/* Natural loop functions
- Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003
+ Copyright (C) 1987, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
Free Software Foundation, Inc.
This file is part of GCC.
unsigned times;
};
-/* Description of loop for simple loop unrolling. */
-struct loop_desc
-{
- int postincr; /* 1 if increment/decrement is done after loop exit condition. */
- rtx stride; /* Value added to VAR in each iteration. */
- rtx var; /* Loop control variable. */
- rtx var_alts; /* List of definitions of its initial value. */
- rtx lim; /* Expression var is compared with. */
- rtx lim_alts; /* List of definitions of its initial value. */
- bool const_iter; /* True if it iterates constant number of times. */
- unsigned HOST_WIDE_INT niter;
- /* Number of iterations if it is constant. */
- bool may_be_zero; /* If we cannot determine that the first iteration will pass. */
- enum rtx_code cond; /* Exit condition. */
- int neg; /* Set to 1 if loop ends when condition is satisfied. */
- edge out_edge; /* The exit edge. */
- edge in_edge; /* And the other one. */
- int n_branches; /* Number of branches inside the loop. */
-};
-
/* Structure to hold information for each natural loop. */
struct loop
{
/* For loop unrolling/peeling decision. */
struct lpt_decision lpt_decision;
- /* Simple loop description. */
- int simple;
- struct loop_desc desc;
- int has_desc;
-
/* Number of loop insns. */
unsigned ninsns;
/* Information derived from the CFG. */
struct cfg
{
- /* The bitmap vector of dominators or NULL if not computed. */
- dominance_info dom;
-
/* The ordering of the basic blocks in a depth first search. */
int *dfs_order;
void (*)(const struct loop *, FILE *, int), int);
extern void flow_loop_dump (const struct loop *, FILE *,
void (*)(const struct loop *, FILE *, int), int);
-extern int flow_loop_scan (struct loops *, struct loop *, int);
+extern int flow_loop_scan (struct loop *, int);
extern void flow_loop_free (struct loop *);
void mark_irreducible_loops (struct loops *);
extern struct loop * find_common_loop (struct loop *, struct loop *);
extern int num_loop_insns (struct loop *);
extern int average_num_loop_insns (struct loop *);
+extern unsigned get_loop_level (const struct loop *);
/* Loops & cfg manipulation. */
extern basic_block *get_loop_body (const struct loop *);
+extern basic_block *get_loop_body_in_dom_order (const struct loop *);
extern edge *get_loop_exit_edges (const struct loop *, unsigned *);
+extern unsigned num_loop_branches (const struct loop *);
extern edge loop_preheader_edge (const struct loop *);
extern edge loop_latch_edge (const struct loop *);
extern void cancel_loop (struct loops *, struct loop *);
extern void cancel_loop_tree (struct loops *, struct loop *);
-extern basic_block loop_split_edge_with (edge, rtx, struct loops *);
+extern basic_block loop_split_edge_with (edge, rtx);
extern int fix_loop_placement (struct loop *);
enum
extern void verify_loop_structure (struct loops *);
/* Loop analysis. */
-extern bool simple_loop_p (struct loops *, struct loop *, struct loop_desc *);
-extern rtx count_loop_iterations (struct loop_desc *, rtx, rtx);
-extern bool just_once_each_iteration_p (struct loops *,struct loop *,
- basic_block);
+extern bool just_once_each_iteration_p (struct loop *, basic_block);
extern unsigned expected_loop_iterations (const struct loop *);
/* Loop manipulation. */
extern struct loop *loopify (struct loops *, edge, edge, basic_block);
extern void unloop (struct loops *, struct loop *);
extern bool remove_path (struct loops *, edge);
-extern edge split_loop_bb (struct loops *, basic_block, rtx);
+extern edge split_loop_bb (basic_block, rtx);
+
+/* Induction variable analysis. */
+
+/* The description of induction variable. The things are a bit complicated
+ due to need to handle subregs and extends. The value of the object described
+ by it can be obtained as follows (all computations are done in extend_mode):
+
+ Value in i-th iteration is
+ delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).
+
+ If first_special is true, the value in the first iteration is
+ delta + mult * base
+
+ If extend = NIL, first_special must be false, delta 0, mult 1 and value is
+ subreg_{mode} (base + i * step)
+
+ The get_iv_value function can be used to obtain these expressions.
+
+ ??? Add a third mode field that would specify the mode in that inner
+ computation is done, which would enable it to be different from the
+ outer one? */
+
+struct rtx_iv
+{
+ /* Its base and step (mode of base and step is supposed to be extend_mode,
+ see the description above). */
+ rtx base, step;
+
+ /* The type of extend applied to it (SIGN_EXTEND, ZERO_EXTEND or NIL). */
+ enum rtx_code extend;
+
+ /* Operations applied in the extended mode. */
+ rtx delta, mult;
+
+ /* The mode it is extended to. */
+ enum machine_mode extend_mode;
+
+ /* The mode the variable iterates in. */
+ enum machine_mode mode;
+
+ /* Whether we have already filled the remaining fields. */
+ unsigned analysed : 1;
+
+ /* Whether the first iteration needs to be handled specially. */
+ unsigned first_special : 1;
+};
+
+/* The description of an exit from the loop and of the number of iterations
+ till we take the exit. */
+
+struct niter_desc
+{
+ /* The edge out of the loop. */
+ edge out_edge;
+
+ /* The other edge leading from the condition. */
+ edge in_edge;
+
+ /* True if we are able to say anything about number of iterations of the
+ loop. */
+ bool simple_p;
+
+ /* True if the loop iterates the constant number of times. */
+ bool const_iter;
+
+ /* Number of iterations if constant. */
+ unsigned HOST_WIDEST_INT niter;
+
+ /* Upper bound on the number of iterations. */
+ unsigned HOST_WIDEST_INT niter_max;
+
+ /* Assumptions under that the rest of the information is valid. */
+ rtx assumptions;
+
+ /* Assumptions under that the loop ends before reaching the latch,
+ even if value of niter_expr says otherwise. */
+ rtx noloop_assumptions;
+
+ /* Condition under that the loop is infinite. */
+ rtx infinite;
+
+ /* Whether the comparison is signed. */
+ bool signed_p;
+
+ /* The mode in that niter_expr should be computed. */
+ enum machine_mode mode;
+
+ /* The number of iterations of the loop. */
+ rtx niter_expr;
+};
+
+extern void iv_analysis_loop_init (struct loop *);
+extern rtx iv_get_reaching_def (rtx, rtx);
+extern bool iv_analyze (rtx, rtx, struct rtx_iv *);
+extern rtx get_iv_value (struct rtx_iv *, rtx);
+extern void find_simple_exit (struct loop *, struct niter_desc *);
+extern void iv_number_of_iterations (struct loop *, rtx, rtx,
+ struct niter_desc *);
+extern void iv_analysis_done (void);
+
+extern struct niter_desc *get_simple_loop_desc (struct loop *loop);
+extern void free_simple_loop_desc (struct loop *loop);
+
+static inline struct niter_desc *
+simple_loop_desc (struct loop *loop)
+{
+ return loop->aux;
+}
/* Loop optimizer initialization. */
extern struct loops *loop_optimizer_init (FILE *);
};
extern void unroll_and_peel_loops (struct loops *, int);
+extern void doloop_optimize_loops (struct loops *);
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