop->pre_header_edges = xmalloc (num * sizeof (edge));
- loop->num_pre_header_edges = num;
-
- /* Store edges in order that they are followed. The source of the first edge
- is the root node of the pre-header extended basic block and the
- destination of the last last edge is the loop header. */
- for (e = loop->entry_edges[0]; num; e = e->src->pred)
- loop->pre_header_edges[--num] = e;
-}
+ header = BASIC_BLOCK (rc_order[b]);
-/* Return the block for the pre-header of the loop with header
- HEADER. Return NULL if there is no pre-header. */
+ loop = alloc_loop ();
+ VEC_quick_push (loop_p, loops->larray, loop);
-static basic_block
-flow_loop_pre_header_find (basic_block header)
-{
- basic_block pre_header;
- edge e;
+ loop->header = header;
+ loop->num = num_loops;
+ num_loops++;
- /* If block p is a predecessor of the header and is the only block
- that the header does not dominate, then it is the pre-header. */
- pre_header = NULL;
- for (e = header->pred; e; e = e->pred_next)
- {
- basic_block node = e->src;
+ flow_loop_tree_node_add (header->loop_father, loop);
+ loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
- if (node != ENTRY_BLOCK_PTR
- && ! dominated_by_p (CDI_DOMINATORS, node, header))
- {
- if (pre_header == NULL)
- pre_header = node;
- else
+ /* Look for the latch for this header block, if it has just a
+ single one. */
+ FOR_EACH_EDGE (e, ei, header->preds)
{
- /* There are multiple edges into the header from outside
- the loop so there is no pre-header block. */
- pre_header = NULL;
- break;
+ basic_block latch = e->src;
+
+ if (flow_bb_inside_loop_p (loop, latch))
+ {
+ if (loop->latch != NULL)
+ {
+ /* More than one latch edge. */
+ loop->latch = NULL;
+ break;
+ }
+ loop->latch = latch;
+ }
}
}
+
+ free (dfs_order);
+ free (rc_order);
}
- return pre_header;
+ sbitmap_free (headers);
+
+ loops->exits = NULL;
+ return VEC_length (loop_p, loops->larray);
}
-static void
-establish_preds (struct loop *loop)
-{
- struct loop *ploop, *father = loop->outer;
+/* Ratio of frequencies of edges so that one of more latch edges is
+ considered to belong to inner loop with same header. */
+#define HEAVY_EDGE_RATIO 8
- loop->depth = father->depth + 1;
- if (loop->pred)
- free (loop->pred);
- loop->pred = xmalloc (sizeof (struct loop *) * loop->depth);
- memcpy (loop->pred, father->pred, sizeof (struct loop *) * father->depth);
- loop->pred[father->depth] = father;
+/* Minimum number of samples for that we apply
+ find_subloop_latch_edge_by_profile heuristics. */
+#define HEAVY_EDGE_MIN_SAMPLES 10
- for (ploop = loop->inner; ploop; ploop = ploop->next)
- establish_preds (ploop);
-}
+/* If the profile info is available, finds an edge in LATCHES that much more
+ frequent than the remaining edges. Returns such an edge, or NULL if we do
+ not find one.
-/* Add LOOP to the loop hierarchy tree where FATHER is father of the
- added loop. If LOOP has some children, take care of that their
- pred field will be initialized correctly. */
+ We do not use guessed profile here, only the measured one. The guessed
+ profile is usually too flat and unreliable for this (and it is mostly based
+ on the loop structure of the program, so it does not make much sense to
+ derive the loop structure from it). */
-void
-flow_loop_tree_node_add (struct loop *father, struct loop *loop)
+static edge
+find_subloop_latch_edge_by_profile (VEC (edge, heap) *latches)
{
- loop->next = father->inner;
- father->inner = loop;
- loop->outer = father;
+ unsigned i;
+ edge e, me = NULL;
+ gcov_type mcount = 0, tcount = 0;
+
+ FOR_EACH_VEC_ELT (edge, latches, i, e)
+ {
+ if (e->count > mcount)
+ {
+ me = e;
+ mcount = e->count;
+ }
+ tcount += e->count;
+ }
- establish_preds (loop);
+ if (tcount < HEAVY_EDGE_MIN_SAMPLES
+ || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount)
+ return NULL;
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using profile information.\n",
+ me->src->index, me->dest->index);
+ return me;
}
-/* Remove LOOP from the loop hierarchy tree. */
+/* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based
+ on the structure of induction variables. Returns this edge, or NULL if we
+ do not find any.
-void
-flow_loop_tree_node_remove (struct loop *loop)
+ We are quite conservative, and look just for an obvious simple innermost
+ loop (which is the case where we would lose the most performance by not
+ disambiguating the loop). More precisely, we look for the following
+ situation: The source of the chosen latch edge dominates sources of all
+ the other latch edges. Additionally, the header does not contain a phi node
+ such that the argument from the chosen edge is equal to the argument from
+ another edge. */
+
+static edge
+find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, VEC (edge, heap) *latches)
{
- struct loop *prev, *father;
+ edge e, latch = VEC_index (edge, latches, 0);
+ unsigned i;
+ gimple phi;
+ gimple_stmt_iterator psi;
+ tree lop;
+ basic_block bb;
- father = loop->outer;
- loop->outer = NULL;
+ /* Find the candidate for the latch edge. */
+ for (i = 1; VEC_iterate (edge, latches, i, e); i++)
+ if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src))
+ latch = e;
- /* Remove loop from the list of sons. */
- if (father->inner == loop)
- father->inner = loop->next;
- else
+ /* Verify that it dominates all the latch edges. */
+ FOR_EACH_VEC_ELT (edge, latches, i, e)
+ if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src))
+ return NULL;
+
+ /* Check for a phi node that would deny that this is a latch edge of
+ a subloop. */
+ for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi))
{
- for (prev = father->inner; prev->next != loop; prev = prev->next);
- prev->next = loop->next;
+ phi = gsi_stmt (psi);
+ lop = PHI_ARG_DEF_FROM_EDGE (phi, latch);
+
+ /* Ignore the values that are not changed inside the subloop. */
