/* Natural loop discovery code for GNU compiler.
- Copyright (C) 2000, 2001 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"
+#include "flags.h"
+#include "tree.h"
+#include "tree-flow.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
-static void flow_loops_cfg_dump PARAMS ((const struct loops *,
- FILE *));
-static void flow_loop_entry_edges_find PARAMS ((struct loop *));
-static void flow_loop_exit_edges_find PARAMS ((struct loop *));
-static int flow_loop_nodes_find PARAMS ((basic_block, struct loop *));
-static void flow_loop_pre_header_scan PARAMS ((struct loop *));
-static basic_block flow_loop_pre_header_find PARAMS ((basic_block,
- dominance_info));
-static int flow_loop_level_compute PARAMS ((struct loop *));
-static int flow_loops_level_compute PARAMS ((struct loops *));
-static basic_block make_forwarder_block PARAMS ((basic_block, int, int,
- edge, int));
-static void canonicalize_loop_headers PARAMS ((void));
-static bool glb_enum_p PARAMS ((basic_block, void *));
-static void redirect_edge_with_latch_update PARAMS ((edge, basic_block));
-static void flow_loop_free PARAMS ((struct loop *));
+#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 int flow_loop_nodes_find (basic_block, struct loop *);
+static int flow_loop_level_compute (struct loop *);
+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 *);
\f
/* Dump loop related CFG information. */
static void
-flow_loops_cfg_dump (loops, file)
- const struct loops *loops;
- FILE *file;
+flow_loops_cfg_dump (const struct loops *loops, FILE *file)
{
int i;
basic_block bb;
- if (! loops->num || ! file || ! loops->cfg.dom)
+ if (! loops->num || ! 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");
}
/* Return nonzero if the nodes of LOOP are a subset of OUTER. */
bool
-flow_loop_nested_p (outer, loop)
- const struct loop *outer;
- const struct loop *loop;
+flow_loop_nested_p (const struct loop *outer, const struct loop *loop)
{
- return loop->depth > outer->depth
- && loop->pred[outer->depth] == outer;
+ return (loop->depth > outer->depth
+ && loop->pred[outer->depth] == outer);
+}
+
+/* Returns the loop such that LOOP is nested DEPTH (indexed from zero)
+ loops within LOOP. */
+
+struct loop *
+superloop_at_depth (struct loop *loop, unsigned depth)
+{
+ gcc_assert (depth <= (unsigned) loop->depth);
+
+ if (depth == (unsigned) loop->depth)
+ return loop;
+
+ return loop->pred[depth];
}
/* Dump the loop information specified by LOOP to the stream FILE
using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
void
-flow_loop_dump (loop, file, loop_dump_aux, verbose)
- const struct loop *loop;
- FILE *file;
- void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
- int verbose;
+flow_loop_dump (const struct loop *loop, FILE *file,
+ void (*loop_dump_aux) (const struct loop *, FILE *, int),
+ int verbose)
{
basic_block *bbs;
- int i;
+ unsigned i;
if (! loop || ! loop->header)
return;
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);
using auxiliary dump callback function LOOP_DUMP_AUX if non null. */
void
-flow_loops_dump (loops, file, loop_dump_aux, verbose)
- const struct loops *loops;
- FILE *file;
- void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
- int verbose;
+flow_loops_dump (const struct loops *loops, FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose)
{
int i;
int num_loops;
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++)
{
}
/* Free data allocated for LOOP. */
-static void
-flow_loop_free (loop)
- struct loop *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);
/* Free all the memory allocated for LOOPS. */
void
-flow_loops_free (loops)
- struct loops *loops;
+flow_loops_free (struct loops *loops)
{
if (loops->parray)
{
- int i;
+ unsigned i;
- if (! loops->num)
- abort ();
+ gcc_assert (loops->num);
/* Free the loop descriptors. */
for (i = 0; i < loops->num; i++)
free (loops->parray);
