re PR tree-optimization/17806 (compiler error: in verify_loop_structure, at…

re PR tree-optimization/17806 (compiler error: in verify_loop_structure, at cfgloop.c:1491 , works -O2, breaks with -O3)

	PR tree-optimization/17806
	* cfghooks.c (split_edge): Update IRREDUCIBLE_LOOP flags.
	* cfgloopmanip.c (loop_split_edge_with): Updating of IRREDUCIBLE_LOOP
	flags moved to split_edge.

From-SVN: r88665

gcc/ChangeLog

+2004-10-07  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR tree-optimization/17806
+	* cfghooks.c (split_edge): Update IRREDUCIBLE_LOOP flags.
+	* cfgloopmanip.c (loop_split_edge_with): Updating of IRREDUCIBLE_LOOP
+	flags moved to split_edge.
+
 2004-10-07  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	PR middle-end/17285

gcc/cfghooks.c

@@ -389,6 +389,7 @@ split_edge (edge e)
   gcov_type count = e->count;
   int freq = EDGE_FREQUENCY (e);
   edge f;
+  bool irr = (e->flags & EDGE_IRREDUCIBLE_LOOP) != 0;
 
   if (!cfg_hooks->split_edge)
     internal_error ("%s does not support split_edge.", cfg_hooks->name);
@@ -399,6 +400,13 @@ split_edge (edge e)
   EDGE_SUCC (ret, 0)->probability = REG_BR_PROB_BASE;
   EDGE_SUCC (ret, 0)->count = count;
 
+  if (irr)
+    {
+      ret->flags |= BB_IRREDUCIBLE_LOOP;
+      EDGE_PRED (ret, 0)->flags |= EDGE_IRREDUCIBLE_LOOP;
+      EDGE_SUCC (ret, 0)->flags |= EDGE_IRREDUCIBLE_LOOP;
+    }
+
   if (dom_computed[CDI_DOMINATORS])
     set_immediate_dominator (CDI_DOMINATORS, ret, EDGE_PRED (ret, 0)->src);
 

gcc/cfgloopmanip.c

@@ -1241,7 +1241,6 @@ loop_split_edge_with (edge e, rtx insns)
 {
   basic_block src, dest, new_bb;
   struct loop *loop_c;
-  edge new_e;
 
   src = e->src;
   dest = e->dest;
@@ -1252,14 +1251,7 @@ loop_split_edge_with (edge e, rtx insns)
 
   new_bb = split_edge (e);
   add_bb_to_loop (new_bb, loop_c);
-  new_bb->flags = insns ? BB_SUPERBLOCK : 0;
-
-  new_e = EDGE_SUCC (new_bb, 0);
-  if (e->flags & EDGE_IRREDUCIBLE_LOOP)
-    {
-      new_bb->flags |= BB_IRREDUCIBLE_LOOP;
-      new_e->flags |= EDGE_IRREDUCIBLE_LOOP;
-    }
+  new_bb->flags |= (insns ? BB_SUPERBLOCK : 0);
 
   if (insns)
     emit_insn_after (insns, BB_END (new_bb));