/* Natural loop functions
- Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
- Free Software Foundation, Inc.
+ Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
+ 2005, 2006, 2007, 2008, 2009 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/>. */
#ifndef GCC_CFGLOOP_H
#define GCC_CFGLOOP_H
#include "basic-block.h"
/* For rtx_code. */
#include "rtl.h"
+#include "vecprim.h"
+#include "double-int.h"
/* Structure to hold decision about unrolling/peeling. */
enum lpt_dec
LPT_UNROLL_STUPID
};
-struct lpt_decision
-{
+struct GTY (()) lpt_decision {
enum lpt_dec decision;
unsigned times;
};
/* The structure describing a bound on number of iterations of a loop. */
-struct nb_iter_bound
-{
- tree bound; /* The constant expression whose value is an upper
- bound on the number of executions of ... */
- tree at_stmt; /* ... this statement during one execution of
- a loop. */
+struct GTY ((chain_next ("%h.next"))) nb_iter_bound {
+ /* The statement STMT is executed at most ... */
+ gimple stmt;
+
+ /* ... BOUND + 1 times (BOUND must be an unsigned constant).
+ The + 1 is added for the following reasons:
+
+ a) 0 would otherwise be unused, while we would need to care more about
+ overflows (as MAX + 1 is sometimes produced as the estimate on number
+ of executions of STMT).
+ b) it is consistent with the result of number_of_iterations_exit. */
+ double_int bound;
+
+ /* True if the statement will cause the loop to be leaved the (at most)
+ BOUND + 1-st time it is executed, that is, all the statements after it
+ are executed at most BOUND times. */
+ bool is_exit;
+
+ /* The next bound in the list. */
struct nb_iter_bound *next;
- /* The next bound in a list. */
};
-/* Structure to hold information for each natural loop. */
-struct loop
+/* Description of the loop exit. */
+
+struct GTY (()) loop_exit {
+ /* The exit edge. */
+ struct edge_def *e;
+
+ /* Previous and next exit in the list of the exits of the loop. */
+ struct loop_exit *prev;
+ struct loop_exit *next;
+
+ /* Next element in the list of loops from that E exits. */
+ struct loop_exit *next_e;
+};
+
+typedef struct loop *loop_p;
+DEF_VEC_P (loop_p);
+DEF_VEC_ALLOC_P (loop_p, heap);
+DEF_VEC_ALLOC_P (loop_p, gc);
+
+/* An integer estimation of the number of iterations. Estimate_state
+ describes what is the state of the estimation. */
+enum loop_estimation
{
+ /* Estimate was not computed yet. */
+ EST_NOT_COMPUTED,
+ /* Estimate is ready. */
+ EST_AVAILABLE
+};
+
+/* Structure to hold information for each natural loop. */
+struct GTY ((chain_next ("%h.next"))) loop {
/* Index into loops array. */
int num;
+ /* Number of loop insns. */
+ unsigned ninsns;
+
/* Basic block of loop header. */
- basic_block header;
+ struct basic_block_def *header;
/* Basic block of loop latch. */
- basic_block latch;
+ struct basic_block_def *latch;
/* For loop unrolling/peeling decision. */
struct lpt_decision lpt_decision;
- /* Number of loop insns. */
- unsigned ninsns;
-
/* Average number of executed insns per iteration. */
unsigned av_ninsns;
/* Number of blocks contained within the loop. */
unsigned num_nodes;
- /* The loop nesting depth. */
- int depth;
-
- /* Superloops of the loop. */
- struct loop **pred;
-
- /* The height of the loop (enclosed loop levels) within the loop
- hierarchy tree. */
- int level;
-
- /* The outer (parent) loop or NULL if outermost loop. */
- struct loop *outer;
+ /* Superloops of the loop, starting with the outermost loop. */
+ VEC (loop_p, gc) *superloops;
/* The first inner (child) loop or NULL if innermost loop. */
struct loop *inner;
/* Link to the next (sibling) loop. */
struct loop *next;
- /* Loop that is copy of this loop. */
- struct loop *copy;
-
/* Auxiliary info specific to a pass. */
- void *aux;
+ PTR GTY ((skip (""))) aux;
- /* The probable number of times the loop is executed at runtime.
+ /* The number of times the latch of the loop is executed.
