/* Natural loop discovery code for GNU compiler.
- Copyright (C) 2000, 2001, 2003 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008
+ 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 "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
-
-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, dominance_info);
-static int flow_loop_level_compute (struct loop *);
-static int flow_loops_level_compute (struct loops *);
-static void establish_preds (struct loop *);
-static basic_block make_forwarder_block (basic_block, int, int, edge, int);
-static void canonicalize_loop_headers (void);
-static bool glb_enum_p (basic_block, void *);
-static void redirect_edge_with_latch_update (edge, basic_block);
+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 || ! loops->cfg.dom)
+ 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]);
+/* Return nonzero if the nodes of LOOP are a subset of OUTER. */
- fputs ("\n", file);
- }
+bool
+flow_loop_nested_p (const struct loop *outer, const struct loop *loop)
+{
+ unsigned odepth = loop_depth (outer);
- /* 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]);
+ return (loop_depth (loop) > odepth
+ && VEC_index (loop_p, loop->superloops, odepth) == outer);
+}
- fputs ("\n", file);
- }
+/* 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)
+{
+ unsigned ldepth = loop_depth (loop);
+
+ gcc_assert (depth <= ldepth);
+
+ if (depth == ldepth)
+ return loop;
+
+ return VEC_index (loop_p, loop->superloops, depth);
}
-/* Return nonzero if the nodes of LOOP are a subset of OUTER. */
+/* Returns the list of the latch edges of LOOP. */
-bool
-flow_loop_nested_p (const struct loop *outer, const struct loop *loop)
+static VEC (edge, heap) *
+get_loop_latch_edges (const struct loop *loop)
{
- return loop->depth > outer->depth
- && loop->pred[outer->depth] == outer;
+ 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 (i = 0; VEC_iterate (edge, latches, i, e); i++)
+ 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 (i = 0; VEC_iterate (loop_p, loops->larray, i, loop); i++)
{
- struct loop *loop = loops->parray[i];
-
if (!loop)
continue;
flow_loop_free (loop);
}
- 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)
- free (loops->cfg.rc_order);
-
- }
-}
-
-/* Find the entry edges into the LOOP. */
-
-static void
-flow_loop_entry_edges_find (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 (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++)
- {
- 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;
- }
+ VEC_free (loop_p, gc, loops->larray);
}
- 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;
- int sp;
+ VEC (basic_block, heap) *stack = NULL;
int num_nodes = 1;
+ edge latch;
+ edge_iterator latch_ei;
+ unsigned depth = loop_depth (loop);
header->loop_father = loop;
- header->loop_depth = loop->depth;
+ header->loop_depth = depth;
- if (loop->latch->loop_father != loop)
+ FOR_EACH_EDGE (latch, latch_ei, loop->header->preds)
{
- stack = (basic_block *) xmalloc (n_basic_blocks * sizeof (basic_block));
- sp = 0;
+ if (latch->src->loop_father == loop
+ || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header))
+ continue;
+
num_nodes++;
- stack[sp++] = loop->latch;
- loop->latch->loop_father = loop;
- loop->latch->loop_depth = loop->depth;
+ VEC_safe_push (basic_block, heap, stack, latch->src);
+ latch->src->loop_father = loop;
+ latch->src->loop_depth = depth;
- while (sp)
+ while (!VEC_empty (basic_block, stack))
{
basic_block node;
edge e;
+ edge_iterator ei;
- node = stack[--sp];
+ node = VEC_pop (basic_block, stack);
- for (e = node->pred; e; e = e->pred_next)
+ FOR_EACH_EDGE (e, ei, node->preds)
{
basic_block ancestor = e->src;
- if (ancestor != ENTRY_BLOCK_PTR
- && ancestor->loop_father != loop)
+ if (ancestor->loop_father != loop)
{
ancestor->loop_father = loop;
- ancestor->loop_depth = loop->depth;
+ ancestor->loop_depth = depth;
num_nodes++;
- stack[sp++] = ancestor;
+ VEC_safe_push (basic_block, heap, stack, ancestor);
}
}
}
- free (stack);
}
- 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 (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;
+ VEC_free (basic_block, heap, stack);
- /* 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 num_nodes;
}
-/* 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. */
-
-static basic_block
-flow_loop_pre_header_find (basic_block header, dominance_info dom)
-{
- basic_block pre_header;
- edge e;
-
- /* 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;
-
- if (node != ENTRY_BLOCK_PTR
- && ! dominated_by_p (dom, 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;
-}
+/* Records the vector of superloops of the loop LOOP, whose immediate
+ superloop is FATHER. */
static void
-establish_preds (struct loop *loop)
+establish_preds (struct loop *loop, struct loop *father)
{
- struct loop *ploop, *father = loop->outer;
+ loop_p ploop;
+ unsigned depth = loop_depth (father) + 1;
+ unsigned i;
- 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;
+ VEC_truncate (loop_p, loop->superloops, 0);
+ VEC_reserve (loop_p, gc, loop->superloops, depth);
+ for (i = 0; VEC_iterate (loop_p, father->superloops, i, ploop); i++)
+ VEC_quick_push (loop_p, loop->superloops, ploop);
+ VEC_quick_push (loop_p, loop->superloops, father);
for (ploop = loop->inner; ploop; ploop = ploop->next)
- establish_preds (ploop);
+ establish_preds (ploop, loop);
}
/* Add LOOP to the loop hierarchy tree where FATHER is father of the
{
loop->next = father->inner;
father->inner = loop;
