#include "rtl.h"
#include "hard-reg-set.h"
#include "basic-block.h"
+#include "toplev.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 int flow_loop_nested_p PARAMS ((struct loop *,
- struct loop *));
-static int flow_loop_entry_edges_find PARAMS ((basic_block, const sbitmap,
- edge **));
-static int flow_loop_exit_edges_find PARAMS ((const sbitmap, edge **));
-static int flow_loop_nodes_find PARAMS ((basic_block, basic_block,
- sbitmap));
+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,
const sbitmap *));
-static void flow_loop_tree_node_add PARAMS ((struct loop *,
- struct loop *));
-static void flow_loops_tree_build PARAMS ((struct loops *));
-static int flow_loop_level_compute PARAMS ((struct loop *, int));
+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 *));
\f
/* Dump loop related CFG information. */
fprintf (file, ";; %d succs { ", bb->index);
for (succ = bb->succ; succ; succ = succ->succ_next)
fprintf (file, "%d ", succ->dest->index);
- flow_nodes_print ("} dom", loops->cfg.dom[bb->index], file);
+ fprintf (file, "}\n");
}
/* Dump the DFS node order. */
/* Return non-zero if the nodes of LOOP are a subset of OUTER. */
-static int
+bool
flow_loop_nested_p (outer, loop)
- struct loop *outer;
- struct loop *loop;
+ const struct loop *outer;
+ const struct loop *loop;
{
- return sbitmap_a_subset_b_p (loop->nodes, outer->nodes);
+ return loop->depth > outer->depth
+ && loop->pred[outer->depth] == outer;
}
/* Dump the loop information specified by LOOP to the stream FILE
void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
int verbose;
{
+ basic_block *bbs;
+ int i;
+
if (! loop || ! loop->header)
return;
- if (loop->first->head && loop->last->end)
- fprintf (file, ";;\n;; Loop %d (%d to %d):%s%s\n",
- loop->num, INSN_UID (loop->first->head),
- INSN_UID (loop->last->end),
- loop->shared ? " shared" : "", loop->invalid ? " invalid" : "");
- else
- fprintf (file, ";;\n;; Loop %d:%s%s\n", loop->num,
- loop->shared ? " shared" : "", loop->invalid ? " invalid" : "");
+ fprintf (file, ";;\n;; Loop %d:%s\n", loop->num,
+ loop->invalid ? " invalid" : "");
- fprintf (file, ";; header %d, latch %d, pre-header %d, first %d, last %d\n",
+ fprintf (file, ";; header %d, latch %d, pre-header %d\n",
loop->header->index, loop->latch->index,
- loop->pre_header ? loop->pre_header->index : -1,
- loop->first->index, loop->last->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));
flow_edge_list_print (";; entry edges", loop->entry_edges,
loop->num_entries, file);
- fprintf (file, ";; %d", loop->num_nodes);
- flow_nodes_print (" nodes", loop->nodes, 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->exits_doms)
- flow_nodes_print (";; exit doms", loop->exits_doms, file);
-
if (loop_dump_aux)
loop_dump_aux (loop, file, verbose);
}
void (*loop_dump_aux) PARAMS((const struct loop *, FILE *, int));
int verbose;
{
- int i, j;
+ int i;
int num_loops;
num_loops = loops->num;
if (! num_loops || ! file)
return;
- fprintf (file, ";; %d loops found, %d levels\n", num_loops, loops->levels);
+ fprintf (file, ";; %d loops found, %d levels\n",
+ num_loops, loops->levels);
+
for (i = 0; i < num_loops; i++)
{
- struct loop *loop = &loops->array[i];
+ struct loop *loop = loops->parray[i];
- flow_loop_dump (loop, file, loop_dump_aux, verbose);
- if (loop->shared)
- for (j = 0; j < i; j++)
- {
- struct loop *oloop = &loops->array[j];
+ if (!loop)
+ continue;
- if (loop->header == oloop->header)
- {
- int disjoint;
- int smaller;
-
- smaller = loop->num_nodes < oloop->num_nodes;
-
- /* If the union of LOOP and OLOOP is different than
- the larger of LOOP and OLOOP then LOOP and OLOOP
- must be disjoint. */
- disjoint = ! flow_loop_nested_p (smaller ? loop : oloop,
