Changing cost propagation and ordering colorable bucket heuristics for PR93564.

2020-02-23  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/93564
	* ira-color.c (struct update_cost_queue_elem): New member start.
	(queue_update_cost, get_next_update_cost): Add new arg start.
	(allocnos_conflict_p): New function.
	(update_costs_from_allocno): Add new arg conflict_cost_update_p.
	Add checking conflicts with allocnos_conflict_p.
	(update_costs_from_prefs, restore_costs_from_copies): Adjust
	update_costs_from_allocno calls.
	(update_conflict_hard_regno_costs): Add checking conflicts with
	allocnos_conflict_p.  Adjust calls of queue_update_cost and
	get_next_update_cost.
	(assign_hard_reg): Adjust calls of queue_update_cost.  Add
	debugging print.
	(bucket_allocno_compare_func): Restore previous version.

gcc/ChangeLog

+2020-02-23  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/93564
+	* ira-color.c (struct update_cost_queue_elem): New member start.
+	(queue_update_cost, get_next_update_cost): Add new arg start.
+	(allocnos_conflict_p): New function.
+	(update_costs_from_allocno): Add new arg conflict_cost_update_p.
+	Add checking conflicts with allocnos_conflict_p.
+	(update_costs_from_prefs, restore_costs_from_copies): Adjust
+	update_costs_from_allocno calls.
+	(update_conflict_hard_regno_costs): Add checking conflicts with
+	allocnos_conflict_p.  Adjust calls of queue_update_cost and
+	get_next_update_cost.
+	(assign_hard_reg): Adjust calls of queue_update_cost.  Add
+	debugging print.
+	(bucket_allocno_compare_func): Restore previous version.
+
 2020-02-21  John David Anglin  <danglin@gcc.gnu.org>
 
 	* gcc/config/pa/pa.c (pa_function_value): Fix check for word and

gcc/ira-color.c

@@ -1199,6 +1199,10 @@ struct update_cost_queue_elem
      connecting this allocno to the one being allocated.  */
   int divisor;
 
+  /* Allocno from which we started chaining costs of connected
+     allocnos. */
+  ira_allocno_t start;
+
   /* Allocno from which we are chaining costs of connected allocnos.
      It is used not go back in graph of allocnos connected by
      copies.  */
@@ -1258,10 +1262,11 @@ start_update_cost (void)
   update_cost_queue = NULL;
 }
 
-/* Add (ALLOCNO, FROM, DIVISOR) to the end of update_cost_queue, unless
+/* Add (ALLOCNO, START, FROM, DIVISOR) to the end of update_cost_queue, unless
    ALLOCNO is already in the queue, or has NO_REGS class.  */
 static inline void
-queue_update_cost (ira_allocno_t allocno, ira_allocno_t from, int divisor)
+queue_update_cost (ira_allocno_t allocno, ira_allocno_t start,
+		   ira_allocno_t from, int divisor)
 {
   struct update_cost_queue_elem *elem;
 
@@ -1270,6 +1275,7 @@ queue_update_cost (ira_allocno_t allocno, ira_allocno_t from, int divisor)
       && ALLOCNO_CLASS (allocno) != NO_REGS)
     {
       elem->check = update_cost_check;
+      elem->start = start;
       elem->from = from;
       elem->divisor = divisor;
       elem->next = NULL;
@@ -1282,10 +1288,11 @@ queue_update_cost (ira_allocno_t allocno, ira_allocno_t from, int divisor)
 }
 
 /* Try to remove the first element from update_cost_queue.  Return
-   false if the queue was empty, otherwise make (*ALLOCNO, *FROM,
-   *DIVISOR) describe the removed element.  */
+   false if the queue was empty, otherwise make (*ALLOCNO, *START,
+   *FROM, *DIVISOR) describe the removed element.  */
 static inline bool
-get_next_update_cost (ira_allocno_t *allocno, ira_allocno_t *from, int *divisor)
+get_next_update_cost (ira_allocno_t *allocno, ira_allocno_t *start,
+		      ira_allocno_t *from, int *divisor)
 {
   struct update_cost_queue_elem *elem;
 
@@ -1294,6 +1301,7 @@ get_next_update_cost (ira_allocno_t *allocno, ira_allocno_t *from, int *divisor)
 
   *allocno = update_cost_queue;
   elem = &update_cost_queue_elems[ALLOCNO_NUM (*allocno)];
+  *start = elem->start;
   *from = elem->from;
   *divisor = elem->divisor;
   update_cost_queue = elem->next;
@@ -1325,18 +1333,41 @@ update_allocno_cost (ira_allocno_t allocno, int hard_regno,
   return true;
 }
 
