* tree-ssa-alias.c (compute_flow_insensitive_aliasing): If type

	memory tag is call clobbered, so are its aliases.
	(group_aliases): When two memory tags being grouped, if one is
	call clobbered, so are the other and its aliases.
	(add_may_alias): Remove call-clobbering stuff.
	(replace_may_alias): Likewise.
	(merge_pointed_to_info): Merge pt_global_mem.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@87182 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 37 insertions, 20 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e1a2ac1dd41..4dc3df11110 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2004-09-08  Jie Zhang  <zhangjie@magima.com.cn>
+
+	* tree-ssa-alias.c (compute_flow_insensitive_aliasing): If type
+	memory tag is call clobbered, so are its aliases.
+	(group_aliases): When two memory tags being grouped, if one is
+	call clobbered, so are the other and its aliases.
+	(add_may_alias): Remove call-clobbering stuff.
+	(replace_may_alias): Likewise.
+	(merge_pointed_to_info): Merge pt_global_mem
+
 2004-09-08  Jan Hubicka  <jh@suse.cz>
 
 	* cgraph.c (cgraph_remove_node): Free DECL_INITIAL field of node.
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 8b49699961c..4bd438b9439 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -930,6 +930,10 @@ compute_flow_insensitive_aliasing (struct alias_info *ai)
 	      num_tag_refs = VARRAY_UINT (ai->num_references, tag_ann->uid);
 	      num_var_refs = VARRAY_UINT (ai->num_references, v_ann->uid);
 
+	      /* If TAG is call clobbered, so is VAR.  */
+	      if (is_call_clobbered (tag))
+		mark_call_clobbered (var);
+
 	      /* Add VAR to TAG's may-aliases set.  */
 	      add_may_alias (tag, var);
 
@@ -1122,8 +1126,29 @@ group_aliases (struct alias_info *ai)
 	  sbitmap_a_and_b (res, tag1_aliases, tag2_aliases);
 	  if (sbitmap_first_set_bit (res) >= 0)
 	    {
+	      size_t k;
+
 	      tree tag2 = var_ann (ai->pointers[j]->var)->type_mem_tag;
 
+	      if (!is_call_clobbered (tag1) && is_call_clobbered (tag2))
+		{
+		  mark_call_clobbered (tag1);
+		  EXECUTE_IF_SET_IN_SBITMAP (tag1_aliases, 0, k,
+		    {
+		      tree var = referenced_var (k);
+		      mark_call_clobbered (var);
+		    });
+		}
+	      else if (is_call_clobbered (tag1) && !is_call_clobbered (tag2))
+		{
+		  mark_call_clobbered (tag2);
+		  EXECUTE_IF_SET_IN_SBITMAP (tag2_aliases, 0, k,
+		    {
+		      tree var = referenced_var (k);
+		      mark_call_clobbered (var);
+		    });
+		}
+
 	      sbitmap_a_or_b (tag1_aliases, tag1_aliases, tag2_aliases);
 
 	      /* TAG2 does not need its aliases anymore.  */
@@ -1640,16 +1665,6 @@ add_may_alias (tree var, tree alias)
     if (alias == VARRAY_TREE (v_ann->may_aliases, i))
       return;
 
-  /* If VAR is a call-clobbered variable, so is its new ALIAS.
-     FIXME, call-clobbering should only depend on whether an address
-     escapes.  It should be independent of aliasing.  */
-  if (is_call_clobbered (var))
-    mark_call_clobbered (alias);
-
-  /* Likewise.  If ALIAS is call-clobbered, so is VAR.  */
-  else if (is_call_clobbered (alias))
-    mark_call_clobbered (var);
-
   VARRAY_PUSH_TREE (v_ann->may_aliases, alias);
   a_ann->is_alias_tag = 1;
 }
@@ -1662,16 +1677,6 @@ replace_may_alias (tree var, size_t i, tree new_alias)
 {
   var_ann_t v_ann = var_ann (var);
   VARRAY_TREE (v_ann->may_aliases, i) = new_alias;
-
-  /* If VAR is a call-clobbered variable, so is NEW_ALIAS.
-     FIXME, call-clobbering should only depend on whether an address
-     escapes.  It should be independent of aliasing.  */
-  if (is_call_clobbered (var))
-    mark_call_clobbered (new_alias);
-
-  /* Likewise.  If NEW_ALIAS is call-clobbered, so is VAR.  */
-  else if (is_call_clobbered (new_alias))
-    mark_call_clobbered (var);
 }
 
 
@@ -1728,6 +1733,8 @@ merge_pointed_to_info (struct alias_info *ai, tree dest, tree orig)
 
   if (orig_pi)
     {
+      dest_pi->pt_global_mem |= orig_pi->pt_global_mem;
+
       /* Notice that we never merge PT_MALLOC.  This attribute is only
 	 true if the pointer is the result of a malloc() call.
 	 Otherwise, we can end up in this situation: