[PATCH] New switch optimization pass (PR tree-optimization/54742)

[Steve Ellcey]

While Jeff works on the threader, I was wondering if I could get approval for
just the dominance.c part of the patch.  This would allow me to use my pass as
a dynamically loaded optimization pass.  But without this change to dominance.c,
the compiler aborts in iterate_fix_dominators when I do that.

Steve Ellcey
sellcey@imgtec.com



2013-05-14  Steve Ellcey  <sellcey@imgtec.com>

	* dominance.c (iterate_fix_dominators): Add null check.


diff --git a/gcc/dominance.c b/gcc/dominance.c
index 5c96dad..d858ad1 100644
--- a/gcc/dominance.c
+++ b/gcc/dominance.c
@@ -1251,6 +1251,7 @@ iterate_fix_dominators (enum cdi_direction dir, vec<basic_block> bbs,
   struct pointer_map_t *map;
   int *parent, *son, *brother;
   unsigned int dir_index = dom_convert_dir_to_idx (dir);
+  void **slot;
 
   /* We only support updating dominators.  There are some problems with
      updating postdominators (need to add fake edges from infinite loops
@@ -1357,7 +1358,10 @@ iterate_fix_dominators (enum cdi_direction dir, vec<basic_block> bbs,
 	  if (dom == bb)
 	    continue;
 
-	  dom_i = (size_t) *pointer_map_contains (map, dom);
+	  slot = pointer_map_contains (map, dom);
+	  if (slot == NULL)
+	    continue;
+	  dom_i = (size_t) *slot;
 
 	  /* Do not include parallel edges to G.  */
 	  if (!bitmap_set_bit ((bitmap) g->vertices[dom_i].data, i))