- smaller ? oloop : loop);
- fprintf (file,
- ";; loop header %d shared by loops %d, %d %s\n",
- loop->header->index, i, j,
- disjoint ? "disjoint" : "nested");
- }
- }
+ flow_loop_dump (loop, file, loop_dump_aux, verbose);
}
if (verbose)
flow_loops_cfg_dump (loops, file);
}
+/* Free data allocated for LOOP. */
+static void
+flow_loop_free (loop)
+ 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;
{
- if (loops->array)
+ if (loops->parray)
{
int i;
/* Free the loop descriptors. */
for (i = 0; i < loops->num; i++)
{
- struct loop *loop = &loops->array[i];
-
- if (loop->pre_header_edges)
- free (loop->pre_header_edges);
- if (loop->nodes)
- sbitmap_free (loop->nodes);
- if (loop->entry_edges)
- free (loop->entry_edges);
- if (loop->exit_edges)
- free (loop->exit_edges);
- if (loop->exits_doms)
- sbitmap_free (loop->exits_doms);
+ struct loop *loop = loops->parray[i];
+
+ if (!loop)
+ continue;
+
+ flow_loop_free (loop);
}
- free (loops->array);
- loops->array = NULL;
+ free (loops->parray);
+ loops->parray = NULL;
if (loops->cfg.dom)
sbitmap_vector_free (loops->cfg.dom);
if (loops->cfg.dfs_order)
free (loops->cfg.dfs_order);
+ if (loops->cfg.rc_order)
+ free (loops->cfg.rc_order);
- if (loops->shared_headers)
- sbitmap_free (loops->shared_headers);
}
}
-/* Find the entry edges into the loop with header HEADER and nodes
- NODES and store in ENTRY_EDGES array. Return the number of entry
- edges from the loop. */
+/* Find the entry edges into the LOOP. */
-static int
-flow_loop_entry_edges_find (header, nodes, entry_edges)
- basic_block header;
- const sbitmap nodes;
- edge **entry_edges;
+static void
+flow_loop_entry_edges_find (loop)
+ struct loop *loop;
{
edge e;
int num_entries;
- *entry_edges = NULL;
-
num_entries = 0;
- for (e = header->pred; e; e = e->pred_next)
+ for (e = loop->header->pred; e; e = e->pred_next)
{
- basic_block src = e->src;
-
- if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
+ if (flow_loop_outside_edge_p (loop, e))
num_entries++;
}
if (! num_entries)
abort ();
- *entry_edges = (edge *) xmalloc (num_entries * sizeof (edge));
+ loop->entry_edges = (edge *) xmalloc (num_entries * sizeof (edge *));
num_entries = 0;
- for (e = header->pred; e; e = e->pred_next)
+ for (e = loop->header->pred; e; e = e->pred_next)
{
- basic_block src = e->src;
-
- if (src == ENTRY_BLOCK_PTR || ! TEST_BIT (nodes, src->index))
- (*entry_edges)[num_entries++] = e;
+ if (flow_loop_outside_edge_p (loop, e))
+ loop->entry_edges[num_entries++] = e;
}
- return num_entries;
+ loop->num_entries = num_entries;
}
-/* Find the exit edges from the loop using the bitmap of loop nodes
- NODES and store in EXIT_EDGES array. Return the number of
- exit edges from the loop. */
+/* Find the exit edges from the LOOP. */
-static int
-flow_loop_exit_edges_find (nodes, exit_edges)
- const sbitmap nodes;
- edge **exit_edges;
+static void
+flow_loop_exit_edges_find (loop)
+ struct loop *loop;
{
edge e;
- int node;
- int num_exits;
+ basic_block node, *bbs;
+ int num_exits, i;
- *exit_edges = NULL;
+ 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 ????? A node can have one jumping edge and one fallthru
- edge so only one of these can exit the loop. */
+ exiting edges. */
num_exits = 0;
- EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
- for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
- {
- basic_block dest = e->dest;
+ 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 (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
+ if (!flow_bb_inside_loop_p (loop, dest))
num_exits++;
- }
- });
+ }
+ }
if (! num_exits)
- return 0;
+ {
+ free (bbs);
+ return;
+ }
- *exit_edges = (edge *) xmalloc (num_exits * sizeof (edge));
+ loop->exit_edges = (edge *) xmalloc (num_exits * sizeof (edge *));
