re PR middle-end/54146 (Very slow compile with attribute((flatten)))

	PR tree-optimization/54146
	* cfgexpand.c (add_scope_conflicts_1): Use bitmap_ior_into.
	(add_scope_conflicts): Iterate in RPO order.
	(add_stack_protection_conflicts): Iterate over the other triangle.
	(fini_vars_expansion): Clear stack_vars_sorted.

From-SVN: r190126

gcc/ChangeLog

-2012-08-03 Marc Glisse <marc.glisse@inria.fr>
+2012-08-03  Michael Matz  <matz@suse.de>
+
+	PR tree-optimization/54146
+	* cfgexpand.c (add_scope_conflicts_1): Use bitmap_ior_into.
+	(add_scope_conflicts): Iterate in RPO order.
+	(add_stack_protection_conflicts): Iterate over the other triangle.
+	(fini_vars_expansion): Clear stack_vars_sorted.
+
+2012-08-03  Marc Glisse  <marc.glisse@inria.fr>
 
 	PR tree-optimization/30318
 	* double-int.c (mul_double_wide_with_sign): New function.

gcc/cfgexpand.c

@@ -429,10 +429,10 @@ add_scope_conflicts_1 (basic_block bb, bitmap work, bool for_conflict)
 	      unsigned i;
 	      EXECUTE_IF_SET_IN_BITMAP (work, 0, i, bi)
 		{
-		  unsigned j;
-		  bitmap_iterator bj;
-		  EXECUTE_IF_SET_IN_BITMAP (work, i + 1, j, bj)
-		    add_stack_var_conflict (i, j);
+		  struct stack_var *a = &stack_vars[i];
+		  if (!a->conflicts)
+		    a->conflicts = BITMAP_ALLOC (NULL);
+		  bitmap_ior_into (a->conflicts, work);
 		}
 	      visit = visit_conflict;
 	    }
@@ -450,6 +450,8 @@ add_scope_conflicts (void)
   basic_block bb;
   bool changed;
   bitmap work = BITMAP_ALLOC (NULL);
+  int *rpo;
+  int n_bbs;
 
   /* We approximate the live range of a stack variable by taking the first
      mention of its name as starting point(s), and by the end-of-scope
@@ -464,13 +466,19 @@ add_scope_conflicts (void)
   FOR_ALL_BB (bb)
     bb->aux = BITMAP_ALLOC (NULL);
 
+  rpo = XNEWVEC (int, last_basic_block);
+  n_bbs = pre_and_rev_post_order_compute (NULL, rpo, false);
+
   changed = true;
   while (changed)
     {
+      int i;
       changed = false;
-      FOR_EACH_BB (bb)
+      for (i = 0; i < n_bbs; i++)
 	{
-	  bitmap active = (bitmap)bb->aux;
+	  bitmap active;
+	  bb = BASIC_BLOCK (rpo[i]);
+	  active = (bitmap)bb->aux;
 	  add_scope_conflicts_1 (bb, work, false);
 	  if (bitmap_ior_into (active, work))
 	    changed = true;
@@ -480,6 +488,7 @@ add_scope_conflicts (void)
   FOR_EACH_BB (bb)
     add_scope_conflicts_1 (bb, work, true);
 
+  free (rpo);
   BITMAP_FREE (work);
   FOR_ALL_BB (bb)
     BITMAP_FREE (bb->aux);
@@ -1344,7 +1353,7 @@ add_stack_protection_conflicts (void)
   for (i = 0; i < n; ++i)
     {
       unsigned char ph_i = phase[i];
-      for (j = 0; j < i; ++j)
+      for (j = i + 1; j < n; ++j)
 	if (ph_i != phase[j])
 	  add_stack_var_conflict (i, j);
     }
@@ -1393,6 +1402,7 @@ fini_vars_expansion (void)
   XDELETEVEC (stack_vars);
   XDELETEVEC (stack_vars_sorted);
   stack_vars = NULL;
+  stack_vars_sorted = NULL;
   stack_vars_alloc = stack_vars_num = 0;
   pointer_map_destroy (decl_to_stack_part);
   decl_to_stack_part = NULL;