This is an INTEGER_CST or an expression containing symbolic
names. Don't access this field directly:
- number_of_iterations_in_loop computes and caches the computed
+ number_of_latch_executions computes and caches the computed
information in this field. */
tree nb_iterations;
- /* An INTEGER_CST estimation of the number of iterations. NULL_TREE
- if there is no estimation. */
- tree estimated_nb_iterations;
+ /* An integer guaranteed to bound the number of iterations of the loop
+ from above. */
+ double_int nb_iterations_upper_bound;
+
+ /* An integer giving the expected number of iterations of the loop. */
+ double_int nb_iterations_estimate;
+
+ bool any_upper_bound;
+ bool any_estimate;
+
+ /* True if the loop can be parallel. */
+ bool can_be_parallel;
+
+ /* An integer estimation of the number of iterations. Estimate_state
+ describes what is the state of the estimation. */
+ enum loop_estimation estimate_state;
/* Upper bound on number of iterations of a loop. */
struct nb_iter_bound *bounds;
- /* If not NULL, loop has just single exit edge stored here (edges to the
- EXIT_BLOCK_PTR do not count. */
- edge single_exit;
+ /* Head of the cyclic list of the exits of the loop. */
+ struct loop_exit *exits;
- /* True when the loop does not carry data dependences, and
- consequently the iterations can be executed in any order. False
- when the loop carries data dependences, or when the property is
- not decidable. */
- bool parallel_p;
+ /* The single induction variable of the loop when the loop is in
+ normal form. */
+ tree single_iv;
};
/* Flags for state of loop structure. */
LOOPS_HAVE_PREHEADERS = 1,
LOOPS_HAVE_SIMPLE_LATCHES = 2,
LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS = 4,
- LOOPS_HAVE_MARKED_SINGLE_EXITS = 8
+ LOOPS_HAVE_RECORDED_EXITS = 8,
+ LOOPS_MAY_HAVE_MULTIPLE_LATCHES = 16,
+ LOOP_CLOSED_SSA = 32,
+ LOOPS_NEED_FIXUP = 64,
+ LOOPS_HAVE_FALLTHRU_PREHEADERS = 128
};
#define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
| LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)
+#define AVOID_CFG_MODIFICATIONS (LOOPS_MAY_HAVE_MULTIPLE_LATCHES)
/* Structure to hold CFG information about natural loops within a function. */
-struct loops
-{
- /* Number of natural loops in the function. */
- unsigned num;
-
+struct GTY (()) loops {
/* State of loops. */
int state;
- /* We store just pointers to loops here.
- Note that a loop in this array may actually be NULL, if the loop
- has been removed and the entire loops structure has not been
- recomputed since that time. */
- struct loop **parray;
+ /* Array of the loops. */
+ VEC (loop_p, gc) *larray;
+
+ /* Maps edges to the list of their descriptions as loop exits. Edges
+ whose sources or destinations have loop_father == NULL (which may
+ happen during the cfg manipulations) should not appear in EXITS. */
+ htab_t GTY((param_is (struct loop_exit))) exits;
/* Pointer to root of loop hierarchy tree. */
struct loop *tree_root;
-
- /* Information derived from the CFG. */
- struct cfg
- {
- /* The ordering of the basic blocks in a depth first search. */
- int *dfs_order;
-
- /* The reverse completion ordering of the basic blocks found in a
- depth first search. */
- int *rc_order;
- } cfg;
-
- /* Headers shared by multiple loops that should be merged. */
- sbitmap shared_headers;
};
-/* The loop tree currently optimized. */
-
-extern struct loops *current_loops;
-
/* Loop recognition. */
extern int flow_loops_find (struct loops *);
+extern void disambiguate_loops_with_multiple_latches (void);
extern void flow_loops_free (struct loops *);
-extern void flow_loops_dump (const struct loops *, FILE *,
+extern void flow_loops_dump (FILE *,
void (*)(const struct loop *, FILE *, int), int);
extern void flow_loop_dump (const struct loop *, FILE *,
void (*)(const struct loop *, FILE *, int), int);
+struct loop *alloc_loop (void);
extern void flow_loop_free (struct loop *);
int flow_loop_nodes_find (basic_block, struct loop *);
-void fix_loop_structure (struct loops *, bitmap changed_bbs);
-void mark_irreducible_loops (struct loops *);
-void mark_single_exit_loops (struct loops *);
+void fix_loop_structure (bitmap changed_bbs);
+bool mark_irreducible_loops (void);
+void release_recorded_exits (void);
+void record_loop_exits (void);
+void rescan_loop_exit (edge, bool, bool);
/* Loop data structure manipulation/querying. */
extern void flow_loop_tree_node_add (struct loop *, struct loop *);
extern void flow_loop_tree_node_remove (struct loop *);
+extern void add_loop (struct loop *, struct loop *);
extern bool flow_loop_nested_p (const struct loop *, const struct loop *);
-extern bool flow_bb_inside_loop_p (const struct loop *, const basic_block);
+extern bool flow_bb_inside_loop_p (const struct loop *, const_basic_block);
extern struct loop * find_common_loop (struct loop *, struct loop *);
struct loop *superloop_at_depth (struct loop *, unsigned);
-extern unsigned tree_num_loop_insns (struct loop *);
-extern int num_loop_insns (struct loop *);
-extern int average_num_loop_insns (struct loop *);
+struct eni_weights_d;
+extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights_d *);
+extern int num_loop_insns (const struct loop *);
+extern int average_num_loop_insns (const struct loop *);
extern unsigned get_loop_level (const struct loop *);
-extern bool loop_exit_edge_p (const struct loop *, edge);
-extern void mark_loop_exit_edges (struct loops *);
+extern bool loop_exit_edge_p (const struct loop *, const_edge);
+extern bool is_loop_exit (struct loop *, basic_block);
+extern void mark_loop_exit_edges (void);
/* Loops & cfg manipulation. */
extern basic_block *get_loop_body (const struct loop *);
+extern unsigned get_loop_body_with_size (const struct loop *, basic_block *,
+ unsigned);
extern basic_block *get_loop_body_in_dom_order (const struct loop *);
extern basic_block *get_loop_body_in_bfs_order (const struct loop *);
-extern edge *get_loop_exit_edges (const struct loop *, unsigned *);
+extern basic_block *get_loop_body_in_custom_order (const struct loop *,
+ int (*) (const void *, const void *));
+
+extern VEC (edge, heap) *get_loop_exit_edges (const struct loop *);
+edge single_exit (const struct loop *);
extern unsigned num_loop_branches (const struct loop *);
extern edge loop_preheader_edge (const struct loop *);
extern void add_bb_to_loop (basic_block, struct loop *);
extern void remove_bb_from_loops (basic_block);
-extern void cancel_loop_tree (struct loops *, struct loop *);
-
-extern basic_block loop_split_edge_with (edge, rtx);
-extern int fix_loop_placement (struct loop *);
+extern void cancel_loop_tree (struct loop *);
+extern void delete_loop (struct loop *);
enum
{
- CP_SIMPLE_PREHEADERS = 1
+ CP_SIMPLE_PREHEADERS = 1,
+ CP_FALLTHRU_PREHEADERS = 2
};
-extern void create_preheaders (struct loops *, int);
-extern void force_single_succ_latches (struct loops *);
+basic_block create_preheader (struct loop *, int);
+extern void create_preheaders (int);
+extern void force_single_succ_latches (void);
-extern void verify_loop_structure (struct loops *);
+extern void verify_loop_structure (void);
/* Loop analysis. */
-extern bool just_once_each_iteration_p (const struct loop *, basic_block);
+extern bool just_once_each_iteration_p (const struct loop *, const_basic_block);
+gcov_type expected_loop_iterations_unbounded (const struct loop *);
extern unsigned expected_loop_iterations (const struct loop *);
extern rtx doloop_condition_get (rtx);
+void estimate_numbers_of_iterations_loop (struct loop *);
+HOST_WIDE_INT estimated_loop_iterations_int (struct loop *, bool);
+bool estimated_loop_iterations (struct loop *, bool, double_int *);
+
/* Loop manipulation. */
-extern bool can_duplicate_loop_p (struct loop *loop);
+extern bool can_duplicate_loop_p (const struct loop *loop);
#define DLTHE_FLAG_UPDATE_FREQ 1 /* Update frequencies in
duplicate_loop_to_header_edge. */
#define DLTHE_FLAG_COMPLETTE_PEEL 4 /* Update frequencies expecting