/* Store all exiting edges into an array. */
num_exits = 0;
- EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, node, {
- for (e = BASIC_BLOCK (node)->succ; e; e = e->succ_next)
- {
- basic_block dest = e->dest;
+ 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 (dest == EXIT_BLOCK_PTR || ! TEST_BIT (nodes, dest->index))
- (*exit_edges)[num_exits++] = e;
+ if (!flow_bb_inside_loop_p (loop, dest))
+ loop->exit_edges[num_exits++] = e;
}
- });
-
- return num_exits;
+ }
+ free (bbs);
+ loop->num_exits = num_exits;
}
-/* Find the nodes contained within the loop with header HEADER and
- latch LATCH and store in NODES. Return the number of nodes within
- the loop. */
+/* 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, latch, nodes)
+flow_loop_nodes_find (header, loop)
basic_block header;
- basic_block latch;
- sbitmap nodes;
+ struct loop *loop;
{
basic_block *stack;
int sp;
- int num_nodes = 0;
-
- stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
- sp = 0;
+ int num_nodes = 1;
+ int findex, lindex;
- /* Start with only the loop header in the set of loop nodes. */
- sbitmap_zero (nodes);
- SET_BIT (nodes, header->index);
- num_nodes++;
- header->loop_depth++;
+ header->loop_father = loop;
+ header->loop_depth = loop->depth;
+ findex = lindex = header->index;
- /* Push the loop latch on to the stack. */
- if (! TEST_BIT (nodes, latch->index))
+ if (loop->latch->loop_father != loop)
{
- SET_BIT (nodes, latch->index);
- latch->loop_depth++;
+ stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
+ sp = 0;
num_nodes++;
- stack[sp++] = latch;
- }
-
- while (sp)
- {
- basic_block node;
- edge e;
-
- node = stack[--sp];
- for (e = node->pred; e; e = e->pred_next)
+ stack[sp++] = loop->latch;
+ loop->latch->loop_father = loop;
+ loop->latch->loop_depth = loop->depth;
+
+ while (sp)
{
- basic_block ancestor = e->src;
+ basic_block node;
+ edge e;
- /* If each ancestor not marked as part of loop, add to set of
- loop nodes and push on to stack. */
- if (ancestor != ENTRY_BLOCK_PTR
- && ! TEST_BIT (nodes, ancestor->index))
+ node = stack[--sp];
+
+ for (e = node->pred; e; e = e->pred_next)
{
- SET_BIT (nodes, ancestor->index);
- ancestor->loop_depth++;
- num_nodes++;
- stack[sp++] = ancestor;
+ basic_block ancestor = e->src;
+
+ 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);
}
- free (stack);
return num_nodes;
}
return pre_header;
}
-/* Add LOOP to the loop hierarchy tree where PREVLOOP was the loop
- previously added. The insertion algorithm assumes that the loops
- are added in the order found by a depth first search of the CFG. */
+/* Add LOOP to the loop hierarchy tree where FATHER is father of the
+ added loop. */
-static void
-flow_loop_tree_node_add (prevloop, loop)
- struct loop *prevloop;
+void
+flow_loop_tree_node_add (father, loop)
+ struct loop *father;
struct loop *loop;
{
-
- if (flow_loop_nested_p (prevloop, loop))
- {
- prevloop->inner = loop;
- loop->outer = prevloop;
- return;
- }
-
- for (; prevloop->outer; prevloop = prevloop->outer)
- if (flow_loop_nested_p (prevloop->outer, loop))
- {
- prevloop->next = loop;
- loop->outer = prevloop->outer;
- return;
- }
-
- prevloop->next = loop;
- loop->outer = NULL;
+ 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;
}
-/* Build the loop hierarchy tree for LOOPS. */
+/* Remove LOOP from the loop hierarchy tree. */
-static void
-flow_loops_tree_build (loops)
- struct loops *loops;
+void
+flow_loop_tree_node_remove (loop)
+ struct loop *loop;
{
- int i;
- int num_loops;
+ struct loop *prev, *father;
- num_loops = loops->num;
- if (! num_loops)
- return;
+ father = loop->outer;
+ loop->outer = NULL;
- /* Root the loop hierarchy tree with the first loop found.
