/* Natural loop discovery code for GNU compiler.
- Copyright (C) 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
#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"
#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 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 *);
fprintf (file, ";;\n;; Loop %d:%s\n", loop->num,
loop->invalid ? " invalid" : "");
- 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, ";; header %d, latch %d\n",
+ loop->header->index, loop->latch->index);
fprintf (file, ";; depth %d, level %d, outer %ld\n",
loop->depth, loop->level,
(long) (loop->outer ? loop->outer->num : -1));
- if (loop->pre_header_edges)
- flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
- loop->num_pre_header_edges, file);
-
- 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);
if (! num_loops || ! file)
return;
- fprintf (file, ";; %d loops found, %d levels\n",
- num_loops, loops->levels);
+ fprintf (file, ";; %d loops found\n", num_loops);
for (i = 0; i < num_loops; i++)
{
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);
}
}
-/* Find the entry edges into the LOOP. */
-
-static void
-flow_loop_entry_edges_find (struct loop *loop)
-{
- edge e;
- edge_iterator ei;
- int num_entries;
-
- num_entries = 0;
- FOR_EACH_EDGE (e, ei, loop->header->preds)
- {
- if (flow_loop_outside_edge_p (loop, e))
- num_entries++;
- }
-
- gcc_assert (num_entries);
-
- loop->entry_edges = xmalloc (num_entries * sizeof (edge *));
-
- num_entries = 0;
- FOR_EACH_EDGE (e, ei, loop->header->preds)
- {
- if (flow_loop_outside_edge_p (loop, e))
- loop->entry_edges[num_entries++] = e;
- }
-
- loop->num_entries = num_entries;
-}
-
-/* Find the exit edges from the LOOP. */
-
-static void
-flow_loop_exit_edges_find (struct loop *loop)
-{
- edge e;
- basic_block node, *bbs;
- unsigned num_exits, i;
-
- loop->exit_edges = NULL;
- loop->num_exits = 0;
-
- /* 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++)
- {
- edge_iterator ei;
- node = bbs[i];
- FOR_EACH_EDGE (e, ei, node->succs)
- {
- basic_block dest = e->dest;
-
- if (!flow_bb_inside_loop_p (loop, dest))
- num_exits++;
- }
- }
-
- if (! num_exits)
- {
- free (bbs);
- return;
- }
-
- loop->exit_edges = xmalloc (num_exits * sizeof (edge *));
-
- /* Store all exiting edges into an array. */
- num_exits = 0;
- for (i = 0; i < loop->num_nodes; i++)
- {
- edge_iterator ei;
- node = bbs[i];
- FOR_EACH_EDGE (e, ei, node->succs)
- {
- basic_block dest = e->dest;
-
- if (!flow_bb_inside_loop_p (loop, dest))
- {
- e->flags |= EDGE_LOOP_EXIT;
- loop->exit_edges[num_exits++] = e;
- }
- }
- }
- free (bbs);
- loop->num_exits = num_exits;
-}
-
/* Find the nodes contained within the LOOP with header HEADER.
