Fix alias verifier buglet

Fix alias verifier buglet

[Diego Novillo]

Found while working on another patch.


Diego.


	* tree-ssa.c (verify_flow_sensitive_alias_info): When
	comparing points-to sets of different pointers, make sure the
	second pointer is actually referenced in the code.

Index: tree-ssa.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-ssa.c,v
retrieving revision 2.25
diff -d -u -p -r2.25 tree-ssa.c
--- tree-ssa.c	28 Jul 2004 17:49:06 -0000	2.25
+++ tree-ssa.c	29 Jul 2004 19:48:24 -0000
@@ -471,7 +471,7 @@ verify_flow_sensitive_alias_info (void)
 	      tree ptr2 = ssa_name (j);
 	      struct ptr_info_def *pi2 = SSA_NAME_PTR_INFO (ptr2);
 
-	      if (!POINTER_TYPE_P (TREE_TYPE (ptr2)))
+	      if (!TREE_VISITED (ptr2) || !POINTER_TYPE_P (TREE_TYPE (ptr2)))
 		continue;
 
 	      if (pi2

Fix alias verifier buglet

[Diego Novillo]

The alias verifier was only looking for may aliases inside memory tags. 
When we group aliases, regular variables will have may aliases as well.

This fixes the alias verification ICE in Ada.  Though I only made it so
far as to build stage2.  Ada dies while building stage3.

Bootstrapped and tested x86, x86-64 and ppc.


Diego.


	* tree-ssa.c (verify_flow_insensitive_alias_info): Process
	every variable that may have aliases, not just tags.

Index: tree-ssa.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-ssa.c,v
retrieving revision 2.24
diff -d -c -p -r2.24 tree-ssa.c
*** tree-ssa.c	28 Jul 2004 05:13:08 -0000	2.24
--- tree-ssa.c	28 Jul 2004 17:47:40 -0000
*************** verify_flow_insensitive_alias_info (void
*** 348,375 ****
  
    for (i = 0; i < num_referenced_vars; i++)
      {
        var_ann_t ann;
  
        var = referenced_var (i);
        ann = var_ann (var);
  
!       if (ann->mem_tag_kind == TYPE_TAG || ann->mem_tag_kind == NAME_TAG)
  	{
! 	  size_t j;
! 	  varray_type may_aliases = ann->may_aliases;
! 
! 	  for (j = 0; may_aliases && j < VARRAY_ACTIVE_SIZE (may_aliases); j++)
! 	    {
! 	      tree alias = VARRAY_TREE (may_aliases, j);
  
! 	      bitmap_set_bit (visited, var_ann (alias)->uid);
  
! 	      if (!may_be_aliased (alias))
! 		{
! 		  error ("Non-addressable variable inside an alias set.");
! 		  debug_variable (alias);
! 		  goto err;
! 		}
  	    }
  	}
      }
--- 348,372 ----
  
    for (i = 0; i < num_referenced_vars; i++)
      {
+       size_t j;
        var_ann_t ann;
+       varray_type may_aliases;
  
        var = referenced_var (i);
        ann = var_ann (var);
+       may_aliases = ann->may_aliases;
  
!       for (j = 0; may_aliases && j < VARRAY_ACTIVE_SIZE (may_aliases); j++)
  	{
! 	  tree alias = VARRAY_TREE (may_aliases, j);
  
! 	  bitmap_set_bit (visited, var_ann (alias)->uid);
  
! 	  if (!may_be_aliased (alias))
! 	    {
! 	      error ("Non-addressable variable inside an alias set.");
! 	      debug_variable (alias);
! 	      goto err;
  	    }
  	}
      }