+ if (TREE_CODE (lop) != SSA_NAME
+ || SSA_NAME_DEF_STMT (lop) == phi)
+ continue;
+ bb = gimple_bb (SSA_NAME_DEF_STMT (lop));
+ if (!bb || !flow_bb_inside_loop_p (loop, bb))
+ continue;
+
+ FOR_EACH_VEC_ELT (edge, latches, i, e)
+ if (e != latch
+ && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop)
+ return NULL;
}
- loop->depth = -1;
- free (loop->pred);
- loop->pred = NULL;
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using iv structure.\n",
+ latch->src->index, latch->dest->index);
+ return latch;
}
-/* Helper function to compute loop nesting depth and enclosed loop level
- for the natural loop specified by LOOP. Returns the loop level. */
+/* If we can determine that one of the several latch edges of LOOP behaves
+ as a latch edge of a separate subloop, returns this edge. Otherwise
+ returns NULL. */
-static int
-flow_loop_level_compute (struct loop *loop)
+static edge
+find_subloop_latch_edge (struct loop *loop)
{
- struct loop *inner;
- int level = 1;
-
- if (! loop)
- return 0;
+ VEC (edge, heap) *latches = get_loop_latch_edges (loop);
+ edge latch = NULL;
- /* Traverse loop tree assigning depth and computing level as the
- maximum level of all the inner loops of this loop. The loop
- level is equivalent to the height of the loop in the loop tree
- and corresponds to the number of enclosed loop levels (including
- itself). */
- for (inner = loop->inner; inner; inner = inner->next)
+ if (VEC_length (edge, latches) > 1)
{
- int ilevel = flow_loop_level_compute (inner) + 1;
-
- if (ilevel > level)
- level = ilevel;
+ latch = find_subloop_latch_edge_by_profile (latches);
+
+ if (!latch
+ /* We consider ivs to guess the latch edge only in SSA. Perhaps we
+ should use cfghook for this, but it is hard to imagine it would
+ be useful elsewhere. */
+ && current_ir_type () == IR_GIMPLE)
+ latch = find_subloop_latch_edge_by_ivs (loop, latches);
}
- loop->level = level;
- return level;
+ VEC_free (edge, heap, latches);
+ return latch;
}
-/* Compute the loop nesting depth and enclosed loop level for the loop
- hierarchy tree specified by LOOPS. Return the maximum enclosed loop
- level. */
+/* Callback for make_forwarder_block. Returns true if the edge E is marked
+ in the set MFB_REIS_SET. */
-static int
-flow_loops_level_compute (struct loops *loops)
+static struct pointer_set_t *mfb_reis_set;
+static bool
+mfb_redirect_edges_in_set (edge e)
{
- return flow_loop_level_compute (loops->tree_root);
+ return pointer_set_contains (mfb_reis_set, e);
}
-/* Scan a single natural loop specified by LOOP collecting information
- about it specified by FLAGS. */
+/* Creates a subloop of LOOP with latch edge LATCH. */
-int
-flow_loop_scan (struct loop *loop, int flags)
+static void
+form_subloop (struct loop *loop, edge latch)
{
- if (flags & LOOP_ENTRY_EDGES)
- {
- /* Find edges which enter the loop header.
- Note that the entry edges should only
- enter the header of a natural loop. */
- flow_loop_entry_edges_find (loop);
- }
+ edge_iterator ei;
+ edge e, new_entry;
+ struct loop *new_loop;
- if (flags & LOOP_EXIT_EDGES)
+ mfb_reis_set = pointer_set_create ();
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
{
- /* Find edges which exit the loop. */
- flow_loop_exit_edges_find (loop);
+ if (e != latch)
+ pointer_set_insert (mfb_reis_set, e);
}
+ new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set,
+ NULL);
+ pointer_set_destroy (mfb_reis_set);
+
+ loop->header = new_entry->src;
+
+ /* Find the blocks and subloops that belong to the new loop, and add it to
+ the appropriate place in the loop tree. */
+ new_loop = alloc_loop ();
+ new_loop->header = new_entry->dest;
+ new_loop->latch = latch->src;
+ add_loop (new_loop, loop);
+}
- if (flags & LOOP_PRE_HEADER)
- {
- /* Look to see if the loop has a pre-header node. */
- loop->pre_header = flow_loop_pre_header_find (loop->header);
+/* Make all the latch edges of LOOP to go to a single forwarder block --
+ a new latch of LOOP. */
- /* Find the blocks within the extended basic block of
- the loop pre-header. */
- flow_loop_pre_header_scan (loop);
+static void
+merge_latch_edges (struct loop *loop)
+{
+ VEC (edge, heap) *latches = get_loop_latch_edges (loop);
+ edge latch, e;
+ unsigned i;
+
+ gcc_assert (VEC_length (edge, latches) > 0);
+
+ if (VEC_length (edge, latches) == 1)
+ loop->latch = VEC_index (edge, latches, 0)->src;
+ else
+ {
+ if (dump_file)
+ fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num);
+
+ mfb_reis_set = pointer_set_create ();
+ FOR_EACH_VEC_ELT (edge, latches, i, e)
+ pointer_set_insert (mfb_reis_set, e);
+ latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set,
+ NULL);
+ pointer_set_destroy (mfb_reis_set);
+
+ loop->header = latch->dest;
+ loop->latch = latch->src;
}
- return 1;
+ VEC_free (edge, heap, latches);
}
-/* A callback to update latch and header info for basic block JUMP created
- by redirecting an edge. */
+/* LOOP may have several latch edges. Transform it into (possibly several)
+ loops with single latch edge. */
static void
-update_latch_info (basic_block jump)
+disambiguate_multiple_latches (struct loop *loop)
{
- alloc_aux_for_block (jump, sizeof (int));
- HEADER_BLOCK (jump) = 0;
- alloc_aux_for_edge (jump->pred, sizeof (int));
- LATCH_EDGE (jump->pred) = 0;
- set_immediate_dominator (CDI_DOMINATORS, jump, jump->pred->src);
+ edge e;
+
+ /* We eliminate the multiple latches by splitting the header to the forwarder
+ block F and the rest R, and redirecting the edges. There are two cases:
+
+ 1) If there is a latch edge E that corresponds to a subloop (we guess
+ that based on profile -- if it is taken much more often than the
+ remaining edges; and on trees, using the information about induction
+ variables of the loops), we redirect E to R, all the remaining edges to
+ F, then rescan the loops and try again for the outer loop.
+ 2) If there is no such edge, we redirect all latch edges to F, and the
+ entry edges to R, thus making F the single latch of the loop. */
+
+ if (dump_file)
+ fprintf (dump_file, "Disambiguating loop %d with multiple latches\n",
+ loop->num);
+
+ /* During latch merging, we may need to redirect the entry edges to a new
+ block. This would cause problems if the entry edge was the one from the
+ entry block. To avoid having to handle this case specially, split
+ such entry edge. */
+ e = find_edge (ENTRY_BLOCK_PTR, loop->header);
+ if (e)
+ split_edge (e);
+
+ while (1)
+ {
+ e = find_subloop_latch_edge (loop);
+ if (!e)
+ break;
+
+ form_subloop (loop, e);
+ }
+
+ merge_latch_edges (loop);
}
-/* 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. */
+/* Split loops with multiple latch edges. */
-static edge mfb_kj_edge;
-static bool
-mfb_keep_just (edge e)
+void
+disambiguate_loops_with_multiple_latches (void)
{
- return e != mfb_kj_edge;
+ loop_iterator li;
+ struct loop *loop;
+
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ if (!loop->latch)
+ disambiguate_multiple_latches (loop);
+ }
}
-/* A callback for make_forwarder block, to redirect the latch edges into an
- entry part. E is the edge for that we should decide whether to redirect
- it. */
+/* Return nonzero if basic block BB belongs to LOOP. */
+bool
+flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb)
+{
+ struct loop *source_loop;
+
+ if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR)
+ return 0;
+
+ source_loop = bb->loop_father;
+ return loop == source_loop || flow_loop_nested_p (loop, source_loop);
+}
+/* Enumeration predicate for get_loop_body_with_size. */
static bool
-mfb_keep_nonlatch (edge e)
+glb_enum_p (const_basic_block bb, const void *glb_loop)
{
- return LATCH_EDGE (e);
+ const struct loop *const loop = (const struct loop *) glb_loop;
+ return (bb != loop->header
+ && dominated_by_p (CDI_DOMINATORS, bb, loop->header));
}
-/* Takes care of merging natural loops with shared headers. */
+/* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs
+ order against direction of edges from latch. Specially, if
+ header != latch, latch is the 1-st block. LOOP cannot be the fake
+ loop tree root, and its size must be at most MAX_SIZE. The blocks
+ in the LOOP body are stored to BODY, and the size of the LOOP is
+ returned. */
-static void
-canonicalize_loop_headers (void)
+unsigned
+get_loop_body_with_size (const struct loop *loop, basic_block *body,
+ unsigned max_size)
{
- basic_block header;
- edge e;
+ return dfs_enumerate_from (loop->header, 1, glb_enum_p,
+ body, max_size, loop);
+}
- alloc_aux_for_blocks (sizeof (int));
- alloc_aux_for_edges (sizeof (int));
+/* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs
+ order against direction of edges from latch. Specially, if
+ header != latch, latch is the 1-st block. */
- /* Split blocks so that each loop has only single latch. */
- FOR_EACH_BB (header)
- {
- int num_latches = 0;
- int have_abnormal_edge = 0;
+basic_block *
+get_loop_body (const struct loop *loop)
+{
+ basic_block *body, bb;
+ unsigned tv = 0;
- for (e = header->pred; e; e = e->pred_next)
- {
- basic_block latch = e->src;
+ gcc_assert (loop->num_nodes);
- if (e->flags & EDGE_ABNORMAL)
- have_abnormal_edge = 1;
+ body = XCNEWVEC (basic_block, loop->num_nodes);
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (CDI_DOMINATORS, latch, header))
- {
- num_latches++;
- LATCH_EDGE (e) = 1;
- }
- }
- if (have_abnormal_edge)
- HEADER_BLOCK (header) = 0;
- else
- HEADER_BLOCK (header) = num_latches;
+ if (loop->latch == EXIT_BLOCK_PTR)
+ {
+ /* There may be blocks unreachable from EXIT_BLOCK, hence we need to
+ special-case the fake loop that contains the whole function. */
+ gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks);
+ body[tv++] = loop->header;
+ body[tv++] = EXIT_BLOCK_PTR;
+ FOR_EACH_BB (bb)
+ body[tv++] = bb;
}
+ else
+ tv = get_loop_body_with_size (loop, body, loop->num_nodes);
- if (HEADER_BLOCK (ENTRY_BLOCK_PTR->succ->dest))
- {
- basic_block bb;
+ gcc_assert (tv == loop->num_nodes);
+ return body;
+}
- /* We could not redirect edges freely here. On the other hand,
- we can simply split the edge from entry block. */
- bb = split_edge (ENTRY_BLOCK_PTR->succ);
+/* Fills dominance descendants inside LOOP of the basic block BB into
+ array TOVISIT from index *TV. */
- alloc_aux_for_edge (bb->succ, sizeof (int));
- LATCH_EDGE (bb->succ) = 0;
- alloc_aux_for_block (bb, sizeof (int));
- HEADER_BLOCK (bb) = 0;
- }
+static void
+fill_sons_in_loop (const struct loop *loop, basic_block bb,
+ basic_block *tovisit, int *tv)
+{
+ basic_block son, postpone = NULL;
- FOR_EACH_BB (header)
+ tovisit[(*tv)++] = bb;
+ for (son = first_dom_son (CDI_DOMINATORS, bb);
+ son;
+ son = next_dom_son (CDI_DOMINATORS, son))
{
- int max_freq, is_heavy;
- edge heavy, tmp_edge;
-
- if (HEADER_BLOCK (header) <= 1)
+ if (!flow_bb_inside_loop_p (loop, son))
continue;
- /* Find a heavy edge. */
- is_heavy = 1;
- heavy = NULL;
- max_freq = 0;
- for (e = header->pred; e; e = e->pred_next)
- if (LATCH_EDGE (e) &&
- EDGE_FREQUENCY (e) > max_freq)
- max_freq = EDGE_FREQUENCY (e);
- for (e = header->pred; e; e = e->pred_next)
- if (LATCH_EDGE (e) &&
- EDGE_FREQUENCY (e) >= max_freq / HEAVY_EDGE_RATIO)
- {
- if (heavy)
- {
- is_heavy = 0;
- break;
- }
- else
- heavy = e;
- }
-
- if (is_heavy)
- {
- /* Split out the heavy edge, and create inner loop for it. */
- mfb_kj_edge = heavy;
- tmp_edge = make_forwarder_block (header, mfb_keep_just,
- update_latch_info);
- alloc_aux_for_block (tmp_edge->dest, sizeof (int));
- HEADER_BLOCK (tmp_edge->dest) = 1;
- alloc_aux_for_edge (tmp_edge, sizeof (int));
- LATCH_EDGE (tmp_edge) = 0;
- HEADER_BLOCK (header)--;
- }
-
- if (HEADER_BLOCK (header) > 1)
+ if (dominated_by_p (CDI_DOMINATORS, loop->latch, son))
{
- /* Create a new latch block. */
- tmp_edge = make_forwarder_block (header, mfb_keep_nonlatch,
- update_latch_info);
- alloc_aux_for_block (tmp_edge->dest, sizeof (int));
- HEADER_BLOCK (tmp_edge->src) = 0;
- HEADER_BLOCK (tmp_edge->dest) = 1;
- alloc_aux_for_edge (tmp_edge, sizeof (int));
