/* Natural loop discovery code for GNU compiler.
- Copyright (C) 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2000-2019 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 "coretypes.h"
-#include "tm.h"
+#include "backend.h"
#include "rtl.h"
-#include "hard-reg-set.h"
-#include "obstack.h"
-#include "basic-block.h"
-#include "toplev.h"
-#include "cfgloop.h"
-#include "flags.h"
#include "tree.h"
-#include "tree-flow.h"
-
-/* Ratio of frequencies of edges so that one of more latch edges is
- considered to belong to inner loop with same header. */
-#define HEAVY_EDGE_RATIO 8
+#include "gimple.h"
+#include "cfghooks.h"
+#include "gimple-ssa.h"
+#include "diagnostic-core.h"
+#include "cfganal.h"
+#include "cfgloop.h"
+#include "gimple-iterator.h"
+#include "dumpfile.h"
-#define HEADER_BLOCK(B) (* (int *) (B)->aux)
-#define LATCH_EDGE(E) (*(int *) (E)->aux)
-
-static void flow_loops_cfg_dump (const struct loops *, FILE *);
-static void flow_loop_entry_edges_find (struct loop *);
-static void flow_loop_exit_edges_find (struct loop *);
-static int flow_loop_nodes_find (basic_block, struct loop *);
-static void flow_loop_pre_header_scan (struct loop *);
-static basic_block flow_loop_pre_header_find (basic_block);
-static int flow_loop_level_compute (struct loop *);
-static int flow_loops_level_compute (struct loops *);
-static void establish_preds (struct loop *);
-static void canonicalize_loop_headers (void);
-static bool glb_enum_p (basic_block, void *);
+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)
+ if (!file)
return;
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
edge succ;
edge_iterator ei;
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]);
-
- fputs ("\n", file);
- }
-
- /* 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]);
-
- fputs ("\n", file);
- }
}
/* Return nonzero if the nodes of LOOP are a subset of OUTER. */
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
+ && (*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 (*loop->superloops)[depth];
+}
+
+/* Returns the list of the latch edges of LOOP. */
+
+static vec<edge>
+get_loop_latch_edges (const struct loop *loop)
+{
+ edge_iterator ei;
+ edge e;
+ vec<edge> ret = vNULL;
+
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ {
+ if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header))
+ ret.safe_push (e);
+ }
+
+ return ret;
}
/* Dump the loop information specified by LOOP to the stream FILE
{
basic_block *bbs;
unsigned i;
+ vec<edge> 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, ", 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_EACH_VEC_ELT (latches, i, e)
+ fprintf (file, " %d", e->src->index);
+ latches.release ();
+ fprintf (file, "\n");
+ }
- fprintf (file, ";; header %d, latch %d, pre-header %d\n",
- loop->header->index, loop->latch->index,
- loop->pre_header ? loop->pre_header->index : -1);
- fprintf (file, ";; depth %d, level %d, outer %ld\n",
- loop->depth, loop->level,
- (long) (loop->outer ? loop->outer->num : -1));
+ fprintf (file, ";; depth %d, outer %ld\n",
+ loop_depth (loop), (long) (loop_outer (loop)
+ ? loop_outer (loop)->num : -1));
- if (loop->pre_header_edges)
- flow_edge_list_print (";; pre-header edges", loop->pre_header_edges,
- loop->num_pre_header_edges, file);
+ if (loop->latch)
+ {
+ bool read_profile_p;
+ gcov_type nit = expected_loop_iterations_unbounded (loop, &read_profile_p);
+ if (read_profile_p && !loop->any_estimate)
+ fprintf (file, ";; profile-based iteration count: %" PRIu64 "\n",
+ (uint64_t) nit);
+ }
- 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;
+ 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 (cfun));
- for (i = 0; i < num_loops; i++)
+ FOR_EACH_LOOP (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->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;
-
- gcc_assert (loops->num);
+ loop_p loop;
/* Free the loop descriptors. */
- for (i = 0; i < loops->num; i++)
+ FOR_EACH_VEC_SAFE_ELT (loops->larray, i, loop)
{
- struct loop *loop = loops->parray[i];
-
if (!loop)
continue;
flow_loop_free (loop);
}
- free (loops->parray);
- loops->parray = NULL;
-
- 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;
- edge_iterator ei;
- int num_entries;
-
- num_entries = 0;
- FOR_EACH_EDGE (e, ei, loop->header->preds)
- {
- if (flow_loop_outside_edge_p (loop, e))
- num_entries++;
- }
-
- gcc_assert (num_entries);
-
- loop->entry_edges = xmalloc (num_entries * sizeof (edge *));
-
- num_entries = 0;
- FOR_EACH_EDGE (e, ei, loop->header->preds)
- {
- if (flow_loop_outside_edge_p (loop, e))
- loop->entry_edges[num_entries++] = e;
- }
-
- loop->num_entries = num_entries;
-}
-
-/* Find the exit edges from the LOOP. */
-
-static void
-flow_loop_exit_edges_find (struct loop *loop)
-{
- edge e;
- basic_block node, *bbs;
- unsigned num_exits, i;
-
- loop->exit_edges = NULL;
- loop->num_exits = 0;
-
- /* Check all nodes within the loop to see if there are any
- successors not in the loop. Note that a node may have multiple
- exiting edges. */
- num_exits = 0;
- bbs = get_loop_body (loop);
- for (i = 0; i < loop->num_nodes; i++)
- {
- edge_iterator ei;
- node = bbs[i];
- FOR_EACH_EDGE (e, ei, node->succs)
- {
- basic_block dest = e->dest;
-
- if (!flow_bb_inside_loop_p (loop, dest))
- num_exits++;
- }
- }
-
- if (! num_exits)
- {
- free (bbs);
- return;
- }
-
- loop->exit_edges = xmalloc (num_exits * sizeof (edge *));
-
- /* Store all exiting edges into an array. */
- num_exits = 0;
- for (i = 0; i < loop->num_nodes; i++)
- {
- edge_iterator ei;
- node = bbs[i];
- FOR_EACH_EDGE (e, ei, node->succs)
- {
- basic_block dest = e->dest;
-
- if (!flow_bb_inside_loop_p (loop, dest))
- {
- e->flags |= EDGE_LOOP_EXIT;
- loop->exit_edges[num_exits++] = e;
- }
- }
+ vec_free (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> stack = vNULL;
int num_nodes = 1;
+ edge latch;
+ edge_iterator latch_ei;
header->loop_father = loop;
- header->loop_depth = loop->depth;
- if (loop->latch->loop_father != loop)
+ FOR_EACH_EDGE (latch, latch_ei, loop->header->preds)
{
- stack = 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;
+ stack.safe_push (latch->src);
+ latch->src->loop_father = loop;
- while (sp)
+ while (!stack.is_empty ())
{
basic_block node;
edge e;
edge_iterator ei;
- node = stack[--sp];
+ node = stack.pop ();
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;
num_nodes++;
- stack[sp++] = ancestor;
+ stack.safe_push (ancestor);
}
}
}
- free (stack);
- }
- return num_nodes;
-}
-
-/* For each loop in the lOOPS tree that has just a single exit
- record the exit edge. */
-
-void
-mark_single_exit_loops (struct loops *loops)
-{
- basic_block bb;
- edge e;
- struct loop *loop;
- unsigned i;
-
- for (i = 1; i < loops->num; i++)
- {
- loop = loops->parray[i];
- if (loop)
- loop->single_exit = NULL;
- }
-
- FOR_EACH_BB (bb)
- {
- edge_iterator ei;
