PR tree-optimization/16688

[pf3gnuchains/gcc-fork.git] / gcc / tree-ssanames.c

diff --git a/gcc/tree-ssanames.c b/gcc/tree-ssanames.c
index 1142492..4e8985a 100644 (file)
--- a/gcc/tree-ssanames.c
+++ b/gcc/tree-ssanames.c
@@ -25,6 +25,7 @@ Boston, MA 02111-1307, USA.  */
 #include "tree.h"
 #include "varray.h"
 #include "ggc.h"
+#include "tree-flow.h"
 
 /* Rewriting a function into SSA form can create a huge number of SSA_NAMEs,
    many of which may be thrown away shortly after their creation if jumps
@@ -57,8 +58,8 @@ Boston, MA 02111-1307, USA.  */
    a very well defined lifetime.  If someone wants to experiment with that
    this is the place to try it.  */
    
-/* Next SSA version number to be allocated.  */
-unsigned int highest_ssa_version;
+/* Array of all SSA_NAMEs used in the function.  */
+varray_type ssa_names;
                                                                                 
 /* Free list of SSA_NAMEs.  This list is wiped at the end of each function
    after we leave SSA form.  */
@@ -78,7 +79,13 @@ unsigned int ssa_name_nodes_created;
 void
 init_ssanames (void)
 {
-  highest_ssa_version = UNUSED_NAME_VERSION + 1;
+  VARRAY_TREE_INIT (ssa_names, 50, "ssa_names table");
+
+  /* Version 0 is special, so reserve the first slot in the table.  Though
+     currently unused, we may use version 0 in alias analysis as part of
+     the heuristics used to group aliases when the alias sets are too
+     large.  */
+  VARRAY_PUSH_TREE (ssa_names, NULL_TREE);
   free_ssanames = NULL;
 }
 
@@ -142,7 +149,8 @@ make_ssa_name (tree var, tree stmt)
   else
     {
       t = make_node (SSA_NAME);
-      SSA_NAME_VERSION (t) = highest_ssa_version++;
+      SSA_NAME_VERSION (t) = num_ssa_names;
+      VARRAY_PUSH_TREE (ssa_names, t);
 #ifdef GATHER_STATISTICS
       ssa_name_nodes_created++;
 #endif
@@ -151,10 +159,13 @@ make_ssa_name (tree var, tree stmt)
   TREE_TYPE (t) = TREE_TYPE (var);
   SSA_NAME_VAR (t) = var;
   SSA_NAME_DEF_STMT (t) = stmt;
+  SSA_NAME_PTR_INFO (t) = NULL;
+  SSA_NAME_IN_FREE_LIST (t) = 0;
 
   return t;
 }
 
+
 /* We no longer need the SSA_NAME expression VAR, release it so that
    it may be reused. 
 
@@ -166,6 +177,11 @@ make_ssa_name (tree var, tree stmt)
 void
 release_ssa_name (tree var)
 {
+  /* Never release the default definition for a symbol.  It's a
+     special SSA name that should always exist once it's created.  */
+  if (var == var_ann (SSA_NAME_VAR (var))->default_def)
+    return;
+
   /* release_ssa_name can be called multiple times on a single SSA_NAME.
      However, it should only end up on our free list one time.   We
      keep a status bit in the SSA_NAME node itself to indicate it has
@@ -181,4 +197,66 @@ release_ssa_name (tree var)
     }
 }
 
+/* Creates a duplicate of a ssa name NAME defined in statement STMT.  */
+
+tree
+duplicate_ssa_name (tree name, tree stmt)
+{
+  tree new_name = make_ssa_name (SSA_NAME_VAR (name), stmt);
+  struct ptr_info_def *old_ptr_info = SSA_NAME_PTR_INFO (name);
+  struct ptr_info_def *new_ptr_info;
+
+  if (!old_ptr_info)
+    return new_name;
+
+  new_ptr_info = ggc_alloc (sizeof (struct ptr_info_def));
+  *new_ptr_info = *old_ptr_info;
+
+  if (old_ptr_info->pt_vars)
+    {
+      new_ptr_info->pt_vars = BITMAP_GGC_ALLOC ();
+      bitmap_copy (new_ptr_info->pt_vars, old_ptr_info->pt_vars);
+    }
+
+  SSA_NAME_PTR_INFO (new_name) = new_ptr_info;
+  return new_name;
+}
+
+
+/* Release all the SSA_NAMEs created by STMT.  */
+
+void
+release_defs (tree stmt)
+{
+  size_t i;
+  v_may_def_optype v_may_defs;
+  v_must_def_optype v_must_defs;
+  def_optype defs;
+  stmt_ann_t ann;
+
+  ann = stmt_ann (stmt);
+  defs = DEF_OPS (ann);
+  v_may_defs = V_MAY_DEF_OPS (ann);
+  v_must_defs = V_MUST_DEF_OPS (ann);
+
+  for (i = 0; i < NUM_DEFS (defs); i++)
+    release_ssa_name (DEF_OP (defs, i));
+
+  for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
+    release_ssa_name (V_MAY_DEF_RESULT (v_may_defs, i));
+
+  for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
+    release_ssa_name (V_MUST_DEF_OP (v_must_defs, i));
+}
+
+
+/* Replace the symbol associated with SSA_NAME with SYM.  */
+
+void
+replace_ssa_name_symbol (tree ssa_name, tree sym)
+{
+  SSA_NAME_VAR (ssa_name) = sym;
+  TREE_TYPE (ssa_name) = TREE_TYPE (sym);
+}
+
 #include "gt-tree-ssanames.h"