- LATCH_EDGE (tmp_edge) = 1;
+ postpone = son;
+ continue;
}
+ fill_sons_in_loop (loop, son, tovisit, tv);
}
- free_aux_for_blocks ();
- free_aux_for_edges ();
-
-#ifdef ENABLE_CHECKING
- verify_dominators (CDI_DOMINATORS);
-#endif
+ if (postpone)
+ fill_sons_in_loop (loop, postpone, tovisit, tv);
}
-/* Find all the natural loops in the function and save in LOOPS structure and
- recalculate loop_depth information in basic block structures. FLAGS
- controls which loop information is collected. Return the number of natural
- loops found. */
+/* Gets body of a LOOP (that must be different from the outermost loop)
+ sorted by dominance relation. Additionally, if a basic block s dominates
+ the latch, then only blocks dominated by s are be after it. */
-int
-flow_loops_find (struct loops *loops, int flags)
+basic_block *
+get_loop_body_in_dom_order (const struct loop *loop)
{
- int i;
- int b;
- int num_loops;
- edge e;
- sbitmap headers;
- int *dfs_order;
- int *rc_order;
- basic_block header;
- basic_block bb;
-
- /* This function cannot be repeatedly called with different
- flags to build up the loop information. The loop tree
- must always be built if this function is called. */
- if (! (flags & LOOP_TREE))
- abort ();
-
- memset (loops, 0, sizeof *loops);
-
- /* Taking care of this degenerate case makes the rest of
- this code simpler. */
- if (n_basic_blocks == 0)
- return 0;
-
- dfs_order = NULL;
- rc_order = NULL;
-
- /* Ensure that the dominators are computed. */
- calculate_dominance_info (CDI_DOMINATORS);
+ basic_block *tovisit;
+ int tv;
- /* Join loops with shared headers. */
- canonicalize_loop_headers ();
+ gcc_assert (loop->num_nodes);
- /* Count the number of loop headers. This should be the
- same as the number of natural loops. */
- headers = sbitmap_alloc (last_basic_block);
- sbitmap_zero (headers);
+ tovisit = XCNEWVEC (basic_block, loop->num_nodes);
- num_loops = 0;
- FOR_EACH_BB (header)
- {
- int more_latches = 0;
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
- header->loop_depth = 0;
-
- /* If we have an abnormal predecessor, do not consider the
- loop (not worth the problems). */
- for (e = header->pred; e; e = e->pred_next)
- if (e->flags & EDGE_ABNORMAL)
- break;
- if (e)
- continue;
-
- for (e = header->pred; e; e = e->pred_next)
- {
- basic_block latch = e->src;
+ tv = 0;
+ fill_sons_in_loop (loop, loop->header, tovisit, &tv);
- if (e->flags & EDGE_ABNORMAL)
- abort ();
+ gcc_assert (tv == (int) loop->num_nodes);
- /* Look for back edges where a predecessor is dominated
- by this block. A natural loop has a single entry
- node (header) that dominates all the nodes in the
- loop. It also has single back edge to the header
- from a latch node. */
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (CDI_DOMINATORS, latch, header))
- {
- /* Shared headers should be eliminated by now. */
- if (more_latches)
- abort ();
- more_latches = 1;
- SET_BIT (headers, header->index);
- num_loops++;
- }
- }
- }
-
- /* Allocate loop structures. */
- loops->parray = xcalloc (num_loops + 1, sizeof (struct loop *));
+ return tovisit;
+}
- /* Dummy loop containing whole function. */
- loops->parray[0] = xcalloc (1, sizeof (struct loop));
- loops->parray[0]->next = NULL;
- loops->parray[0]->inner = NULL;
- loops->parray[0]->outer = NULL;
- loops->parray[0]->depth = 0;
- loops->parray[0]->pred = NULL;
- loops->parray[0]->num_nodes = n_basic_blocks + 2;
- loops->parray[0]->latch = EXIT_BLOCK_PTR;
- loops->parray[0]->header = ENTRY_BLOCK_PTR;
- ENTRY_BLOCK_PTR->loop_father = loops->parray[0];
- EXIT_BLOCK_PTR->loop_father = loops->parray[0];
-
- loops->tree_root = loops->parray[0];
+/* Gets body of a LOOP sorted via provided BB_COMPARATOR. */
- /* Find and record information about all the natural loops
- in the CFG. */
- loops->num = 1;
- FOR_EACH_BB (bb)
- bb->loop_father = loops->tree_root;
+basic_block *
+get_loop_body_in_custom_order (const struct loop *loop,
+ int (*bb_comparator) (const void *, const void *))
+{
+ basic_block *bbs = get_loop_body (loop);
- if (num_loops)
- {
- /* Compute depth first search order of the CFG so that outer
- natural loops will be found before inner natural loops. */
- dfs_order = xmalloc (n_basic_blocks * sizeof (int));
- rc_order = xmalloc (n_basic_blocks * sizeof (int));
- flow_depth_first_order_compute (dfs_order, rc_order);
+ qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator);
- /* Save CFG derived information to avoid recomputing it. */
- loops->cfg.dfs_order = dfs_order;
- loops->cfg.rc_order = rc_order;
+ return bbs;
+}
- num_loops = 1;
+/* Get body of a LOOP in breadth first sort order. */
- for (b = 0; b < n_basic_blocks; b++)
- {
- struct loop *loop;
+basic_block *
+get_loop_body_in_bfs_order (const struct loop *loop)
+{
+ basic_block *blocks;
+ basic_block bb;
+ bitmap visited;
+ unsigned int i = 0;
+ unsigned int vc = 1;
- /* Search the nodes of the CFG in reverse completion order
- so that we can find outer loops first. */
- if (!TEST_BIT (headers, rc_order[b]))
- continue;
+ gcc_assert (loop->num_nodes);
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
- header = BASIC_BLOCK (rc_order[b]);
+ blocks = XCNEWVEC (basic_block, loop->num_nodes);
+ visited = BITMAP_ALLOC (NULL);
- loop = loops->parray[num_loops] = xcalloc (1, sizeof (struct loop));
+ bb = loop->header;
+ while (i < loop->num_nodes)
+ {
+ edge e;
+ edge_iterator ei;
- loop->header = header;
- loop->num = num_loops;
- num_loops++;
+ if (bitmap_set_bit (visited, bb->index))
+ /* This basic block is now visited */
+ blocks[i++] = bb;
- /* Look for the latch for this header block. */
- for (e = header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (flow_bb_inside_loop_p (loop, e->dest))
{
- basic_block latch = e->src;
-
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (CDI_DOMINATORS, latch, header))
- {
- loop->latch = latch;
- break;
- }
+ if (bitmap_set_bit (visited, e->dest->index))
+ blocks[i++] = e->dest;
}
-
- flow_loop_tree_node_add (header->loop_father, loop);
- loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
}
- /* Assign the loop nesting depth and enclosed loop level for each