- if (bb->loop_father == loops->tree_root)
- continue;
- FOR_EACH_EDGE (e, ei, bb->succs)
- {
- if (e->dest == EXIT_BLOCK_PTR)
- continue;
-
- if (flow_bb_inside_loop_p (bb->loop_father, e->dest))
- continue;
-
- for (loop = bb->loop_father;
- loop != e->dest->loop_father;
- loop = loop->outer)
- {
- /* If we have already seen an exit, mark this by the edge that
- surely does not occur as any exit. */
- if (loop->single_exit)
- loop->single_exit = EDGE_SUCC (ENTRY_BLOCK_PTR, 0);
- else
- loop->single_exit = e;
- }
- }
}
+ stack.release ();
- for (i = 1; i < loops->num; i++)
- {
- loop = loops->parray[i];
- if (!loop)
- continue;
-
- if (loop->single_exit == EDGE_SUCC (ENTRY_BLOCK_PTR, 0))
- loop->single_exit = NULL;
- }
-
- loops->state |= LOOPS_HAVE_MARKED_SINGLE_EXITS;
-}
-
-/* Find the root node of the loop pre-header extended basic block and
- the edges along the trace from the root node to the loop header. */
-
-static void
-flow_loop_pre_header_scan (struct loop *loop)
-{
- int num;
- basic_block ebb;
- edge e;
-
- loop->num_pre_header_edges = 0;
- if (loop->num_entries != 1)
- return;
-
- ebb = loop->entry_edges[0]->src;
- if (ebb == ENTRY_BLOCK_PTR)
- return;
-
- /* Count number of edges along trace from loop header to
- root of pre-header extended basic block. Usually this is
- only one or two edges. */
- for (num = 1;
- EDGE_PRED (ebb, 0)->src != ENTRY_BLOCK_PTR && EDGE_COUNT (ebb->preds) == 1;
- num++)
- ebb = EDGE_PRED (ebb, 0)->src;
-
- loop->pre_header_edges = xmalloc (num * sizeof (edge));
- loop->num_pre_header_edges = num;
-
- /* Store edges in order that they are followed. The source of the first edge
- is the root node of the pre-header extended basic block and the
- destination of the last last edge is the loop header. */
- for (e = loop->entry_edges[0]; num; e = EDGE_PRED (e->src, 0))
- loop->pre_header_edges[--num] = e;
+ return num_nodes;
}
-/* Return the block for the pre-header of the loop with header
- HEADER. Return NULL if there is no pre-header. */
-
-static basic_block
-flow_loop_pre_header_find (basic_block header)
-{
- basic_block pre_header;
- edge e;
- edge_iterator ei;
-
- /* If block p is a predecessor of the header and is the only block
- that the header does not dominate, then it is the pre-header. */
- pre_header = NULL;
- FOR_EACH_EDGE (e, ei, header->preds)
- {
- basic_block node = e->src;
-
- if (node != ENTRY_BLOCK_PTR
- && ! dominated_by_p (CDI_DOMINATORS, node, header))
- {
- if (pre_header == NULL)
- pre_header = node;
- else
- {
- /* There are multiple edges into the header from outside
- the loop so there is no pre-header block. */
- pre_header = NULL;
- break;
- }
- }
- }
-
- return pre_header;
-}
+/* 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;
+ loop->superloops = 0;
+ vec_alloc (loop->superloops, depth);
+ FOR_EACH_VEC_SAFE_ELT (father->superloops, i, ploop)
+ loop->superloops->quick_push (ploop);
+ loop->superloops->quick_push (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
added loop. If LOOP has some children, take care of that their
- pred field will be initialized correctly. */
+ pred field will be initialized correctly. If AFTER is non-null
+ then it's expected it's a pointer into FATHERs inner sibling
+ list and LOOP is added behind AFTER, otherwise it's added in front
+ of FATHERs siblings. */
void
-flow_loop_tree_node_add (struct loop *father, struct loop *loop)
+flow_loop_tree_node_add (struct loop *father, struct loop *loop,
+ struct loop *after)
{
- loop->next = father->inner;
- father->inner = loop;
- loop->outer = father;
+ if (after)
+ {
+ loop->next = after->next;
+ after->next = loop;
+ }
+ else
+ {
+ loop->next = father->inner;
+ father->inner = loop;
+ }
- 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;
+ loop->superloops = NULL;
}
-/* Helper function to compute loop nesting depth and enclosed loop level
- for the natural loop specified by LOOP. Returns the loop level. */
+/* Allocates and returns new loop structure. */
-static int
-flow_loop_level_compute (struct loop *loop)
+struct loop *
+alloc_loop (void)
{
- 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;
+ struct loop *loop = ggc_cleared_alloc<struct loop> ();
+
+ loop->exits = ggc_cleared_alloc<loop_exit> ();
+ loop->exits->next = loop->exits->prev = loop->exits;
+ loop->can_be_parallel = false;
+ loop->constraints = 0;
+ loop->nb_iterations_upper_bound = 0;
+ loop->nb_iterations_likely_upper_bound = 0;
+ loop->nb_iterations_estimate = 0;
+ return loop;
}
-/* Compute the loop nesting depth and enclosed loop level for the loop
- hierarchy tree specified by LOOPS. Return the maximum enclosed loop
- level. */
+/* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops
+ (including the root of the loop tree). */
-static int
-flow_loops_level_compute (struct loops *loops)
+void
+init_loops_structure (struct function *fn,
+ struct loops *loops, unsigned num_loops)
{
- return flow_loop_level_compute (loops->tree_root);
+ struct loop *root;
+
+ memset (loops, 0, sizeof *loops);
+ vec_alloc (loops->larray, num_loops);
+
+ /* Dummy loop containing whole function. */
+ root = alloc_loop ();
+ root->num_nodes = n_basic_blocks_for_fn (fn);
+ root->latch = EXIT_BLOCK_PTR_FOR_FN (fn);
+ root->header = ENTRY_BLOCK_PTR_FOR_FN (fn);
+ ENTRY_BLOCK_PTR_FOR_FN (fn)->loop_father = root;
+ EXIT_BLOCK_PTR_FOR_FN (fn)->loop_father = root;
+
+ loops->larray->quick_push (root);
+ loops->tree_root = root;
}
-/* Scan a single natural loop specified by LOOP collecting information
- about it specified by FLAGS. */
+/* Returns whether HEADER is a loop header. */
-int
-flow_loop_scan (struct loop *loop, int flags)
+bool
+bb_loop_header_p (basic_block header)
{
- 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);
- }
+ edge_iterator ei;
+ edge e;
- if (flags & LOOP_EXIT_EDGES)
- {
- /* Find edges which exit the loop. */
- flow_loop_exit_edges_find (loop);
- }
+ /* If we have an abnormal predecessor, do not consider the
+ loop (not worth the problems). */
+ if (bb_has_abnormal_pred (header))
+ return false;
- if (flags & LOOP_PRE_HEADER)
+ /* 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. */
+ FOR_EACH_EDGE (e, ei, header->preds)
{
- /* Look to see if the loop has a pre-header node. */
- loop->pre_header = flow_loop_pre_header_find (loop->header);
-
- /* Find the blocks within the extended basic block of
- the loop pre-header. */
- flow_loop_pre_header_scan (loop);
+ basic_block latch = e->src;
+ if (latch != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+ && dominated_by_p (CDI_DOMINATORS, latch, header))
+ return true;
}
- return 1;
+ return false;
}
-/* 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)
+/* Find all the natural loops in the function and save in LOOPS structure and
+ recalculate loop_father information in basic block structures.