- loop->outer = father;
- establish_preds (loop);
+ establish_preds (loop, father);
}
/* Remove LOOP from the loop hierarchy tree. */
{
struct loop *prev, *father;
- father = loop->outer;
- loop->outer = NULL;
+ father = loop_outer (loop);
/* 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);
+ for (prev = father->inner; prev->next != loop; prev = prev->next)
+ continue;
prev->next = loop->next;
}
- 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. Returns the loop level. */
-
-static int
-flow_loop_level_compute (struct loop *loop)
-{
- struct loop *inner;
- int level = 1;
-
- if (! loop)
- return 0;
-
- /* 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)
- {
- int ilevel = flow_loop_level_compute (inner) + 1;
-
- if (ilevel > level)
- level = ilevel;
- }
-
- loop->level = level;
- return level;
+ VEC_truncate (loop_p, loop->superloops, 0);
}
-/* Compute the loop nesting depth and enclosed loop level for the loop
- hierarchy tree specified by LOOPS. Return the maximum enclosed loop
- level. */
+/* Allocates and returns new loop structure. */
-static int
-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 loops *loops, struct loop *loop, int flags)
+struct loop *
+alloc_loop (void)
{
- 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);
- }
+ struct loop *loop = GGC_CNEW (struct loop);
- 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 (edge e, basic_block to)
-{
- basic_block jump;
+ loop->exits = GGC_CNEW (struct loop_exit);
+ loop->exits->next = loop->exits->prev = loop->exits;
+ loop->can_be_parallel = false;
+ loop->single_iv = NULL_TREE;
- 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 loop;
}
-/* 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. */
+/* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops
+ (including the root of the loop tree). */
-static basic_block
-make_forwarder_block (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));
-
- /* For empty block split_block will return NULL. */
- if (bb->end == insn)
- emit_note_after (NOTE_INSN_DELETED, insn);
-
- 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 (void)
+init_loops_structure (struct loops *loops, unsigned num_loops)
{
- 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)
- {
- 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
- && dominated_by_p (dom, latch, header))
- {
- num_latches++;
- LATCH_EDGE (e) = 1;
- }
- }
- if (have_abnormal_edge)
- HEADER_BLOCK (header) = 0;
- else
- HEADER_BLOCK (header) = num_latches;
- }
+ struct loop *root;
- 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);
- }
+ memset (loops, 0, sizeof *loops);
+ loops->larray = VEC_alloc (loop_p, gc, num_loops);
- free_aux_for_blocks ();
- free_aux_for_edges ();
- free_dominance_info (dom);
+ /* 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;
}
/* 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;
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);
+ /* Ensure that the dominators are computed. */
+ calculate_dominance_info (CDI_DOMINATORS);
/* Taking care of this degenerate case makes the rest of
this code simpler. */
- if (n_basic_blocks == 0)
- return 0;
+ if (n_basic_blocks == NUM_FIXED_BLOCKS)
+ {
+ init_loops_structure (loops, 1);
+ return 1;
+ }
dfs_order = NULL;
rc_order = NULL;
- /* 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)
{
- int more_latches = 0;
+ edge_iterator ei;
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 ();
- 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];
+ init_loops_structure (loops, num_loops + 1);
/* 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;
{
/* 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));
- 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;
+ 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);
num_loops = 1;
- for (b = 0; b < n_basic_blocks; b++)
+ for (b = 0; b < n_basic_blocks - NUM_FIXED_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. */
header = BASIC_BLOCK (rc_order[b]);
- loop = loops->parray[num_loops] = xcalloc (1, sizeof (struct loop));
+ loop = alloc_loop ();
+ VEC_quick_push (loop_p, loops->larray, loop);
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)
+ flow_loop_tree_node_add (header->loop_father, loop);
+ loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
+
+ /* Look for the latch for this header block, if it has just a
+ single one. */
+ FOR_EACH_EDGE (e, ei, header->preds)
{
basic_block latch = e->src;
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (dom, latch, header))
+ if (flow_bb_inside_loop_p (loop, latch))
{
+ if (loop->latch != NULL)
+ {
+ /* More than one latch edge. */
+ loop->latch = NULL;
+ break;
+ }
loop->latch = latch;
- break;
}
}
-
- flow_loop_tree_node_add (header->loop_father, loop);
- loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
}
- sbitmap_free (headers);
+ free (dfs_order);
+ free (rc_order);
+ }
- /* Assign the loop nesting depth and enclosed loop level for each
- loop. */
- loops->levels = flow_loops_level_compute (loops);
+ sbitmap_free (headers);
- /* Scan the loops. */
- for (i = 1; i < num_loops; i++)
- flow_loop_scan (loops, loops->parray[i], flags);
+ loops->exits = NULL;
+ return VEC_length (loop_p, loops->larray);
+}
- loops->num = num_loops;
- }
- else
+/* 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
+
+/* Minimum number of samples for that we apply
+ find_subloop_latch_edge_by_profile heuristics. */
+#define HEAVY_EDGE_MIN_SAMPLES 10
+
+/* 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.
