IPA ICF: use fibonacci heap instead of list as a worklist.

2019-06-04  Martin Liska  <mliska@suse.cz>

	* ipa-icf.c (sem_item_optimizer::add_item_to_class): Count
	number of references.
	(sem_item_optimizer::do_congruence_step):
	(sem_item_optimizer::worklist_push): Dump how references
	a class has.
	(sem_item_optimizer::worklist_pop): Use heap.
	(sem_item_optimizer::process_cong_reduction): Likewise.
	* ipa-icf.h: Use fibonacci_heap insteam of std::list.

From-SVN: r271901

3 files changed, 24 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8fbeb6e..d249d12 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,16 @@
 2019-06-04  Martin Liska  <mliska@suse.cz>
 
+	* ipa-icf.c (sem_item_optimizer::add_item_to_class): Count
+	number of references.
+	(sem_item_optimizer::do_congruence_step):
+	(sem_item_optimizer::worklist_push): Dump how references
+	a class has.
+	(sem_item_optimizer::worklist_pop): Use heap.
+	(sem_item_optimizer::process_cong_reduction): Likewise.
+	* ipa-icf.h: Use fibonacci_heap insteam of std::list.
+
+2019-06-04  Martin Liska  <mliska@suse.cz>
+
 	* ipa-icf.h (struct sem_usage_pair_hash): New.
 	(sem_usage_pair_hash::hash): Likewise.
 	(sem_usage_pair_hash::equal): Likewise.
diff --git a/gcc/ipa-icf.c b/gcc/ipa-icf.c
index 9f1e2c8..19b45b3 100644
--- a/gcc/ipa-icf.c
+++ b/gcc/ipa-icf.c
@@ -80,6 +80,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "print-tree.h"
 #include "ipa-utils.h"
 #include "ipa-icf-gimple.h"
+#include "fibonacci_heap.h"
 #include "ipa-icf.h"
 #include "stor-layout.h"
 #include "dbgcnt.h"
@@ -2624,6 +2625,7 @@ sem_item_optimizer::add_item_to_class (congruence_class *cls, sem_item *item)
 {
   item->index_in_class = cls->members.length ();
   cls->members.safe_push (item);
+  cls->referenced_by_count += item->referenced_by_count;
   item->cls = cls;
 }
 
@@ -3186,7 +3188,8 @@ sem_item_optimizer::do_congruence_step (congruence_class *cls)
   {
     if (dump_file && (dump_flags & TDF_DETAILS))
       fprintf (dump_file, "  processing congruence step for class: %u "
-	       "(%u items), index: %u\n", cls->id, cls->members.length (), i);
+	       "(%u items, %u references), index: %u\n", cls->id,
+	       cls->referenced_by_count, cls->members.length (), i);
     do_congruence_step_for_index (cls, i);
 
     if (splitter_class_removed)
@@ -3206,7 +3209,7 @@ sem_item_optimizer::worklist_push (congruence_class *cls)
     return;
 
   cls->in_worklist = true;
-  worklist.push_back (cls);
+  worklist.insert (cls->referenced_by_count, cls);
 }
 
 /* Pops a class from worklist. */
@@ -3218,8 +3221,7 @@ sem_item_optimizer::worklist_pop (void)
 
   while (!worklist.empty ())
     {
-      cls = worklist.front ();
-      worklist.pop_front ();
+      cls = worklist.extract_min ();
       if (cls->in_worklist)
 	{
 	  cls->in_worklist = false;
@@ -3251,7 +3253,7 @@ sem_item_optimizer::process_cong_reduction (void)
 
   if (dump_file)
     fprintf (dump_file, "Worklist has been filled with: %lu\n",
-	     (unsigned long) worklist.size ());
+	     (unsigned long) worklist.nodes ());
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     fprintf (dump_file, "Congruence class reduction\n");
diff --git a/gcc/ipa-icf.h b/gcc/ipa-icf.h
index ede4c94..6b81eb3 100644
--- a/gcc/ipa-icf.h
+++ b/gcc/ipa-icf.h
@@ -29,7 +29,8 @@ class congruence_class
 {
 public:
   /* Congruence class constructor for a new class with _ID.  */
-  congruence_class (unsigned int _id): in_worklist (false), id(_id)
+  congruence_class (unsigned int _id): in_worklist (false), id (_id),
+  referenced_by_count (0)
   {
   }
 
@@ -54,6 +55,9 @@ public:
 
   /* Global unique class identifier.  */
   unsigned int id;
+
+  /* Total number of references to items of this class.  */
+  unsigned referenced_by_count;
 };
 
 /* Semantic item type enum.  */
@@ -530,7 +534,7 @@ public:
 
   /* Worklist of congruence classes that can potentially
      refine classes of congruence.  */
-  std::list<congruence_class *> worklist;
+  fibonacci_heap<unsigned, congruence_class> worklist;
 
   /* Remove semantic ITEM and release memory.  */
   void remove_item (sem_item *item);