+ If LOOPS is non-NULL then the loop structures for already recorded loops
+ will be re-used and their number will not change. We assume that no
+ stale loops exist in LOOPS.
+ When LOOPS is NULL it is allocated and re-built from scratch.
+ Return the built LOOPS structure. */
+
+struct loops *
+flow_loops_find (struct loops *loops)
{
- alloc_aux_for_block (jump, sizeof (int));
- HEADER_BLOCK (jump) = 0;
- alloc_aux_for_edge (EDGE_PRED (jump, 0), sizeof (int));
- LATCH_EDGE (EDGE_PRED (jump, 0)) = 0;
- set_immediate_dominator (CDI_DOMINATORS, jump, EDGE_PRED (jump, 0)->src);
-}
-
-/* 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. */
+ bool from_scratch = (loops == NULL);
+ int *rc_order;
+ int b;
+ unsigned i;
-static edge mfb_kj_edge;
-static bool
-mfb_keep_just (edge e)
-{
- return e != mfb_kj_edge;
-}
+ /* Ensure that the dominators are computed. */
+ calculate_dominance_info (CDI_DOMINATORS);
-/* 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. */
+ if (!loops)
+ {
+ loops = ggc_cleared_alloc<struct loops> ();
+ init_loops_structure (cfun, loops, 1);
+ }
-static bool
-mfb_keep_nonlatch (edge e)
-{
- return LATCH_EDGE (e);
-}
+ /* Ensure that loop exits were released. */
+ gcc_assert (loops->exits == NULL);
-/* Takes care of merging natural loops with shared headers. */
+ /* Taking care of this degenerate case makes the rest of
+ this code simpler. */
+ if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS)
+ return loops;
-static void
-canonicalize_loop_headers (void)
-{
- basic_block header;
- edge e;
+ /* The root loop node contains all basic-blocks. */
+ loops->tree_root->num_nodes = n_basic_blocks_for_fn (cfun);
- alloc_aux_for_blocks (sizeof (int));
- alloc_aux_for_edges (sizeof (int));
+ /* Compute depth first search order of the CFG so that outer
+ natural loops will be found before inner natural loops. */
+ rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
+ pre_and_rev_post_order_compute (NULL, rc_order, false);
- /* Split blocks so that each loop has only single latch. */
- FOR_EACH_BB (header)
+ /* Gather all loop headers in reverse completion order and allocate
+ loop structures for loops that are not already present. */
+ auto_vec<loop_p> larray (loops->larray->length ());
+ for (b = 0; b < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; b++)
{
- edge_iterator ei;
- int num_latches = 0;
- int have_abnormal_edge = 0;
-
- FOR_EACH_EDGE (e, ei, header->preds)
+ basic_block header = BASIC_BLOCK_FOR_FN (cfun, rc_order[b]);
+ if (bb_loop_header_p (header))
{
- basic_block latch = e->src;
-
- if (e->flags & EDGE_ABNORMAL)
- have_abnormal_edge = 1;
+ struct loop *loop;
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (CDI_DOMINATORS, latch, header))
+ /* The current active loop tree has valid loop-fathers for
+ header blocks. */
+ if (!from_scratch
+ && header->loop_father->header == header)
+ {
+ loop = header->loop_father;
+ /* If we found an existing loop remove it from the
+ loop tree. It is going to be inserted again
+ below. */
+ flow_loop_tree_node_remove (loop);
+ }
+ else
{
- num_latches++;
- LATCH_EDGE (e) = 1;
+ /* Otherwise allocate a new loop structure for the loop. */
+ loop = alloc_loop ();
+ /* ??? We could re-use unused loop slots here. */
+ loop->num = loops->larray->length ();
+ vec_safe_push (loops->larray, loop);
+ loop->header = header;
+
+ if (!from_scratch
+ && dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "flow_loops_find: discovered new "
+ "loop %d with header %d\n",
+ loop->num, header->index);
}
+ /* Reset latch, we recompute it below. */
+ loop->latch = NULL;
+ larray.safe_push (loop);
}
- if (have_abnormal_edge)
- HEADER_BLOCK (header) = 0;
- else
- HEADER_BLOCK (header) = num_latches;
- }
-
- if (HEADER_BLOCK (EDGE_SUCC (ENTRY_BLOCK_PTR, 0)->dest))
- {
- basic_block bb;
- /* We could not redirect edges freely here. On the other hand,
- we can simply split the edge from entry block. */
- bb = split_edge (EDGE_SUCC (ENTRY_BLOCK_PTR, 0));
-
- alloc_aux_for_edge (EDGE_SUCC (bb, 0), sizeof (int));
- LATCH_EDGE (EDGE_SUCC (bb, 0)) = 0;
- alloc_aux_for_block (bb, sizeof (int));
- HEADER_BLOCK (bb) = 0;
+ /* Make blocks part of the loop root node at start. */
+ header->loop_father = loops->tree_root;
}
- FOR_EACH_BB (header)
+ free (rc_order);
+
+ /* Now iterate over the loops found, insert them into the loop tree
+ and assign basic-block ownership. */
+ for (i = 0; i < larray.length (); ++i)
{
- int max_freq, is_heavy;
- edge heavy, tmp_edge;
+ struct loop *loop = larray[i];
+ basic_block header = loop->header;
edge_iterator ei;
+ edge e;
- if (HEADER_BLOCK (header) <= 1)
- continue;
+ flow_loop_tree_node_add (header->loop_father, loop);
+ loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
- /* Find a heavy edge. */
- is_heavy = 1;
- heavy = NULL;
- max_freq = 0;
+ /* Look for the latch for this header block, if it has just a
+ single one. */
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)--;
- }
+ basic_block latch = e->src;
- 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;
+ if (flow_bb_inside_loop_p (loop, latch))
+ {
+ if (loop->latch != NULL)
+ {
+ /* More than one latch edge. */
+ loop->latch = NULL;
+ break;
+ }
+ loop->latch = latch;
+ }
}
}
- free_aux_for_blocks ();
- free_aux_for_edges ();
-
-#ifdef ENABLE_CHECKING
- verify_dominators (CDI_DOMINATORS);
-#endif
+ return loops;
}
-/* Initialize all the parallel_p fields of the loops structure to true. */
+/* qsort helper for sort_sibling_loops. */
-static void
-initialize_loops_parallel_p (struct loops *loops)
+static int *sort_sibling_loops_cmp_rpo;
+static int
+sort_sibling_loops_cmp (const void *la_, const void *lb_)
{
- unsigned int i;
-
- for (i = 0; i < loops->num; i++)
- {
- struct loop *loop = loops->parray[i];
- loop->parallel_p = true;
- }
+ const struct loop *la = *(const struct loop * const *)la_;
+ const struct loop *lb = *(const struct loop * const *)lb_;
+ return (sort_sibling_loops_cmp_rpo[la->header->index]
+ - sort_sibling_loops_cmp_rpo[lb->header->index]);
}
-/* 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. */
+/* Sort sibling loops in RPO order. */
-int
-flow_loops_find (struct loops *loops, int flags)
+void
+sort_sibling_loops (function *fn)
{
- int i;
- int b;
- int num_loops;
- edge e;
- sbitmap headers;
- 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. */
- gcc_assert (flags & LOOP_TREE);
+ /* Match flow_loops_find in the order we sort sibling loops. */
+ sort_sibling_loops_cmp_rpo = XNEWVEC (int, last_basic_block_for_fn (cfun));
+ int *rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
+ pre_and_rev_post_order_compute_fn (fn, NULL, rc_order, false);
+ for (int i = 0; i < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; ++i)
+ sort_sibling_loops_cmp_rpo[rc_order[i]] = i;
+ free (rc_order);
+
+ auto_vec<loop_p, 3> siblings;
+ loop_p loop;
+ FOR_EACH_LOOP_FN (fn, loop, LI_INCLUDE_ROOT)
+ if (loop->inner && loop->inner->next)
+ {
+ loop_p sibling = loop->inner;
+ do
+ {
+ siblings.safe_push (sibling);
+ sibling = sibling->next;
+ }
+ while (sibling);
+ siblings.qsort (sort_sibling_loops_cmp);
+ loop_p *siblingp = &loop->inner;
+ for (unsigned i = 0; i < siblings.length (); ++i)
+ {
+ *siblingp = siblings[i];
+ siblingp = &(*siblingp)->next;
+ }
+ *siblingp = NULL;
+ siblings.truncate (0);
+ }
- memset (loops, 0, sizeof *loops);
+ free (sort_sibling_loops_cmp_rpo);
+ sort_sibling_loops_cmp_rpo = NULL;
+}
- /* Taking care of this degenerate case makes the rest of
- this code simpler. */
- if (n_basic_blocks == 0)
- return 0;
+/* 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
- dfs_order = NULL;
- rc_order = NULL;
+/* Minimum number of samples for that we apply
+ find_subloop_latch_edge_by_profile heuristics. */
+#define HEAVY_EDGE_MIN_SAMPLES 10
- /* Ensure that the dominators are computed. */
- calculate_dominance_info (CDI_DOMINATORS);
+/* 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.
- /* Join loops with shared headers. */
- canonicalize_loop_headers ();
+ 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). */
- /* Count the number of loop headers. This should be the
- same as the number of natural loops. */
- headers = sbitmap_alloc (last_basic_block);
- sbitmap_zero (headers);
+static edge
+find_subloop_latch_edge_by_profile (vec<edge> latches)
+{
+ unsigned i;
+ edge e, me = NULL;
+ profile_count mcount = profile_count::zero (), tcount = profile_count::zero ();
- num_loops = 0;
- FOR_EACH_BB (header)
+ FOR_EACH_VEC_ELT (latches, i, e)
{
- edge_iterator ei;
- int more_latches = 0;
+ if (e->count ()> mcount)
+ {
+ me = e;
+ mcount = e->count();
+ }
+ tcount += e->count();
+ }
- header->loop_depth = 0;
+ if (!tcount.initialized_p () || !(tcount.ipa () > HEAVY_EDGE_MIN_SAMPLES)
+ || (tcount - mcount).apply_scale (HEAVY_EDGE_RATIO, 1) > tcount)
+ return NULL;
- /* If we have an abnormal predecessor, do not consider the
- loop (not worth the problems). */
- FOR_EACH_EDGE (e, ei, header->preds)
- if (e->flags & EDGE_ABNORMAL)
- break;
- if (e)
- continue;
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using profile information.\n",
+ me->src->index, me->dest->index);
+ return me;
+}
- FOR_EACH_EDGE (e, ei, header->preds)
- {
- basic_block latch = e->src;
+/* 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.
- gcc_assert (!(e->flags & EDGE_ABNORMAL));
+ 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. */
- /* 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 (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++;
- }
- }
+static edge
+find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, vec<edge> latches)
+{
+ edge e, latch = latches[0];
+ unsigned i;
+ gphi *phi;
+ gphi_iterator psi;
+ tree lop;
+ basic_block bb;
+
+ /* Find the candidate for the latch edge. */
+ for (i = 1; latches.iterate (i, &e); i++)
+ if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src))
+ latch = e;
+
+ /* Verify that it dominates all the latch edges. */
+ FOR_EACH_VEC_ELT (latches, i, e)
+ 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 = psi.phi ();
+ 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_EACH_VEC_ELT (latches, i, e)
+ if (e != latch
+ && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop)
+ return NULL;
}
- /* Allocate loop structures. */
- loops->parray = xcalloc (num_loops + 1, sizeof (struct loop *));
+ if (dump_file)
+ fprintf (dump_file,
+ "Found latch edge %d -> %d using iv structure.\n",
+ latch->src->index, latch->dest->index);
+ return latch;
+}
- /* Dummy loop containing whole function. */
- loops->parray[0] = xcalloc (1, sizeof (struct loop));
- loops->parray[0]->next = NULL;
- loops->parray[0]->inner = NULL;
- loops->parray[0]->outer = NULL;
- loops->parray[0]->depth = 0;
- loops->parray[0]->pred = NULL;
- loops->parray[0]->num_nodes = n_basic_blocks + 2;
- loops->parray[0]->latch = EXIT_BLOCK_PTR;
- loops->parray[0]->header = ENTRY_BLOCK_PTR;
- ENTRY_BLOCK_PTR->loop_father = loops->parray[0];
- EXIT_BLOCK_PTR->loop_father = loops->parray[0];
-
- loops->tree_root = loops->parray[0];
-
- /* Find and record information about all the natural loops
- in the CFG. */
- loops->num = 1;
- FOR_EACH_BB (bb)
- bb->loop_father = loops->tree_root;
-
- if (num_loops)
+/* 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> latches = get_loop_latch_edges (loop);
+ edge latch = NULL;
+
+ if (latches.length () > 1)
{
- /* Compute depth first search order of the CFG so that outer
- natural loops will be found before inner natural loops. */
- dfs_order = xmalloc (n_basic_blocks * sizeof (int));
- rc_order = xmalloc (n_basic_blocks * sizeof (int));
- flow_depth_first_order_compute (dfs_order, rc_order);
+ 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);
+ }
- /* Save CFG derived information to avoid recomputing it. */
- loops->cfg.dfs_order = dfs_order;
- loops->cfg.rc_order = rc_order;
+ latches.release ();
+ return latch;
+}
- num_loops = 1;
+/* Callback for make_forwarder_block. Returns true if the edge E is marked
+ in the set MFB_REIS_SET. */
- for (b = 0; b < n_basic_blocks; b++)
- {
- struct loop *loop;
- edge_iterator ei;
+static hash_set<edge> *mfb_reis_set;
+static bool
+mfb_redirect_edges_in_set (edge e)
+{
+ return mfb_reis_set->contains (e);
+}
- /* Search the nodes of the CFG in reverse completion order
- so that we can find outer loops first. */
- if (!TEST_BIT (headers, rc_order[b]))
- continue;
+/* 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;
- header = BASIC_BLOCK (rc_order[b]);
+ mfb_reis_set = new hash_set<edge>;
+ FOR_EACH_EDGE (e, ei, loop->header->preds)
+ {
+ if (e != latch)
+ mfb_reis_set->add (e);
+ }
+ new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set,
+ NULL);
+ delete 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);
+}
- loop = loops->parray[num_loops] = xcalloc (1, sizeof (struct loop));
+/* Make all the latch edges of LOOP to go to a single forwarder block --
+ a new latch of LOOP. */
- loop->header = header;
- loop->num = num_loops;
- num_loops++;
+static void
+merge_latch_edges (struct loop *loop)
+{
+ vec<edge> latches = get_loop_latch_edges (loop);
+ edge latch, e;
+ unsigned i;
- /* Look for the latch for this header block. */
- FOR_EACH_EDGE (e, ei, header->preds)
- {
- basic_block latch = e->src;
+ gcc_assert (latches.length () > 0);
- if (latch != ENTRY_BLOCK_PTR
- && dominated_by_p (CDI_DOMINATORS, latch, header))
- {
- loop->latch = latch;
- break;
- }
- }
+ if (latches.length () == 1)
+ loop->latch = latches[0]->src;
+ else
+ {
+ if (dump_file)
+ fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num);
+
+ mfb_reis_set = new hash_set<edge>;
+ FOR_EACH_VEC_ELT (latches, i, e)
+ mfb_reis_set->add (e);
+ latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set,
+ NULL);
+ delete mfb_reis_set;
+
+ loop->header = latch->dest;
+ loop->latch = latch->src;
+ }
- flow_loop_tree_node_add (header->loop_father, loop);
- loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
- }
+ latches.release ();
+}
- /* Assign the loop nesting depth and enclosed loop level for each
- loop. */
- loops->levels = flow_loops_level_compute (loops);
+/* LOOP may have several latch edges. Transform it into (possibly several)
+ loops with single latch edge. */
- /* Scan the loops. */
- for (i = 1; i < num_loops; i++)
- flow_loop_scan (loops->parray[i], flags);
+static void
+disambiguate_multiple_latches (struct loop *loop)
+{
+ edge e;
- loops->num = num_loops;
- initialize_loops_parallel_p (loops);
+ /* 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_FOR_FN (cfun), loop->header);
+ if (e)
+ split_edge (e);
+
+ while (1)
+ {
+ e = find_subloop_latch_edge (loop);
+ if (!e)
+ break;
+
+ form_subloop (loop, e);
}
- sbitmap_free (headers);
+ merge_latch_edges (loop);
+}
- loops->state = 0;
-#ifdef ENABLE_CHECKING
- verify_flow_info ();
- verify_loop_structure (loops);
-#endif
+/* Split loops with multiple latch edges. */
- return loops->num;
+void
+disambiguate_loops_with_multiple_latches (void)
+{
+ struct loop *loop;
+
+ FOR_EACH_LOOP (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;
- if (bb == ENTRY_BLOCK_PTR || bb == EXIT_BLOCK_PTR)
+ if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)
+ || bb == EXIT_BLOCK_PTR_FOR_FN (cfun))
return 0;
source_loop = bb->loop_father;
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)
{
- gcc_assert (e->dest == loop->header);
- 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. 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 = xcalloc (loop->num_nodes, sizeof (basic_block));
- tovisit[tv++] = loop->header;
+ body = XNEWVEC (basic_block, loop->num_nodes);
- if (loop->latch == EXIT_BLOCK_PTR)
- {
- /* There may be blocks unreachable from EXIT_BLOCK. */
- gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks + 2);
- FOR_EACH_BB (bb)
- tovisit[tv++] = bb;
- tovisit[tv++] = EXIT_BLOCK_PTR;
- }
- else if (loop->latch != loop->header)
+ if (loop->latch == EXIT_BLOCK_PTR_FOR_FN (cfun))
{
- tv = dfs_enumerate_from (loop->latch, 1, glb_enum_p,
- tovisit + 1, loop->num_nodes - 1,
- loop->header) + 1;
+ /* 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_for_fn (cfun));
+ body[tv++] = loop->header;
+ body[tv++] = EXIT_BLOCK_PTR_FOR_FN (cfun);
+ FOR_EACH_BB_FN (bb, cfun)
+ 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
gcc_assert (loop->num_nodes);
- tovisit = xcalloc (loop->num_nodes, sizeof (basic_block));
+ tovisit = XNEWVEC (basic_block, loop->num_nodes);
- gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun));
tv = 0;
fill_sons_in_loop (loop, loop->header, tovisit, &tv);
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 *
{
basic_block *blocks;
basic_block bb;
- bitmap visited;
- unsigned int i = 0;
- unsigned int vc = 1;
+ unsigned int i = 1;
+ unsigned int vc = 0;
gcc_assert (loop->num_nodes);
- gcc_assert (loop->latch != EXIT_BLOCK_PTR);
-
- blocks = xcalloc (loop->num_nodes, sizeof (basic_block));
- visited = BITMAP_XMALLOC ();
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun));
- bb = loop->header;
+ blocks = XNEWVEC (basic_block, loop->num_nodes);
+ auto_bitmap visited;
+ blocks[0] = loop->header;
+ bitmap_set_bit (visited, loop->header->index);
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);
-
+ gcc_assert (i > vc);
bb = blocks[vc++];
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (flow_bb_inside_loop_p (loop, e->dest))
+ {
+ /* This bb is now visited. */
+ if (bitmap_set_bit (visited, e->dest->index))
+ blocks[i++] = e->dest;
+ }
+ }
}
-
- BITMAP_XFREE (visited);
+
return blocks;
}
-/* Gets exit edges of a LOOP, returning their number in N_EDGES. */
-edge *
-get_loop_exit_edges (const struct loop *loop, unsigned int *n_edges)
+/* Hash function for struct loop_exit. */
+
+hashval_t
+loop_exit_hasher::hash (loop_exit *exit)
{
- edge *edges, e;
- unsigned i, n;
- basic_block * body;
+ return htab_hash_pointer (exit->e);
+}
+
+/* Equality function for struct loop_exit. Compares with edge. */
+
+bool
+loop_exit_hasher::equal (loop_exit *exit, edge e)
+{
+ return exit->e == e;
+}
+
+/* Frees the list of loop exit descriptions EX. */
+
+void
+loop_exit_hasher::remove (loop_exit *exit)
+{
+ loop_exit *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 current_loops->exits->find_with_hash (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)
+{
+ 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_alloc<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;
+
+ loop_exit **slot
+ = current_loops->exits->find_slot_with_hash (e, htab_hash_pointer (e),
+ exits ? INSERT : NO_INSERT);
+ if (!slot)
+ return;
+
+ if (exits)
+ {
+ if (*slot)
+ loop_exit_hasher::remove (*slot);
+ *slot = exits;
+ }
+ else
+ current_loops->exits->clear_slot (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;
- gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+ if (!current_loops)
+ return;
- body = get_loop_body (loop);
- n = 0;
- for (i = 0; i < loop->num_nodes; i++)
- FOR_EACH_EDGE (e, ei, body[i]->succs)
- if (!flow_bb_inside_loop_p (loop, e->dest))
- n++;
- edges = xmalloc (n * sizeof (edge));
- *n_edges = n;
- n = 0;
- for (i = 0; i < loop->num_nodes; i++)
- FOR_EACH_EDGE (e, ei, body[i]->succs)
- if (!flow_bb_inside_loop_p (loop, e->dest))
- edges[n++] = e;
- free (body);
+ 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
+ = hash_table<loop_exit_hasher>::create_ggc (2 * number_of_loops (cfun));
+
+ FOR_EACH_BB_FN (bb, cfun)
+ {
+ 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. */
+
+int
+dump_recorded_exit (loop_exit **slot, FILE *file)
+{
+ struct loop_exit *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",
+ 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;
+ current_loops->exits->traverse<FILE *, dump_recorded_exit> (file);
+}
+
+/* Releases lists of loop exits. */
+
+void
+release_recorded_exits (function *fn)
+{
+ gcc_assert (loops_state_satisfies_p (fn, LOOPS_HAVE_RECORDED_EXITS));
+ loops_for_fn (fn)->exits->empty ();
+ loops_for_fn (fn)->exits = NULL;
+ loops_state_clear (fn, LOOPS_HAVE_RECORDED_EXITS);
+}
+
+/* Returns the list of the exit edges of a LOOP. */
+
+vec<edge>
+get_loop_exit_edges (const struct loop *loop)
+{
+ vec<edge> edges = vNULL;
+ edge e;
+ unsigned i;
+ basic_block *body;
+ edge_iterator ei;
+ struct loop_exit *exit;
+
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun));
+
+ /* 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)
+ edges.safe_push (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))
+ edges.safe_push (e);
+ }
+ free (body);
+ }
return edges;
}
unsigned i, n;
basic_block * body;
- gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+ gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun));
body = get_loop_body (loop);
n = 0;
void
add_bb_to_loop (basic_block bb, struct loop *loop)
{
- int i;
+ unsigned i;
+ loop_p ploop;
+ edge_iterator ei;
+ edge e;
- bb->loop_father = loop;
- bb->loop_depth = loop->depth;
- loop->num_nodes++;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->num_nodes++;
- }
+ gcc_assert (bb->loop_father == NULL);
+ bb->loop_father = loop;
+ loop->num_nodes++;
+ FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop)
+ ploop->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;
+ unsigned i;
+ struct loop *loop = bb->loop_father;
+ loop_p ploop;
+ edge_iterator ei;
+ edge e;
- loop->num_nodes--;
- for (i = 0; i < loop->depth; i++)
- loop->pred[i]->num_nodes--;
- bb->loop_father = NULL;
- bb->loop_depth = 0;
- }
+ gcc_assert (loop != NULL);
+ loop->num_nodes--;
+ FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop)
+ ploop->num_nodes--;
+ bb->loop_father = NULL;
+
+ 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 = (*loop_d->superloops)[sdepth];
+ else if (sdepth > ddepth)
+ loop_s = (*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. */
+ (*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);
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);
+ free (bbs);
+ 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
-- loop latches have only single successor that is header of their loop
-- irreducible loops are correctly marked
+ -- the cached loop depth and loop father of each bb is correct
*/
-void
-verify_loop_structure (struct loops *loops)
+DEBUG_FUNCTION void
+verify_loop_structure (void)
{
unsigned *sizes, i, j;
- sbitmap irreds;
- basic_block *bbs, bb;
+ basic_block bb, *bbs;
struct loop *loop;
int err = 0;
edge e;
+ unsigned num = number_of_loops (cfun);
+ struct loop_exit *exit, *mexit;
+ bool dom_available = dom_info_available_p (CDI_DOMINATORS);
- /* Check sizes. */
- sizes = xcalloc (loops->num, sizeof (int));
- sizes[0] = 2;
+ if (loops_state_satisfies_p (LOOPS_NEED_FIXUP))
+ {
+ error ("loop verification on loop tree that needs fixup");
+ err = 1;
+ }
- FOR_EACH_BB (bb)
- for (loop = bb->loop_father; loop; loop = loop->outer)
- sizes[loop->num]++;
+ /* We need up-to-date dominators, compute or verify them. */
+ if (!dom_available)
+ calculate_dominance_info (CDI_DOMINATORS);
+ else
+ verify_dominators (CDI_DOMINATORS);
+
+ /* Check the loop tree root. */
+ if (current_loops->tree_root->header != ENTRY_BLOCK_PTR_FOR_FN (cfun)
+ || current_loops->tree_root->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)
+ || (current_loops->tree_root->num_nodes
+ != (unsigned) n_basic_blocks_for_fn (cfun)))
+ {
+ error ("corrupt loop tree root");
+ err = 1;
+ }
+
+ /* Check the headers. */
+ FOR_EACH_BB_FN (bb, cfun)
+ if (bb_loop_header_p (bb))
+ {
+ if (bb->loop_father->header == NULL)
+ {
+ error ("loop with header %d marked for removal", bb->index);
+ err = 1;
+ }
+ else if (bb->loop_father->header != bb)
+ {
+ error ("loop with header %d not in loop tree", bb->index);
+ err = 1;
+ }
+ }
+ else if (bb->loop_father->header == bb)
+ {
+ error ("non-loop with header %d not marked for removal", bb->index);
+ err = 1;
+ }
- for (i = 0; i < loops->num; i++)
+ /* Check the recorded loop father and sizes of loops. */
+ auto_sbitmap visited (last_basic_block_for_fn (cfun));
+ bitmap_clear (visited);
+ bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun));
+ FOR_EACH_LOOP (loop, LI_FROM_INNERMOST)
{
- if (!loops->parray[i])
- continue;
+ unsigned n;
- if (loops->parray[i]->num_nodes != sizes[i])
+ if (loop->header == NULL)
{
- error ("Size of loop %d should be %d, not %d.",
- i, sizes[i], loops->parray[i]->num_nodes);
+ error ("removed loop %d in loop tree", loop->num);
err = 1;
+ continue;
}
- }
- /* Check get_loop_body. */
- for (i = 1; i < loops->num; i++)
- {
- loop = loops->parray[i];
- if (!loop)
- continue;
- bbs = get_loop_body (loop);
+ n = get_loop_body_with_size (loop, bbs, n_basic_blocks_for_fn (cfun));
+ if (loop->num_nodes != n)
+ {
+ error ("size of loop %d should be %d, not %d",
+ loop->num, n, loop->num_nodes);
+ err = 1;
+ }
- for (j = 0; j < loop->num_nodes; j++)
- if (!flow_bb_inside_loop_p (loop, bbs[j]))
- {
- error ("Bb %d do not belong to loop %d.",
- bbs[j]->index, i);
- err = 1;
- }
- free (bbs);
+ for (j = 0; j < n; j++)
+ {
+ bb = bbs[j];
+
+ if (!flow_bb_inside_loop_p (loop, bb))
+ {
+ error ("bb %d does not belong to loop %d",
+ bb->index, loop->num);
+ err = 1;
+ }
+
+ /* Ignore this block if it is in an inner loop. */
+ if (bitmap_bit_p (visited, bb->index))
+ continue;
+ bitmap_set_bit (visited, bb->index);
+
+ if (bb->loop_father != loop)
+ {
+ error ("bb %d has father loop %d, should be loop %d",
+ bb->index, bb->loop_father->num, loop->num);
+ err = 1;
+ }
+ }
}
+ free (bbs);
/* Check headers and latches. */
- for (i = 1; i < loops->num; i++)
+ FOR_EACH_LOOP (loop, 0)
{
- loop = loops->parray[i];
- if (!loop)
+ i = loop->num;
+ if (loop->header == NULL)
continue;
-
- if ((loops->state & LOOPS_HAVE_PREHEADERS)
+ if (!bb_loop_header_p (loop->header))
+ {
+ error ("loop %d%'s header is not a loop header", i);
+ err = 1;
+ }
+ 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 (loop->latch)
+ {
+ if (!find_edge (loop->latch, loop->header))
+ {
+ error ("loop %d%'s latch does not have an edge to its header", i);
+ err = 1;
+ }
+ if (!dominated_by_p (CDI_DOMINATORS, loop->latch, loop->header))
+ {
+ error ("loop %d%'s latch is not dominated by its header", i);
+ err = 1;
+ }
+ }
+ if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES))
{
- if (EDGE_COUNT (loop->latch->succs) != 1)
+ if (!single_succ_p (loop->latch))
{
- error ("Loop %d's latch does not have exactly 1 successor.", i);
+ error ("loop %d%'s latch does not have exactly 1 successor", i);
err = 1;
}
- if (EDGE_SUCC (loop->latch, 0)->dest != loop->header)
+ if (single_succ (loop->latch) != loop->header)
{
- error ("Loop %d's latch does not have header as successor.", i);
+ 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))
{