+
+ 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). */
+
+static edge
+find_subloop_latch_edge_by_profile (VEC (edge, heap) *latches)
+{
+ unsigned i;
+ edge e, me = NULL;
+ gcov_type mcount = 0, tcount = 0;
+
+ for (i = 0; VEC_iterate (edge, latches, i, e); i++)
{
- loops->cfg.dom = NULL;
- free_dominance_info (dom);
+ if (e->count > mcount)
+ {
+ me = e;
+ mcount = e->count;
+ }
+ tcount += e->count;
}
- loops->state = 0;
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
- verify_loop_structure (loops);
-#endif
+ if (tcount < HEAVY_EDGE_MIN_SAMPLES
+ || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount)
+ return NULL;
- return loops->num;
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using profile information.\n",
+ me->src->index, me->dest->index);
+ return me;
}
-/* Update the information regarding the loops in the CFG
- specified by LOOPS. */
+/* 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.
-int
-flow_loops_update (struct loops *loops, int flags)
+ 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)
{
- /* 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);
+ edge e, latch = VEC_index (edge, latches, 0);
+ unsigned i;
+ gimple phi;
+ gimple_stmt_iterator psi;
+ tree lop;
+ basic_block bb;
- return flow_loops_find (loops, flags);
-}
+ /* 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;
-/* Return nonzero if basic block BB belongs to LOOP. */
-bool
-flow_bb_inside_loop_p (const struct loop *loop, const basic_block bb)
+ /* Verify that it dominates all the latch edges. */
+ for (i = 0; VEC_iterate (edge, latches, i, e); i++)
+ 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))
+ {
+ 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 (i = 0; VEC_iterate (edge, latches, i, e); i++)
+ if (e != latch
+ && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop)
+ return NULL;
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using iv structure.\n",
+ latch->src->index, latch->dest->index);
+ return latch;
+}
+
+/* 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 edge
+find_subloop_latch_edge (struct loop *loop)
+{
+ VEC (edge, heap) *latches = get_loop_latch_edges (loop);
+ edge latch = NULL;
+
+ if (VEC_length (edge, latches) > 1)
+ {
+ 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);
+ }
+
+ VEC_free (edge, heap, latches);
+ return latch;
+}
+
+/* Callback for make_forwarder_block. Returns true if the edge E is marked
+ in the set MFB_REIS_SET. */
+
+static struct pointer_set_t *mfb_reis_set;
+static bool
+mfb_redirect_edges_in_set (edge e)
+{
+ return pointer_set_contains (mfb_reis_set, e);
+}
+
+/* Creates a subloop of LOOP with latch edge LATCH. */
+
+static void
+form_subloop (struct loop *loop, edge latch)
+{
+ edge_iterator ei;
+ edge e, new_entry;
+ struct loop *new_loop;
+
+ mfb_reis_set = pointer_set_create ();
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ {
+ 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);
+}
+
+/* Make all the latch edges of LOOP to go to a single forwarder block --
+ a new latch of 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 (i = 0; VEC_iterate (edge, latches, i, e); i++)
+ 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;
+ }
+
+ VEC_free (edge, heap, latches);
+}
+
+/* LOOP may have several latch edges. Transform it into (possibly several)
+ loops with single latch edge. */
+
+static void
+disambiguate_multiple_latches (struct loop *loop)
+{
+ 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);
+}
+
+/* Split loops with multiple latch edges. */
+
+void
+disambiguate_loops_with_multiple_latches (void)
+{
+ loop_iterator li;
+ struct loop *loop;
+
+ FOR_EACH_LOOP (li, loop, 0)
+ {
+ if (!loop->latch)
+ disambiguate_multiple_latches (loop);
+ }
+}
+
+/* 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;
return loop == source_loop || flow_loop_nested_p (loop, source_loop);
}
-/* Return nonzero if edge E enters header of LOOP from outside of LOOP. */
-
-bool
-flow_loop_outside_edge_p (const struct loop *loop, edge e)
+/* Enumeration predicate for get_loop_body_with_size. */
+static bool
+glb_enum_p (const_basic_block bb, const void *glb_loop)
{
- if (e->dest != loop->header)
- abort ();
- return !flow_bb_inside_loop_p (loop, e->src);
+ const struct loop *const loop = (const struct loop *) glb_loop;
