/* Natural loop discovery code for GNU compiler.
- Copyright (C) 2000, 2001, 2003, 2004, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "flags.h"
#include "tree.h"
#include "tree-flow.h"
-
-/* Ratio of frequencies of edges so that one of more latch edges is
- considered to belong to inner loop with same header. */
-#define HEAVY_EDGE_RATIO 8
-
-#define HEADER_BLOCK(B) (* (int *) (B)->aux)
-#define LATCH_EDGE(E) (*(int *) (E)->aux)
+#include "pointer-set.h"
+#include "output.h"
+#include "ggc.h"
static void flow_loops_cfg_dump (FILE *);
-static void establish_preds (struct loop *);
-static void canonicalize_loop_headers (void);
-static bool glb_enum_p (basic_block, void *);
\f
/* Dump loop related CFG information. */
bool
flow_loop_nested_p (const struct loop *outer, const struct loop *loop)
{
- return (loop->depth > outer->depth
- && loop->pred[outer->depth] == outer);
+ unsigned odepth = loop_depth (outer);
+
+ return (loop_depth (loop) > odepth
+ && VEC_index (loop_p, loop->superloops, odepth) == outer);
}
/* Returns the loop such that LOOP is nested DEPTH (indexed from zero)
struct loop *
superloop_at_depth (struct loop *loop, unsigned depth)
{
- gcc_assert (depth <= (unsigned) loop->depth);
+ unsigned ldepth = loop_depth (loop);
+
+ gcc_assert (depth <= ldepth);
- if (depth == (unsigned) loop->depth)
+ if (depth == ldepth)
return loop;
- return loop->pred[depth];
+ return VEC_index (loop_p, loop->superloops, depth);
+}
+
+/* Returns the list of the latch edges of LOOP. */
+
+static VEC (edge, heap) *
+get_loop_latch_edges (const struct loop *loop)
+{
+ edge_iterator ei;
+ edge e;
+ VEC (edge, heap) *ret = NULL;
+
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ {
+ if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header))
+ VEC_safe_push (edge, heap, ret, e);
+ }
+
+ return ret;
}
/* Dump the loop information specified by LOOP to the stream FILE
{
basic_block *bbs;
unsigned i;
+ VEC (edge, heap) *latches;
+ edge e;
if (! loop || ! loop->header)
return;
fprintf (file, ";;\n;; Loop %d\n", loop->num);
- fprintf (file, ";; header %d, latch %d\n",
- loop->header->index, loop->latch->index);
+ 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");
+ }
+
fprintf (file, ";; depth %d, outer %ld\n",
- loop->depth, (long) (loop->outer ? loop->outer->num : -1));
+ loop_depth (loop), (long) (loop_outer (loop)
+ ? loop_outer (loop)->num : -1));
fprintf (file, ";; nodes:");
bbs = get_loop_body (loop);
}
/* Free data allocated for LOOP. */
+
void
flow_loop_free (struct loop *loop)
{
struct loop_exit *exit, *next;
- if (loop->pred)
- free (loop->pred);
+ 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)
+ for (exit = loop->exits->next; exit != loop->exits; exit = next)
{
next = exit->next;
exit->next = exit;
exit->prev = exit;
}
-
- free (loop);
+
+ ggc_free (loop->exits);
+ ggc_free (loop);
}
/* Free all the memory allocated for LOOPS. */
flow_loop_free (loop);
}
- VEC_free (loop_p, heap, loops->larray);
- loops->larray = NULL;
+ VEC_free (loop_p, gc, loops->larray);
}
}
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 = XNEWVEC (basic_block, n_basic_blocks);
- 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_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);
}
+ VEC_free (basic_block, heap, stack);
+
return num_nodes;
}
+/* 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->depth = father->depth + 1;
-