+ auto_edge_flag saved_irr_mask (cfun);
/* Record old info. */
- irreds = sbitmap_alloc (last_basic_block);
- FOR_EACH_BB (bb)
+ auto_sbitmap irreds (last_basic_block_for_fn (cfun));
+ FOR_EACH_BB_FN (bb, cfun)
{
edge_iterator ei;
if (bb->flags & BB_IRREDUCIBLE_LOOP)
- SET_BIT (irreds, bb->index);
+ bitmap_set_bit (irreds, bb->index);
else
- RESET_BIT (irreds, bb->index);
+ bitmap_clear_bit (irreds, bb->index);
FOR_EACH_EDGE (e, ei, bb->succs)
if (e->flags & EDGE_IRREDUCIBLE_LOOP)
- e->flags |= EDGE_ALL_FLAGS + 1;
+ e->flags |= saved_irr_mask;
}
/* Recount it. */
- mark_irreducible_loops (loops);
+ mark_irreducible_loops ();
/* Compare. */
- FOR_EACH_BB (bb)
+ FOR_EACH_BB_FN (bb, cfun)
{
edge_iterator ei;
if ((bb->flags & BB_IRREDUCIBLE_LOOP)
- && !TEST_BIT (irreds, bb->index))
+ && !bitmap_bit_p (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))
+ && bitmap_bit_p (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_EACH_EDGE (e, ei, bb->succs)
{
if ((e->flags & EDGE_IRREDUCIBLE_LOOP)
- && !(e->flags & (EDGE_ALL_FLAGS + 1)))
+ && !(e->flags & saved_irr_mask))
{
- 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)))
+ && (e->flags & saved_irr_mask))
{
- 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;
}
- e->flags &= ~(EDGE_ALL_FLAGS + 1);
+ e->flags &= ~saved_irr_mask;
+ }
+ }
+ }
+
+ /* Check the recorded loop exits. */
+ FOR_EACH_LOOP (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;
}
}
- free (irreds);
}
- /* Check the single_exit. */
- if (loops->state & LOOPS_HAVE_MARKED_SINGLE_EXITS)
+ if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
{
- memset (sizes, 0, sizeof (unsigned) * loops->num);
- FOR_EACH_BB (bb)
+ unsigned n_exits = 0, eloops;
+
+ sizes = XCNEWVEC (unsigned, num);
+ memset (sizes, 0, sizeof (unsigned) * num);
+ FOR_EACH_BB_FN (bb, cfun)
{
edge_iterator ei;
- if (bb->loop_father == loops->tree_root)
+ if (bb->loop_father == current_loops->tree_root)
continue;
FOR_EACH_EDGE (e, ei, bb->succs)
{
- if (e->dest == EXIT_BLOCK_PTR)
- continue;
-
if (flow_bb_inside_loop_p (bb->loop_father, e->dest))
continue;
+ 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 != e->dest->loop_father
+ /* When a loop exit is also an entry edge which
+ can happen when avoiding CFG manipulations
+ then the last loop exited is the outer loop
+ of the loop entered. */
+ && loop != loop_outer (e->dest->loop_father);
+ loop = loop_outer (loop))
{
+ eloops--;
sizes[loop->num]++;
- if (loop->single_exit
- && loop->single_exit != e)
- {
- error ("Wrong single exit %d->%d recorded for loop %d.",
- loop->single_exit->src->index,
- loop->single_exit->dest->index,
- loop->num);
- error ("Right exit is %d->%d.",
- e->src->index, e->dest->index);
- err = 1;
- }
+ }
+
+ if (eloops != 0)
+ {
+ error ("wrong list of exited loops for edge %d->%d",
+ e->src->index, e->dest->index);
+ err = 1;
}
}
}
- for (i = 1; i < loops->num; i++)
+ if (n_exits != current_loops->exits->elements ())
{
- loop = loops->parray[i];
- if (!loop)
- continue;
-
- if (sizes[i] == 1
- && !loop->single_exit)
- {
- error ("Single exit not recorded for loop %d.", loop->num);
- err = 1;
- }
+ error ("too many loop exits recorded");
+ err = 1;
+ }
- if (sizes[i] != 1
- && loop->single_exit)
+ FOR_EACH_LOOP (loop, 0)
+ {
+ eloops = 0;
+ for (exit = loop->exits->next; exit->e; exit = exit->next)
+ eloops++;
+ if (eloops != sizes[loop->num])
{
- error ("Loop %d should not have single exit (%d -> %d).",
- loop->num,
- loop->single_exit->src->index,
- loop->single_exit->dest->index);
+ error ("%d exits recorded for loop %d (having %d exits)",
+ eloops, loop->num, sizes[loop->num]);
err = 1;
}
}
+
+ free (sizes);
}
gcc_assert (!err);
- free (sizes);
+ if (!dom_available)
+ free_dominance_info (CDI_DOMINATORS);
}
/* Returns latch edge of LOOP. */
edge e;
edge_iterator ei;
+ gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)
+ && ! loops_state_satisfies_p (LOOPS_MAY_HAVE_MULTIPLE_LATCHES));
+
FOR_EACH_EDGE (e, ei, loop->header->preds)
if (e->src != loop->latch)
break;
+ if (! e)
+ {
+ gcc_assert (! loop_outer (loop));
+ return single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+ }
+
return e;
}
+
+/* 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
+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 incoming edge exiting LOOP. */
+
+bool
+loop_exits_to_bb_p (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;
+}
+
+/* Returns true when BB has an outgoing edge exiting LOOP. */
+
+bool
+loop_exits_from_bb_p (struct loop *loop, basic_block bb)
+{
+ edge e;
+ edge_iterator ei;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ if (loop_exit_edge_p (loop, e))
+ return true;
+
+ return false;
+}
+
+/* Return location corresponding to the loop control condition if possible. */
+
+dump_user_location_t
+get_loop_location (struct loop *loop)
+{
+ rtx_insn *insn = NULL;
+ struct niter_desc *desc = NULL;
+ edge exit;
+
+ /* For a for or while loop, we would like to return the location
+ of the for or while statement, if possible. To do this, look
+ for the branch guarding the loop back-edge. */
+
+ /* If this is a simple loop with an in_edge, then the loop control
+ branch is typically at the end of its source. */
+ desc = get_simple_loop_desc (loop);
+ if (desc->in_edge)
+ {
+ FOR_BB_INSNS_REVERSE (desc->in_edge->src, insn)
+ {
+ if (INSN_P (insn) && INSN_HAS_LOCATION (insn))
+ return insn;
+ }
+ }
+ /* If loop has a single exit, then the loop control branch
+ must be at the end of its source. */
+ if ((exit = single_exit (loop)))
+ {
+ FOR_BB_INSNS_REVERSE (exit->src, insn)
+ {
+ if (INSN_P (insn) && INSN_HAS_LOCATION (insn))
+ return insn;
+ }
+ }
+ /* Next check the latch, to see if it is non-empty. */
+ FOR_BB_INSNS_REVERSE (loop->latch, insn)
+ {
+ if (INSN_P (insn) && INSN_HAS_LOCATION (insn))
+ return insn;
+ }
+ /* Finally, if none of the above identifies the loop control branch,
+ return the first location in the loop header. */
+ FOR_BB_INSNS (loop->header, insn)
+ {
+ if (INSN_P (insn) && INSN_HAS_LOCATION (insn))
+ return insn;
+ }
+ /* If all else fails, simply return the current function location. */
+ return dump_user_location_t::from_function_decl (current_function_decl);
+}
+
+/* Records that every statement in LOOP is executed I_BOUND times.