loops->parray = NULL;
- if (loops->cfg.dom)
- free_dominance_info (loops->cfg.dom);
-
if (loops->cfg.dfs_order)
free (loops->cfg.dfs_order);
if (loops->cfg.rc_order)
}
}
-/* Find the entry edges into the LOOP. */
-
-static void
-flow_loop_entry_edges_find (loop)
- struct loop *loop;
-{
- edge e;
- int num_entries;
-
- num_entries = 0;
- for (e = loop->header->pred; e; e = e->pred_next)
- {
- if (flow_loop_outside_edge_p (loop, e))
- num_entries++;
- }
-
- if (! num_entries)
- abort ();
-
- loop->entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
-
- 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;
- }
-
- loop->num_entries = num_entries;
-}
-
-/* Find the exit edges from the LOOP. */
-
-static void
-flow_loop_exit_edges_find (loop)
- struct loop *loop;
-{
- edge e;
- basic_block node, *bbs;
- int 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++)
- {
- node = bbs[i];
- for (e = node->succ; e; e = e->succ_next)
- {
- basic_block dest = e->dest;
-
- if (!flow_bb_inside_loop_p (loop, dest))
- num_exits++;
- }
- }
-
- if (! num_exits)
- {
- free (bbs);
- return;
- }
-
- loop->exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
-
- /* 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;
-
- if (!flow_bb_inside_loop_p (loop, dest))
- 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
-flow_loop_nodes_find (header, loop)
- basic_block header;
- struct loop *loop;
+flow_loop_nodes_find (basic_block header, struct loop *loop)
{
basic_block *stack;
int sp;
if (loop->latch->loop_father != loop)
{
- stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
+ 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;
-
+
while (sp)
{
basic_block node;
edge e;
+ edge_iterator ei;
node = stack[--sp];
-
- for (e = node->pred; e; e = e->pred_next)
+
+ FOR_EACH_EDGE (e, ei, node->preds)
{
basic_block ancestor = e->src;
return num_nodes;
}
-/* 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 (loop)
- 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; ebb->pred->src != ENTRY_BLOCK_PTR && ! ebb->pred->pred_next;
- num++)
- ebb = ebb->pred->src;
-
- loop->pre_header_edges = (edge *) 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;
-}
-
-/* Return the block for the pre-header of the loop with header
- HEADER where DOM specifies the dominator information. Return NULL if
- there is no pre-header. */
+/* For each loop in the lOOPS tree that has just a single exit
+ record the exit edge. */
-static basic_block
-flow_loop_pre_header_find (header, dom)
- basic_block header;
- dominance_info dom;
+void
+mark_single_exit_loops (struct loops *loops)
{
- basic_block pre_header;
+ basic_block bb;
edge e;
+ struct loop *loop;
+ unsigned i;
- /* 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)
+ for (i = 1; i < loops->num; i++)
{
- basic_block node = e->src;
+ loop = loops->parray[i];
+ if (loop)
+ loop->single_exit = NULL;
+ }
- if (node != ENTRY_BLOCK_PTR
- && ! dominated_by_p (dom, node, header))
+ FOR_EACH_BB (bb)
+ {
+ edge_iterator ei;
+ if (bb->loop_father == loops->tree_root)
+ continue;
+ FOR_EACH_EDGE (e, ei, bb->succs)
{
- if (pre_header == NULL)
- pre_header = node;
- else
+ if (e->dest == EXIT_BLOCK_PTR)
+ continue;
+
+ if (flow_bb_inside_loop_p (bb->loop_father, e->dest))
+ continue;
+
+ for (loop = bb->loop_father;
+ loop != e->dest->loop_father;
+ loop = loop->outer)
{
- /* There are multiple edges into the header from outside
- the loop so there is no pre-header block. */
- pre_header = NULL;
- break;
+ /* 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);
+ else
+ loop->single_exit = e;
}
}
}
- return pre_header;
+ for (i = 1; i < loops->num; i++)
+ {
+ loop = loops->parray[i];
+ if (!loop)
+ continue;
+
+ if (loop->single_exit == EDGE_SUCC (ENTRY_BLOCK_PTR, 0))
+ loop->single_exit = NULL;
+ }
+
+ loops->state |= LOOPS_HAVE_MARKED_SINGLE_EXITS;
+}
+
+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);