- /* Remember the current loop depth if it is the largest seen so far. */
- cfun->max_loop_depth = MAX (cfun->max_loop_depth, loop->depth);
+ loop_p ploop;
+ unsigned depth = loop_depth (father) + 1;
+ unsigned i;
- if (loop->pred)
- free (loop->pred);
- loop->pred = XNEWVEC (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;
-}
-
-/* A callback to update latch and header info for basic block JUMP created
- by redirecting an edge. */
-
-static void
-update_latch_info (basic_block jump)
-{
- alloc_aux_for_block (jump, sizeof (int));
- HEADER_BLOCK (jump) = 0;
- alloc_aux_for_edge (single_pred_edge (jump), sizeof (int));
- LATCH_EDGE (single_pred_edge (jump)) = 0;
- set_immediate_dominator (CDI_DOMINATORS, jump, single_pred (jump));
+ VEC_truncate (loop_p, loop->superloops, 0);
}
-/* A callback for make_forwarder block, to redirect all edges except for
- MFB_KJ_EDGE to the entry part. E is the edge for that we should decide
- whether to redirect it. */
+/* Allocates and returns new loop structure. */
-static edge mfb_kj_edge;
-static bool
-mfb_keep_just (edge e)
+struct loop *
+alloc_loop (void)
{
- return e != mfb_kj_edge;
-}
+ struct loop *loop = GGC_CNEW (struct loop);
-/* A callback for make_forwarder block, to redirect the latch edges into an
- entry part. E is the edge for that we should decide whether to redirect
- it. */
+ 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;
-static bool
-mfb_keep_nonlatch (edge e)
-{
- return LATCH_EDGE (e);
+ return loop;
}
-/* Takes care of merging natural loops with shared headers. */
+/* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops
+ (including the root of the loop tree). */
static void
-canonicalize_loop_headers (void)
+init_loops_structure (struct loops *loops, unsigned num_loops)
{
- basic_block header;
- edge e;
-
- alloc_aux_for_blocks (sizeof (int));
- alloc_aux_for_edges (sizeof (int));
-
- /* Split blocks so that each loop has only single latch. */
- FOR_EACH_BB (header)
- {
- edge_iterator ei;
- int num_latches = 0;
- int have_abnormal_edge = 0;
-
- FOR_EACH_EDGE (e, ei, header->preds)
- {
- basic_block latch = e->src;
-
- if (e->flags & EDGE_ABNORMAL)
- have_abnormal_edge = 1;
-
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (CDI_DOMINATORS, latch, header))
- {
- num_latches++;
- LATCH_EDGE (e) = 1;
- }
- }
- if (have_abnormal_edge)
- HEADER_BLOCK (header) = 0;
- else
- HEADER_BLOCK (header) = num_latches;
- }
-
- if (HEADER_BLOCK (single_succ (ENTRY_BLOCK_PTR)))
- {
- basic_block bb;
-
- /* We could not redirect edges freely here. On the other hand,
- we can simply split the edge from entry block. */
- bb = split_edge (single_succ_edge (ENTRY_BLOCK_PTR));
-
- alloc_aux_for_edge (single_succ_edge (bb), sizeof (int));
- LATCH_EDGE (single_succ_edge (bb)) = 0;
- alloc_aux_for_block (bb, sizeof (int));
- HEADER_BLOCK (bb) = 0;
- }
-
- FOR_EACH_BB (header)
- {
- int max_freq, is_heavy;
- edge heavy, tmp_edge;
- edge_iterator ei;
-
- if (HEADER_BLOCK (header) <= 1)
- continue;
-
- /* Find a heavy edge. */
- is_heavy = 1;
- heavy = NULL;
- max_freq = 0;
- FOR_EACH_EDGE (e, ei, header->preds)
- if (LATCH_EDGE (e) &&
- EDGE_FREQUENCY (e) > max_freq)
- max_freq = EDGE_FREQUENCY (e);
- FOR_EACH_EDGE (e, ei, header->preds)
- if (LATCH_EDGE (e) &&
- EDGE_FREQUENCY (e) >= max_freq / HEAVY_EDGE_RATIO)
- {
- if (heavy)
- {
- is_heavy = 0;
- break;
- }
- else
- heavy = e;
- }
-