- loop. */
- loops->levels = flow_loops_level_compute (loops);
+ gcc_assert (i >= vc);
- /* Scan the loops. */
- for (i = 1; i < num_loops; i++)
- flow_loop_scan (loops->parray[i], flags);
-
- loops->num = num_loops;
+ bb = blocks[vc++];
}
- sbitmap_free (headers);
+ BITMAP_FREE (visited);
+ return blocks;
+}
+
+/* Hash function for struct loop_exit. */
- loops->state = 0;
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
- verify_loop_structure (loops);
-#endif
+static hashval_t
+loop_exit_hash (const void *ex)
+{
+ const struct loop_exit *const exit = (const struct loop_exit *) ex;
- return loops->num;
+ return htab_hash_pointer (exit->e);
}
-/* Update the information regarding the loops in the CFG
- specified by LOOPS. */
+/* Equality function for struct loop_exit. Compares with edge. */
-int
-flow_loops_update (struct loops *loops, int flags)
+static int
+loop_exit_eq (const void *ex, const void *e)
{
- /* One day we may want to update the current loop data. For now
- throw away the old stuff and rebuild what we need. */
- if (loops->parray)
- flow_loops_free (loops);
+ const struct loop_exit *const exit = (const struct loop_exit *) ex;
- return flow_loops_find (loops, flags);
+ return exit->e == e;
}
-/* Return nonzero if basic block BB belongs to LOOP. */
-bool
-flow_bb_inside_loop_p (const struct loop *loop, const basic_block bb)
+/* Frees the list of loop exit descriptions EX. */
+
+static void
+loop_exit_free (void *ex)
{
- struct loop *source_loop;
+ struct loop_exit *exit = (struct loop_exit *) ex, *next;
- if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR)
- return 0;
+ for (; exit; exit = next)
+ {
+ next = exit->next_e;
- source_loop = bb->loop_father;
- return loop == source_loop || flow_loop_nested_p (loop, source_loop);
+ exit->next->prev = exit->prev;
+ exit->prev->next = exit->next;
+
+ ggc_free (exit);
+ }
}
-/* Return nonzero if edge E enters header of LOOP from outside of LOOP. */
+/* Returns the list of records for E as an exit of a loop. */
-bool
-flow_loop_outside_edge_p (const struct loop *loop, edge e)
+static struct loop_exit *
+get_exit_descriptions (edge e)
{
- if (e->dest != loop->header)
- abort ();
- return !flow_bb_inside_loop_p (loop, e->src);
+ return (struct loop_exit *) htab_find_with_hash (current_loops->exits, e,
+ htab_hash_pointer (e));
}
-/* Enumeration predicate for get_loop_body. */
-static bool
-glb_enum_p (basic_block bb, void *glb_header)
-{
- return bb != (basic_block) glb_header;
-}
+/* Updates the lists of loop exits in that E appears.
+ If REMOVED is true, E is being removed, and we
+ just remove it from the lists of exits.
+ If NEW_EDGE is true and E is not a loop exit, we
+ do not try to remove it from loop exit lists. */
-/* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs
- order against direction of edges from latch. Specially, if
- header != latch, latch is the 1-st block. */
-basic_block *
-get_loop_body (const struct loop *loop)
+void
+rescan_loop_exit (edge e, bool new_edge, bool removed)
{
- basic_block *tovisit, bb;
- unsigned tv = 0;
+ void **slot;
+ struct loop_exit *exits = NULL, *exit;
+ struct loop *aloop, *cloop;
- if (!loop->num_nodes)
- abort ();
-
- tovisit = xcalloc (loop->num_nodes, sizeof (basic_block));
- tovisit[tv++] = loop->header;
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ return;
- if (loop->latch == EXIT_BLOCK_PTR)
+ if (!removed
+ && e->src->loop_father != NULL
+ && e->dest->loop_father != NULL
+ && !flow_bb_inside_loop_p (e->src->loop_father, e->dest))
{
- /* There may be blocks unreachable from EXIT_BLOCK. */
- if (loop->num_nodes != (unsigned) n_basic_blocks + 2)
- abort ();
- FOR_EACH_BB (bb)
- tovisit[tv++] = bb;
- tovisit[tv++] = EXIT_BLOCK_PTR;
+ cloop = find_common_loop (e->src->loop_father, e->dest->loop_father);
+ for (aloop = e->src->loop_father;
+ aloop != cloop;
+ aloop = loop_outer (aloop))
+ {
+ exit = ggc_alloc_loop_exit ();
+ exit->e = e;
+
+ exit->next = aloop->exits->next;
+ exit->prev = aloop->exits;
+ exit->next->prev = exit;
+ exit->prev->next = exit;
+
+ exit->next_e = exits;
+ exits = exit;
+ }
}
- else if (loop->latch != loop->header)
+
+ if (!exits && new_edge)
+ return;
+
+ slot = htab_find_slot_with_hash (current_loops->exits, e,
+ htab_hash_pointer (e),
+ exits ? INSERT : NO_INSERT);
+ if (!slot)
+ return;
+
+ if (exits)
{
- tv = dfs_enumerate_from (loop->latch, 1, glb_enum_p,
- tovisit + 1, loop->num_nodes - 1,
- loop->header) + 1;
+ if (*slot)
+ loop_exit_free (*slot);
+ *slot = exits;
}
-
- if (tv != loop->num_nodes)
- abort ();
- return tovisit;
+ else
+ htab_clear_slot (current_loops->exits, slot);
}
-/* Fills dominance descendants inside LOOP of the basic block BB into
- array TOVISIT from index *TV. */
+/* For each loop, record list of exit edges, and start maintaining these
+ lists. */
-static void
-fill_sons_in_loop (const struct loop *loop, basic_block bb,
- basic_block *tovisit, int *tv)
+void
+record_loop_exits (void)
{
- basic_block son, postpone = NULL;
+ basic_block bb;
+ edge_iterator ei;
+ edge e;
- tovisit[(*tv)++] = bb;
- for (son = first_dom_son (CDI_DOMINATORS, bb);
- son;
- son = next_dom_son (CDI_DOMINATORS, son))
- {
- if (!flow_bb_inside_loop_p (loop, son))
- continue;
+ if (!current_loops)
+ return;
- if (dominated_by_p (CDI_DOMINATORS, loop->latch, son))
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ return;
+ loops_state_set (LOOPS_HAVE_RECORDED_EXITS);
+
+ gcc_assert (current_loops->exits == NULL);
+ current_loops->exits = htab_create_ggc (2 * number_of_loops (),
+ loop_exit_hash, loop_exit_eq,
+ loop_exit_free);
+
+ FOR_EACH_BB (bb)
+ {
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
- postpone = son;
- continue;
+ rescan_loop_exit (e, true, false);
}
- fill_sons_in_loop (loop, son, tovisit, tv);
}
-
- if (postpone)
- fill_sons_in_loop (loop, postpone, tovisit, tv);
}
-/* Gets body of a LOOP (that must be different from the outermost loop)
- sorted by dominance relation. Additionally, if a basic block s dominates
- the latch, then only blocks dominated by s are be after it. */
+/* Dumps information about the exit in *SLOT to FILE.