- Since we used a depth first search this should be the
- outermost loop. */
- loops->tree_root = &loops->array[0];
- loops->tree_root->outer = loops->tree_root->inner
- = loops->tree_root->next = NULL;
+ /* 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);
+ prev->next = loop->next;
+ }
- /* Add the remaining loops to the tree. */
- for (i = 1; i < num_loops; i++)
- flow_loop_tree_node_add (&loops->array[i - 1], &loops->array[i]);
+ loop->depth = -1;
+ free (loop->pred);
+ loop->pred = NULL;
}
/* Helper function to compute loop nesting depth and enclosed loop level
- for the natural loop specified by LOOP at the loop depth DEPTH.
- Returns the loop level. */
+ for the natural loop specified by LOOP. Returns the loop level. */
static int
-flow_loop_level_compute (loop, depth)
+flow_loop_level_compute (loop)
struct loop *loop;
- int depth;
{
struct loop *inner;
int level = 1;
itself). */
for (inner = loop->inner; inner; inner = inner->next)
{
- int ilevel = flow_loop_level_compute (inner, depth + 1) + 1;
+ int ilevel = flow_loop_level_compute (inner) + 1;
- level = MAX (ilevel, level);
+ if (ilevel > level)
+ level = ilevel;
}
loop->level = level;
- loop->depth = depth;
return level;
}
flow_loops_level_compute (loops)
struct loops *loops;
{
- int levels = 0;
- struct loop *loop;
- int level;
-
- /* Traverse all the outer level loops. */
- for (loop = loops->tree_root; loop; loop = loop->next)
- {
- level = flow_loop_level_compute (loop, 1);
- levels = MAX (levels, level);
- }
-
- return levels;
+ return flow_loop_level_compute (loops->tree_root);
}
/* Scan a single natural loop specified by LOOP collecting information
struct loop *loop;
int flags;
{
- /* Determine prerequisites. */
- if ((flags & LOOP_EXITS_DOMS) && ! loop->exit_edges)
- flags |= LOOP_EXIT_EDGES;
-
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. */
- loop->num_entries = flow_loop_entry_edges_find (loop->header, loop->nodes,
- &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. */
- loop->num_exits
- = flow_loop_exit_edges_find (loop->nodes, &loop->exit_edges);
-
- if (flags & LOOP_EXITS_DOMS)
{
- int j;
-
- /* Determine which loop nodes dominate all the exits
- of the loop. */
- loop->exits_doms = sbitmap_alloc (last_basic_block);
- sbitmap_copy (loop->exits_doms, loop->nodes);
- for (j = 0; j < loop->num_exits; j++)
- sbitmap_a_and_b (loop->exits_doms, loop->exits_doms,
- loops->cfg.dom[loop->exit_edges[j]->src->index]);
-
- /* The header of a natural loop must dominate
- all exits. */
- if (! TEST_BIT (loop->exits_doms, loop->header->index))
- abort ();
+ /* Find edges which exit the loop. */
+ flow_loop_exit_edges_find (loop);
}
if (flags & LOOP_PRE_HEADER)
return 1;
}
+#define HEADER_BLOCK(B) (* (int *) (B)->aux)
+#define LATCH_EDGE(E) (*(int *) (E)->aux)
+
+/* Redirect edge and update latch and header info. */
+static void
+redirect_edge_with_latch_update (e, to)
+ edge e;
+ basic_block to;
+{
+ 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;
+ }
+}
+
+/* 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));
+
+ 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;
+}
+
+/* Takes care of merging natural loops with shared headers. */
+static void
+canonicalize_loop_headers ()
+{
+ sbitmap *dom;
+ basic_block header;
+ edge e;
+
+ /* Compute the dominators. */
+ dom = sbitmap_vector_alloc (last_basic_block, last_basic_block);
+ calculate_dominance_info (NULL, dom, 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)
+ {
+ int num_latches = 0;
+ int have_abnormal_edge = 0;
+
+ for (e = header->pred; e; e = e->pred_next)
+ {
+ basic_block latch = e->src;
+
+ if (e->flags & EDGE_ABNORMAL)
+ have_abnormal_edge = 1;
+
+ if (latch != ENTRY_BLOCK_PTR
+ && TEST_BIT (dom[latch->index], header->index))
+ {
+ num_latches++;
+ LATCH_EDGE (e) = 1;
+ }
+ }
+ if (have_abnormal_edge)
+ HEADER_BLOCK (header) = 0;
+ else
+ HEADER_BLOCK (header) = num_latches;
+ }
+
+ if (HEADER_BLOCK (ENTRY_BLOCK_PTR->succ->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;
+ 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;
+
+ num_latch = HEADER_BLOCK (header);