Return the number of nodes within the loop. */
-static int
+int
flow_loop_nodes_find (basic_block header, struct loop *loop)
{
basic_block *stack;
/* 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 = EDGE_SUCC (ENTRY_BLOCK_PTR, 0);
+ loop->single_exit = single_succ_edge (ENTRY_BLOCK_PTR);
else
loop->single_exit = e;
}
if (!loop)
continue;
- if (loop->single_exit == EDGE_SUCC (ENTRY_BLOCK_PTR, 0))
+ if (loop->single_exit == single_succ_edge (ENTRY_BLOCK_PTR))
loop->single_exit = NULL;
}
loops->state |= LOOPS_HAVE_MARKED_SINGLE_EXITS;
}
-/* 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. */
-
-static void
-flow_loop_pre_header_scan (struct loop *loop)
-{
- int num;
- basic_block ebb;
- edge e;
-
- loop->num_pre_header_edges = 0;
- if (loop->num_entries != 1)
- return;
-
- ebb = loop->entry_edges[0]->src;
- if (ebb == ENTRY_BLOCK_PTR)
- return;
-
- /* 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;
- EDGE_PRED (ebb, 0)->src != ENTRY_BLOCK_PTR && EDGE_COUNT (ebb->preds) == 1;
- num++)
- ebb = EDGE_PRED (ebb, 0)->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 = EDGE_PRED (e->src, 0))
- loop->pre_header_edges[--num] = e;
-}
-
-/* Return the block for the pre-header of the loop with header
- HEADER. Return NULL if there is no pre-header. */
-
-static basic_block
-flow_loop_pre_header_find (basic_block header)
-{
- basic_block pre_header;
- edge e;
- edge_iterator ei;
-
- /* 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_EACH_EDGE (e, ei, header->preds)
- {
- basic_block node = e->src;
-
- if (node != ENTRY_BLOCK_PTR
- && ! dominated_by_p (CDI_DOMINATORS, node, header))
- {
- if (pre_header == NULL)
- pre_header = node;
- else
- {
- /* There are multiple edges into the header from outside
- the loop so there is no pre-header block. */
- pre_header = NULL;
- break;
- }
- }
- }
-
- return pre_header;
-}
-
static void
establish_preds (struct loop *loop)
{
struct loop *ploop, *father = loop->outer;
loop->depth = father->depth + 1;
+
+ /* Remember the current loop depth if it is the largest seen so far. */
+ cfun->max_loop_depth = MAX (cfun->max_loop_depth, loop->depth);
+
if (loop->pred)
free (loop->pred);
loop->pred = xmalloc (sizeof (struct loop *) * loop->depth);
hierarchy tree specified by LOOPS. Return the maximum enclosed loop
level. */
-static int
+static void
flow_loops_level_compute (struct loops *loops)
{
- return flow_loop_level_compute (loops->tree_root);
-}
-
-/* Scan a single natural loop specified by LOOP collecting information
- about it specified by FLAGS. */
-
-int
-flow_loop_scan (struct loop *loop, int flags)
-{
- 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);
- }
-
- if (flags & LOOP_EXIT_EDGES)
- {
- /* Find edges which exit the loop. */
- flow_loop_exit_edges_find (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);
-
- /* Find the blocks within the extended basic block of
- the loop pre-header. */
- flow_loop_pre_header_scan (loop);
- }
-
- return 1;
+ flow_loop_level_compute (loops->tree_root);
}
/* A callback to update latch and header info for basic block JUMP created
{
alloc_aux_for_block (jump, sizeof (int));
HEADER_BLOCK (jump) = 0;
- alloc_aux_for_edge (EDGE_PRED (jump, 0), sizeof (int));
- LATCH_EDGE (EDGE_PRED (jump, 0)) = 0;
- set_immediate_dominator (CDI_DOMINATORS, jump, EDGE_PRED (jump, 0)->src);
+ alloc_aux_for_edge (single_pred_edge (jump), sizeof (int));
+ LATCH_EDGE (single_pred_edge (jump)) = 0;
+ set_immediate_dominator (CDI_DOMINATORS, jump, single_pred (jump));
}
/* A callback for make_forwarder block, to redirect all edges except for
HEADER_BLOCK (header) = num_latches;
}
- if (HEADER_BLOCK (EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest))
+ if (HEADER_BLOCK (single_succ (ENTRY_BLOCK_PTR)))
{
basic_block bb;
/* We could not redirect edges freely here. On the other hand,
we can simply split the edge from entry block. */
- bb = split_edge (EDGE_SUCC (ENTRY_BLOCK_PTR, 0));
+ bb = split_edge (single_succ_edge (ENTRY_BLOCK_PTR));
- alloc_aux_for_edge (EDGE_SUCC (bb, 0), sizeof (int));
- LATCH_EDGE (EDGE_SUCC (bb, 0)) = 0;
+ alloc_aux_for_edge (single_succ_edge (bb), sizeof (int));
+ LATCH_EDGE (single_succ_edge (bb)) = 0;
alloc_aux_for_block (bb, sizeof (int));
HEADER_BLOCK (bb) = 0;
}
#endif
}
+/* Initialize all the parallel_p fields of the loops structure to true. */
+
+static void
+initialize_loops_parallel_p (struct loops *loops)
+{
+ unsigned int i;
+
+ for (i = 0; i < loops->num; i++)
+ {
+ struct loop *loop = loops->parray[i];
+ loop->parallel_p = true;
+ }
+}
+
/* 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. */
+ recalculate loop_depth information in basic block structures.