+ Callback for htab_traverse. */
-basic_block *
-get_loop_body_in_dom_order (const struct loop *loop)
+static int
+dump_recorded_exit (void **slot, void *file)
{
- basic_block *tovisit;
- int tv;
+ struct loop_exit *exit = (struct loop_exit *) *slot;
+ unsigned n = 0;
+ edge e = exit->e;
- if (!loop->num_nodes)
- abort ();
+ for (; exit != NULL; exit = exit->next_e)
+ n++;
- tovisit = xcalloc (loop->num_nodes, sizeof (basic_block));
+ fprintf ((FILE*) file, "Edge %d->%d exits %u loops\n",
+ e->src->index, e->dest->index, n);
- if (loop->latch == EXIT_BLOCK_PTR)
- abort ();
+ return 1;
+}
- tv = 0;
- fill_sons_in_loop (loop, loop->header, tovisit, &tv);
+/* Dumps the recorded exits of loops to FILE. */
+
+extern void dump_recorded_exits (FILE *);
+void
+dump_recorded_exits (FILE *file)
+{
+ if (!current_loops->exits)
+ return;
+ htab_traverse (current_loops->exits, dump_recorded_exit, file);
+}
- if (tv != (int) loop->num_nodes)
- abort ();
+/* Releases lists of loop exits. */
- return tovisit;
+void
+release_recorded_exits (void)
+{
+ gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS));
+ htab_delete (current_loops->exits);
+ current_loops->exits = NULL;
+ loops_state_clear (LOOPS_HAVE_RECORDED_EXITS);
}
-/* Gets exit edges of a LOOP, returning their number in N_EDGES. */
-edge *
-get_loop_exit_edges (const struct loop *loop, unsigned int *n_edges)
+/* Returns the list of the exit edges of a LOOP. */
+
+VEC (edge, heap) *
+get_loop_exit_edges (const struct loop *loop)
{
- edge *edges, e;
- unsigned i, n;
- basic_block * body;
+ VEC (edge, heap) *edges = NULL;
+ edge e;
+ unsigned i;
+ basic_block *body;
+ edge_iterator ei;
+ struct loop_exit *exit;
- if (loop->latch == EXIT_BLOCK_PTR)
- abort ();
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
- body = get_loop_body (loop);
- n = 0;
- 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))
- n++;
- edges = xmalloc (n * sizeof (edge));
- *n_edges = n;
- n = 0;
- 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))
- edges[n++] = e;
- free (body);
+ /* If we maintain the lists of exits, use them. Otherwise we must
+ scan the body of the loop. */
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ {
+ for (exit = loop->exits->next; exit->e; exit = exit->next)
+ VEC_safe_push (edge, heap, edges, exit->e);
+ }
+ else
+ {
+ body = get_loop_body (loop);
+ for (i = 0; i < loop->num_nodes; i++)
+ FOR_EACH_EDGE (e, ei, body[i]->succs)
+ {
+ if (!flow_bb_inside_loop_p (loop, e->dest))
+ VEC_safe_push (edge, heap, edges, e);
+ }
+ free (body);
+ }
return edges;
}
unsigned i, n;
basic_block * body;
- if (loop->latch == EXIT_BLOCK_PTR)
- abort ();
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
body = get_loop_body (loop);
n = 0;
for (i = 0; i < loop->num_nodes; i++)
- if (body[i]->succ && body[i]->succ->succ_next)
+ if (EDGE_COUNT (body[i]->succs) >= 2)
n++;
free (body);
void
add_bb_to_loop (basic_block bb, struct loop *loop)
{
- int i;
+ unsigned i;
+ loop_p ploop;
+ edge_iterator ei;
+ edge e;
- bb->loop_father = loop;
- bb->loop_depth = loop->depth;
- loop->num_nodes++;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->num_nodes++;
- }
+ gcc_assert (bb->loop_father == NULL);
+ bb->loop_father = loop;
+ bb->loop_depth = loop_depth (loop);
+ loop->num_nodes++;
+ FOR_EACH_VEC_ELT (loop_p, loop->superloops, i, ploop)
+ ploop->num_nodes++;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ rescan_loop_exit (e, true, false);
+ }
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ rescan_loop_exit (e, true, false);
+ }
+}
/* Remove basic block BB from loops. */
void
remove_bb_from_loops (basic_block bb)
{
- int i;
- struct loop *loop = bb->loop_father;
+ int i;
+ struct loop *loop = bb->loop_father;
+ loop_p ploop;
+ edge_iterator ei;
+ edge e;
- loop->num_nodes--;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->num_nodes--;
- bb->loop_father = NULL;
- bb->loop_depth = 0;
- }
+ gcc_assert (loop != NULL);
+ loop->num_nodes--;
+ FOR_EACH_VEC_ELT (loop_p, loop->superloops, i, ploop)
+ ploop->num_nodes--;
+ bb->loop_father = NULL;
+ bb->loop_depth = 0;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ rescan_loop_exit (e, false, true);
+ }
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ rescan_loop_exit (e, false, true);
+ }
+}
/* Finds nearest common ancestor in loop tree for given loops. */
struct loop *
find_common_loop (struct loop *loop_s, struct loop *loop_d)
{
+ unsigned sdepth, ddepth;
+
if (!loop_s) return loop_d;
if (!loop_d) return loop_s;
- if (loop_s->depth < loop_d->depth)
- loop_d = loop_d->pred[loop_s->depth];
- else if (loop_s->depth > loop_d->depth)
- loop_s = loop_s->pred[loop_d->depth];
+ sdepth = loop_depth (loop_s);
+ ddepth = loop_depth (loop_d);
+
+ if (sdepth < ddepth)
+ loop_d = VEC_index (loop_p, loop_d->superloops, sdepth);
+ else if (sdepth > ddepth)
+ loop_s = VEC_index (loop_p, loop_s->superloops, ddepth);
while (loop_s != loop_d)
{
- loop_s = loop_s->outer;
- loop_d = loop_d->outer;
+ loop_s = loop_outer (loop_s);
+ loop_d = loop_outer (loop_d);
}
return loop_s;
}
-/* Cancels the LOOP; it must be innermost one. */
+/* Removes LOOP from structures and frees its data. */
+
void
-cancel_loop (struct loops *loops, struct loop *loop)
+delete_loop (struct loop *loop)
+{
+ /* Remove the loop from structure. */
+ flow_loop_tree_node_remove (loop);
+
+ /* Remove loop from loops array. */
+ VEC_replace (loop_p, current_loops->larray, loop->num, NULL);
+
+ /* Free loop data. */