+ memcpy (loop->pred, father->pred, sizeof (struct loop *) * father->depth);
+ loop->pred[father->depth] = father;
+
+ for (ploop = loop->inner; ploop; ploop = ploop->next)
+ establish_preds (ploop);
}
/* Add LOOP to the loop hierarchy tree where FATHER is father of the
- added loop. */
+ added loop. If LOOP has some children, take care of that their
+ pred field will be initialized correctly. */
void
-flow_loop_tree_node_add (father, loop)
- struct loop *father;
- struct loop *loop;
+flow_loop_tree_node_add (struct loop *father, struct loop *loop)
{
loop->next = father->inner;
father->inner = loop;
loop->outer = father;
- loop->depth = father->depth + 1;
- loop->pred = xmalloc (sizeof (struct loop *) * loop->depth);
- memcpy (loop->pred, father->pred, sizeof (struct loop *) * father->depth);
- loop->pred[father->depth] = father;
+ establish_preds (loop);
}
/* Remove LOOP from the loop hierarchy tree. */
void
-flow_loop_tree_node_remove (loop)
- struct loop *loop;
+flow_loop_tree_node_remove (struct loop *loop)
{
struct loop *prev, *father;
for the natural loop specified by LOOP. Returns the loop level. */
static int
-flow_loop_level_compute (loop)
- struct loop *loop;
+flow_loop_level_compute (struct loop *loop)
{
struct loop *inner;
int level = 1;
hierarchy tree specified by LOOPS. Return the maximum enclosed loop
level. */
-static int
-flow_loops_level_compute (loops)
- struct loops *loops;
+static void
+flow_loops_level_compute (struct loops *loops)
{
- return flow_loop_level_compute (loops->tree_root);
+ flow_loop_level_compute (loops->tree_root);
}
-/* Scan a single natural loop specified by LOOP collecting information
- about it specified by FLAGS. */
+/* A callback to update latch and header info for basic block JUMP created
+ by redirecting an edge. */
-int
-flow_loop_scan (loops, loop, flags)
- struct loops *loops;
- struct loop *loop;
- int flags;
+static void
+update_latch_info (basic_block jump)
{
- 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, loops->cfg.dom);
-
- /* Find the blocks within the extended basic block of
- the loop pre-header. */
- flow_loop_pre_header_scan (loop);
- }
-
- return 1;
+ 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);
}
-#define HEADER_BLOCK(B) (* (int *) (B)->aux)
-#define LATCH_EDGE(E) (*(int *) (E)->aux)
+/* 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. */
-/* Redirect edge and update latch and header info. */
-static void
-redirect_edge_with_latch_update (e, to)
- edge e;
- basic_block to;
+static edge mfb_kj_edge;
+static bool
+mfb_keep_just (edge e)
{
- basic_block jump;
-
- jump = redirect_edge_and_branch_force (e, to);
- if (jump)
- {
- alloc_aux_for_block (jump, sizeof (int));
- HEADER_BLOCK (jump) = 0;
- alloc_aux_for_edge (jump->pred, sizeof (int));
- LATCH_EDGE (jump->succ) = LATCH_EDGE (e);
- LATCH_EDGE (jump->pred) = 0;
- }
+ return e != mfb_kj_edge;
}
-/* Split BB into entry part and rest; if REDIRECT_LATCH, redirect edges
- marked as latch into entry part, analogically for REDIRECT_NONLATCH.
- In both of these cases, ignore edge EXCEPT. If CONN_LATCH, set edge
- between created entry part and BB as latch one. Return created entry
- part. */
-
-static basic_block
-make_forwarder_block (bb, redirect_latch, redirect_nonlatch, except,
- conn_latch)
- basic_block bb;
- int redirect_latch;
- int redirect_nonlatch;
- edge except;
- int conn_latch;
-{
- edge e, next_e, fallthru;
- basic_block dummy;
- rtx insn;
-
- insn = PREV_INSN (first_insn_after_basic_block_note (bb));
+/* 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. */
- fallthru = split_block (bb, insn);
- dummy = fallthru->src;
- bb = fallthru->dest;
-
- bb->aux = xmalloc (sizeof (int));
- HEADER_BLOCK (dummy) = 0;
- HEADER_BLOCK (bb) = 1;
-
- /* Redirect back edges we want to keep. */
- for (e = dummy->pred; e; e = next_e)
- {
- next_e = e->pred_next;