a complete peeling. */
-extern struct loop * duplicate_loop (struct loops *, struct loop *,
- struct loop *);
-extern bool duplicate_loop_to_header_edge (struct loop *, edge, struct loops *,
- unsigned, sbitmap, edge, edge *,
- unsigned *, int);
-extern struct loop *loopify (struct loops *, edge, edge,
- basic_block, edge, edge, bool);
-struct loop * loop_version (struct loops *, struct loop *, void *,
- basic_block *, bool);
-extern bool remove_path (struct loops *, edge);
+extern edge create_empty_if_region_on_edge (edge, tree);
+extern struct loop *create_empty_loop_on_edge (edge, tree, tree, tree, tree,
+ tree *, tree *, struct loop *);
+extern struct loop * duplicate_loop (struct loop *, struct loop *);
+extern void duplicate_subloops (struct loop *, struct loop *);
+extern bool duplicate_loop_to_header_edge (struct loop *, edge,
+ unsigned, sbitmap, edge,
+ VEC (edge, heap) **, int);
+extern struct loop *loopify (edge, edge,
+ basic_block, edge, edge, bool,
+ unsigned, unsigned);
+struct loop * loop_version (struct loop *, void *,
+ basic_block *, unsigned, unsigned, unsigned, bool);
+extern bool remove_path (edge);
+void scale_loop_frequencies (struct loop *, int, int);
/* Induction variable analysis. */
If first_special is true, the value in the first iteration is
delta + mult * base
-
+
If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
subreg_{mode} (base + i * step)
extern bool biv_p (rtx, rtx);
extern void find_simple_exit (struct loop *, struct niter_desc *);
extern void iv_analysis_done (void);
-extern struct df *iv_current_loop_df (void);
extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
extern void free_simple_loop_desc (struct loop *loop);
return (struct niter_desc *) loop->aux;
}
+/* Accessors for the loop structures. */
+
+/* Returns the loop with index NUM from current_loops. */
+
+static inline struct loop *
+get_loop (unsigned num)
+{
+ return VEC_index (loop_p, current_loops->larray, num);
+}
+
+/* Returns the number of superloops of LOOP. */
+
+static inline unsigned
+loop_depth (const struct loop *loop)
+{
+ return VEC_length (loop_p, loop->superloops);
+}
+
+/* Returns the immediate superloop of LOOP, or NULL if LOOP is the outermost
+ loop. */
+
+static inline struct loop *
+loop_outer (const struct loop *loop)
+{
+ unsigned n = VEC_length (loop_p, loop->superloops);
+
+ if (n == 0)
+ return NULL;
+
+ return VEC_index (loop_p, loop->superloops, n - 1);
+}
+
+/* Returns the list of loops in current_loops. */
+
+static inline VEC (loop_p, gc) *
+get_loops (void)
+{
+ if (!current_loops)
+ return NULL;
+
+ return current_loops->larray;
+}
+
+/* Returns the number of loops in current_loops (including the removed
+ ones and the fake loop that forms the root of the loop tree). */
+
+static inline unsigned
+number_of_loops (void)
+{
+ if (!current_loops)
+ return 0;
+
+ return VEC_length (loop_p, current_loops->larray);
+}
+
+/* Returns true if state of the loops satisfies all properties
+ described by FLAGS. */
+
+static inline bool
+loops_state_satisfies_p (unsigned flags)
+{
+ return (current_loops->state & flags) == flags;
+}
+
+/* Sets FLAGS to the loops state. */
+
+static inline void
+loops_state_set (unsigned flags)
+{
+ current_loops->state |= flags;
+}
+
+/* Clears FLAGS from the loops state. */
+
+static inline void
+loops_state_clear (unsigned flags)
+{
+ if (!current_loops)
+ return;
+ current_loops->state &= ~flags;
+}
+
+/* Loop iterators. */
+
+/* Flags for loop iteration. */
+
+enum li_flags
+{
+ LI_INCLUDE_ROOT = 1, /* Include the fake root of the loop tree. */
+ LI_FROM_INNERMOST = 2, /* Iterate over the loops in the reverse order,
+ starting from innermost ones. */
+ LI_ONLY_INNERMOST = 4 /* Iterate only over innermost loops. */
+};
+
+/* The iterator for loops. */
+
+typedef struct
+{
+ /* The list of loops to visit. */
+ VEC(int,heap) *to_visit;
+
+ /* The index of the actual loop. */
+ unsigned idx;
+} loop_iterator;
+
+static inline void