+ return (bb != loop->header
+ && dominated_by_p (CDI_DOMINATORS, bb, loop->header));
}
-/* Enumeration predicate for get_loop_body. */
-static bool
-glb_enum_p (basic_block bb, void *glb_header)
+/* 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. */
+
+unsigned
+get_loop_body_with_size (const struct loop *loop, basic_block *body,
+ unsigned max_size)
{
- return bb != (basic_block) glb_header;
+ return dfs_enumerate_from (loop->header, 1, glb_enum_p,
+ body, max_size, loop);
}
-/* 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 (const struct loop *loop)
{
- basic_block *tovisit, bb;
+ basic_block *body, bb;
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;
+ body = XCNEWVEC (basic_block, loop->num_nodes);
if (loop->latch == EXIT_BLOCK_PTR)
{
- /* There may be blocks unreachable from EXIT_BLOCK. */
- if (loop->num_nodes != (unsigned) n_basic_blocks + 2)
- abort ();
+ /* 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)
- tovisit[tv++] = bb;
- tovisit[tv++] = EXIT_BLOCK_PTR;
+ body[tv++] = bb;
}
- else if (loop->latch != loop->header)
+ else
+ tv = get_loop_body_with_size (loop, body, loop->num_nodes);
+
+ gcc_assert (tv == loop->num_nodes);
+ return body;
+}
+
+/* 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))
{
- tv = dfs_enumerate_from (loop->latch, 1, glb_enum_p,
- tovisit + 1, loop->num_nodes - 1,
- loop->header) + 1;
+ 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 (tv != loop->num_nodes)
- abort ();
+ 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 = XCNEWVEC (basic_block, loop->num_nodes);
+
+ 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;
}
-/* 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)
+/* Gets body of a LOOP sorted via provided BB_COMPARATOR. */
+
+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);
+
+ qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator);
+
+ return bbs;
+}
+
+/* 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 = XCNEWVEC (basic_block, loop->num_nodes);
+ 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;
+}
+
+/* Hash function for struct loop_exit. */
+
+static hashval_t
+loop_exit_hash (const void *ex)
+{
+ const struct loop_exit *const exit = (const struct loop_exit *) ex;
+
+ return htab_hash_pointer (exit->e);
+}
+
+/* Equality function for struct loop_exit. Compares with edge. */
+
+static int
+loop_exit_eq (const void *ex, const void *e)
+{
+ const struct loop_exit *const exit = (const struct loop_exit *) ex;
+
+ return exit->e == e;
+}
+
+/* Frees the list of loop exit descriptions EX. */
+
+static void
+loop_exit_free (void *ex)
+{
+ struct loop_exit *exit = (struct loop_exit *) ex, *next;
+
+ for (; exit; exit = next)
+ {
+ next = exit->next_e;
+
+ exit->next->prev = exit->prev;
+ exit->prev->next = exit->next;
+
+ ggc_free (exit);
+ }
+}
+
+/* Returns the list of records for E as an exit of a loop. */
+
+static struct loop_exit *
+get_exit_descriptions (edge e)
+{
+ return (struct loop_exit *) htab_find_with_hash (current_loops->exits, e,
+ htab_hash_pointer (e));
+}
+
+/* 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. */
+
+void
+rescan_loop_exit (edge e, bool new_edge, bool removed)
+{
+ void **slot;
+ struct loop_exit *exits = NULL, *exit;
+ struct loop *aloop, *cloop;
+
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+ return;
+
+ if (!removed
+ && e->src->loop_father != NULL
+ && e->dest->loop_father != NULL
+ && !flow_bb_inside_loop_p (e->src->loop_father, e->dest))
+ {
+ 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_NEW (struct 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;
+ }
+ }
+
+ 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)
+ {
+ if (*slot)
+ loop_exit_free (*slot);
+ *slot = exits;
+ }
+ else
+ htab_clear_slot (current_loops->exits, slot);
+}
+
+/* For each loop, record list of exit edges, and start maintaining these
+ lists. */
+
+void
+record_loop_exits (void)
+{
+ basic_block bb;
+ edge_iterator ei;
+ edge e;
+
+ if (!current_loops)
+ return;
+
+ 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_alloc (2 * number_of_loops (),
+ loop_exit_hash,
+ loop_exit_eq,
+ loop_exit_free,
+ ggc_calloc, ggc_free);
+
+ FOR_EACH_BB (bb)
+ {
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ rescan_loop_exit (e, true, false);
+ }
+ }
+}
+
+/* Dumps information about the exit in *SLOT to FILE.