+/* Return TRUE if allocnos A1 and A2 conflicts. Here we are
+   interesting only in conflicts of allocnos with intersected allocno
+   classes. */
+static bool
+allocnos_conflict_p (ira_allocno_t a1, ira_allocno_t a2)
+{
+  ira_object_t obj, conflict_obj;
+  ira_object_conflict_iterator oci;
+  int word, nwords = ALLOCNO_NUM_OBJECTS (a1);
+  
+  for (word = 0; word < nwords; word++)
+    {
+      obj = ALLOCNO_OBJECT (a1, word);
+      /* Take preferences of conflicting allocnos into account.  */
+      FOR_EACH_OBJECT_CONFLICT (obj, conflict_obj, oci)
+	if (OBJECT_ALLOCNO (conflict_obj) == a2)
+	  return true;
+    }
+  return false;
+}  
+
 /* Update (decrease if DECR_P) HARD_REGNO cost of allocnos connected
    by copies to ALLOCNO to increase chances to remove some copies as
-   the result of subsequent assignment.  Record cost updates if
-   RECORD_P is true.  */
+   the result of subsequent assignment.  Update conflict costs only
+   for true CONFLICT_COST_UPDATE_P.  Record cost updates if RECORD_P is
+   true.  */
 static void
 update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
-			   int divisor, bool decr_p, bool record_p)
+			   int divisor, bool decr_p, bool record_p,
+			   bool conflict_cost_update_p)
 {
   int cost, update_cost, update_conflict_cost;
   machine_mode mode;
   enum reg_class rclass, aclass;
-  ira_allocno_t another_allocno, from = NULL;
+  ira_allocno_t another_allocno, start = allocno, from = NULL;
   ira_copy_t cp, next_cp;
 
   rclass = REGNO_REG_CLASS (hard_regno);
@@ -1359,7 +1390,8 @@ update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
 	  else
 	    gcc_unreachable ();
 
-	  if (another_allocno == from)
+	  if (another_allocno == from
+	      || allocnos_conflict_p (another_allocno, start))
 	    continue;
 
 	  aclass = ALLOCNO_CLASS (another_allocno);
@@ -1384,7 +1416,8 @@ update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
 	  if (decr_p)
 	    cost = -cost;
 
-	  update_conflict_cost = update_cost = cp->freq * cost / divisor;
+	  update_cost = cp->freq * cost / divisor;
+	  update_conflict_cost = conflict_cost_update_p ? update_cost : 0;
 
 	  if (ALLOCNO_COLOR_DATA (another_allocno) != NULL
 	      && (ALLOCNO_COLOR_DATA (allocno)->first_thread_allocno
@@ -1399,7 +1432,8 @@ update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
 	  if (! update_allocno_cost (another_allocno, hard_regno,
 				     update_cost, update_conflict_cost))
 	    continue;
-	  queue_update_cost (another_allocno, allocno, divisor * COST_HOP_DIVISOR);
+	  queue_update_cost (another_allocno, start, allocno,
+			     divisor * COST_HOP_DIVISOR);
 	  if (record_p && ALLOCNO_COLOR_DATA (another_allocno) != NULL)
 	    ALLOCNO_COLOR_DATA (another_allocno)->update_cost_records
 	      = get_update_cost_record (hard_regno, divisor,
@@ -1407,7 +1441,7 @@ update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
 					->update_cost_records);
 	}
     }
-  while (get_next_update_cost (&allocno, &from, &divisor));
+  while (get_next_update_cost (&allocno, &start, &from, &divisor));
 }
 
 /* Decrease preferred ALLOCNO hard register costs and costs of
@@ -1420,7 +1454,7 @@ update_costs_from_prefs (ira_allocno_t allocno)
   start_update_cost ();
   for (pref = ALLOCNO_PREFS (allocno); pref != NULL; pref = pref->next_pref)
     update_costs_from_allocno (allocno, pref->hard_regno,
-			       COST_HOP_DIVISOR, true, true);
+			       COST_HOP_DIVISOR, true, true, false);
 }
 
 /* Update (decrease if DECR_P) the cost of allocnos connected to
@@ -1435,7 +1469,7 @@ update_costs_from_copies (ira_allocno_t allocno, bool decr_p, bool record_p)
   hard_regno = ALLOCNO_HARD_REGNO (allocno);
   ira_assert (hard_regno >= 0 && ALLOCNO_CLASS (allocno) != NO_REGS);
   start_update_cost ();
-  update_costs_from_allocno (allocno, hard_regno, 1, decr_p, record_p);
+  update_costs_from_allocno (allocno, hard_regno, 1, decr_p, record_p, true);
 }
 
 /* Update conflict_allocno_hard_prefs of allocnos conflicting with
@@ -1485,7 +1519,7 @@ restore_costs_from_copies (ira_allocno_t allocno)
   start_update_cost ();
   for (curr = records; curr != NULL; curr = curr->next)
     update_costs_from_allocno (allocno, curr->hard_regno,
-			       curr->divisor, true, false);
+			       curr->divisor, true, false, true);
   free_update_cost_record_list (records);
   ALLOCNO_COLOR_DATA (allocno)->update_cost_records = NULL;
 }
@@ -1503,10 +1537,10 @@ update_conflict_hard_regno_costs (int *costs, enum reg_class aclass,
   int *conflict_costs;
   bool cont_p;
   enum reg_class another_aclass;
-  ira_allocno_t allocno, another_allocno, from;
+  ira_allocno_t allocno, another_allocno, start, from;
   ira_copy_t cp, next_cp;
 