- if (e == except
- || !((redirect_latch && LATCH_EDGE (e))
- || (redirect_nonlatch && !LATCH_EDGE (e))))
- {
- dummy->frequency -= EDGE_FREQUENCY (e);
- dummy->count -= e->count;
- if (dummy->frequency < 0)
- dummy->frequency = 0;
- if (dummy->count < 0)
- dummy->count = 0;
- redirect_edge_with_latch_update (e, bb);
- }
- }
-
- alloc_aux_for_edge (fallthru, sizeof (int));
- LATCH_EDGE (fallthru) = conn_latch;
-
- return dummy;
+static bool
+mfb_keep_nonlatch (edge e)
+{
+ return LATCH_EDGE (e);
}
/* Takes care of merging natural loops with shared headers. */
+
static void
-canonicalize_loop_headers ()
+canonicalize_loop_headers (void)
{
- dominance_info dom;
basic_block header;
edge e;
-
- /* Compute the dominators. */
- dom = calculate_dominance_info (CDI_DOMINATORS);
alloc_aux_for_blocks (sizeof (int));
alloc_aux_for_edges (sizeof (int));
/* Split blocks so that each loop has only single latch. */
FOR_EACH_BB (header)
{
+ edge_iterator ei;
int num_latches = 0;
int have_abnormal_edge = 0;
- for (e = header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, header->preds)
{
basic_block latch = e->src;
have_abnormal_edge = 1;
if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (dom, latch, header))
+ && dominated_by_p (CDI_DOMINATORS, latch, header))
{
num_latches++;
LATCH_EDGE (e) = 1;
HEADER_BLOCK (header) = num_latches;
}
- if (HEADER_BLOCK (ENTRY_BLOCK_PTR->succ->dest))
+ if (HEADER_BLOCK (EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest))
{
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 (ENTRY_BLOCK_PTR->succ);
-
- alloc_aux_for_edge (bb->succ, sizeof (int));
- LATCH_EDGE (bb->succ) = 0;
+ bb = split_edge (EDGE_SUCC (ENTRY_BLOCK_PTR, 0));
+
+ alloc_aux_for_edge (EDGE_SUCC (bb, 0), sizeof (int));
+ LATCH_EDGE (EDGE_SUCC (bb, 0)) = 0;
alloc_aux_for_block (bb, sizeof (int));
HEADER_BLOCK (bb) = 0;
}
FOR_EACH_BB (header)
{
- int num_latch;
- int want_join_latch;
int max_freq, is_heavy;
- edge heavy;
-
- if (!HEADER_BLOCK (header))
- continue;
+ edge heavy, tmp_edge;
+ edge_iterator ei;
- num_latch = HEADER_BLOCK (header);
-
- want_join_latch = (num_latch > 1);
-
- if (!want_join_latch)
+ if (HEADER_BLOCK (header) <= 1)
continue;
/* Find a heavy edge. */
is_heavy = 1;
heavy = NULL;
max_freq = 0;
- for (e = header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, header->preds)
if (LATCH_EDGE (e) &&
EDGE_FREQUENCY (e) > max_freq)
max_freq = EDGE_FREQUENCY (e);
- for (e = header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, header->preds)
if (LATCH_EDGE (e) &&
EDGE_FREQUENCY (e) >= max_freq / HEAVY_EDGE_RATIO)
{
if (is_heavy)
{
- basic_block new_header =
- make_forwarder_block (header, true, true, heavy, 0);
- if (num_latch > 2)
- make_forwarder_block (new_header, true, false, NULL, 1);
+ /* 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)
+ {
+ /* 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;
}
- else
- make_forwarder_block (header, true, false, NULL, 1);
}
free_aux_for_blocks ();
free_aux_for_edges ();
- free_dominance_info (dom);
+
+#ifdef ENABLE_CHECKING
+ verify_dominators (CDI_DOMINATORS);
+#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 (loops, flags)
- struct loops *loops;
- int flags;
+flow_loops_find (struct loops *loops)
{
- int i;
int b;
int num_loops;
edge e;
sbitmap headers;
- dominance_info dom;
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);
+ /* 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)
dfs_order = NULL;
rc_order = NULL;
+ /* Ensure that the dominators are computed. */
+ calculate_dominance_info (CDI_DOMINATORS);
+
/* Join loops with shared headers. */
canonicalize_loop_headers ();
- /* Compute the dominators. */
- dom = loops->cfg.dom = calculate_dominance_info (CDI_DOMINATORS);
-
/* Count the number of loop headers. This should be the
same as the number of natural loops. */
headers = sbitmap_alloc (last_basic_block);
num_loops = 0;