+fel_next (loop_iterator *li, loop_p *loop)
+{
+ int anum;
+
+ while (VEC_iterate (int, li->to_visit, li->idx, anum))
+ {
+ li->idx++;
+ *loop = get_loop (anum);
+ if (*loop)
+ return;
+ }
+
+ VEC_free (int, heap, li->to_visit);
+ *loop = NULL;
+}
+
+static inline void
+fel_init (loop_iterator *li, loop_p *loop, unsigned flags)
+{
+ struct loop *aloop;
+ unsigned i;
+ int mn;
+
+ li->idx = 0;
+ if (!current_loops)
+ {
+ li->to_visit = NULL;
+ *loop = NULL;
+ return;
+ }
+
+ li->to_visit = VEC_alloc (int, heap, number_of_loops ());
+ mn = (flags & LI_INCLUDE_ROOT) ? 0 : 1;
+
+ if (flags & LI_ONLY_INNERMOST)
+ {
+ for (i = 0; VEC_iterate (loop_p, current_loops->larray, i, aloop); i++)
+ if (aloop != NULL
+ && aloop->inner == NULL
+ && aloop->num >= mn)
+ VEC_quick_push (int, li->to_visit, aloop->num);
+ }
+ else if (flags & LI_FROM_INNERMOST)
+ {
+ /* Push the loops to LI->TO_VISIT in postorder. */
+ for (aloop = current_loops->tree_root;
+ aloop->inner != NULL;
+ aloop = aloop->inner)
+ continue;
+
+ while (1)
+ {
+ if (aloop->num >= mn)
+ VEC_quick_push (int, li->to_visit, aloop->num);
+
+ if (aloop->next)
+ {
+ for (aloop = aloop->next;
+ aloop->inner != NULL;
+ aloop = aloop->inner)
+ continue;
+ }
+ else if (!loop_outer (aloop))
+ break;
+ else
+ aloop = loop_outer (aloop);
+ }
+ }
+ else
+ {
+ /* Push the loops to LI->TO_VISIT in preorder. */
+ aloop = current_loops->tree_root;
+ while (1)
+ {
+ if (aloop->num >= mn)
+ VEC_quick_push (int, li->to_visit, aloop->num);
+
+ if (aloop->inner != NULL)
+ aloop = aloop->inner;
+ else
+ {
+ while (aloop != NULL && aloop->next == NULL)
+ aloop = loop_outer (aloop);
+ if (aloop == NULL)
+ break;
+ aloop = aloop->next;
+ }
+ }
+ }
+
+ fel_next (li, loop);
+}
+
+#define FOR_EACH_LOOP(LI, LOOP, FLAGS) \
+ for (fel_init (&(LI), &(LOOP), FLAGS); \
+ (LOOP); \
+ fel_next (&(LI), &(LOOP)))
+
+#define FOR_EACH_LOOP_BREAK(LI) \
+ { \
+ VEC_free (int, heap, (LI)->to_visit); \
+ break; \
+ }
+
/* The properties of the target. */
-extern unsigned target_avail_regs; /* Number of available registers. */
-extern unsigned target_res_regs; /* Number of reserved registers. */
-extern unsigned target_small_cost; /* The cost for register when there
- is a free one. */
-extern unsigned target_pres_cost; /* The cost for register when there are
- not too many free ones. */
-extern unsigned target_spill_cost; /* The cost for register when we need
- to spill. */
+extern unsigned target_avail_regs;
+extern unsigned target_res_regs;
+extern unsigned target_reg_cost [2];
+extern unsigned target_spill_cost [2];
/* Register pressure estimation for induction variable optimizations & loop
invariant motion. */
-extern unsigned global_cost_for_size (unsigned, unsigned, unsigned);
+extern unsigned estimate_reg_pressure_cost (unsigned, unsigned, bool);
extern void init_set_costs (void);
/* Loop optimizer initialization. */
-extern struct loops *loop_optimizer_init (unsigned);
-extern void loop_optimizer_finalize (struct loops *);
+extern void loop_optimizer_init (unsigned);
+extern void loop_optimizer_finalize (void);
/* Optimization passes. */
-extern void unswitch_loops (struct loops *);
+extern void unswitch_loops (void);
enum
{
UAP_PEEL = 1, /* Enables loop peeling. */
- UAP_UNROLL = 2, /* Enables peeling of loops if it seems profitable. */
- UAP_UNROLL_ALL = 4 /* Enables peeling of all loops. */
+ UAP_UNROLL = 2, /* Enables unrolling of loops if it seems profitable. */
+ UAP_UNROLL_ALL = 4 /* Enables unrolling of all loops. */
};
-extern void unroll_and_peel_loops (struct loops *, int);
-extern void doloop_optimize_loops (struct loops *);
-extern void move_loop_invariants (struct loops *);
-extern void record_estimate (struct loop *, tree, tree, tree);
+extern void unroll_and_peel_loops (int);
+extern void doloop_optimize_loops (void);
+extern void move_loop_invariants (void);
+extern bool finite_loop_p (struct loop *);
#endif /* GCC_CFGLOOP_H */
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