+ Callback for htab_traverse. */
+
+static int
+dump_recorded_exit (void **slot, void *file)
+{
+ struct loop_exit *exit = (struct loop_exit *) *slot;
+ unsigned n = 0;
+ edge e = exit->e;
+
+ for (; exit != NULL; exit = exit->next_e)
+ n++;
+
+ fprintf ((FILE*) file, "Edge %d->%d exits %u loops\n",
+ e->src->index, e->dest->index, n);
+
+ return 1;
+}
+
+/* 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);
+}
+
+/* Releases lists of loop exits. */
+
+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);
+}
+
+/* Returns the list of the exit edges of a LOOP. */
+
+VEC (edge, heap) *
+get_loop_exit_edges (const struct loop *loop)
+{
+ VEC (edge, heap) *edges = NULL;
+ edge e;
+ unsigned i;
+ basic_block *body;
+ edge_iterator ei;
+ struct loop_exit *exit;
+
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+
+ /* 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;
+}
+
+/* Counts the number of conditional branches inside LOOP. */
+
+unsigned
+num_loop_branches (const struct loop *loop)
{
- edge *edges, e;
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++)
- 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;
+ if (EDGE_COUNT (body[i]->succs) >= 2)
+ n++;
free (body);
- return edges;
+ return n;
}
/* Adds basic block BB to LOOP. */
void
add_bb_to_loop (basic_block bb, struct loop *loop)
{
- int i;
+ unsigned i;
+ loop_p ploop;
+ edge_iterator ei;
+ edge e;
+
+ gcc_assert (bb->loop_father == NULL);
+ bb->loop_father = loop;
+ bb->loop_depth = loop_depth (loop);
+ loop->num_nodes++;
+ for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++)
+ ploop->num_nodes++;
- bb->loop_father = loop;
- bb->loop_depth = loop->depth;
- loop->num_nodes++;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->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;
+
+ gcc_assert (loop != NULL);
+ loop->num_nodes--;
+ for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++)
+ ploop->num_nodes--;
+ bb->loop_father = NULL;
+ bb->loop_depth = 0;
- loop->num_nodes--;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->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);
+ bbs[i]->loop_father = outer;
- /* Remove loop from loops array. */
- loops->parray[loop->num] = NULL;
-
- /* Free loop data. */
- flow_loop_free (loop);
+ 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
-- irreducible loops are correctly marked
*/
void
-verify_loop_structure (struct loops *loops)
+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;
}
}
- free (sizes);
-
/* 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);
}
- if (err)
- abort ();
+ /* 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))
+ {
+ unsigned n_exits = 0, eloops;
+
+ memset (sizes, 0, sizeof (unsigned) * num);
+ FOR_EACH_BB (bb)
+ {
+ edge_iterator ei;
+ if (bb->loop_father == current_loops->tree_root)
+ continue;
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ 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))
+ {
+ eloops--;
+ sizes[loop->num]++;
+ }
+
+ if (eloops != 0)
+ {
+ error ("Wrong list of exited loops for edge %d->%d",
+ e->src->index, e->dest->index);
+ err = 1;
+ }
+ }
+ }
+
+ if (n_exits != htab_elements (current_loops->exits))
+ {
+ error ("Too many loop exits recorded");
+ err = 1;
+ }
+
+ 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 ("%d exits recorded for loop %d (having %d exits)",
+ eloops, loop->num, sizes[loop->num]);
+ err = 1;
+ }
+ }
+ }
+
+ gcc_assert (!err);
+
+ free (sizes);
}
/* Returns latch edge of LOOP. */
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;
+
+ gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS));
- 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 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 edge exiting LOOP. */
+
+bool
+is_loop_exit (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;
}
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