FOR_EACH_BB (header)
{
+ edge_iterator ei;
int more_latches = 0;
-
+
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)
+ FOR_EACH_EDGE (e, ei, header->preds)
if (e->flags & EDGE_ABNORMAL)
break;
if (e)
continue;
- for (e = header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, header->preds)
{
basic_block latch = e->src;
- if (e->flags & EDGE_ABNORMAL)
- abort ();
+ gcc_assert (!(e->flags & EDGE_ABNORMAL));
/* 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 (dom, latch, header))
+ if (latch != ENTRY_BLOCK_PTR
+ && dominated_by_p (CDI_DOMINATORS, latch, header))
{
/* Shared headers should be eliminated by now. */
- if (more_latches)
- abort ();
+ gcc_assert (!more_latches);
more_latches = 1;
SET_BIT (headers, header->index);
num_loops++;
}
/* Allocate loop structures. */
- loops->parray = (struct loop **) xcalloc (num_loops + 1, sizeof (struct loop *));
+ loops->parray = xcalloc (num_loops + 1, sizeof (struct loop *));
/* Dummy loop containing whole function. */
loops->parray[0] = xcalloc (1, sizeof (struct loop));
{
/* Compute depth first search order of the CFG so that outer
natural loops will be found before inner natural loops. */
- dfs_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
- rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
+ 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);
/* Save CFG derived information to avoid recomputing it. */
- loops->cfg.dom = dom;
loops->cfg.dfs_order = dfs_order;
loops->cfg.rc_order = rc_order;
for (b = 0; b < n_basic_blocks; b++)
{
struct loop *loop;
+ edge_iterator ei;
/* Search the nodes of the CFG in reverse completion order
so that we can find outer loops first. */
continue;
header = BASIC_BLOCK (rc_order[b]);
-
+
loop = loops->parray[num_loops] = xcalloc (1, sizeof (struct loop));
loop->header = header;
num_loops++;
/* Look for the latch for this header block. */
- for (e = header->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, header->preds)
{
basic_block latch = e->src;
if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (dom, latch, header))
+ && dominated_by_p (CDI_DOMINATORS, latch, header))
{
loop->latch = latch;
break;
loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
}
- sbitmap_free (headers);
-
/* 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, loops->parray[i], flags);
+ flow_loops_level_compute (loops);
loops->num = num_loops;
+ initialize_loops_parallel_p (loops);
}
- else
- {
- loops->cfg.dom = NULL;
- free_dominance_info (dom);
- }
+
+ sbitmap_free (headers);
+
+ loops->state = 0;
#ifdef ENABLE_CHECKING
verify_flow_info ();
- verify_loop_structure (loops, 0);
+ verify_loop_structure (loops);
#endif
return loops->num;
}
-/* Update the information regarding the loops in the CFG
- specified by LOOPS. */
-
-int
-flow_loops_update (loops, flags)
- 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 (loop, bb)
- const struct loop *loop;
- const basic_block bb;
+flow_bb_inside_loop_p (const struct loop *loop, const basic_block bb)
{
struct loop *source_loop;
/* Return nonzero if edge E enters header of LOOP from outside of LOOP. */
bool
-flow_loop_outside_edge_p (loop, e)
- const struct loop *loop;
- edge e;
+flow_loop_outside_edge_p (const struct loop *loop, edge e)
{
- if (e->dest != loop->header)
- abort ();
+ gcc_assert (e->dest == loop->header);
return !flow_bb_inside_loop_p (loop, e->src);
}
/* Enumeration predicate for get_loop_body. */
static bool
-glb_enum_p (bb, glb_header)
- basic_block bb;
- void *glb_header;
+glb_enum_p (basic_block bb, void *glb_header)
{
return bb != (basic_block) glb_header;
}
-/* Gets basic blocks of a loop. */
+/* 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 (loop)
- const struct loop *loop;
+get_loop_body (const struct loop *loop)
{
basic_block *tovisit, bb;
- int tv = 0;
+ unsigned tv = 0;
- if (!loop->num_nodes)
- abort ();
+ gcc_assert (loop->num_nodes);
