* doc/loop.texi: Document recording of loop exits.

	* cfgloopmanip.c (loopify, duplicate_loop): Use alloc_loop.
	(update_single_exits_after_duplication,
	update_single_exit_for_duplicated_loop,
	update_single_exit_for_duplicated_loops): Removed.
	(duplicate_loop_to_header_edge): Do not call
	update_single_exits_after_duplication and
	update_single_exit_for_duplicated_loops.
	(loop_version): Do not update single_exit information.
	(fix_loop_structure): Use record_loop_exits instead of
	mark_single_exit_loops.
	* tree-ssa-loop-manip.c (tree_transform_and_unroll_loop): Update
	the lists of loop exits.
	* cfghooks.c (redirect_edge_and_branch, redirect_edge_and_branch_force,
	split_edge, merge_blocks): Update the lists of loop exits.
	* modulo-sched.c (sms_schedule): Pass LOOPS_HAVE_RECORDED_EXITS to
	loop_optimizer_init.
	* loop-init.c (loop_optimizer_init): Call record_loop_exits instead
	of mark_single_exit_loops.
	(loop_optimizer_finalize): Call release_recorded_exits.
	* tree-ssa-loop.c (tree_loop_optimizer_init): Pass
	LOOPS_HAVE_RECORDED_EXITS to loop_optimizer_init.
	* tree-vectorizer.c (slpeel_tree_duplicate_loop_to_edge_cfg): Do not
	update single exit information.
	* lambda-code.c (perfect_nestify): Ditto.
	* cfgloop.c (flow_loop_free): Destroy the list of exits of the loop.
	(mark_single_exit_loops): Removed.
	(alloc_loop, loop_exit_hash, loop_exit_eq, loop_exit_free,
	get_exit_descriptions, rescan_loop_exit, record_loop_exits,
	dump_recorded_exit, dump_recorded_exits, release_recorded_exits): New
	functions.
	(get_loop_exit_edges, single_exit): Use recorded exit lists.
	(add_bb_to_loop, remove_bb_from_loops): Update the lists of loop exits.
	(verify_loop_structure): Verify consistency of the exit lists.
	(flow_loops_find): Use alloc_loop.  Initialize exits hash.
	(set_single_exit): Removed.
	* cfgloop.h (struct loop_exit): New function.
	(struct loop): single_exit_ field replaced by exits field.
	(LOOPS_HAVE_MARKED_SINGLE_EXITS): Replaced by LOOPS_HAVE_RECORDED_EXITS.
	(struct loops): Added exits hash.
	(mark_single_exit_loops, set_single_exit): Declaration removed.
	(release_recorded_exits, record_loop_exits, rescan_loop_exit): Declare.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@120728 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 7 deletions

diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
index 3116abf3767..ec1149c8bb8 100644
--- a/gcc/cfgloop.h
+++ b/gcc/cfgloop.h
@@ -74,6 +74,21 @@ struct nb_iter_bound
   struct nb_iter_bound *next;
 };
 
+/* Description of the loop exit.  */
+
+struct loop_exit
+{
+  /* The exit edge.  */
+  edge 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;
+};
+
 /* Structure to hold information for each natural loop.  */
 struct loop
 {
@@ -142,10 +157,8 @@ struct loop
   /* 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.  Do not use directly; this field should
-     only be accessed via single_exit/set_single_exit functions.  */
-  edge single_exit_;
+  /* Head of the cyclic list of the exits of the loop.  */
+  struct loop_exit exits;
 };
 
 /* Flags for state of loop structure.  */
@@ -154,7 +167,7 @@ enum
   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
 };
 
 #define LOOPS_NORMAL (LOOPS_HAVE_PREHEADERS | LOOPS_HAVE_SIMPLE_LATCHES \
@@ -173,6 +186,11 @@ struct loops
   /* Array of the loops.  */
   VEC (loop_p, heap) *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 exits;
+
   /* Pointer to root of loop hierarchy tree.  */
   struct loop *tree_root;
 };
@@ -184,11 +202,14 @@ 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 (bitmap changed_bbs);
 void mark_irreducible_loops (void);
-void mark_single_exit_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 *);
@@ -210,7 +231,6 @@ 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 VEC (edge, heap) *get_loop_exit_edges (const struct loop *);
 edge single_exit (const struct loop *);
-void set_single_exit (struct loop *, edge);
 extern unsigned num_loop_branches (const struct loop *);
 
 extern edge loop_preheader_edge (const struct loop *);