Re: Infrastructure to let ipcp to remove unused arguments from calls

[Jan Hubicka <jh at suse dot cz>]

Hi,
this is updated version of patch.  Previous one incorrectly handled
void_list_node markers as pointed out by Richard.

Honza

	* tree.c (build_function_type_skip_args, build_function_decl_skip_args):
	New functions.
	* tree.h (build_function_type_skip_args, build_function_decl_skip_args):
	Declare.
	* gimple.c (gimple_call_skip_args): New function.
	(gimple_call_skip_args): Declare.

Index: tree.c
===================================================================
--- tree.c	(revision 139571)
+++ tree.c	(working copy)
@@ -5878,6 +5878,66 @@ build_function_type (tree value_type, tr
   return t;
 }
 
+/* Build variant of function type ORIG_TYPE skipping ARGS_TO_SKIP.  */
+
+tree
+build_function_type_skip_args (tree orig_type, bitmap args_to_skip)
+{
+  tree new_type = copy_node (orig_type);
+  tree args, new_args = NULL, t;
+  tree new_reversed;
+  int i;
+
+  /* This is a new type, not a copy of an old type.  Need to reassociate
+     variants.  We can handle everything except the main variant lazily.  */
+  t = TYPE_MAIN_VARIANT (orig_type);
+  if (orig_type != t)
+    {
+      TYPE_MAIN_VARIANT (new_type) = t;
+      TYPE_NEXT_VARIANT (new_type) = TYPE_NEXT_VARIANT (t);
+      TYPE_NEXT_VARIANT (t) = new_type;
+    }
+  else
+    {
+      TYPE_MAIN_VARIANT (new_type) = new_type;
+      TYPE_NEXT_VARIANT (new_type) = NULL;
+    }
+  for (args = TYPE_ARG_TYPES (orig_type), i = 0; args && args != void_list_node;
+       args = TREE_CHAIN (args), i++)
+    if (!bitmap_bit_p (args_to_skip, i))
+      new_args = tree_cons (NULL_TREE, TREE_VALUE (args), new_args);
+
+  new_reversed = nreverse (new_args);
+  if (args)
+    {
+      if (new_reversed)
+        TREE_CHAIN (new_args) = void_list_node;
+      else
+	new_reversed = void_list_node;
+    }
+  TYPE_ARG_TYPES (new_type) = new_reversed;
+  return new_type;
+}
+
+/* Build variant of function type ORIG_TYPE skipping ARGS_TO_SKIP.  
+  
+   Arguments from DECL_ARGUMENTS list can't be removed now, since they are
+   linked by TREE_CHAIN directly.  It is caller responsibility to eliminate
+   them when they are being duplicated (i.e. copy_arguments_for_versioning).  */
+
+tree
+build_function_decl_skip_args (tree orig_decl, bitmap args_to_skip)
+{
+  tree new_decl = copy_node (orig_decl);
+  tree new_type;
+
+  new_type = TREE_TYPE (orig_decl);
+  if (prototype_p (new_type))
+    new_type = build_function_type_skip_args (new_type, args_to_skip);
+  TREE_TYPE (orig_decl) = new_type;
+  return new_decl;
+}
+
 /* Build a function type.  The RETURN_TYPE is the type returned by the
    function. If VAARGS is set, no void_type_node is appended to the
    the list. ARGP muse be alway be terminated be a NULL_TREE.  */
@@ -5893,9 +5953,9 @@ build_function_type_list_1 (bool vaargs,
 
   if (vaargs)
     {
-	  last = args;
-	  if (args != NULL_TREE)
-	    args = nreverse (args);
+      last = args;
+      if (args != NULL_TREE)
+	args = nreverse (args);
       gcc_assert (args != NULL_TREE && last != void_list_node);
     }
   else if (args == NULL_TREE)
Index: tree.h
===================================================================
--- tree.h	(revision 139571)
+++ tree.h	(working copy)
@@ -3994,6 +3994,8 @@ extern tree build_index_2_type (tree, tr
 extern tree build_array_type (tree, tree);
 extern tree build_function_type (tree, tree);
 extern tree build_function_type_list (tree, ...);
+extern tree build_function_type_skip_args (tree, bitmap);
+extern tree build_function_decl_skip_args (tree, bitmap);
 extern tree build_varargs_function_type_list (tree, ...);
 extern tree build_method_type_directly (tree, tree, tree);
 extern tree build_method_type (tree, tree);
Index: gimple.c
===================================================================
--- gimple.c	(revision 139571)
+++ gimple.c	(working copy)
@@ -3180,4 +3180,37 @@ canonicalize_cond_expr_cond (tree t)
   return NULL_TREE;
 }
 
+/* Build call same as STMT but skipping arguments ARGS_TO_SKIP.  */
+gimple
+gimple_call_skip_args (gimple stmt, bitmap args_to_skip)
+{
+  int i;
+  tree fn = gimple_call_fn (stmt);
+  int nargs = gimple_call_num_args (stmt);
+  VEC(tree, heap) *vargs = VEC_alloc (tree, heap, nargs);
+  gimple new_stmt;
+
+  for (i = 0; i < nargs; i++)
+    if (!bitmap_bit_p (args_to_skip, i))
+      VEC_quick_push (tree, vargs, gimple_call_arg (stmt, i));
+
+  new_stmt = gimple_build_call_vec (fn, vargs);
+  VEC_free (tree, heap, vargs);
+  if (gimple_call_lhs (stmt))
+    gimple_call_set_lhs (new_stmt, gimple_call_lhs (stmt));
+
+  gimple_set_block (new_stmt, gimple_block (stmt));
+  if (gimple_has_location (stmt))
+    gimple_set_location (new_stmt, gimple_location (stmt));
+
+  /* Carry all the flags to the new GIMPLE_CALL.  */
+  gimple_call_set_chain (new_stmt, gimple_call_chain (stmt));
+  gimple_call_set_tail (new_stmt, gimple_call_tail_p (stmt));
+  gimple_call_set_cannot_inline (new_stmt, gimple_call_cannot_inline_p (stmt));
+  gimple_call_set_return_slot_opt (new_stmt, gimple_call_return_slot_opt_p (stmt));
+  gimple_call_set_from_thunk (new_stmt, gimple_call_from_thunk_p (stmt));
+  gimple_call_set_va_arg_pack (new_stmt, gimple_call_va_arg_pack_p (stmt));
+  return new_stmt;
+}
+
 #include "gt-gimple.h"
Index: gimple.h
===================================================================
--- gimple.h	(revision 139571)
+++ gimple.h	(working copy)
@@ -4471,6 +4471,7 @@ basic_block gsi_insert_on_edge_immediate
 basic_block gsi_insert_seq_on_edge_immediate (edge, gimple_seq);
 void gsi_commit_one_edge_insert (edge, basic_block *);
 void gsi_commit_edge_inserts (void);
+gimple gimple_call_skip_args (gimple, bitmap);
 
 
 /* Convenience routines to walk all statements of a gimple function.