tovisit = xcalloc (loop->num_nodes, sizeof (basic_block));
tovisit[tv++] = loop->header;
if (loop->latch == EXIT_BLOCK_PTR)
{
/* There may be blocks unreachable from EXIT_BLOCK. */
- if (loop->num_nodes != n_basic_blocks + 2)
- abort ();
+ gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks + 2);
FOR_EACH_BB (bb)
tovisit[tv++] = bb;
tovisit[tv++] = EXIT_BLOCK_PTR;
loop->header) + 1;
}
- if (tv != loop->num_nodes)
- abort ();
+ gcc_assert (tv == loop->num_nodes);
return tovisit;
}
+/* Fills dominance descendants inside LOOP of the basic block BB into
+ array TOVISIT from index *TV. */
+
+static void
+fill_sons_in_loop (const struct loop *loop, basic_block bb,
+ basic_block *tovisit, int *tv)
+{
+ basic_block son, postpone = NULL;
+
+ 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 (dominated_by_p (CDI_DOMINATORS, loop->latch, son))
+ {
+ postpone = son;
+ continue;
+ }
+ 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. */
+
+basic_block *
+get_loop_body_in_dom_order (const struct loop *loop)
+{
+ basic_block *tovisit;
+ int tv;
+
+ gcc_assert (loop->num_nodes);
+
+ tovisit = xcalloc (loop->num_nodes, sizeof (basic_block));
+
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+
+ tv = 0;
+ fill_sons_in_loop (loop, loop->header, tovisit, &tv);
+
+ gcc_assert (tv == (int) loop->num_nodes);
+
+ return tovisit;
+}
+
+/* Get body of a LOOP in breadth first sort order. */
+
+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;
+
+ gcc_assert (loop->num_nodes);
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+
+ blocks = xcalloc (loop->num_nodes, sizeof (basic_block));
+ visited = BITMAP_ALLOC (NULL);
+
+ bb = loop->header;
+ while (i < loop->num_nodes)
+ {
+ edge e;
+ edge_iterator ei;
+
+ if (!bitmap_bit_p (visited, bb->index))
+ {
+ /* This basic block is now visited */
+ bitmap_set_bit (visited, bb->index);
+ blocks[i++] = bb;
+ }
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (flow_bb_inside_loop_p (loop, e->dest))
+ {
+ if (!bitmap_bit_p (visited, e->dest->index))
+ {
+ bitmap_set_bit (visited, e->dest->index);
+ blocks[i++] = e->dest;
+ }
+ }
+ }
+
+ gcc_assert (i >= vc);
+
+ bb = blocks[vc++];
+ }
+
+ 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)
+{
+ edge *edges, e;
+ unsigned i, n;
+ basic_block * body;
+ edge_iterator ei;
+
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+
+ body = get_loop_body (loop);
+ n = 0;
+ 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))
+ n++;
+ edges = xmalloc (n * sizeof (edge));
+ *n_edges = n;
+ n = 0;
+ 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))
+ edges[n++] = e;
+ free (body);
+
+ return edges;
+}
+
+/* Counts the number of conditional branches inside LOOP. */
+
+unsigned
+num_loop_branches (const struct loop *loop)
+{
+ unsigned i, n;
+ basic_block * body;
+
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+
+ body = get_loop_body (loop);
+ n = 0;
+ for (i = 0; i < loop->num_nodes; i++)
+ if (EDGE_COUNT (body[i]->succs) >= 2)
+ n++;
+ free (body);
+
+ return n;
+}
+
/* Adds basic block BB to LOOP. */
void
-add_bb_to_loop (bb, loop)
- basic_block bb;
- struct loop *loop;
- {
+add_bb_to_loop (basic_block bb, struct loop *loop)
+{
int i;
-
+
bb->loop_father = loop;
bb->loop_depth = loop->depth;
loop->num_nodes++;
/* Remove basic block BB from loops. */
void
-remove_bb_from_loops (bb)
- basic_block bb;
- {
+remove_bb_from_loops (basic_block bb)
+{
int i;
struct loop *loop = bb->loop_father;
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 *
-find_common_loop (loop_s, loop_d)
- struct loop *loop_s;
- struct loop *loop_d;
+find_common_loop (struct loop *loop_s, struct loop *loop_d)
{
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)
return loop_s;
}
-/* Checks that LOOPS are allright:
- -- sizes of loops are allright
+/* Cancels the LOOP; it must be innermost one. */
+void
+cancel_loop (struct loops *loops, struct loop *loop)