-  while (get_next_update_cost (&allocno, &from, &divisor))
+  while (get_next_update_cost (&allocno, &start, &from, &divisor))
     for (cp = ALLOCNO_COPIES (allocno); cp != NULL; cp = next_cp)
       {
 	if (cp->first == allocno)
@@ -1522,7 +1556,8 @@ update_conflict_hard_regno_costs (int *costs, enum reg_class aclass,
 	else
 	  gcc_unreachable ();
 
-	if (another_allocno == from)
+	if (another_allocno == from
+	    || allocnos_conflict_p (another_allocno, start))
 	  continue;
 
  	another_aclass = ALLOCNO_CLASS (another_allocno);
@@ -1568,7 +1603,7 @@ update_conflict_hard_regno_costs (int *costs, enum reg_class aclass,
 			   * COST_HOP_DIVISOR
 			   * COST_HOP_DIVISOR
 			   * COST_HOP_DIVISOR))
-	  queue_update_cost (another_allocno, allocno, divisor * COST_HOP_DIVISOR);
+	  queue_update_cost (another_allocno, start, from, divisor * COST_HOP_DIVISOR);
       }
 }
 
@@ -1837,8 +1872,7 @@ assign_hard_reg (ira_allocno_t a, bool retry_p)
 		      continue;
 		    full_costs[j] -= conflict_costs[k];
 		  }
-	      queue_update_cost (conflict_a, NULL, COST_HOP_DIVISOR);
-
+	      queue_update_cost (conflict_a, conflict_a, NULL, COST_HOP_DIVISOR);
 	    }
 	}
     }
@@ -1852,7 +1886,7 @@ assign_hard_reg (ira_allocno_t a, bool retry_p)
   if (! retry_p)
     {
       start_update_cost ();
-      queue_update_cost (a, NULL,  COST_HOP_DIVISOR);
+      queue_update_cost (a, a, NULL, COST_HOP_DIVISOR);
       update_conflict_hard_regno_costs (full_costs, aclass, false);
     }
   min_cost = min_full_cost = INT_MAX;
@@ -1897,6 +1931,8 @@ assign_hard_reg (ira_allocno_t a, bool retry_p)
 	  best_hard_regno = hard_regno;
 	  ira_assert (hard_regno >= 0);
 	}
+      if (internal_flag_ira_verbose > 5 && ira_dump_file != NULL)
+	fprintf (ira_dump_file, "(%d=%d,%d) ", hard_regno, cost, full_cost);
     }
   if (min_full_cost > mem_cost
       /* Do not spill static chain pointer pseudo when non-local goto
@@ -2259,16 +2295,6 @@ bucket_allocno_compare_func (const void *v1p, const void *v2p)
   ira_allocno_t t2 = ALLOCNO_COLOR_DATA (a2)->first_thread_allocno;
   int cl1 = ALLOCNO_CLASS (a1), cl2 = ALLOCNO_CLASS (a2);
 
-  /* Push allocnos with minimal hard_reg_prefs first.  */
-  pref1 = ALLOCNO_COLOR_DATA (a1)->hard_reg_prefs;
-  pref2 = ALLOCNO_COLOR_DATA (a2)->hard_reg_prefs;
-  if ((diff = pref1 - pref2) != 0)
-    return diff;
-  /* Push allocnos with minimal conflict_allocno_hard_prefs first.  */
-  pref1 = ALLOCNO_COLOR_DATA (a1)->conflict_allocno_hard_prefs;
-  pref2 = ALLOCNO_COLOR_DATA (a2)->conflict_allocno_hard_prefs;
-  if ((diff = pref1 - pref2) != 0)
-    return diff;
   freq1 = ALLOCNO_COLOR_DATA (t1)->thread_freq;
   freq2 = ALLOCNO_COLOR_DATA (t2)->thread_freq;
   if ((diff = freq1 - freq2) != 0)
@@ -2294,6 +2320,11 @@ bucket_allocno_compare_func (const void *v1p, const void *v2p)
   a2_num = ALLOCNO_COLOR_DATA (a2)->available_regs_num;
   if ((diff = a2_num - a1_num) != 0)
     return diff;
+  /* Push allocnos with minimal conflict_allocno_hard_prefs first.  */
+  pref1 = ALLOCNO_COLOR_DATA (a1)->conflict_allocno_hard_prefs;
+  pref2 = ALLOCNO_COLOR_DATA (a2)->conflict_allocno_hard_prefs;
+  if ((diff = pref1 - pref2) != 0)
+    return diff;
   return ALLOCNO_NUM (a2) - ALLOCNO_NUM (a1);
 }