* 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, 31 insertions, 7 deletions

diff --git a/gcc/cfghooks.c b/gcc/cfghooks.c
index 50aca9f1b69..d6a981d1db8 100644
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -310,6 +310,11 @@ redirect_edge_and_branch (edge e, basic_block dest)
 
   ret = cfg_hooks->redirect_edge_and_branch (e, dest);
 
+  /* If RET != E, then the edge E was removed since RET already lead to the
+     same destination.  */
+  if (ret != NULL && current_loops != NULL)
+    rescan_loop_exit (e, false, ret != e);
+
   return ret;
 }
 
@@ -320,19 +325,27 @@ redirect_edge_and_branch (edge e, basic_block dest)
 basic_block
 redirect_edge_and_branch_force (edge e, basic_block dest)
 {
-  basic_block ret;
+  basic_block ret, src = e->src;
   struct loop *loop;
 
   if (!cfg_hooks->redirect_edge_and_branch_force)
     internal_error ("%s does not support redirect_edge_and_branch_force",
 		    cfg_hooks->name);
 
+  if (current_loops != NULL)
+    rescan_loop_exit (e, false, true);
+
   ret = cfg_hooks->redirect_edge_and_branch_force (e, dest);
-  if (current_loops != NULL && ret != NULL)
+  if (current_loops != NULL)
     {
-      loop = find_common_loop (single_pred (ret)->loop_father,
-			       single_succ (ret)->loop_father);
-      add_bb_to_loop (ret, loop);
+      if (ret != NULL)
+	{
+	  loop = find_common_loop (single_pred (ret)->loop_father,
+				   single_succ (ret)->loop_father);
+	  add_bb_to_loop (ret, loop);
+	}
+      else if (find_edge (src, dest) == e)
+	rescan_loop_exit (e, true, false);
     }
 
   return ret;
@@ -452,6 +465,9 @@ split_edge (edge e)
   if (!cfg_hooks->split_edge)
     internal_error ("%s does not support split_edge", cfg_hooks->name);
 
+  if (current_loops != NULL)
+    rescan_loop_exit (e, false, true);
+
   ret = cfg_hooks->split_edge (e);
   ret->count = count;
   ret->frequency = freq;
@@ -595,11 +611,19 @@ merge_blocks (basic_block a, basic_block b)
      whole lot of them and hope the caller knows what they're doing.  */
 
   while (EDGE_COUNT (a->succs) != 0)
-   remove_edge (EDGE_SUCC (a, 0));
+    {
+      if (current_loops != NULL)
+	rescan_loop_exit (EDGE_SUCC (a, 0), false, true);
+      remove_edge (EDGE_SUCC (a, 0));
+    }
 
   /* Adjust the edges out of B for the new owner.  */
   FOR_EACH_EDGE (e, ei, b->succs)
-    e->src = a;
+    {
+      e->src = a;
+      if (current_loops != NULL)
+	rescan_loop_exit (e, true, false);
+    }
   a->succs = b->succs;
   a->flags |= b->flags;