+{
+ basic_block *bbs;
+ unsigned i;
+
+ 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;
+
+ /* Free loop data. */
+ flow_loop_free (loop);
+}
+
+/* Cancels LOOP and all its subloops. */
+void
+cancel_loop_tree (struct loops *loops, struct loop *loop)
+{
+ while (loop->inner)
+ cancel_loop_tree (loops, loop->inner);
+ cancel_loop (loops, loop);
+}
+
+/* Checks that LOOPS are all right:
+ -- 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 (loops, flags)
- struct loops *loops;
- int flags;
+verify_loop_structure (struct loops *loops)
{
- int *sizes, i, j;
+ unsigned *sizes, i, j;
+ sbitmap irreds;
basic_block *bbs, bb;
struct loop *loop;
int err = 0;
+ edge e;
/* Check sizes. */
sizes = xcalloc (loops->num, sizeof (int));
}
}
- free (sizes);
-
/* Check get_loop_body. */
for (i = 1; i < loops->num; i++)
{
if (!loop)
continue;
- if ((flags & VLS_EXPECT_PREHEADERS)
- && (!loop->header->pred->pred_next
- || loop->header->pred->pred_next->pred_next))
+ if ((loops->state & LOOPS_HAVE_PREHEADERS)
+ && EDGE_COUNT (loop->header->preds) != 2)
{
error ("Loop %d's header does not have exactly 2 entries.", i);
err = 1;
}
- if (flags & VLS_EXPECT_SIMPLE_LATCHES)
+ if (loops->state & LOOPS_HAVE_SIMPLE_LATCHES)
{
- if (!loop->latch->succ
- || loop->latch->succ->succ_next)
+ if (EDGE_COUNT (loop->latch->succs) != 1)
{
error ("Loop %d's latch does not have exactly 1 successor.", i);
err = 1;
}
- if (loop->latch->succ->dest != loop->header)
+ if (EDGE_SUCC (loop->latch, 0)->dest != loop->header)
{
error ("Loop %d's latch does not have header as successor.", i);
err = 1;
error ("Loop %d's header does not belong directly to it.", i);
err = 1;
}
+ if ((loops->state & 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);
+ err = 1;
+ }
+ }
+
+ /* Check irreducible loops. */
+ if (loops->state & 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_EACH_EDGE (e, ei, bb->succs)
+ if (e->flags & EDGE_IRREDUCIBLE_LOOP)
+ e->flags |= EDGE_ALL_FLAGS + 1;
+ }
+
+ /* Recount it. */
+ mark_irreducible_loops (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);
+ 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);
+ err = 1;
+ }
+ 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.",
+ 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.",
+ e->src->index, e->dest->index);
+ err = 1;
+ }
+ e->flags &= ~(EDGE_ALL_FLAGS + 1);
+ }
+ }
+ free (irreds);
+ }
+
+ /* Check the single_exit. */
+ if (loops->state & LOOPS_HAVE_MARKED_SINGLE_EXITS)
+ {
+ memset (sizes, 0, sizeof (unsigned) * loops->num);
+ FOR_EACH_BB (bb)
+ {
+ edge_iterator ei;
+ if (bb->loop_father == loops->tree_root)
+ continue;
+ 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;
+
+ for (loop = bb->loop_father;
+ loop != e->dest->loop_father;
+ loop = loop->outer)
+ {
+ 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;
+ }
+ }
+ }
+ }
+
+ for (i = 1; i < loops->num; i++)
+ {
+ 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;
+ }
+
+ if (sizes[i] != 1
+ && loop->single_exit)
+ {
+ error ("Loop %d should not have single exit (%d -> %d).",
+ loop->num,
+ loop->single_exit->src->index,
+ loop->single_exit->dest->index);
+ err = 1;
+ }
+ }
}
- if (err)
- abort ();
+ gcc_assert (!err);
+
+ free (sizes);
}
/* Returns latch edge of LOOP. */
edge
-loop_latch_edge (loop)
- struct loop *loop;
+loop_latch_edge (const struct loop *loop)
{
- edge e;
-
- for (e = loop->header->pred; e->src != loop->latch; e = e->pred_next)
- continue;
-
- return e;
+ return find_edge (loop->latch, loop->header);
}
/* Returns preheader edge of LOOP. */
edge
-loop_preheader_edge (loop)
- struct loop *loop;
+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;
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ if (e->src != loop->latch)
+ break;
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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