- if (is_heavy)
- {
- /* Split out the heavy edge, and create inner loop for it. */
- mfb_kj_edge = heavy;
- tmp_edge = make_forwarder_block (header, mfb_keep_just,
- update_latch_info);
- alloc_aux_for_block (tmp_edge->dest, sizeof (int));
- HEADER_BLOCK (tmp_edge->dest) = 1;
- alloc_aux_for_edge (tmp_edge, sizeof (int));
- LATCH_EDGE (tmp_edge) = 0;
- HEADER_BLOCK (header)--;
- }
-
- if (HEADER_BLOCK (header) > 1)
- {
- /* Create a new latch block. */
- tmp_edge = make_forwarder_block (header, mfb_keep_nonlatch,
- update_latch_info);
- alloc_aux_for_block (tmp_edge->dest, sizeof (int));
- HEADER_BLOCK (tmp_edge->src) = 0;
- HEADER_BLOCK (tmp_edge->dest) = 1;
- alloc_aux_for_edge (tmp_edge, sizeof (int));
- LATCH_EDGE (tmp_edge) = 1;
- }
- }
-
- free_aux_for_blocks ();
- free_aux_for_edges ();
-
-#ifdef ENABLE_CHECKING
- verify_dominators (CDI_DOMINATORS);
-#endif
-}
+ struct loop *root;
-/* Allocates and returns new loop structure. */
+ memset (loops, 0, sizeof *loops);
+ loops->larray = VEC_alloc (loop_p, gc, num_loops);
-struct loop *
-alloc_loop (void)
-{
- struct loop *loop = XCNEW (struct loop);
+ /* 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;
- loop->exits.next = loop->exits.prev = &loop->exits;
- return loop;
+ 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
int *rc_order;
basic_block header;
basic_block bb;
- struct loop *root;
-
- memset (loops, 0, sizeof *loops);
- /* We are going to recount the maximum loop depth,
- so throw away the last count. */
- cfun->max_loop_depth = 0;
+ /* 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 == NUM_FIXED_BLOCKS)
- return 0;
+ {
+ init_loops_structure (loops, 1);
+ return 1;
+ }
dfs_order = NULL;
rc_order = NULL;
- /* Ensure that the dominators are computed. */
- calculate_dominance_info (CDI_DOMINATORS);
-
- /* Join loops with shared headers. */
- canonicalize_loop_headers ();
-
/* Count the number of loop headers. This should be the
same as the number of natural loops. */
headers = sbitmap_alloc (last_basic_block);
FOR_EACH_BB (header)
{
edge_iterator ei;
- int more_latches = 0;
header->loop_depth = 0;
&& dominated_by_p (CDI_DOMINATORS, latch, header))
{
/* Shared headers should be eliminated by now. */
- gcc_assert (!more_latches);
- more_latches = 1;
SET_BIT (headers, header->index);
num_loops++;
}
}
/* Allocate loop structures. */
- loops->larray = VEC_alloc (loop_p, heap, num_loops + 1);
-
- /* 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;
+ init_loops_structure (loops, num_loops + 1);
/* Find and record information about all the natural loops
in the CFG. */
loop->num = num_loops;
num_loops++;
- /* Look for the latch for this header block. */
+ 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 (CDI_DOMINATORS, 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);
}
free (dfs_order);
sbitmap_free (headers);
loops->exits = NULL;
- loops->state = 0;
return VEC_length (loop_p, loops->larray);
}
+/* 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++)
+ {
+ if (e->count > mcount)
+ {
+ me = e;
+ mcount = e->count;
+ }
+ tcount += e->count;
+ }
+
+ if (tcount < HEAVY_EDGE_MIN_SAMPLES
+ || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount)
+ return NULL;
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using profile information.\n",
+ me->src->index, me->dest->index);
+ return me;
+}
+
+/* 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.