+ flow_loop_free (loop);
+}
+
+/* Cancels the LOOP; it must be innermost one. */
+
+static void
+cancel_loop (struct loop *loop)
{
basic_block *bbs;
unsigned i;
+ struct loop *outer = loop_outer (loop);
- if (loop->inner)
- abort ();
+ gcc_assert (!loop->inner);
/* Move blocks up one level (they should be removed as soon as possible). */
bbs = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++)
- bbs[i]->loop_father = loop->outer;
-
- /* Remove the loop from structure. */
- flow_loop_tree_node_remove (loop);
-
- /* Remove loop from loops array. */
- loops->parray[loop->num] = NULL;
+ bbs[i]->loop_father = outer;
- /* Free loop data. */
- flow_loop_free (loop);
+ free (bbs);
+ delete_loop (loop);
}
/* Cancels LOOP and all its subloops. */
void
-cancel_loop_tree (struct loops *loops, struct loop *loop)
+cancel_loop_tree (struct loop *loop)
{
while (loop->inner)
- cancel_loop_tree (loops, loop->inner);
- cancel_loop (loops, loop);
+ cancel_loop_tree (loop->inner);
+ cancel_loop (loop);
}
-/* Checks that LOOPS are all right:
+/* Checks that information about loops is correct
-- sizes of loops are all right
-- results of get_loop_body really belong to the loop
-- loop header have just single entry edge and single latch edge
-- loop latches have only single successor that is header of their loop
-- irreducible loops are correctly marked
*/
-void
-verify_loop_structure (struct loops *loops)
+DEBUG_FUNCTION void
+verify_loop_structure (void)
{
unsigned *sizes, i, j;
sbitmap irreds;
struct loop *loop;
int err = 0;
edge e;
+ unsigned num = number_of_loops ();
+ loop_iterator li;
+ struct loop_exit *exit, *mexit;
/* Check sizes. */
- sizes = xcalloc (loops->num, sizeof (int));
+ sizes = XCNEWVEC (unsigned, num);
sizes[0] = 2;
FOR_EACH_BB (bb)
- for (loop = bb->loop_father; loop; loop = loop->outer)
+ for (loop = bb->loop_father; loop; loop = loop_outer (loop))
sizes[loop->num]++;
- for (i = 0; i < loops->num; i++)
+ FOR_EACH_LOOP (li, loop, LI_INCLUDE_ROOT)
{
- if (!loops->parray[i])
- continue;
+ i = loop->num;
- if (loops->parray[i]->num_nodes != sizes[i])
+ if (loop->num_nodes != sizes[i])
{
- error ("Size of loop %d should be %d, not %d.",
- i, sizes[i], loops->parray[i]->num_nodes);
+ error ("size of loop %d should be %d, not %d",
+ i, sizes[i], loop->num_nodes);
err = 1;
}
}
/* Check get_loop_body. */
- for (i = 1; i < loops->num; i++)
+ FOR_EACH_LOOP (li, loop, 0)
{
- loop = loops->parray[i];
- if (!loop)
- continue;
bbs = get_loop_body (loop);
for (j = 0; j < loop->num_nodes; j++)
if (!flow_bb_inside_loop_p (loop, bbs[j]))
{
- error ("Bb %d do not belong to loop %d.",
- bbs[j]->index, i);
+ error ("bb %d do not belong to loop %d",
+ bbs[j]->index, loop->num);
err = 1;
}
free (bbs);
}
/* Check headers and latches. */
- for (i = 1; i < loops->num; i++)
+ FOR_EACH_LOOP (li, loop, 0)
{
- loop = loops->parray[i];
- if (!loop)
- continue;
+ i = loop->num;
- if ((loops->state & LOOPS_HAVE_PREHEADERS)
- && (!loop->header->pred->pred_next
- || loop->header->pred->pred_next->pred_next))
+ if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)
+ && EDGE_COUNT (loop->header->preds) != 2)
{
- error ("Loop %d's header does not have exactly 2 entries.", i);
+ error ("loop %d%'s header does not have exactly 2 entries", i);
err = 1;
}
- if (loops->state & LOOPS_HAVE_SIMPLE_LATCHES)
+ if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
{
- if (!loop->latch->succ
- || loop->latch->succ->succ_next)
+ if (!single_succ_p (loop->latch))
{
- error ("Loop %d's latch does not have exactly 1 successor.", i);
+ error ("loop %d%'s latch does not have exactly 1 successor", i);
err = 1;
}
- if (loop->latch->succ->dest != loop->header)
+ if (single_succ (loop->latch) != loop->header)
{
- error ("Loop %d's latch does not have header as successor.", i);
+ error ("loop %d%'s latch does not have header as successor", i);
err = 1;
}
if (loop->latch->loop_father != loop)
{
- error ("Loop %d's latch does not belong directly to it.", i);
+ error ("loop %d%'s latch does not belong directly to it", i);
err = 1;
}
}
if (loop->header->loop_father != loop)
{
- error ("Loop %d's header does not belong directly to it.", i);
+ error ("loop %d%'s header does not belong directly to it", i);
err = 1;
}
- if ((loops->state & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
&& (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP))
{
- error ("Loop %d's latch is marked as part of irreducible region.", i);
+ error ("loop %d%'s latch is marked as part of irreducible region", i);
err = 1;
}
}
/* Check irreducible loops. */
- if (loops->state & LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS))
{
/* Record old info. */
irreds = sbitmap_alloc (last_basic_block);
FOR_EACH_BB (bb)
{
+ edge_iterator ei;
if (bb->flags & BB_IRREDUCIBLE_LOOP)
SET_BIT (irreds, bb->index);
else
RESET_BIT (irreds, bb->index);
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags & EDGE_IRREDUCIBLE_LOOP)
e->flags |= EDGE_ALL_FLAGS + 1;
}
/* Recount it. */
- mark_irreducible_loops (loops);
+ mark_irreducible_loops ();
/* Compare. */
FOR_EACH_BB (bb)
{
+ edge_iterator ei;
+
if ((bb->flags & BB_IRREDUCIBLE_LOOP)
&& !TEST_BIT (irreds, bb->index))
{
- error ("Basic block %d should be marked irreducible.", bb->index);
+ error ("basic block %d should be marked irreducible", bb->index);
err = 1;
}
else if (!(bb->flags & BB_IRREDUCIBLE_LOOP)
&& TEST_BIT (irreds, bb->index))
{
- error ("Basic block %d should not be marked irreducible.", bb->index);
