re PR tree-optimization/19121 (ICE: in merge_alias_info, at tree-ssa-copy.c:236)

	PR tree-optimization/19121
	* tree-ssa-alias.c (compute_flow_sensitive_aliasing): When
	adding aliases to a name tag, also add them to the pointer's
	type tag.
	* tree-ssa-copy.c (merge_alias_info): Do not merge flow
	sensitive alias info at all.  Only check that the two pointers
	have compatible pointed-to sets.
	* tree-ssa.c (verify_name_tags): Verify that the alias set of
	a pointer's type tag is a superset of the alias set of the
	pointer's name tag.

testsuite/ChangeLog:

	PR tree-optimization/19121
	* gcc.c-torture/compile/pr19121.c: New test.

From-SVN: r93810

1 files changed, 59 insertions, 14 deletions

diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c
index 24b5697..fe608f6 100644
--- a/gcc/tree-ssa.c
+++ b/gcc/tree-ssa.c
@@ -469,7 +469,11 @@ DEF_VEC_MALLOC_P (bitmap);
    same name tag must have the same points-to set. 
    So we check a single variable for each name tag, and verify that its
    points-to set is different from every other points-to set for other name
-   tags.  */
+   tags.
+
+   Additionally, given a pointer P_i with name tag NMT and type tag
+   TMT, this function verified the alias set of TMT is a superset of
+   the alias set of NMT.  */
 
 static void
 verify_name_tags (void)
@@ -479,25 +483,62 @@ verify_name_tags (void)
   bitmap first, second;  
   VEC (tree) *name_tag_reps = NULL;
   VEC (bitmap) *pt_vars_for_reps = NULL;
+  bitmap type_aliases = BITMAP_XMALLOC ();
 
   /* First we compute the name tag representatives and their points-to sets.  */
   for (i = 0; i < num_ssa_names; i++)
     {
-      if (ssa_name (i))
+      struct ptr_info_def *pi;
+      tree tmt, ptr = ssa_name (i);
+
+      if (ptr == NULL_TREE)
+	continue;
+      
+      pi = SSA_NAME_PTR_INFO (ptr);
+
+      if (!TREE_VISITED (ptr) 
+	  || !POINTER_TYPE_P (TREE_TYPE (ptr)) 
+	  || !pi
+	  || !pi->name_mem_tag 
+	  || TREE_VISITED (pi->name_mem_tag))
+	continue;
+
+      TREE_VISITED (pi->name_mem_tag) = 1;
+
+      if (pi->pt_vars == NULL)
+	continue;
+
+      VEC_safe_push (tree, name_tag_reps, ptr);
+      VEC_safe_push (bitmap, pt_vars_for_reps, pi->pt_vars);
+
+      /* Verify that alias set of PTR's type tag is a superset of the
+	 alias set of PTR's name tag.  */
+      tmt = var_ann (SSA_NAME_VAR (ptr))->type_mem_tag;
+      if (tmt)
 	{
-	  tree ptr = ssa_name (i);
-	  struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
-	  if (!TREE_VISITED (ptr) 
-	      || !POINTER_TYPE_P (TREE_TYPE (ptr)) 
-	      || !pi
-	      || !pi->name_mem_tag 
-	      || TREE_VISITED (pi->name_mem_tag))
+	  size_t i;
+	  varray_type aliases = var_ann (tmt)->may_aliases;
+	  bitmap_clear (type_aliases);
+	  for (i = 0; aliases && i < VARRAY_ACTIVE_SIZE (aliases); i++)
+	    {
+	      tree alias = VARRAY_TREE (aliases, i);
+	      bitmap_set_bit (type_aliases, var_ann (alias)->uid);
+	    }
+
+	  /* When grouping, we may have added PTR's type tag into the
+	     alias set of PTR's name tag.  To prevent a false
+	     positive, pretend that TMT is in its own alias set.  */
+	  bitmap_set_bit (type_aliases, var_ann (tmt)->uid);
+
+	  if (bitmap_equal_p (type_aliases, pi->pt_vars))
 	    continue;
-	  TREE_VISITED (pi->name_mem_tag) = 1;
-	  if (pi->pt_vars != NULL)
-	    {    
-	      VEC_safe_push (tree, name_tag_reps, ptr);
-	      VEC_safe_push (bitmap, pt_vars_for_reps, pi->pt_vars);
+
+	  if (!bitmap_intersect_compl_p (type_aliases, pi->pt_vars))
+	    {
+	      error ("Alias set of a pointer's type tag should be a superset of the corresponding name tag");
+	      debug_variable (tmt);
+	      debug_variable (pi->name_mem_tag);
+	      goto err;
 	    }
 	}
     }
@@ -532,13 +573,17 @@ verify_name_tags (void)
 	  TREE_VISITED (pi->name_mem_tag) = 0;
 	}
     } 
+
   VEC_free (bitmap, pt_vars_for_reps);
+  BITMAP_FREE (type_aliases);
   return;
   
 err:
   debug_variable (VEC_index (tree, name_tag_reps, i));
   internal_error ("verify_name_tags failed");
 }
+
+
 /* Verify the consistency of aliasing information.  */
 
 static void