+ Return the number of natural loops found. */
int
-flow_loops_find (struct loops *loops, int flags)
+flow_loops_find (struct loops *loops)
{
- int i;
int b;
int num_loops;
edge e;
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. */
- gcc_assert (flags & LOOP_TREE);
-
memset (loops, 0, sizeof *loops);
+ /* We are going to recount the maximum loop depth,
+ so throw away the last count. */
+ cfun->max_loop_depth = 0;
+
/* Taking care of this degenerate case makes the rest of
this code simpler. */
if (n_basic_blocks == 0)
/* Assign the loop nesting depth and enclosed loop level for each
loop. */
- loops->levels = flow_loops_level_compute (loops);
-
- /* Scan the loops. */
- for (i = 1; i < num_loops; i++)
- flow_loop_scan (loops->parray[i], flags);
+ flow_loops_level_compute (loops);
loops->num = num_loops;
+ initialize_loops_parallel_p (loops);
}
sbitmap_free (headers);
return loops->num;
}
-/* Update the information regarding the loops in the CFG
- specified by LOOPS. */
-
-int
-flow_loops_update (struct loops *loops, int flags)
-{
- /* 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);
-
- return flow_loops_find (loops, flags);
-}
-
/* Return nonzero if basic block BB belongs to LOOP. */
bool
flow_bb_inside_loop_p (const struct loop *loop, const basic_block bb)
gcc_assert (loop->latch != EXIT_BLOCK_PTR);
blocks = xcalloc (loop->num_nodes, sizeof (basic_block));
- visited = BITMAP_XMALLOC ();
+ visited = BITMAP_ALLOC (NULL);
bb = loop->header;
while (i < loop->num_nodes)
bb = blocks[vc++];
}
- BITMAP_XFREE (visited);
+ BITMAP_FREE (visited);
return blocks;
}
/* 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)
+get_loop_exit_edges (const struct loop *loop, unsigned int *num_edges)
{
edge *edges, e;
unsigned i, n;
if (!flow_bb_inside_loop_p (loop, e->dest))
n++;
edges = xmalloc (n * sizeof (edge));
- *n_edges = n;
+ *num_edges = n;
n = 0;
for (i = 0; i < loop->num_nodes; i++)
FOR_EACH_EDGE (e, ei, body[i]->succs)
loop->pred[i]->num_nodes--;
bb->loop_father = NULL;
bb->loop_depth = 0;
- }
+}
/* Finds nearest common ancestor in loop tree for given loops. */
struct loop *
}
if (loops->state & LOOPS_HAVE_SIMPLE_LATCHES)
{
- if (EDGE_COUNT (loop->latch->succs) != 1)
+ if (!single_succ_p (loop->latch))
{
error ("Loop %d's latch does not have exactly 1 successor.", i);
err = 1;
}
- if (EDGE_SUCC (loop->latch, 0)->dest != loop->header)
+ if (single_succ (loop->latch) != loop->header)
{
error ("Loop %d's latch does not have header as successor.", i);
err = 1;
edge
loop_latch_edge (const struct loop *loop)
{
- edge e;
- edge_iterator ei;
-
- FOR_EACH_EDGE (e, ei, loop->header->preds)
- if (e->src == loop->latch)
- break;
-
- return e;
+ return find_edge (loop->latch, loop->header);
}
/* Returns preheader edge of LOOP. */
return e;
}
+
+/* Returns true if E is an exit of LOOP. */
+
+bool
+loop_exit_edge_p (const struct loop *loop, edge e)
+{
+ return (flow_bb_inside_loop_p (loop, e->src)
+ && !flow_bb_inside_loop_p (loop, e->dest));
+}
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