tree-ssa-alias.c (new_type_alias): New procedure to create a type memory tag for…

tree-ssa-alias.c (new_type_alias): New procedure to create a type memory tag for a pointer with a may-alias set...

2005-05-29  Keith Besaw  <kbesaw@us.ibm.com>

        * tree-ssa-alias.c (new_type_alias): New procedure to
        create a type memory tag for a pointer with a may-alias
        set determined from a variable declaration.
        * tree-flow.h: export declaration of new_type_alias
        * tree-optimize.c (init_tree_optimization_passes): document
        that pass_may_alias cannot be called after pass_vectorize.
        * tree-vect-transform (vect_create_data_ref_ptr): Call
        new_type_alias when an type memory tag isn't available
        for a reference.
        (vectorizable_store): Use copy_virtual_operands to update
        virtual defs in place (so that loop_version can be called).
        Call mark_for_renaming for the virtual defs in case peeling
        is done and virtual uses outside the loop need to be updated.

From-SVN: r100322

gcc/ChangeLog

+2005-05-29  Keith Besaw  <kbesaw@us.ibm.com>
+
+	* tree-ssa-alias.c (new_type_alias): New procedure to
+	create a type memory tag for a pointer with a may-alias
+	set determined from a variable declaration.
+	* tree-flow.h: export declaration of new_type_alias
+	* tree-optimize.c (init_tree_optimization_passes): document
+	that pass_may_alias cannot be called after pass_vectorize.
+	* tree-vect-transform (vect_create_data_ref_ptr): Call
+	new_type_alias when an type memory tag isn't available
+	for a reference.
+	(vectorizable_store): Use copy_virtual_operands to update
+	virtual defs in place (so that loop_version can be called).
+	Call mark_for_renaming for the virtual defs in case peeling
+	is done and virtual uses outside the loop need to be updated.
+
 2005-05-29  Dorit Naishlos  <dorit@il.ibm.com>
 
 	PR tree-optimization/21639

gcc/tree-flow.h

@@ -570,6 +570,7 @@ extern void debug_points_to_info_for (tree);
 extern bool may_be_aliased (tree);
 extern struct ptr_info_def *get_ptr_info (tree);
 extern void add_type_alias (tree, tree);
+extern void new_type_alias (tree, tree);
 extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
 static inline subvar_t get_subvars_for_var (tree);
 static inline bool ref_contains_array_ref (tree);

gcc/tree-optimize.c

@@ -478,6 +478,9 @@ init_tree_optimization_passes (void)
   NEXT_PASS (pass_iv_canon);
   NEXT_PASS (pass_if_conversion);
   NEXT_PASS (pass_vectorize);
+  /* NEXT_PASS (pass_may_alias) cannot be done again because the
+     vectorizer creates alias relations that are not supported by
+     pass_may_alias.  */
   NEXT_PASS (pass_lower_vector_ssa);
   NEXT_PASS (pass_complete_unroll);
   NEXT_PASS (pass_iv_optimize);

gcc/tree-ssa-alias.c

@@ -2776,6 +2776,39 @@ found_tag:
 }
 
 
+/* Create a type tag for PTR.  Construct the may-alias list of this type tag
+   so that it has the aliasing of VAR.  */
+
+void
+new_type_alias (tree ptr, tree var)
+{
+  var_ann_t p_ann = var_ann (ptr);
+  tree tag_type = TREE_TYPE (TREE_TYPE (ptr));
+  var_ann_t v_ann = var_ann (var);
+  tree tag;
+  subvar_t svars;
+
+  gcc_assert (p_ann->type_mem_tag == NULL_TREE);
+  gcc_assert (v_ann->mem_tag_kind == NOT_A_TAG);
+  tag = create_memory_tag (tag_type, true);
+  p_ann->type_mem_tag = tag;
+
+  /* Add VAR to the may-alias set of PTR's new type tag.  If VAR has
+     subvars, add the subvars to the tag instead of the actual var.  */
+  if (var_can_have_subvars (var)
+      && (svars = get_subvars_for_var (var)))
+    {
+      subvar_t sv;      
+      for (sv = svars; sv; sv = sv->next)
+        add_may_alias (tag, sv->var);
+    }
+  else
+    add_may_alias (tag, var);
+
+  /* Note, TAG and its set of aliases are not marked for renaming.  */
+}
+
+
 /* This structure is simply used during pushing fields onto the fieldstack
    to track the offset of the field, since bitpos_of_field gives it relative
    to its immediate containing type, and we want it relative to the ultimate

gcc/tree-vect-transform.c

@@ -350,13 +350,10 @@ vect_create_data_ref_ptr (tree stmt, block_stmt_iterator *bsi, tree offset,
   tag = STMT_VINFO_MEMTAG (stmt_info);
   gcc_assert (tag);
 
-  /* If the memory tag of the original reference was not a type tag or
-     if the pointed-to type of VECT_PTR has an alias set number
-     different than TAG's, then we need to create a new type tag for
-     VECT_PTR and add TAG to its alias set.  */
-  if (var_ann (tag)->mem_tag_kind == NOT_A_TAG
-      || get_alias_set (tag) != get_alias_set (TREE_TYPE (vect_ptr_type)))
-    add_type_alias (vect_ptr, tag);
+  /* If tag is a variable (and NOT_A_TAG) than a new type alias
+     tag must be created with tag added to its may alias list.  */
+  if (var_ann (tag)->mem_tag_kind == NOT_A_TAG)
+    new_type_alias (vect_ptr, tag);
   else
     var_ann (vect_ptr)->type_mem_tag = tag;
 
@@ -896,8 +893,8 @@ vectorizable_store (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
   enum machine_mode vec_mode;
   tree dummy;
   enum dr_alignment_support alignment_support_cheme;
-  ssa_op_iter iter;
   tree def;
+  ssa_op_iter iter;
 
   /* Is vectorizable store? */
 
@@ -955,15 +952,21 @@ vectorizable_store (tree stmt, block_stmt_iterator *bsi, tree *vec_stmt)
   *vec_stmt = build2 (MODIFY_EXPR, vectype, data_ref, vec_oprnd1);
   vect_finish_stmt_generation (stmt, *vec_stmt, bsi);
 
-  /* Mark all non-SSA variables in the statement for rewriting.  */
-  mark_new_vars_to_rename (*vec_stmt);
+  /* Copy the V_MAY_DEFS representing the aliasing of the original array
+     element's definition to the vector's definition then update the
+     defining statement.  The original is being deleted so the same
+     SSA_NAMEs can be used.  */
+  copy_virtual_operands (*vec_stmt, stmt);
 
-  /* The new vectorized statement will have better aliasing
-     information, so some of the virtual definitions of the old
-     statement will likely disappear from the IL.  Mark them to have
-     their SSA form updated.  */
   FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_VMAYDEF)
+    {
+      SSA_NAME_DEF_STMT (def) = *vec_stmt;
+
+      /* If this virtual def has a use outside the loop and a loop peel is performed
+         then the def may be renamed by the peel.  Mark it for renaming so the
+         later use will also be renamed.  */
       mark_sym_for_renaming (SSA_NAME_VAR (def));
+    }
 
   return true;
 }