+
+ 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)
+{
+ edge e, latch = VEC_index (edge, latches, 0);
+ unsigned i;
+ gimple phi;
+ gimple_stmt_iterator psi;
+ tree lop;
+ basic_block bb;
+
+ /* 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;
+
+ /* 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)
+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);
}
-/* Enumeration predicate for get_loop_body. */
+/* Enumeration predicate for get_loop_body_with_size. */
static bool
-glb_enum_p (basic_block bb, void *glb_header)
+glb_enum_p (const_basic_block bb, const void *glb_loop)
{
- return bb != (basic_block) glb_header;
+ const struct loop *const loop = (const struct loop *) glb_loop;
+ return (bb != loop->header
+ && dominated_by_p (CDI_DOMINATORS, bb, loop->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 dfs_enumerate_from (loop->header, 1, glb_enum_p,
+ body, max_size, 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;
gcc_assert (loop->num_nodes);
- tovisit = XCNEWVEC (basic_block, loop->num_nodes);
- 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. */
+ /* 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;
- }
- 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;
+ body[tv++] = bb;
}
+ else
+ tv = get_loop_body_with_size (loop, body, loop->num_nodes);
gcc_assert (tv == loop->num_nodes);
- return tovisit;
+ return body;
}
/* Fills dominance descendants inside LOOP of the basic block BB into
return tovisit;
}
+/* 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 *
static hashval_t
loop_exit_hash (const void *ex)
{
- struct loop_exit *exit = (struct loop_exit *) ex;
+ const struct loop_exit *const exit = (const struct loop_exit *) ex;
return htab_hash_pointer (exit->e);
}
static int
loop_exit_eq (const void *ex, const void *e)
{
- struct loop_exit *exit = (struct loop_exit *) ex;
+ const struct loop_exit *const exit = (const struct loop_exit *) ex;
return exit->e == e;
}
for (; exit; exit = next)
{
next = exit->next_e;
-
+
exit->next->prev = exit->prev;
exit->prev->next = exit->next;
- free (exit);
+ ggc_free (exit);
}
}
static struct loop_exit *
get_exit_descriptions (edge e)
{
- return htab_find_with_hash (current_loops->exits, e,
- htab_hash_pointer (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.
struct loop_exit *exits = NULL, *exit;
struct loop *aloop, *cloop;
- if ((current_loops->state & LOOPS_HAVE_RECORDED_EXITS) == 0)
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
return;
if (!removed
cloop = find_common_loop (e->src->loop_father, e->dest->loop_father);
for (aloop = e->src->loop_father;
aloop != cloop;
- aloop = aloop->outer)
+ aloop = loop_outer (aloop))
{
- exit = XNEW (struct loop_exit);
+ exit = GGC_NEW (struct loop_exit);
exit->e = e;
- exit->next = aloop->exits.next;
- exit->prev = &aloop->exits;
+ 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;
edge_iterator ei;
edge e;
- if (current_loops->state & LOOPS_HAVE_RECORDED_EXITS)
+ if (!current_loops)
return;
- current_loops->state |= LOOPS_HAVE_RECORDED_EXITS;
+
+ 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 (2 * number_of_loops (),
- loop_exit_hash,
- loop_exit_eq,
- loop_exit_free);
+ 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)
{
static int
dump_recorded_exit (void **slot, void *file)
{
- struct loop_exit *exit = *slot;
+ 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, "Edge %d->%d exits %u loops\n",
+ fprintf ((FILE*) file, "Edge %d->%d exits %u loops\n",
e->src->index, e->dest->index, n);
return 1;
void
release_recorded_exits (void)
{
- gcc_assert (current_loops->state & LOOPS_HAVE_RECORDED_EXITS);
+ gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS));
htab_delete (current_loops->exits);
current_loops->exits = NULL;
- current_loops->state &= ~LOOPS_HAVE_RECORDED_EXITS;
+ loops_state_clear (LOOPS_HAVE_RECORDED_EXITS);
}
/* Returns the list of the exit edges of a LOOP. */
/* If we maintain the lists of exits, use them. Otherwise we must
scan the body of the loop. */