+ REALISTIC is true if I_BOUND is expected to be close to the real number
+ of iterations. UPPER is true if we are sure the loop iterates at most
+ I_BOUND times. */
+
+void
+record_niter_bound (struct loop *loop, const widest_int &i_bound,
+ bool realistic, bool upper)
+{
+ /* Update the bounds only when there is no previous estimation, or when the
+ current estimation is smaller. */
+ if (upper
+ && (!loop->any_upper_bound
+ || wi::ltu_p (i_bound, loop->nb_iterations_upper_bound)))
+ {
+ loop->any_upper_bound = true;
+ loop->nb_iterations_upper_bound = i_bound;
+ if (!loop->any_likely_upper_bound)
+ {
+ loop->any_likely_upper_bound = true;
+ loop->nb_iterations_likely_upper_bound = i_bound;
+ }
+ }
+ if (realistic
+ && (!loop->any_estimate
+ || wi::ltu_p (i_bound, loop->nb_iterations_estimate)))
+ {
+ loop->any_estimate = true;
+ loop->nb_iterations_estimate = i_bound;
+ }
+ if (!realistic
+ && (!loop->any_likely_upper_bound
+ || wi::ltu_p (i_bound, loop->nb_iterations_likely_upper_bound)))
+ {
+ loop->any_likely_upper_bound = true;
+ loop->nb_iterations_likely_upper_bound = i_bound;
+ }
+
+ /* If an upper bound is smaller than the realistic estimate of the
+ number of iterations, use the upper bound instead. */
+ if (loop->any_upper_bound
+ && loop->any_estimate
+ && wi::ltu_p (loop->nb_iterations_upper_bound,
+ loop->nb_iterations_estimate))
+ loop->nb_iterations_estimate = loop->nb_iterations_upper_bound;
+ if (loop->any_upper_bound
+ && loop->any_likely_upper_bound
+ && wi::ltu_p (loop->nb_iterations_upper_bound,
+ loop->nb_iterations_likely_upper_bound))
+ loop->nb_iterations_likely_upper_bound = loop->nb_iterations_upper_bound;
+}
+
+/* Similar to get_estimated_loop_iterations, but returns the estimate only
+ if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
+ on the number of iterations of LOOP could not be derived, returns -1. */
+
+HOST_WIDE_INT
+get_estimated_loop_iterations_int (struct loop *loop)
+{
+ widest_int nit;
+ HOST_WIDE_INT hwi_nit;
+
+ if (!get_estimated_loop_iterations (loop, &nit))
+ return -1;
+
+ if (!wi::fits_shwi_p (nit))
+ return -1;
+ hwi_nit = nit.to_shwi ();
+
+ return hwi_nit < 0 ? -1 : hwi_nit;
+}
+
+/* Returns an upper bound on the number of executions of statements
+ in the LOOP. For statements before the loop exit, this exceeds
+ the number of execution of the latch by one. */
+
+HOST_WIDE_INT
+max_stmt_executions_int (struct loop *loop)
+{
+ HOST_WIDE_INT nit = get_max_loop_iterations_int (loop);
+ HOST_WIDE_INT snit;
+
+ if (nit == -1)
+ return -1;
+
+ snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1);
+
+ /* If the computation overflows, return -1. */
+ return snit < 0 ? -1 : snit;
+}
+
+/* Returns an likely upper bound on the number of executions of statements
+ in the LOOP. For statements before the loop exit, this exceeds
+ the number of execution of the latch by one. */
+
+HOST_WIDE_INT
+likely_max_stmt_executions_int (struct loop *loop)
+{
+ HOST_WIDE_INT nit = get_likely_max_loop_iterations_int (loop);
+ HOST_WIDE_INT snit;
+
+ if (nit == -1)
+ return -1;
+
+ snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1);
+
+ /* If the computation overflows, return -1. */
+ return snit < 0 ? -1 : snit;
+}
+
+/* Sets NIT to the estimated number of executions of the latch of the
+ LOOP. If we have no reliable estimate, the function returns false, otherwise
+ returns true. */
+
+bool
+get_estimated_loop_iterations (struct loop *loop, widest_int *nit)
+{
+ /* Even if the bound is not recorded, possibly we can derrive one from
+ profile. */
+ if (!loop->any_estimate)
+ {
+ if (loop->header->count.reliable_p ())
+ {
+ *nit = gcov_type_to_wide_int
+ (expected_loop_iterations_unbounded (loop) + 1);
+ return true;
+ }
+ return false;
+ }
+
+ *nit = loop->nb_iterations_estimate;
+ return true;
+}
+
+/* Sets NIT to an upper bound for the maximum number of executions of the
+ latch of the LOOP. If we have no reliable estimate, the function returns
+ false, otherwise returns true. */
+
+bool
+get_max_loop_iterations (const struct loop *loop, widest_int *nit)
+{
+ if (!loop->any_upper_bound)
+ return false;
+
+ *nit = loop->nb_iterations_upper_bound;
+ return true;
+}
+
+/* Similar to get_max_loop_iterations, but returns the estimate only
+ if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
+ on the number of iterations of LOOP could not be derived, returns -1. */
+
+HOST_WIDE_INT
+get_max_loop_iterations_int (const struct loop *loop)
+{
+ widest_int nit;
+ HOST_WIDE_INT hwi_nit;
+
+ if (!get_max_loop_iterations (loop, &nit))
+ return -1;
+
+ if (!wi::fits_shwi_p (nit))
+ return -1;
+ hwi_nit = nit.to_shwi ();
+
+ return hwi_nit < 0 ? -1 : hwi_nit;
+}
+
+/* Sets NIT to an upper bound for the maximum number of executions of the
+ latch of the LOOP. If we have no reliable estimate, the function returns
+ false, otherwise returns true. */
+
+bool
+get_likely_max_loop_iterations (struct loop *loop, widest_int *nit)
+{
+ if (!loop->any_likely_upper_bound)
+ return false;
+
+ *nit = loop->nb_iterations_likely_upper_bound;
+ return true;
+}
+
+/* Similar to get_max_loop_iterations, but returns the estimate only
+ if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
+ on the number of iterations of LOOP could not be derived, returns -1. */
+
+HOST_WIDE_INT
+get_likely_max_loop_iterations_int (struct loop *loop)
+{
+ widest_int nit;
+ HOST_WIDE_INT hwi_nit;
+
+ if (!get_likely_max_loop_iterations (loop, &nit))
+ return -1;
+
+ if (!wi::fits_shwi_p (nit))
+ return -1;
+ hwi_nit = nit.to_shwi ();
+
+ return hwi_nit < 0 ? -1 : hwi_nit;
+}
+
+/* Returns the loop depth of the loop BB belongs to. */
+
+int
+bb_loop_depth (const_basic_block bb)
+{
+ return bb->loop_father ? loop_depth (bb->loop_father) : 0;
+}
+
+/* Marks LOOP for removal and sets LOOPS_NEED_FIXUP. */
+
+void
+mark_loop_for_removal (loop_p loop)
+{
+ if (loop->header == NULL)
+ return;
+ loop->former_header = loop->header;
+ loop->header = NULL;
+ loop->latch = NULL;
+ loops_state_set (LOOPS_NEED_FIXUP);
+}
projects / thirdparty / gcc.git / blobdiff