+
+ want_join_latch = (num_latch > 1);
+
+ if (!want_join_latch)
+ 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)
+ {
+ 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);
+ }
+ else
+ make_forwarder_block (header, true, false, NULL, 1);
+ }
+
+ free_aux_for_blocks ();
+ free_aux_for_edges ();
+ sbitmap_vector_free (dom);
+}
+
/* 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
dfs_order = NULL;
rc_order = NULL;
+ /* Join loops with shared headers. */
+ canonicalize_loop_headers ();
+
/* Compute the dominators. */
- dom = sbitmap_vector_alloc (last_basic_block, last_basic_block);
+ loops->cfg.dom = dom = sbitmap_vector_alloc (last_basic_block, last_basic_block);
calculate_dominance_info (NULL, dom, CDI_DOMINATORS);
- /* Count the number of loop edges (back edges). This should be the
+ /* 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)
{
+ int more_latches = 0;
+
header->loop_depth = 0;
for (e = header->pred; e; e = e->pred_next)
{
basic_block latch = e->src;
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ if (more_latches)
+ {
+ RESET_BIT (headers, header->index);
+ num_loops--;
+ }
+ break;
+ }
+
/* 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. Note that multiple natural loops
- may share the same header. */
- if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index], header->index))
- num_loops++;
+ from a latch node. */
+ if (latch != ENTRY_BLOCK_PTR && TEST_BIT (dom[latch->index],
+ header->index))
+ {
+ /* 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 = (struct loop **) xcalloc (num_loops + 1, sizeof (struct loop *));
+
+ /* 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];
+
+ /* 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;
+
if (num_loops)
{
/* Compute depth first search order of the CFG so that outer
loops->cfg.dfs_order = dfs_order;
loops->cfg.rc_order = rc_order;
- /* Allocate loop structures. */
- loops->array
- = (struct loop *) xcalloc (num_loops, sizeof (struct loop));
-
- headers = sbitmap_alloc (last_basic_block);
- sbitmap_zero (headers);
+ num_loops = 1;
- loops->shared_headers = sbitmap_alloc (last_basic_block);
- sbitmap_zero (loops->shared_headers);
-
- /* Find and record information about all the natural loops
- in the CFG. */
- num_loops = 0;
- for (b = n_basic_blocks - 1; b >= 0; b--)
+ for (b = 0; b < n_basic_blocks; b++)
{
- basic_block latch;
+ struct loop *loop;
/* Search the nodes of the CFG in reverse completion order
so that we can find outer loops first. */
- latch = BASIC_BLOCK (rc_order[b]);
+ if (!TEST_BIT (headers, rc_order[b]))
+ continue;
+
+ header = BASIC_BLOCK (rc_order[b]);
+
+ loop = loops->parray[num_loops] = xcalloc (1, sizeof (struct loop));
- /* Look for all the possible headers for this latch block. */
- for (e = latch->succ; e; e = e->succ_next)
+ loop->header = header;
+ loop->num = num_loops;
+ num_loops++;
+
+ /* Look for the latch for this header block. */
+ for (e = header->pred; e; e = e->pred_next)
{
- basic_block header = e->dest;
-
- /* Look for forward edges where this block is dominated by
- a successor of 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. Note that multiple natural loops may share
- the same header. */
- if (header != EXIT_BLOCK_PTR
+ basic_block latch = e->src;
+
+ if (latch != ENTRY_BLOCK_PTR
&& TEST_BIT (dom[latch->index], header->index))
{
- struct loop *loop;
-
- loop = loops->array + num_loops;
-
- loop->header = header;
loop->latch = latch;
- loop->num = num_loops;
-
- num_loops++;
+ break;
}
}
- }
-
- for (i = 0; i < num_loops; i++)
- {
- struct loop *loop = &loops->array[i];
-
- /* Keep track of blocks that are loop headers so
- that we can tell which loops should be merged. */
- if (TEST_BIT (headers, loop->header->index))
- SET_BIT (loops->shared_headers, loop->header->index);
- SET_BIT (headers, loop->header->index);
-
- /* Find nodes contained within the loop. */
- loop->nodes = sbitmap_alloc (last_basic_block);
- loop->num_nodes
- = flow_loop_nodes_find (loop->header, loop->latch, loop->nodes);
-
- /* Compute first and last blocks within the loop.