- if (current_loops->state & LOOPS_HAVE_RECORDED_EXITS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
{
- for (exit = loop->exits.next; exit->e; exit = exit->next)
+ for (exit = loop->exits->next; exit->e; exit = exit->next)
VEC_safe_push (edge, heap, edges, exit->e);
}
else
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;
+ bb->loop_depth = loop_depth (loop);
loop->num_nodes++;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->num_nodes++;
+ for (i = 0; VEC_iterate (loop_p, loop->superloops, i, ploop); i++)
+ ploop->num_nodes++;
FOR_EACH_EDGE (e, ei, bb->succs)
{
{
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; i < loop->depth; i++)
- loop->pred[i]->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;
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;
}
{
basic_block *bbs;
unsigned i;
+ struct loop *outer = loop_outer (loop);
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;
+ bbs[i]->loop_father = outer;
delete_loop (loop);
}
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_EACH_LOOP (li, loop, LI_INCLUDE_ROOT)
{
i = loop->num;
- if ((current_loops->state & LOOPS_HAVE_PREHEADERS)
+ 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);
err = 1;
}
- if (current_loops->state & LOOPS_HAVE_SIMPLE_LATCHES)
+ if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
{
if (!single_succ_p (loop->latch))
{
error ("loop %d's header does not belong directly to it", i);
err = 1;
}
- if ((current_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);
}
/* Check irreducible loops. */
- if (current_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);
/* Check the recorded loop exits. */
FOR_EACH_LOOP (li, loop, 0)
{
- if (loop->exits.e != NULL)
+ if (!loop->exits || loop->exits->e != NULL)
{
error ("corrupted head of the exits list of loop %d",
loop->num);
{
/* 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;
+ for (mexit = loop->exits, exit = mexit->next, i = 0;
exit->e && exit != mexit;
exit = exit->next)
{
mexit = mexit->next;
}
- if (exit != &loop->exits)
+ if (exit != loop->exits)
{
error ("corrupted exits list of loop %d", loop->num);
err = 1;
}
}
- if ((current_loops->state & LOOPS_HAVE_RECORDED_EXITS) == 0)
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
{
- if (loop->exits.next != &loop->exits)
+ if (loop->exits->next != loop->exits)
{
error ("nonempty exits list of loop %d, but exits are not recorded",
loop->num);
}
}
- if (current_loops->state & LOOPS_HAVE_RECORDED_EXITS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
{
unsigned n_exits = 0, eloops;
exit = get_exit_descriptions (e);
if (!exit)
{
- error ("Exit %d->%d not recorded",
+ error ("Exit %d->%d not recorded",
e->src->index, e->dest->index);
err = 1;
}
for (loop = bb->loop_father;
loop != e->dest->loop_father;
- loop = loop->outer)
+ loop = loop_outer (loop))
{
eloops--;
sizes[loop->num]++;
if (eloops != 0)
{
- error ("Wrong list of exited loops for edge %d->%d",
+ error ("Wrong list of exited loops for edge %d->%d",
e->src->index, e->dest->index);
err = 1;
}
FOR_EACH_LOOP (li, loop, 0)
{
eloops = 0;
- for (exit = loop->exits.next; exit->e; exit = exit->next)
+ for (exit = loop->exits->next; exit->e; exit = exit->next)
eloops++;
if (eloops != sizes[loop->num])
{
edge e;
edge_iterator ei;
+ gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS));
+
FOR_EACH_EDGE (e, ei, loop->header->preds)
if (e->src != loop->latch)
break;
/* Returns true if E is an exit of LOOP. */
bool
-loop_exit_edge_p (const struct loop *loop, edge e)
+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));
edge
single_exit (const struct loop *loop)
{
- struct loop_exit *exit = loop->exits.next;
+ struct loop_exit *exit = loop->exits->next;
- if ((current_loops->state & LOOPS_HAVE_RECORDED_EXITS) == 0)
+ if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
return NULL;
- if (exit->e && exit->next == &loop->exits)
+ 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_EACH_EDGE (e, ei, bb->preds)
+ if (loop_exit_edge_p (loop, e))
+ return true;
+
+ return false;
+}
OSDN Git Service