+ error ("basic block %d should not be marked irreducible", bb->index);
err = 1;
}
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
if ((e->flags & EDGE_IRREDUCIBLE_LOOP)
&& !(e->flags & (EDGE_ALL_FLAGS + 1)))
{
- error ("Edge from %d to %d should be marked irreducible.",
+ error ("edge from %d to %d should be marked irreducible",
e->src->index, e->dest->index);
err = 1;
}
else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP)
&& (e->flags & (EDGE_ALL_FLAGS + 1)))
{
- error ("Edge from %d to %d should not be marked irreducible.",
+ error ("edge from %d to %d should not be marked irreducible",
e->src->index, e->dest->index);
err = 1;
}
free (irreds);
}
- /* Check the single_exit. */
- if (loops->state & LOOPS_HAVE_MARKED_SINGLE_EXITS)
+ /* Check the recorded loop exits. */
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ if (!loop->exits || loop->exits->e != NULL)
+ {
+ error ("corrupted head of the exits list of loop %d",
+ loop->num);
+ err = 1;
+ }
+ else
+ {
+ /* Check that the list forms a cycle, and all elements except
+ for the head are nonnull. */
+ for (mexit = loop->exits, exit = mexit->next, i = 0;
+ exit->e && exit != mexit;
+ exit = exit->next)
+ {
+ if (i++ & 1)
+ mexit = mexit->next;
+ }
+
+ if (exit != loop->exits)
+ {
+ error ("corrupted exits list of loop %d", loop->num);
+ err = 1;
+ }
+ }
+
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ {
+ if (loop->exits->next != loop->exits)
+ {
+ error ("nonempty exits list of loop %d, but exits are not recorded",
+ loop->num);
+ err = 1;
+ }
+ }
+ }
+
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
{
- memset (sizes, 0, sizeof (unsigned) * loops->num);
+ unsigned n_exits = 0, eloops;
+
+ memset (sizes, 0, sizeof (unsigned) * num);
FOR_EACH_BB (bb)
{
- if (bb->loop_father == loops->tree_root)
+ edge_iterator ei;
+ if (bb->loop_father == current_loops->tree_root)
continue;
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
- if (e->dest == EXIT_BLOCK_PTR)
- continue;
-
if (flow_bb_inside_loop_p (bb->loop_father, e->dest))
continue;
+ n_exits++;
+ exit = get_exit_descriptions (e);
+ if (!exit)
+ {
+ error ("exit %d->%d not recorded",
+ e->src->index, e->dest->index);
+ err = 1;
+ }
+ eloops = 0;
+ for (; exit; exit = exit->next_e)
+ eloops++;
+
for (loop = bb->loop_father;
loop != e->dest->loop_father;
- loop = loop->outer)
+ loop = loop_outer (loop))
{
+ eloops--;
sizes[loop->num]++;
- if (loop->single_exit
- && loop->single_exit != e)
- {
- error ("Wrong single exit %d->%d recorded for loop %d.",
- loop->single_exit->src->index,
- loop->single_exit->dest->index,
- loop->num);
- error ("Right exit is %d->%d.",
- e->src->index, e->dest->index);
- err = 1;
- }
+ }
+
+ if (eloops != 0)
+ {
+ error ("wrong list of exited loops for edge %d->%d",
+ e->src->index, e->dest->index);
+ err = 1;
}
}
}
- for (i = 1; i < loops->num; i++)
+ if (n_exits != htab_elements (current_loops->exits))
{
- loop = loops->parray[i];
- if (!loop)
- continue;
-
- if (sizes[i] == 1
- && !loop->single_exit)
- {
- error ("Single exit not recorded for loop %d.", loop->num);
- err = 1;
- }
+ error ("too many loop exits recorded");
+ err = 1;
+ }
- if (sizes[i] != 1
- && loop->single_exit)
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ eloops = 0;
+ for (exit = loop->exits->next; exit->e; exit = exit->next)
+ eloops++;
+ if (eloops != sizes[loop->num])
{
- error ("Loop %d should not have single exit (%d -> %d).",
- loop->num,
- loop->single_exit->src->index,
- loop->single_exit->dest->index);
+ error ("%d exits recorded for loop %d (having %d exits)",
+ eloops, loop->num, sizes[loop->num]);
err = 1;
}
}
}
- if (err)
- abort ();
+ gcc_assert (!err);
free (sizes);
}
edge
loop_latch_edge (const struct loop *loop)
{
+ return find_edge (loop->latch, loop->header);
+}
+
+/* Returns preheader edge of LOOP. */
+edge
+loop_preheader_edge (const struct loop *loop)
+{
edge e;
+ edge_iterator ei;
- for (e = loop->header->pred; e->src != loop->latch; e = e->pred_next)
- continue;
+ gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS));
+
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ if (e->src != loop->latch)
+ break;
return e;
}
-/* Returns preheader edge of LOOP. */
+/* Returns true if E is an exit of LOOP. */
+
+bool
+loop_exit_edge_p (const struct loop *loop, const_edge e)
+{
+ return (flow_bb_inside_loop_p (loop, e->src)
+ && !flow_bb_inside_loop_p (loop, e->dest));
+}
+
+/* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit
+ or more than one exit. If loops do not have the exits recorded, NULL
+ is returned always. */
+
edge
-loop_preheader_edge (const struct loop *loop)
+single_exit (const struct loop *loop)
+{
+ struct loop_exit *exit = loop->exits->next;
+
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ return NULL;
+
+ if (exit->e && exit->next == loop->exits)
+ return exit->e;
+ else
+ return NULL;
+}
+
+/* Returns true when BB has an incoming edge exiting LOOP. */
+
+bool
+loop_exits_to_bb_p (struct loop *loop, basic_block bb)
{
edge e;
+ edge_iterator ei;
- for (e = loop->header->pred; e->src == loop->latch; e = e->pred_next)
- continue;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (loop_exit_edge_p (loop, e))
+ return true;
- return e;
+ return false;
+}
+
+/* Returns true when BB has an outgoing edge exiting LOOP. */
+
+bool
+loop_exits_from_bb_p (struct loop *loop, basic_block bb)
+{
+ edge e;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (loop_exit_edge_p (loop, e))
+ return true;
+
+ return false;
}