- These are often the same as the loop header and
- loop latch respectively, but this is not always
- the case. */
-
- FOR_EACH_BB (bb)
- if (TEST_BIT (loop->nodes, bb->index))
- break;
- loop->first = bb;
-
- FOR_EACH_BB_REVERSE (bb)
- if (TEST_BIT (loop->nodes, bb->index))
- break;
- loop->last = bb;
- flow_loop_scan (loops, loop, flags);
+ flow_loop_tree_node_add (header->loop_father, loop);
+ loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
}
- /* Natural loops with shared headers may either be disjoint or
- nested. Disjoint loops with shared headers cannot be inner
- loops and should be merged. For now just mark loops that share
- headers. */
- for (i = 0; i < num_loops; i++)
- if (TEST_BIT (loops->shared_headers, loops->array[i].header->index))
- loops->array[i].shared = 1;
-
sbitmap_free (headers);
- }
- else
- sbitmap_vector_free (dom);
- loops->num = num_loops;
+ /* Assign the loop nesting depth and enclosed loop level for each
+ loop. */
+ loops->levels = flow_loops_level_compute (loops);
- /* Build the loop hierarchy tree. */
- flow_loops_tree_build (loops);
+ /* Scan the loops. */
+ for (i = 1; i < num_loops; i++)
+ flow_loop_scan (loops, loops->parray[i], flags);
- /* Assign the loop nesting depth and enclosed loop level for each
- loop. */
- loops->levels = flow_loops_level_compute (loops);
+ loops->num = num_loops;
+ }
+ else
+ {
+ loops->cfg.dom = NULL;
+ sbitmap_vector_free (dom);
+ }
+#ifdef ENABLE_CHECKING
+ verify_flow_info ();
+ verify_loop_structure (loops, 0);
+#endif
- return num_loops;
+ return loops->num;
}
/* Update the information regarding the loops in the CFG
{
/* 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->array)
+ if (loops->parray)
flow_loops_free (loops);
return flow_loops_find (loops, flags);
}
+/* Return non-zero if basic block BB belongs to LOOP. */
+bool
+flow_bb_inside_loop_p (loop, bb)
+ 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);
+}
+
/* Return non-zero if edge E enters header of LOOP from outside of LOOP. */
-int
+bool
flow_loop_outside_edge_p (loop, e)
const struct loop *loop;
edge e;
{
if (e->dest != loop->header)
abort ();
+ 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;
+{
+ return bb != (basic_block) glb_header;
+}
+
+/* Gets basic blocks of a loop. */
+basic_block *
+get_loop_body (loop)
+ const struct loop *loop;
+{
+ basic_block *tovisit, bb;
+ int tv = 0;
+
+ if (!loop->num_nodes)
+ abort ();
+
+ 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 ();
+ FOR_EACH_BB (bb)
+ tovisit[tv++] = bb;
+ tovisit[tv++] = EXIT_BLOCK_PTR;
+ }
+ else if (loop->latch != loop->header)
+ {
+ tv = dfs_enumerate_from (loop->latch, 1, glb_enum_p,
+ tovisit + 1, loop->num_nodes - 1,
+ loop->header) + 1;
+ }
+
+ if (tv != loop->num_nodes)
+ abort ();
+ return tovisit;
+}
+
+/* Adds basic block BB to LOOP. */
+void
+add_bb_to_loop (bb, loop)
+ basic_block bb;
+ struct loop *loop;
+ {
+ int i;
+
+ bb->loop_father = loop;
+ bb->loop_depth = loop->depth;
+ loop->num_nodes++;
+ for (i = 0; i < loop->depth; i++)
+ loop->pred[i]->num_nodes++;
+ }
+
+/* Remove basic block BB from loops. */
+void
+remove_bb_from_loops (bb)
+ basic_block bb;
+ {
+ int i;
+ struct loop *loop = bb->loop_father;
+
+ loop->num_nodes--;
+ for (i = 0; i < loop->depth; i++)
+ 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;
+{
+ 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];
+
+ while (loop_s != loop_d)
+ {
+ loop_s = loop_s->outer;
+ loop_d = loop_d->outer;
+ }
+ return loop_s;
+}
+
+/* Checks that LOOPS are allright:
+ -- sizes of loops are allright
+ -- 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
+ */
+void
+verify_loop_structure (loops, flags)
+ struct loops *loops;
+ int flags;
+{
+ int *sizes, i, j;
+ basic_block *bbs, bb;
+ struct loop *loop;
+ int err = 0;
+
+ /* Check sizes. */
+ sizes = xcalloc (loops->num, sizeof (int));
+ sizes[0] = 2;
+
+ FOR_EACH_BB (bb)
+ for (loop = bb->loop_father; loop; loop = loop->outer)
+ sizes[loop->num]++;
+
+ for (i = 0; i < loops->num; i++)
+ {
+ if (!loops->parray[i])
+ continue;
+
+ if (loops->parray[i]->num_nodes != sizes[i])
+ {
+ error ("Size of loop %d should be %d, not %d.",
+ i, sizes[i], loops->parray[i]->num_nodes);
+ err = 1;
+ }
+ }
+
+ free (sizes);
+
+ /* Check get_loop_body. */
+ for (i = 1; i < loops->num; i++)
+ {
+ 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);
+ err = 1;
+ }
+ free (bbs);
+ }
+
+ /* Check headers and latches. */
+ for (i = 1; i < loops->num; i++)
+ {
+ loop = loops->parray[i];
+ if (!loop)
+ continue;
+
+ if ((flags & VLS_EXPECT_PREHEADERS)
+ && (!loop->header->pred->pred_next
+ || loop->header->pred->pred_next->pred_next))
+ {
+ error ("Loop %d's header does not have exactly 2 entries.", i);
+ err = 1;
+ }
+ if (flags & VLS_EXPECT_SIMPLE_LATCHES)
+ {
+ if (!loop->latch->succ
+ || loop->latch->succ->succ_next)
+ {
+ error ("Loop %d's latch does not have exactly 1 successor.", i);
+ err = 1;
+ }
+ if (loop->latch->succ->dest != loop->header)
+ {
+ 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);
+ err = 1;
+ }
+ }
+ if (loop->header->loop_father != loop)
+ {
+ error ("Loop %d's header does not belong directly to it.", i);
+ err = 1;
+ }
+ }
+
+ if (err)
+ abort ();
+}
+
+/* Returns latch edge of LOOP. */
+edge
+loop_latch_edge (loop)
+ struct loop *loop;
+{
+ edge e;
+
+ for (e = loop->header->pred; e->src != loop->latch; e = e->pred_next)
+ continue;
- return (e->src == ENTRY_BLOCK_PTR)
- || ! TEST_BIT (loop->nodes, e->src->index);
+ return e;
}
+
+/* Returns preheader edge of LOOP. */
+edge
+loop_preheader_edge (loop)
+ struct loop *loop;
+{
+ edge e;
+
+ for (e = loop->header->pred; e->src == loop->latch; e = e->pred_next)
+ continue;
+
+ return e;
+}
+
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